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Sample records for canada sedimentary basin

  1. Biodegradation and origin of oil sands in the Western Canada Sedimentary Basin

    Institute of Scientific and Technical Information of China (English)

    Zhou Shuqing; Huang Haiping; Liu Yuming

    2008-01-01

    The oil sands deposits in the Western Canada Sedimentary Basin (WCSB) comprise of at least 85% of the total immobile bitumen in place in the world and are so concentrated as to be virtually the only such deposits that are economically recoverable for conversion to oil.The major deposits are in three geographic and geologic regions of Alberta: Athabasca,Cold Lake and Peace River.The bitumen reserves have oil gravities ranging from 8 to 12° API,and are hosted in the reservoirs of varying age,ranging from Devonian (Grosmont Formation) to Early Cretaceous (Mannville Group).They were derived from light oils in the southern Alberta and migrated to the north and east for over 100 km during the Laramide Orogeny,which was responsible for the uplift of the Rocky Mountains.Biodegradation is the only process that transforms light oil into bitumen in such a dramatic way that overshadowed other alterations with minor contributions.The levels of biodegradation in the basin increasing from west (non-biodegraded) to east (extremely biodegraded) can be attributed to decreasing reservoir temperature,which played the primary role in controlling the biodegradation regime.Once the reservoir was heated to approximately 80 ℃,it was pasteurized and no biodegradation would further occur.However,reservoir temperature could not alone predict the variations of the oil composition and physical properties.Compositional gradients and a wide range of biodegradation degree at single reservoir column indicate that the water-leg size or the volume ratio of oil to water is one of the critical local controls for the vertical variations of biodegradation degree and oil physical properties.Late charging and mixing of the fresh and degraded oils ultimately dictate the final distribution of compositions and physical properties found in the heavy oil and oil sand fields.Oil geochemistry can reveal precisely the processes and levels that control these variations in a given field,which opens the

  2. Using technology for E and P success - the practices of leader companies in Western Canada Sedimentary Basin strategies

    International Nuclear Information System (INIS)

    The technologies that create a competitive advantage for the leaders in various exploration and production (E and P) strategies were demonstrated. The western Canadian E and P industry has evolved since the oil price shock of 1986 and the gas price shock of 1990-92. Performance of the leaders in broadly defined E and P strategy areas in the western Canada Sedimentary Basin are compared. Success of the industry as a whole was evaluated based on measurement of one of the most critical success factors, technology utilization

  3. Implications of Spatial Variability in Heat Flow for Geothermal Resource Evaluation in Large Foreland Basins: The Case of the Western Canada Sedimentary Basin

    Directory of Open Access Journals (Sweden)

    Simon Weides

    2014-04-01

    Full Text Available Heat flow and geothermal gradient of the sedimentary succession of the Western Canada Sedimentary Basin (WCSB are mapped based on a large thermal database. Heat flow in the deep part of the basin varies from 30 mW/m2 in the south to high 100 mW/m2 in the north. As permeable strata are required for a successful geothermal application, the most important aquifers are discussed and evaluated. Regional temperature distribution within different aquifers is mapped for the first time, enabling a delineation of the most promising areas based on thermal field and aquifer properties. Results of previous regional studies on the geothermal potential of the WCSB are newly evaluated and discussed. In parts of the WCSB temperatures as high as 100–210 °C exist at depths of 3–5 km. Fluids from deep aquifers in these “hot” regions of the WCSB could be used in geothermal power plants to produce electricity. The geothermal resources of the shallower parts of the WCSB (>2 km could be used for warm water provision (>50 °C or district heating (>70 °C in urban areas.

  4. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares

  5. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with

  6. Submarine Landslides in Arctic Sedimentation: Canada Basin

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  7. Clay minerals and sedimentary basin history

    OpenAIRE

    Merriman, Richard J.

    2005-01-01

    Clay minerals in the mud and soil that coat the Earth's surface are part of a clay cycle that breaks down and creates rock in the crust. Clays generated by surface weathering and shallow diagenetic processes are transformed into mature clay mineral assemblages in the mudrocks found in sedimentary basins. During metamorphism, the release of alkali elements and boron from clay minerals generates magmas that are subsequently weathered and recycled, representing the magma-to-mud pathway of the cl...

  8. Geology, exploration status of Uruguay's sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Goso, C.; Santa Ana, H. de (Administracion Nacional de Combustibles, Alcohol y Portland (Uruguay))

    1994-02-07

    This article attempts to present the geological characteristics and tectonic and sedimentary evolution of Uruguayan basins and the extent to which they have been explored. Uruguay is on the Atlantic coast of South America. The country covers about 318,000 sq km, including offshore and onshore territories corresponding to more than 65% of the various sedimentary basins. Four basins underlie the country: the Norte basin, the Santa Lucia basin, the offshore Punta del Este basin, and the offshore-onshore Pelotas-Merin basin. The Norte basin is a Paleozoic basin while the others are Mesozoic basins. Each basin has been explored to a different extent, as this paper explains.

  9. Tectonics and Sedimentary Basins of the South China Sea: Challenges and Progresses

    Institute of Scientific and Technical Information of China (English)

    Zhou Di; Yao Bochu

    2009-01-01

    @@ The special issue "Tectonics and Sedimentary Basins of the South China Sea" consists of 19 articles arranged in the order of deep structure,general tectonics,tectonic modeling,and sedimentary basins especially the deepwater sedimentary basins.

  10. Sedimentary charateristics and hydrocarbon accumulation in Northeast Sichuan basin

    Institute of Scientific and Technical Information of China (English)

    Jianming LI; Xiling WU; Rufeng LI; Liangjie TANG; Lei LI

    2008-01-01

    Northeast Sichuan basin is a Mesozoic-Cenozoic basin in the northern margin of the Yangtze plate which has a complex tectonic background and hydrocarbon accumulation history.By means of the analysis method of wave processes,major cycles of sedimentary wave process in this basin have been studied.The results show that there are five-order cycles corresponding to 760,220,100,35 and 20 Ma respectively,two first-order sedimentary cycles (220 Ma) and four secondorder sedimentary cycles (100 Ma).The authors find that the second-order sedimentary cycles are well matched with reservoir formation cycles through studying the relationship between second-order sedimentary cycles and reservoir formation cycles,and divide three reservoir formation cycles in this basin.

  11. NATURAL GAS RESOURCES IN DEEP SEDIMENTARY BASINS

    Energy Technology Data Exchange (ETDEWEB)

    Thaddeus S. Dyman; Troy Cook; Robert A. Crovelli; Allison A. Henry; Timothy C. Hester; Ronald C. Johnson; Michael D. Lewan; Vito F. Nuccio; James W. Schmoker; Dennis B. Riggin; Christopher J. Schenk

    2002-02-05

    From a geological perspective, deep natural gas resources are generally defined as resources occurring in reservoirs at or below 15,000 feet, whereas ultra-deep gas occurs below 25,000 feet. From an operational point of view, ''deep'' is often thought of in a relative sense based on the geologic and engineering knowledge of gas (and oil) resources in a particular area. Deep gas can be found in either conventionally-trapped or unconventional basin-center accumulations that are essentially large single fields having spatial dimensions often exceeding those of conventional fields. Exploration for deep conventional and unconventional basin-center natural gas resources deserves special attention because these resources are widespread and occur in diverse geologic environments. In 1995, the U.S. Geological Survey estimated that 939 TCF of technically recoverable natural gas remained to be discovered or was part of reserve appreciation from known fields in the onshore areas and State waters of the United. Of this USGS resource, nearly 114 trillion cubic feet (Tcf) of technically-recoverable gas remains to be discovered from deep sedimentary basins. Worldwide estimates of deep gas are also high. The U.S. Geological Survey World Petroleum Assessment 2000 Project recently estimated a world mean undiscovered conventional gas resource outside the U.S. of 844 Tcf below 4.5 km (about 15,000 feet). Less is known about the origins of deep gas than about the origins of gas at shallower depths because fewer wells have been drilled into the deeper portions of many basins. Some of the many factors contributing to the origin of deep gas include the thermal stability of methane, the role of water and non-hydrocarbon gases in natural gas generation, porosity loss with increasing thermal maturity, the kinetics of deep gas generation, thermal cracking of oil to gas, and source rock potential based on thermal maturity and kerogen type. Recent experimental simulations

  12. Wave tectono-sedimentary processes in Tarim basin

    Institute of Scientific and Technical Information of China (English)

    JIN Zhijun; ZHANG Yiwei; CHEN Shuping

    2005-01-01

    Based on the unconformities, the formation times of structures, and geological wave filtering applied to basin fills of typical wells around the Manjiaer area in the Tarim basin, the wave tectono-sedimentary processes in the Tarim Basin are discussed. The results of geological wave filtering of basin fills of typical wells show that, in time domain, the evolution of the Tarim basin was controlled by various wave processes with the periods of 740±Ma, 200±Ma, 100±Ma and 30±Ma. The analyses of basin fills, basin subsidence and unconformities show that the trends of the sedimentary facies belts, depocenters, and centers of subsidence migrated and interchanged periodically with periods of 200±Ma. These show the propagation of wave movements in space domain. The wave evolution of the Tarim basin is of significance to understanding the formation of the oil and gas reservoirs in the basin.

  13. Preliminary catalog of the sedimentary basins of the United States

    Science.gov (United States)

    Coleman, James L.; Cahan, Steven M.

    2012-01-01

    One hundred forty-four sedimentary basins (or groups of basins) in the United States (both onshore and offshore) are identified, located, and briefly described as part of a Geographic Information System (GIS) data base in support of the Geologic Carbon Dioxide Sequestration National Assessment Project (Brennan and others, 2010). This catalog of basins is designed to provide a check list and basic geologic framework for compiling more detailed geologic and reservoir engineering data for this project and other future investigations.

  14. Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic: ocean-continent transformation (late Paleozoic to early mid-Triassic); intracontinental rift basin (late mid-Triassic to early Jurassic); down-warped basin (middle to late Jurassic); foreland basin (Cretaceous); and strike-slip basin (Cenozoic). Three major genetic types of Ag-Cu polymetailic ore deposits, including the reworked hydrothermal sedimentary, sedimentary-hydrothermally reworked and hydrothermal vein types, are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages. Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation, migration direction and emplacement processes of the basin fluids, thus causing differences in mineralization styles as well as in genetic types of ore deposit.

  15. Estimating tectonic history through basin simulation-enhanced seismic inversion: Geoinformatics for sedimentary basins

    Science.gov (United States)

    Tandon, K.; Tuncay, K.; Hubbard, K.; Comer, J.; Ortoleva, P.

    2004-01-01

    A data assimilation approach is demonstrated whereby seismic inversion is both automated and enhanced using a comprehensive numerical sedimentary basin simulator to study the physics and chemistry of sedimentary basin processes in response to geothermal gradient in much greater detail than previously attempted. The approach not only reduces costs by integrating the basin analysis and seismic inversion activities to understand the sedimentary basin evolution with respect to geodynamic parameters-but the technique also has the potential for serving as a geoinfomatics platform for understanding various physical and chemical processes operating at different scales within a sedimentary basin. Tectonic history has a first-order effect on the physical and chemical processes that govern the evolution of sedimentary basins. We demonstrate how such tectonic parameters may be estimated by minimizing the difference between observed seismic reflection data and synthetic ones constructed from the output of a reaction, transport, mechanical (RTM) basin model. We demonstrate the method by reconstructing the geothermal gradient. As thermal history strongly affects the rate of RTM processes operating in a sedimentary basin, variations in geothermal gradient history alter the present-day fluid pressure, effective stress, porosity, fracture statistics and hydrocarbon distribution. All these properties, in turn, affect the mechanical wave velocity and sediment density profiles for a sedimentary basin. The present-day state of the sedimentary basin is imaged by reflection seismology data to a high degree of resolution, but it does not give any indication of the processes that contributed to the evolution of the basin or causes for heterogeneities within the basin that are being imaged. Using texture and fluid properties predicted by our Basin RTM simulator, we generate synthetic seismograms. Linear correlation using power spectra as an error measure and an efficient quadratic

  16. Self-Organized Megastructures in Sedimentary Basins

    Energy Technology Data Exchange (ETDEWEB)

    Peter J. Ortoleva

    2004-06-30

    The overall theme of the project is to develop a quantitative understanding of basin reaction/transport/mechanical (RTM) processes on a broad range of scales. Our approach starts with the development of novel formulations of the basic RTM process rate laws (e.g. rock deformation, texture dynamics, and fracturing). We then set forth algorithms for solving the resulting partial differential equations numerically. As many of the parameters in the subsurface are not well known, we embed the entire approach in a probabilistic framework through information theory. The result is a set of novel software and conceptual papers that have been the first quantitative theory of a number of fundamental phenomena that take into account the full RTM dynamics of these systems.

  17. The Prediction of Predominant Convection in Sedimentary Basin Systems

    Science.gov (United States)

    Musuuza, J. L.; Radu, F. A.; Attinger, S.

    2012-12-01

    We study a thermohaline system in which the density gradients arise from salinity and temperature differences. Such systems arise in practical applications e.g. geological waste storage and geothermal energy exploitation. A sedimentary-basin set-up is investigated where salinity and temperature increase with depth. In such systems, the buoyancy forces caused by salinity and temperature gradients give rise to counter-acting convection cells. The homogenization theory ideas from Held, Attinnger and Kinzelbach (2005) are applied to the solute and heat transport equations and the two resulting cell problems solved with the coupling between the heat and solute transport preserved. A dimensionless number whose sign changes to negative when thermal-convection is predominant is derived from the solutions to the cell problems in terms of physical variables. The number is tested against numerical simulations performed with the software package d3f on sufficiently refined grids that deliver stable numerical solutions without upwind techniques.

  18. Tectonics of Chukchi Sea Shelf sedimentary basins and its influence on petroleum systems

    Science.gov (United States)

    Agasheva, Mariia; Antonina, Stoupakova; Anna, Suslova; Yury, Karpov

    2016-04-01

    The Chukchi Sea Shelf placed in the East Arctic offshore of Russia between East Siberian Sea Shelf and North Slope Alaska. The Chukchi margin is considered as high petroleum potential play. The major problem is absence of core material from drilling wells in Russian part of Chukchi Shelf, hence strong complex geological and geophysical analyses such as seismic stratigraphy interpretation should be provided. In addition, similarity to North Slope and Beaufort Basins (North Chukchi) and Hope Basin (South Chukchi) allow to infer the resembling sedimentary succession and petroleum systems. The Chukchi Sea Shelf include North and South Chukchi Basins, which are separated by Wrangel-Herald Arch and characterized by different opening time. The North Chukchi basin is formed as a general part of Canada Basin opened in Early Cretaceous. The South Chukchi Basin is characterized by a transtensional origin of the basin, this deformation related to motion on the Kobuk Fault [1]. Because seismic reflections follow chronostratigraphic correlations, it is possible to achieve stratigraphic interpretation. The main seismic horizons were indicated as: PU, JU, LCU, BU, mBU marking each regional unconformities. Reconstruction of main tectonic events of basin is important for building correct geological model. Since there are no drilling wells in the North and South Chukchi basins, source rocks could not be proven. Referring to the North Chukchi basin, source rocks equivalents of Lower Cretaceous Pebble Shale Formation, Lower Jurassic Kingdak shales and Upper Triassic Shublik Formation (North Slope) is possible exhibited [2]. In the South Chukchi, it is possible that Cretaceous source rocks could be mature for hydrocarbon generation. Erosions and uplifts that could effect on hydrocarbon preservation was substantially in Lower Jurassic and Early Cretaceous periods. Most of the structures may be connected with fault and stratigraphy traps. The structure formed at Wrangel-Herald Arch to

  19. PUMa - modelling the groundwater flow in Baltic Sedimentary Basin

    Science.gov (United States)

    Kalvane, G.; Marnica, A.; Bethers, U.

    2012-04-01

    In 2009-2012 at University of Latvia and Latvia University of Agriculture project "Establishment of interdisciplinary scientist group and modelling system for groundwater research" is implemented financed by the European Social Fund. The aim of the project is to develop groundwater research in Latvia by establishing interdisciplinary research group and modelling system covering groundwater flow in the Baltic Sedimentary Basin. Researchers from fields like geology, chemistry, mathematical modelling, physics and environmental engineering are involved in the project. The modelling system is used as a platform for addressing scientific problems such as: (1) large-scale groundwater flow in Baltic Sedimentary Basin and impact of human activities on it; (2) the evolution of groundwater flow since the last glaciation and subglacial groundwater recharge; (3) the effects of climate changes on shallow groundwater and interaction of hydrographical network and groundwater; (4) new programming approaches for groundwater modelling. Within the frame of the project most accessible geological information such as description of geological wells, geological maps and results of seismic profiling in Latvia as well as Estonia and Lithuania are collected and integrated into modelling system. For example data form more then 40 thousands wells are directly used to automatically generate the geological structure of the model. Additionally a groundwater sampling campaign is undertaken. Contents of CFC, stabile isotopes of O and H and radiocarbon are the most significant parameters of groundwater that are established in unprecedented scale for Latvia. The most important modelling results will be published in web as a data set. Project number: 2009/0212/1DP/1.1.1.2.0/09/APIA/VIAA/060. Project web-site: www.puma.lu.lv

  20. Land subsidence and hydrodynamic compaction of sedimentary basins

    Directory of Open Access Journals (Sweden)

    H. Kooi

    1998-01-01

    Full Text Available A one-dimensional model is used to investigate the relationship between land subsidence and compaction of basin sediments in response to sediment loading. Analysis of the model equations and numerical experiments demonstrate quasi-linear systems behaviour and show that rates of land subsidence due to compaction: (i can attain a significant fraction (>40% of the long-term sedimentation rate; (ii are hydrodynamically delayed with respect to sediment loading. The delay is controlled by a compaction response time τc that can reach values of 10-5-107 yr for thick shale sequences. Both the behaviour of single sediment layers and multiple-layer systems are analysed. Subsequently the model is applied to the coastal area of the Netherlands to illustrate that lateral variability in compaction-derived land subsidence in sedimentary basins largely reflects the spatial variability in both sediment loading and compaction response time. Typical rates of compaction-derived subsidence predicted by the model are of the order of 0.1 mm/yr but may reach values in excess of 1 mm/yr under favourable conditions.

  1. Petroleum prospectivity of the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Grantz, A.; Hart, P.E.

    2012-01-01

    Reconnaissance seismic reflection data indicate that Canada Basin is a >700,000 sq. km. remnant of the Amerasia Basin of the Arctic Ocean that lies south of the Alpha-Mendeleev Large Igneous Province, which was constructed across the northern part of the Amerasia Basin between about 127 and 89-83.5 Ma. Canada Basin was filled by Early Jurassic to Holocene detritus from the Beaufort-Mackenzie Deltaic System, which drains the northern third of interior North America, with sizable contributions from Alaska and Northwest Canada. The basin contains roughly 5 or 6 million cubic km of sediment. Three fourths or more of this volume generates low amplitude seismic reflections, interpreted to represent hemipelagic deposits, which contain lenses to extensive interbeds of moderate amplitude reflections interpreted to represent unconfined turbidite and amalgamated channel deposits.Extrapolation from Arctic Alaska and Northwest Canada suggests that three fourths of the section in Canada Basin is correlative with stratigraphic sequences in these areas that contain intervals of hydrocarbon source rocks. In addition, worldwide heat flow averages suggest that about two thirds of Canada Basin lies in the oil or gas windows. Structural, stratigraphic and combined structural and stratigraphic features of local to regional occurrence offer exploration targets in Canada Basin, and at least one of these contains bright spots. However, deep water (to almost 4000 m), remoteness from harbors and markets, and thick accumulations of seasonal to permanent sea ice (until its possible removal by global warming later this century) will require the discovery of very large deposits for commercial success in most parts of Canada Basin. ?? 2011 Elsevier Ltd.

  2. DETERMINATION OF TECTONIC EVOLUTION OF A SEDIMENTARY BASIN FROM SANDSTONE COMPONENTS

    Institute of Scientific and Technical Information of China (English)

    Lei SHAO; Chuanlian LIU; Karl STATTEGGER

    2001-01-01

    Terrigenous sedimentary rocks are the dominant rock types in continental sedimentary basin, the components of these rocks are mainly controlled by source rocks. Through systematically analyzing the components of terrigenous sedimentary rocks, the tectonic evolution of a sedimentary basin can be reconstructed. The Turpan Basin was examined using sandstone petrological and geochemical methods.The consistency of the petrographical and geochemical results shows that the tectonic evolution of the basin can be subdivided into four stages: the first stage covers the Permian; the second stage the Triassic;the third stage from the Lower Jurassic to Upper Jurassic and the fourth stage from the Cretaceous to Tertiary. The components of sandstones among these stages are different, which reflect the influence of tectonics movements on the evolution of the basin and surrounding areas.

  3. Sequence associations of sedimentary facies in continental basins and their applications to palaeogeographic mapping

    Institute of Scientific and Technical Information of China (English)

    TANG Hua-feng; CHENG Ri-hui; KONG Qing-ying; BAI Yun-feng; YU Ming-feng

    2004-01-01

    According to the characteristics of sedimentary facies and their vertical associations, sequence association of sedimentary facies can be divided into 2 types and 28 subtypes. The first type (type A) is a sedimentary sequence without volcanic rocks, including 18 subtypes. The second type (type B) is a volcanogenic succession including 10 subtypes.Each subtype may reflect certain filling condition under certain sedimentary environment. Time and space distribution of different types of sequence associations can reflect tectonics that controlled the basin evolution, sedimentary environments and palaeogeography.

  4. Edge detection in gravity field of the Gheshm sedimentary basin

    Directory of Open Access Journals (Sweden)

    Ali Akbar Hosseini

    2013-06-01

    Full Text Available Edge detection and edge enhancement techniques play an essential role in interpreting potential field data. This paper describes the application of various edge detection techniques to gravity data in order to delineate the edges of subsurface structures. The edge detection methods comprise analytic signal, total horizontal derivative (THDR, theta angle, tilt angle, hyperbolic of tilt angle (HTA, normalised total horizontal gradient (TDX and normalised horizontal derivative (NTHD. The results showed that almost all filters delineated edges of anomalies successfully. However, the capability of these filters in edge detection decreased as the depth of sources increased. Of the edge enhancement filters, normalized standard deviation filter provided much better results in delineating deeper sources. The edge detection techniques were further applied on a real gravity data from the Gheshm sedimentary basin in the Persian Gulf in Iran. All filters specified a northeast-southwest structural trend. The THDR better outlined the structural morphology and trend. Moreover, it indicated the salt plugs much better than other filters. Analytic signal and THDR successfully enhanced the edges of the shorter wavelength residual structures. Normalized standard deviation (NSTD, TDX and hyperbolic of tilt angle (HTA filters highlighted the likely fault pattern and lineaments, with a dominant northeast-southwest structural trend. This case study shows that the edge detection techniques provides valuable information for geologists and petroleum engineers to outline the horizontal location of geological sources including salt plugs and stand out buried faults, contacts and other tectonic and geological features.

  5. Clustering of Sedimentary Basins Using Associative Neural memories (ART2

    Directory of Open Access Journals (Sweden)

    LAKSHMIPRASAD BOPPANA

    2011-08-01

    Full Text Available Associative Memory (AM research covers technologies enabling implementation of associative memory which enables thought process and links previous experience to novel situations. Each neuralnetwork system requires a memory for storing and retrieval of associated concepts, based on a combination of the base concept and the context. Adaptive Resonance Theory is a kind of associativeneural memory model as unsupervised neural network model. The aim of this article is to present identification and recognition of Magneto-telluric data for sedimentary basins using associative neural memory with Adaptive Resonance Theory (ART2.The ART2 is an unsupervised learning algorithm where the network is provided with inputs but not with desired outputs. The system itself to decide what features it will use to group the input data. Several sets of data consisting of 17 phases and 17 apparent resistivity values and their respective tag values are given. These sets of data are used for training the network, and other sets of data are used to test the network for clustering. The testing will result in the approximate identification of the data patterns with tag value of 1 where there is sediment ofhydrocarbon and a tag value of 0 where there is no sediment of hydrocarbon in the given data set. The recognition rate in the proposed system lies between 90% and 100%.

  6. Simulations of hydraulic fracturing and leakage in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Lothe, Ane Elisabeth

    2004-01-01

    Hydraulic fracturing and leakage of water through the caprock is described from sedimentary basin over geological time scale. Abnormal pressure accumulations reduce the effective stresses in the underground and trigger the initiation of hydraulic fractures. The major faults in the basin define these pressure compartments. In this Thesis, basin simulations of hydraulic fracturing and leakage have been carried out. A simulator (Pressim) is used to calculate pressure generation and dissipitation between the compartments. The flux between the compartments and not the flow within the compartments is modelled. The Griffith-Coulomb failure criterion determines initial failure at the top structures of overpressured compartments, whereas the frictional sliding criterion is used for reactivation along the same fractures. The minimum horizontal stress is determined from different formulas, and an empirical one seems to give good results compared to measured pressures and minimum horizontal stresses. Simulations have been carried out on two datasets; one covering the Halten Terrace area and one the Tune Field area in the northern North Sea. The timing of hydraulic fracturing and amount of leakage has been quantified in the studies from the Halten Terrace area. This is mainly controlled by the lateral fluid flow and the permeability of the major faults in the basin. Low fault permeability gives early failure, while high fault permeabilities results in no or late hydraulic fracturing and leakage from overpressured parts of the basin. In addition to varying the transmissibility of all faults in a basin, the transmissibility across individual faults can be varied. Increasing the transmissibility across faults is of major importance in overpressured to intermediately pressured areas. However, to obtain change in the flow, a certain pressure difference has to be the situation between the different compartments. The coefficient of internal friction and the coefficient of frictional

  7. Tectonic and climatic controls on late quaternary sedimentary processes in a neotectonic intramontane basin. (The Pitalito Basin, South Colombia).

    NARCIS (Netherlands)

    Bakker, J.

    1990-01-01

    The present study deals with the influence of tectonics and climatic changes on sedimentation patterns in the Quaternary Pitalito Basin (lat. 1°52'N, long. 76°02'W). This intramontane sedimentary basin is 15 km in width and 20 kin in length and is located in the Eastern Cordillera of the southern Co

  8. Managing the Cumulative Impacts of Land Uses in the Western Canadian Sedimentary Basin: A Modeling Approach

    Directory of Open Access Journals (Sweden)

    Stan Boutin

    2003-07-01

    Full Text Available This case study from northeastern Alberta, Canada, demonstrates a fundamentally different approach to forest management in which stakeholders balance conservation and economic objectives by weighing current management options from the point of view of their long-term effects on the forest. ALCES®, a landscape-scale simulation model, is used to quantify the effects of the current regulatory framework and typical industrial practices on a suite of ecological and economic indicators over the next 100 yr. These simulations suggest that, if current practices continue, the combined activities of the energy and forestry industries in our 59,000 km2 study area will cause the density of edge of human origin to increase from 1.8 km/km 2 to a maximum of 8.0 km/km2. We also predict that older age classes of merchantable forest stands will be largely eliminated from the landscape, habitat availability for woodland caribou will decline from 43 to 6%, and there will be a progressive shortfall in the supply of softwood timber beginning in approximately 60 yr. Additional simulations involving a suite of "best practices" demonstrate that substantial improvements in ecological outcome measures could be achieved through alternative management scenarios while still maintaining a sustainable flow of economic benefits. We discuss the merits of our proposed approach to land use planning and apply it to the Western Canadian Sedimentary Basin.

  9. Crustal-scale geological and thermal models of the Beaufort-Mackenzie Basin, Arctic Canada

    Science.gov (United States)

    Sippel, Judith; Scheck-Wenderoth, Magdalena; Kröger, Karsten; Lewerenz, Björn

    2010-05-01

    The Beaufort-Mackenzie Basin is a petroliferous province in northwest Arctic Canada and one of the best-known segments of the Arctic Ocean margin due to decades of exploration. Our study is part of the programme MOM (Methane On the Move), which aims to quantify the methane contribution from natural petroleum systems to the atmosphere over geological times. Models reflecting the potential of a sedimentary basin to release methane require well-assessed boundary conditions such as the crustal structure and large-scale temperature variation. We focus on the crustal-scale thermal field of the Beaufort-Mackenzie Basin. This Basin has formed on a post-rift, continental margin which, during the Late Cretaceous and Tertiary, developed into the foreland of the North American Cordilleran foldbelt providing space for the accumulation of up to 16 km of foreland deposits. We present a 3D geological model which integrates the present topography, depth maps of Upper Cretaceous and Tertiary horizons (Kroeger et al., 2008, 2009), tops of formations derived from interpreted 2D reflection seismic lines and 284 boreholes (released by the National Energy Board of Canada), and the sequence stratigraphic framework established by previous studies (e.g. Dixon et al., 1996). To determine the position and geometry of the crust-mantle boundary, an isostatic calculation (Airýs model) is applied to the geological model. We present different crustal-scale models combining isostatic modelling, published deep reflection and refraction seismic lines (e.g. Stephenson et al., 1994; O'Leary et al., 1995), and calculations of the 3D conductive thermal field. References: Dixon, J., 1996. Geological Atlas of the Beaufort-Mackenzie Area, Geological Survey of Canada Miscellaneous Report, 59, Ottawa, 173 pp. Kroeger, K.F., Ondrak, R., di Primio, R. and Horsfield, B., 2008. A three-dimensional insight into the Mackenzie Basin (Canada): Implications for the thermal history and hydrocarbon generation potential

  10. Stress Map 2.0: Updating the Stress Map of the Western Canadian Sedimentary Basin

    Science.gov (United States)

    Mallyon, D.; Schmitt, D. R.; Currie, C. A.; Gu, Y. J.; Heidbach, O.

    2015-12-01

    The greatest horizontal compression in much of the Western Canada Sedimentary Basin appears to uniformly trend NE-SW. Beyond this, major gaps remain in our knowledge of stress magnitudes and even faulting regimes. This lack of quantitative information impedes a proper understanding of seismic events that appear to be linked to hydraulic fracturing stimulations. Apart from this immediate concern, such seismicity could impact long term green-house gas sequestration and geothermal energy development. As part of the Helmholtz-Alberta geothermal collaboration, we are developing a program to update this crustal stress state information. The program consists of more immediate studies related to conventional analysis of borehole image logs, core fractures, and transient pressure records as can be made available. Data sets analyzed to date include logs to 3.5 km depth from areas experiencing induced seismicity, from 2.5 km depth within the Precambrian craton in NE Alberta, and to 400 m depth within a large carbonate platform. All these data largely confirm the NE-SW stress directions. In some cases, the configurations of drilling induced tensile fractures and borehole breakouts allow the faulting regime to be constrained. The addition of new seismometers to the region is also allowing for the refinement of earthquake focal mechanisms. Finally, a dramatic contrast in lithosphere thickness, composition and geothermal gradient exists at the contact between the Cordillera and the North American craton; therefore, lithosphere-scale numerical models are also being developed to quantify the relative contribution of geodynamic processes, such as mantle flow and contact geometry, to the observed stress regime within the basin.

  11. Wrench faulting in the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Hutchinson, D. R.; Jackson, H. R.; Shimeld, J.; Houseknecht, D. W.; Chian, D.; Li, Q.; Saltus, R. W.; Oakey, G. N.

    2015-12-01

    Synthesis of seismic velocity, potential field, and geologic data from within the Canada Basin of the Arctic Ocean and its surrounding margins suggests that a northeast-trending structural fabric has influenced the origin, evolution, and current tectonics of the basin. This fabric is defined by a diverse set of observations, including (1) a magnetic lineament extending from offshore Prince Patrick Island to the bend in the Canada Basin Gravity Low that separates higher magnetic amplitudes to the northwest from a region of more subdued anomalies to the southeast; (2) the orientation of the 600-km long Northwind Escarpment along the edge of the Canada Basin; (3) a large, linear, positive magnetic anomaly that parallels Northwind Escarpment; (4) negative flower structures along the base of the Northwind Escarpment identified in seismic reflection profiles; (5) the edges of a linear, 150-km-long by 20-km-wide by 2000-m deep, basin in the Chukchi Plateau; (6) the sub-parallel ridges of Sever Spur along the Canadian margin north of Prince Patrick Island; (7) an oblong gravity low interpreted to indicate thick sediments beneath an inferred rift basin at 78oN in ~3600 m water depth; (8) the offshore extensions of the Canning sinistral and Richardson dextral fault zones; (9) the offshore extension of the D3 magnetic terrain of Saltus et al. (2011); and (10) the association of dredged rocks of the Chukchi Borderland with the Pearya terrane ~2000 km northeast of its present location (Brumley et al., 2015). Ongoing deformation of the Beaufort margin by impingement of the Brooks Range tectonic front is recorded by modern seismicity along the Canning and Richardson fault zones, which imply that deformation is accommodated by slip along the northeast-trending fabric. Together, these features are interpreted to indicate long-lived northeast-southwest oriented tectonic fabric in the development of the Canada Basin from initial rifting to modern deformation of the Beaufort margin

  12. Estimate of the Geothermal Energy Resource in the Major Sedimentary Basins in the United States (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, A.; Porro, C.; Augustine, C.; Roberts, B.

    2012-09-01

    Because most sedimentary basins have been explored for oil and gas, well logs, temperatures at depth, and reservoir properties such as depth to basement and formation thickness are well known. The availability of this data reduces exploration risk and allows development of geologic exploration models for each basin. This study estimates the magnitude of recoverable geothermal energy from 15 major known U.S. sedimentary basins and ranks these basins relative to their potential. The total available thermal resource for each basin was estimated using the volumetric heat-in-place method originally proposed by (Muffler, 1979). A qualitative recovery factor was determined for each basin based on data on flow volume, hydrothermal recharge, and vertical and horizontal permeability. Total sedimentary thickness maps, stratigraphic columns, cross sections, and temperature gradient information was gathered for each basin from published articles, USGS reports, and state geological survey reports. When published data were insufficient, thermal gradients and reservoir properties were derived from oil and gas well logs obtained on oil and gas commission databases. Basin stratigraphy, structural history, and groundwater circulation patterns were studied in order to develop a model that estimates resource size, temperature distribution, and a probable quantitative recovery factor.

  13. Estimate of Geothermal Energy Resource in Major U.S. Sedimentary Basins (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Porro, C.; Augustine, C.

    2012-04-01

    This study estimates the magnitude of geothermal energy from fifteen major known US sedimentary basins and ranks these basins relative to their potential. Because most sedimentary basins have been explored for oil and gas, well logs, temperatures at depth, and reservoir properties are known. This reduces exploration risk and allows development of geologic exploration models for each basin as well as a relative assessment of geologic risk elements for each play. The total available thermal resource for each basin was estimated using the volumetric heat-in-place method originally proposed by Muffler (USGS). Total sedimentary thickness maps, stratigraphic columns, cross sections, and temperature gradient Information were gathered for each basin from published articles, USGS reports, and state geological survey reports. When published data was insufficient, thermal gradients and reservoir properties were derived from oil and gas well logs obtained on oil and gas commission websites. Basin stratigraphy, structural history, and groundwater circulation patterns were studied in order to develop a model that estimates resource size and temperature distribution, and to qualitatively assess reservoir productivity.

  14. Permo-Carboniferous sedimentary basins related to the distribution of planetary cryptoblemes

    Science.gov (United States)

    Windolph, J.F.

    1997-01-01

    Massive/high velocity solar, galactic, and cosmic debris impacting the Earths surface may account for the enormous energy required for the formation of Permo-Carboniferous sedimentary basins and related mountain building orogenies. Analysis of satellite immagry, sea floor sonar, geophysical data, and geotectonic fabrics show a strong correlation throughout geologic time between sedimentary basin origin and planetary cryptoblemes. Cryptoblemes are subtile, multi-ringed, radial centric impact shock signatures covering the entire terrestrial surface and ocean floors, having a geometry and distribution strikingly similar to the surfaces of the lunar planetary bodies in the solar system. Investigations of Permo-Carboniferous basins show an intensely overprinted pattern of cryptoblemes coinciding with partial obliteration and elliptical compression of pre-existing basins and accompanying shock patterns. Large distorted cryptoblemes may incorporate thin skin deformation, localized sediment diagenesis, regional metamorphism, and juxtaposed exotic terrains. These data, related to basin morphogenic symmetry, suggest that large episodic impact events are the primary cause of tectonogenic features, geologic boundary formation and mass extinction episodes on the planet Earth. Plate tectonics may be only a slow moving, low energy secondary effect defined and set in motion by megacosmic accretion events. Permo-Carboniferous sediments of note are preserved or accumulated in relatively small rectangular to arcuate rift valleys and synclinal down warps, such as the Narraganset basin of Massachusetts, USA, and Paganzo basin in Argentina, S.A. These deposits and depocenters may originate from dynamic reinforcement/cancellation impact effects, as can be seen in the Basin Range of Nevada and Utah, USA. Large circular to oval sedimentary basins commonly include internal ring structures indicating post depositional subsidence and rebound adjustments with growth faulting, notable in the

  15. Evolutionary sequences and hydrocarbon potential of Kenya sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Cregg, A.K. (Western Atlas International, Inc., Carrollton, TX (United States))

    1991-03-01

    Kenya basins have evolved primarily through extension related to episodic continental rifting. In eastern Kenya, thick accumulations of sediments formed within grabens during the prerift phase (Precambrian to Carboniferous) of the Gondwana breakup. Synrift sedimentation (Late Carboniferous to Middle Jurassic) occurred within a north-south rift system, which included the Mandera basin, South Anza basin, and Lamu embayment. During the Early Jurassic, a marine transgression invaded the margins of the eastern Kenya rift basins, resulting in the deposition of platform carbonates and shales. A Callovian-aged salt basin formed in the offshore regions of the Lamu embayment. Intermittent tectonic activity and eustatic sea-level changes controlled sedimentation, which produced marine shales, carbonates or evaporites, and fluvio-deltaic to lacustrine sandstones. From the Early Cretaceous to recent, continental sediments were deposited within the North Anza and Turkana basins. These fluvial-lacustrine sediments are similar to the Lower Cretaceous sequences that have produced oil in the Mesozoic Sudanese Abu Gabra rift. Although exploration activities began in the early 1950s, significant occurrences of potential reservoir, source, and seal lithologies as well as trapping configurations remain in many areas. Favorable structures and sequences of reservoir sandstones and carbonates overlain by potentially sealing lacustrine or marine shales, evaporites, or volcanics have been noted. Potential source beds are believed to be present within shales of the lacustrine or marine depositional environments.

  16. Response of sedimentary nucleic acids to benthic disturbance in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, C.E.G.; DeSouza, M.J.B.D.; Nair, S.; LokaBharathi, P.A.

    Information on the response of nucleic acids (i.e., DNA and RNA) to simulated benthic disturbance was obtained from samples collected from eight sediment cores (0-10 cm) located in the Central Indian Basin (CIB). In general the total sedimentary DNA...

  17. Exploring Sedimentary Basins with High Frequency Receiver Function: the Dublin Basin Case Study

    Science.gov (United States)

    Licciardi, A.; Piana Agostinetti, N.

    2015-12-01

    The Receiver Function (RF) method is a widely applied seismological tool for the imaging of crustal and lithospheric structures beneath a single seismic station with one to tens kilometers of vertical resolution. However, detailed information about the upper crust (0-10 km depth) can also be retrieved by increasing the frequency content of the analyzed RF data-set (with a vertical resolution lower than 0.5km). This information includes depth of velocity contrasts, S-wave velocities within layers, as well as presence and location of seismic anisotropy or dipping interfaces (e.g., induced by faulting) at depth. These observables provides valuable constraints on the structural settings and properties of sedimentary basins both for scientific and industrial applications. To test the RF capabilities for this high resolution application, six broadband seismic stations have been deployed across the southwestern margin of the Dublin Basin (DB), Ireland, whose geothermal potential has been investigated in the last few years. With an inter-station distance of about 1km, this closely spaced array has been designed to provide a clear picture of the structural transition between the margin and the inner portion of the basin. In this study, a Bayesian approach is used to retrieve the posterior probability distributions of S-wave velocity at depth beneath each seismic station. A multi-frequency RF data-set is analyzed and RF and curves of apparent velocity are jointly inverted to better constrain absolute velocity variations. A pseudo 2D section is built to observe the lateral changes in elastic properties across the margin of the basin with a focus in the shallow portion of the crust. Moreover, by means of the harmonic decomposition technique, the azimuthal variations in the RF data-set are isolated and interpreted in terms of anisotropy and dipping interfaces associated with the major fault system in the area. These results are compared with the available information from

  18. Sedimentary geology of the middle Carboniferous of the Donbas region (Dniepr-Donets Basin, Ukraine).

    Science.gov (United States)

    van Hinsbergen, Douwe J J; Abels, Hemmo A; Bosch, Wolter; Boekhout, Flora; Kitchka, Alexander; Hamers, Maartje; van der Meer, Douwe G; Geluk, Mark; Stephenson, Randell A

    2015-03-20

    The Paleozoic Dniepr-Donets Basin in Belarus, Ukraine, and Russia forms a major hydrocarbon province. Although well- and seismic data have established a 20 km thick stratigraphy, field-studies of its sediments are scarce. The inverted Donbas segment (Ukraine) exposes the middle Carboniferous part of the basin's stratigraphy. Here, we provide detailed sedimentological data from 13 sections that cover 1.5 of the total of 5 km of the Bashkirian and Moscovian stages and assess the paleoenvironment and paleo-current directions. Middle Carboniferous deposition occurred in a shelf environment, with coal deposition, subordinate fluvial facies, and abundant lower and middle shoreface facies, comprising an intercalated package of potential source and reservoir rocks. Sedimentary facies indicate a paleodepth range from below storm wave base to near-coastal swamp environments. Sedimentation and subsidence were hence in pace, with subtle facies changes likely representing relative sea-level changes. Paleocurrent directions are remarkably consistently southeastward in time and space in the different sedimentary facies across the Donbas Fold Belt, illustrating a dominant sedimentary infill along the basin axis, with little basin margin influence. This suggests that the middle Carboniferous stratigraphy of the Dniepr-Donets basin to the northwest probably contains significant amounts of fluvial sandstones, important for assessing hydrocarbon reservoir potential.

  19. The Cretaceous Songliao Basin: Volcanogenic Succession,Sedimentary Sequence and Tectonic Evolution, NE China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Songliao basin (SB) is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyroclastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of siliciclastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including (1) Alptian and preAptian: a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt (MOCB); (2) Albian to Companian: a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; (3) since Maastrichtian:a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin.

  20. Sedimentary basin geochemistry and fluid/rock interactions workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    Fundamental research related to organic geochemistry, fluid-rock interactions, and the processes by which fluids migrate through basins has long been a part of the U.S. Department of Energy Geosciences program. Objectives of this program were to emphasize those principles and processes which would be applicable to a wide range of problems associated with petroleum discovery, occurrence and extraction, waste disposal of all kinds, and environmental management. To gain a better understanding of the progress being made in understanding basinal fluids, their geochemistry and movement, and related research, and to enhance communication and interaction between principal investigators and DOE and other Federal program managers interested in this topic, this workshop was organized by the School of Geology and Geophysics and held in Norman, Oklahoma in November, 1991.

  1. Sedimentary basin analysis and petroleum potential of the Cretaceous and Tertiary strata in Korea.

    Energy Technology Data Exchange (ETDEWEB)

    Son, Jin-Dam; Kwak, Young-Hoon; Bong, Pil-Yoon [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

    1999-12-01

    Since 1992 sedimentary basin analysis to assess petroleum potential of the Cretaceous and Tertiary strata in the Korean onshore and continental shelf have been carried out. The Cretaceous non-marine strata mainly occupy the Gyeongsang Basin in southeastern part of the Korean Peninsula and small basins such as Haenam and Gyeokpo depressions in western coastal areas. The Tertiary strata are mostly distributed in Domi, Cheju, Socotra subbasins, and Okinawa Trough in the South Continental Shelf, and Kunsan and Heuksan basins in the West. The basin evolution and petroleum potential for each basins are characterized as follow. The Cretaceous Gyeongsang sediments were deposited in three subbasins including Milyang, Euisung and Yongyang subbasins. The black shales in Nakdong and Jinju formations are interpreted to contain abundant organic matter during the deposition, thermal maturity reaching up to the zone of dry gas formation. Because porosity and permeability are too low, the sandstones can act as a tight gas reservoir rather than conventional oil and gas reservoir. The latest Cretaceous strata of Haenam and Kyeokpo depressions in western coastal area are correlated into the Yuchon Volcanic Group of the Gyeongsang Basin. Petroleum potential of the Early Cretaceous basin in the West Continental Shelf could be relatively high in terms of sedimentary basin filled with thick lacustrine sediments. The Kunsan basin in the West Continental Shelf originated in the Early Cretaceous time expanded during the Paleocene time followed by regional erosion at the end of Paleocene on which Neogene sediment have been accumulated. The Paleocene-Eocene sublacustrine shales may play an major role as a source and cap rocks. South Continental Shelf Basin is subdivided by Cheju subbasin in the center, Socotra Subbasin to the west, Domi Subbasin to the northeast and Okinawa Trough to the East. The potential hydrocarbon traps associated with anticline, titled fault blocks, fault, unconformity

  2. BasinVis 1.0: A MATLAB®-based program for sedimentary basin subsidence analysis and visualization

    Science.gov (United States)

    Lee, Eun Young; Novotny, Johannes; Wagreich, Michael

    2016-06-01

    Stratigraphic and structural mapping is important to understand the internal structure of sedimentary basins. Subsidence analysis provides significant insights for basin evolution. We designed a new software package to process and visualize stratigraphic setting and subsidence evolution of sedimentary basins from well data. BasinVis 1.0 is implemented in MATLAB®, a multi-paradigm numerical computing environment, and employs two numerical methods: interpolation and subsidence analysis. Five different interpolation methods (linear, natural, cubic spline, Kriging, and thin-plate spline) are provided in this program for surface modeling. The subsidence analysis consists of decompaction and backstripping techniques. BasinVis 1.0 incorporates five main processing steps; (1) setup (study area and stratigraphic units), (2) loading well data, (3) stratigraphic setting visualization, (4) subsidence parameter input, and (5) subsidence analysis and visualization. For in-depth analysis, our software provides cross-section and dip-slip fault backstripping tools. The graphical user interface guides users through the workflow and provides tools to analyze and export the results. Interpolation and subsidence results are cached to minimize redundant computations and improve the interactivity of the program. All 2D and 3D visualizations are created by using MATLAB plotting functions, which enables users to fine-tune the results using the full range of available plot options in MATLAB. We demonstrate all functions in a case study of Miocene sediment in the central Vienna Basin.

  3. Oil source rocks in sedimentary basins of the CIS

    Energy Technology Data Exchange (ETDEWEB)

    Neruchev, S. (VNIGRI, St. Petersburg (Russian Federation))

    1993-09-01

    Oil source rocks with dominant kerogen of types I or II and a concentration of organic carbon of 6-7% are widely distributed at specific stratigraphic levels in the Phanerozoic section of the world and control the petroleum richness of the main productive basins. Nineteen stratigraphic levels of source rock distribution have been identified and almost all of these stratigraphic levels are found in basins of the Commonwealth of Independent States. This paper contains a review of their distribution. Black shales and oil shales enriched by P, U, V, Mo, and, occasionally, by Ir, Os and other metals, are found in the same stratigraphic intervals outside petroleum basins. High concentrations of uranium have been identified in terrestrial rocks at several of the stratigraphic intervals. A high concentration of kerogen in oil source rocks is commonly explained by depositional conditions (anoxia and upwelling) that favor accumulation and preservation of organic matter. However, the main factor determining organic matter enrichment of sediments is rifting activity and its associated increase in phosphorus, radioactive elements and heavy metals. This results in ecological crises and global blossoming of plankton (cianobacteria, green algae, zooplankton in the Silurian and diatoms in the Miocene). Rocks with increased concentrations of radioactive elements are present at the boundaries of large stratigraphic units that can be identified by paleontologic data. These rocks mark major events of fauna extinction and other important biotic events. The periodicity of the major global events is about 220 m.y., which corresponds to duration of the galactic year. Smaller periodicity of about 30 m.y. is identified inside the major periods. These regularities in the organic-rich rock distribution can be used to predict the presence of oil source rocks, oil shales, and shales enriched by metals.

  4. Sedimentary history and economic geology of San Juan Basin, New Mexico and Colorado

    International Nuclear Information System (INIS)

    The San Juan Basin contains up to 15,000 ft of sedimentary rocks ranging in age from Cambrian to Recent. The earliest development of the area as a sedimentary basin or trough apparently took place in Pennsylvanian time, and the basin was maintained, with changing rates of subsidence and filling, through the remainder of geologic time. During the Early Paleozoic, sedimentation was dominated by marine transgressions across the northwestern flank of the regional Transcontinental Arch. The Late Paleozoic history was strongly influenced by tectonism related to development of the Ancestral Rocky Mountains Uplifts and associated downwarping. The Early Mesozoic is characterized by fluvial and eolian environments, interrupted periodically by thin marine transgressive deposits of nearshore redbeds. The final Mesozoic event was the widespread Late Cretaceous marine transgression which deposited a thick cyclic sequence of marine gray shale and sandstone, with interbedded coal. Late Tertiary regional uplift and resulting volcanism were accompanied by a regional dissection of the area by stream systems that evolved into the present drainage pattern of superposed streams. The sedimentary history is directly related to the occurrence of economic deposits in the basin. Major reserves of petroleum and gas are in Cretaceous and Pennsylvanian rocks, coal in Cretaceous, and uranium in Jurassic and Cretaceous. Abstract only

  5. Stratigraphy of Upper Cretaceous-Paleogene deposits of northwestern Zeya-Burya sedimentary basin

    Institute of Scientific and Technical Information of China (English)

    T.V. Kezina; N.D. Litvinenko

    2007-01-01

    In the northwestern Zeya-Bureya sedimentary basin, the authors studied coal deposits, including Ivanovsko-Erkovetskyu brown coal square on which is worked off largest Erkovetsky field of brown coal, extending to south flank of the Mesozoic-Cenozoic Belogor'e depression. The verified stratigraphic scheme of the coalfield sedimentary sequence is substantiated by palynological data on core samples from 18 boreholes sampled in the course of detailed prospecting and by paleobotanical analysis of sections in the Yuzhnyi sector of the coalfield. Sections of the Erkovtsy, Arkhara Boguchan, and Raichikha brown-coal mines are correlated. Stratigraphic subdivisions distinguished in the studied sedimentary succession are the middle and upper Tsagayan subformations (the latter incorporating the Kivda Beds), Raichikha and Mukhino formations.

  6. Investigating the elastic properties of sedimentary basins on different spatial scales

    Science.gov (United States)

    Krause, Martin; Methe, Pascal; Goepel, Andreas; Bleibinhaus, Florian; Kukowski, Nina

    2014-05-01

    The study of subsurface fluid motion is important e.g. for understanding ground water motion or processes of compaction, diagenesis, and hydrocarbon migration in sedimentary basins. The multidisciplinary project INFLUINS (INtegrated FLUid dynamics IN Sedimentary basins) aims for investigating the coupled dynamics of near surface and deep fluid patterns and material transport in the Thuringian Basin (Germany). In order to gain information on how fluid flow processes depend on basin architecture, and therefore its physical properties, we first image the subsurface structure of the Thuringian Basin using seismic methods. Then, relations between hydraulic and elastic material parameters are required to also image the hydraulic structure of the basin's subsurface. As hydraulic properties often significantly vary with spatial scales, such a study requires a combination of small- to large-scale seismic data sets. In the framework of INFLUINS a variety of seismic data sets aiming for different subsurface parameters and spatial scales have been acquired. Basin scale seismic data sets are available from a set of 2D reflection seismic profiles as well as 2.5D and 3D seismic travel time tomography. Laboratory scale seismic data characterizing the basin's rocks is provided by ultrasound experiments on drill cores from the Thuringian Basin. Deep drilling conducted in the framework of INFLUINS in 2013 provides further useful data sets for our purpose: we acquired core material for laboratory ultrasound analysis and sonic-log data. As the drill site is located at the cross point of two seismic reflection profiles and also within the array of seismic stations we used for the 3D travel time tomography, it serves a direct transfer of elastic properties between different scales.

  7. X-ray diffraction analysis of clay stones, Muglad Sedimentary Basin, Sudan

    International Nuclear Information System (INIS)

    This study deals with the theoretical and experimental aspects of X-ray diffraction (XRD) technique. Moreover the XRD technique has been used to investigate the clay mineral types and their distribution for samples obtained from exploration wells in the Mugald Sedimentary Basin in Western Sudan. The studied samples range in depth from 1524 m to 4572 m. The XRD analysis of samples shows that they consist of kaolinite, smectite, illite, chlorite and the mixed-layer smectite/illite. Kaolinite has higher abundance (15 - 72 %) followed by illite (7 - 34 %), smectite (11 - 76 %) and the less abundance of chlorite and the mixed-layer smectite/illite. Non-clay minerals found include quartz and cristabolite. The clay mineral types and their vertical distribution reflect various controls such as environmental, burial diagenesis, source rocks and climatic influences in the Muglad Sedimentary Basin. (author). 19 refs., 11 figs., 3 tabs

  8. Sedimentary features and exploration targets of Middle Permian reservoirs in the SW Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Guoming Xu

    2015-11-01

    Full Text Available The exploration direction and targets for the large-scale Middle Permian gas reservoirs in the Sichuan Basin are hot spots and challenges in current exploration researches. The exploration successes of large gas field of Cambrian Longwangmiao Formation in Gaoshiti-Moxi region, Central Sichuan Basin, indicated that prospective sedimentary facies belt was the basis for the formation of large gas fields. In this paper, based on seismic data, outcrop data and drilling data, the tectonic framework and sedimentary features of the Middle Permian in the SW Sichuan Basin were comprehensively studied. The following conclusions were reached from the perspective of sedimentary facies control: (1 during the Middle Permian, this region was in shallow water gentle slope belts with high energy, where thick reef flat facies were deposited; (2 the basement was uplifted during Middle Permian, resulting in the unconformity weathering crust at the top of Maokou Formation due to erosion; the SW Sichuan Basin was located in the karst slope belt, where epigenic karstification was intense; and (3 reef flat deposits superimposed by karst weathering crust was favorable for the formation of large-scale reef flat karst reservoirs. Based on the combination of the resources conditions and hydrocarbon accumulation conditions in this region, it was pointed out that the Middle Permian has great potential of large-scale reef flat karst gas reservoir due to its advantageous geological conditions; the Middle Permian traps with good hydrocarbon accumulation conditions were developed in the Longmen Mountain front closed structural belt in the SW Sichuan Basin and Western Sichuan Basin depression slope belt, which are favorable targets for large-scale reef flat karst reservoirs.

  9. Depositional features and sedimentary model of Buqu Stage in Mid-Jurassic in Qangtang Basin, Xizang (Tibet), China

    Institute of Scientific and Technical Information of China (English)

    WANG Xingtao; ZHAI Shikui; LIU Binde; ZHOU Shuxin

    2004-01-01

    The largest Mesozoic northward transgression in Qangtang Basin of Qinghai-Xizang (Tibet) Plateau occurred during the Buqu Stage, Middle Jurassic. Mainly filled with carbonate rocks, the whole basin is composed of transgression-regression sedimentary cycle. Field outcrops and indoor analysis revealed 8 types of sedimentary facies markers in this region. 4 types of sedimentary facies have been recognized: platform facies, platform marginal facies, foreslope facies and basin facies. Influenced by the northern Lazhuglung-Jinshajiang suture zone, central uplift region and southern Bangongco-Nujiang suture zone, these facies belts extended east-west. The sedimentary model was established based on observed depositional features. From their biological features and sedimentary characteristics, it is suggested that the paleoclimate was warm and humid at that time. The Buqu Formation is a promising target for oil and gas exploration in Shuanghu-Duoyong area in future.

  10. The problems of Paleozoic beds and reconstruction of the Middle Permian sedimentary basin in western Slovenia

    OpenAIRE

    Ivan Mlakar

    2003-01-01

    In the first part of paper geologic data from smaller outcrops of Val Gardena Formation in west Slovenia are assembled. Together with the already published information from larger outcrops they permit the reconstruction of the Middle Permian sedimentary basin on which the accent of paper is based. Attention is drawn to general problems of Upper Paleozoic beds, and conclusions regarding lithologic, stratigraphic and structural control of uranium and copper deposits in this part of Slovenia are...

  11. The problems of Paleozoic beds and reconstruction of the Middle Permian sedimentary basin in western Slovenia

    Directory of Open Access Journals (Sweden)

    Ivan Mlakar

    2003-06-01

    Full Text Available In the first part of paper geologic data from smaller outcrops of Val Gardena Formation in west Slovenia are assembled. Together with the already published information from larger outcrops they permit the reconstruction of the Middle Permian sedimentary basin on which the accent of paper is based. Attention is drawn to general problems of Upper Paleozoic beds, and conclusions regarding lithologic, stratigraphic and structural control of uranium and copper deposits in this part of Slovenia are given.

  12. Sedimentary characteristics of tide-dominated estuary in Donghetang Formation(Upper Devonian), central Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Donghetang Formation (Upper Devonian) in central Tarim Basin has been thought an important oil and gas reservoir since the abundant oil and gas resources were found in the wells W16, W20, W34, and other fields. However, the sedimentary environment of the Donghetang Formation has been disputed because it suffered from both tidal and fluvial actions and there were not rich fossils in the sandstone. After the authors analyzed sedimentary features by means of drill cores, well logging data, paleosols, and with SEM obseruations, three kinds of sedimentary environments were distinguished: alluvial fan, tide-dominated estuary, and shelf. Particularly, the sedimentary features of tide-dominated estuary were studied in detail. Besides, the authors discussed sedimentary characteristics of the Donghetang Formation which was divided into two fourth-order sequences and five system tracts. At the same time, according to the forming process of five system tracts, the whole vertical evolution and lateral transition of tide-dominated estuary were illustrated clearly. Finally, the reservoir quality was evaluated based on porosity and permeability.

  13. Oceanic Crust in the Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Hutchinson, Deborah; Chian, Deping; Jackson, Ruth; Lebedeva-Ivanova, Nina; Shimeld, John; Li, Qingmou; Mosher, David; Saltus, Richard; Oakey, Gordon

    2015-04-01

    Crustal velocities from 85 expendable sonobuoys in the Canada Basin of the Arctic Ocean acquired between 2007 and 2011 distinguish oceanic, transitional, and extended continental crust. Crustal type was based on objective assignments of diagnostic velocities - oceanic from the presence of layer 3 velocities (6.7-7.2 km/s); transitional from the presence of a lower-most, high velocity layer (7.2-7.7 km/s), and continental for velocities typical of continental crust (≤6.6 km/s). Combined interpretations of sonobuoys, coincident multichannel seismic reflection profiles and existing maps of potential field (gravity and magnetic) are used to refine the distribution of oceanic crust. Oceanic crust forms a polygon approximately 320-350 km wide (east-west) by ~500 km (north-south). The northern segment of the Canada Basin Gravity Low (CBGL) bisects this zone of oceanic crust, as would be expected from the axis of the spreading center. The multichannel profiles also image a prominent bathymetric valley along this segment of the CBGL, similar to axial valleys found on slow and ultra-slow spreading ridges. Paired magnetic anomalies are associated only with crust that has typical oceanic velocities and are interpreted to represent possibly Mesozoic marine magnetic anomalies M0r - M4 (?), for a duration of opening of 8 million years, and a half spreading rate of ~10 mm/a. The southern segment of the CBGL, where it trends toward the Mackenzie Delta/fan, is associated with transitional velocities that are interpreted to represent serpentinized peridotite (mantle). As a result of being close to the inferred pole of rotation, this southern area may have had a spreading rate too low to support magmatism, producing amagmatic transitional crust. Further north, near Alpha Ridge and along Northwind Ridge, transitional crust is interpreted to be underplated or intruded material related to the emplacement of the High Arctic Large Igneous Province. Seismic reflection profiles across the

  14. The Lusi eruption and implications for understanding fossil piercement structures in sedimentary basins

    Science.gov (United States)

    Svensen, Henrik; Mazzini, Adriano; Planke, Sverre; Hadi, Soffian

    2016-04-01

    The Lusi eruption started in northeast Java, Indonesia, on May 29th 2006, and it has been erupting rocks, mud, water, and gas ever since. We have been doing field work and research on Lusi ever since the eruption commenced. This work was initially motivated from studying the initiation of a mud volcano. However, the longevity of the eruption has made it possible to describe and monitor the lifespan of this unique piercement structure. . One of the first-order questions regarding the eruption is how it should be classified and if there are any other modern or fossil analogues that can place Lusi in a relevant geological context. During the initial stages of eruption, Lusi was classified as a mud volcano, but following geochemical studies the eruption did not show the typical CH4-dominated gas composition of other mud volcanoes and the temperature was also too high. Moreover, mud volcano eruptions normally last a few days, but Lusi never stopped during the past decade. In particular, the crater fluid geochemistry suggests a connection to the neighboring volcanic complex. Lusi represent a sedimentary hosted hydrothermal system. This opens up new possibilities for understanding fossil hydrothermal systems in sedimentary basins, such as hydrothermal vent complexes and breccia-pipes found in sedimentary basins affected by the formation of Large igneous provinces. We will present examples from the Karoo Basin (South Africa) and the Vøring Basin (offshore Norway) and discuss how Lusi can be used to refine existing formation models. Finally, by comparing Lusi to fossil hydrothermal systems we may get insight into the processes operating at depth where the Lusi system interacts with the igneous rocks of the neighbouring volcanic arc.

  15. Applications of Natural Radiation-Induced Paramagnetic Defects in Quartz to Exploration in Sedimentary Basins

    Institute of Scientific and Technical Information of China (English)

    Pan Y M; Botis S; Nokhrin S

    2006-01-01

    Quartz grains in contact with uranium-bearing minerals or fluids are characterized by natural radiation-induced paramagnetic defects (e. G. , oxygen vacancy centers, silicon vacancy centers, and peroxy radicals), which are amenable to study by electron paramagnetic resonance (EPR) spectroscopy.These natural radiation-induced paramagnetic defects, except for the oxygen vacancy centers, in quartz are concentrated in narrow bands penetrated by α particles: (1) in halos around U- and Th-bearing mineral inclusions and (2) in outer rims or along fractures. The second type of occurrence provides information about uranium mineralization or remobilization (I. E. , sources of uranium, timing of mineralization or remobilization, pathways of uranium-bearing fluids). It can also be used to evaluate sedimentary basins for potential of uranium mineralization. In particular, the peroxy radicals are stable up to 800℃and, therefore, are useful for evaluating metasedimentary rocks (e. G. , Paleoproterozoic metasedimentary sequences in the central zone of the North China craton). EPR study of the Changcheng Series can focus on quartz from the sediment-basement unconformity and faults to determine the presence and types of natural radiation-induced paramagnetic defects, with which to identify and prioritize uranium anomalies. Other potential applications of natural radiation-induced paramagnetic defects in quartz include uranium-bearing hydrocarbon deposits in sedimentary basins. For example, the Junggar, Ordos, and Tarim basins in northwestern China all contain important oil and natural gas fields and are well known for elevated uranium concentrations, including economic sandstone-hosted uranium deposits. Therefore,systematic studies on the distribution of natural radiation-induced paramagnetic defects in quartz from host sedimentary sequences are expected to provide information about the migration of oil and natural gas in those basins.

  16. Identification of a late Quaternary alluvial-aeolian sedimentary sequence in the Sichuan Basin, China

    Science.gov (United States)

    Feng, Jin-Liang; Ju, Jian-Ting; Chen, Feng; Hu, Zhao-Guo; Zhao, Xiang; Gao, Shao-Peng

    2016-03-01

    The late Quaternary sedimentary sequence in the northwestern part of the Sichuan Basin consists of five lithological units and with increasing depth include the: Chengdu Clay; Brown Clay; Red Clay; Sandy Silt; and basal Muddy Gravel. The genesis, provenance and age of the sediments, as well as the possible presence of hiatuses within this sequence are debated. Measurements of grain-size, magnetic susceptibility, quartz content, quartz δ18O values, element composition, and Sr-Nd isotopic concentrations of samples from a typical sedimentary sequence in the area provides new insights into the genesis and history of the sequence. The new data confirm that the sediments in study site are alluvial-aeolian in origin, with basal alluvial deposits overlain by aeolian deposits. Like the uppermost Chengdu Clay, the underlying Brown Clay and Red Clay are aeolian in origin. In contrast, the Silty Sand, like the basal Muddy Gravel, is an alluvial deposit and not an aeolian deposit as previously thought. Moreover, the succession of the aeolian deposits very likely contains two significant sedimentary hiatuses. Sedimentological analysis demonstrates that the source materials for the aeolian deposits in the northwestern part of the Sichuan Basin and those on the eastern Tibetan Plateau are different. Furthermore, the loess deposits on the eastern Tibetan Plateau are derived from heterogeneous local sources.

  17. Sedimentary cycles in coal and evaporite basins and the reconstruction of Paleozoic climate (Utrecht Studies in Earth Sciences 21)

    NARCIS (Netherlands)

    van den Belt, F.J.G.

    2012-01-01

    This thesis deals with large-scale processes controlling the formation of sedimentary cycles in coal and evaporite basins and their relation to large-scale fluctuations of Palaeozoic climate. Coal-clastic cycles dominate Pennsylvanian sequences in palaeo-equatorial basins from Euramerica. They forme

  18. Intrusive large igneous provinces below sedimentary basins: An example from the Exmouth Plateau (NW Australia)

    Science.gov (United States)

    Rohrman, Max

    2013-08-01

    igneous provinces (LIPs) are commonly characterized by extrusion of huge outpourings of flood basalts. However, some LIPs associated with thick sedimentary basins display mainly intrusive sill and dike complexes and a relative absence of extrusives as evidenced on the Exmouth Plateau. Here a breakup-related 150 km × 400 km sill complex imaged on seismic reflection data intruded mainly Triassic sedimentary rocks between the Late Jurassic and the Early Cretaceous. The sill complex is most likely sourced by a mafic or an ultramafic magma chamber, seismically imaged as a high-velocity body (HVB) and covering ~16 × 104 km2. This magma chamber is located at the base of the crust and did not generate extrusives. Simple hydrostatic calculations suggest that melt became vertically arrested in the basin sediments, primarily owing to a reduction in the magmatic overpressure gradient as a result of the differences between fracture and melt gradients controlled by upward decreasing densities of the basin fill. Furthermore, magma overpressures at the source between 5 and 20 MPa are required to explain the presence of sill complexes at 4-11 km depth, indicating that the HVB is the source of the sill/dike complex on the Exmouth Plateau. The extent and outline of the HVB places constraints on the origin of magmatism and LIP formation. In combination with published data, the results suggest a thermal anomaly (upwelling or plume) source for the observed magmatism.

  19. Three cycles of sedimentation in ancient sedimentary basins of southern Ireland: insights from detrital zircon U-Pb ages

    Science.gov (United States)

    Fairey, Brenton; Kerrison, Aidan; Meere, Patrick; Mulchrone, Kieran; Linnemann, Ulf; Hofmann, Mandy; Gaertner, Andreas; Sonntag, Benita-Lisette; Byrne, Keith

    2016-04-01

    Previous work has shown that sedimentary rocks from the Lower Devonian Dingle Basin were uplifted and recycled by Acadian orogenic activity into the Upper Devonian Munster Basin. This is particularly applicable for sediments deposited in the western part of the Munster Basin. In the present study, a new dataset of U-Pb ages for detrital zircons has been established that spans a large geographic area which includes the Dingle and Munster basins as well as the offshore Mesozoic North Celtic Sea, South Celtic Sea, 'Goban Spur' and Fastnet basins. The study is the first of its kind in any of these sedimentary basins. The aim is to investigate whether sediments deposited in the offshore basins during the Mesozoic reflect three erosion-deposition cycles. Detritus that has undergone three sedimentary cycles would yield super-mature sediments suitable for hydrocarbon storage. Detrital zircon age spectra for Lower Devonian Dingle Basin samples indicate strong sediment input from Avalonian (~600 Ma) and Laurentian (~1.7 Ga and ~1.1 Ga) sources with some input from Caledonian orogenic sources (400-480 Ma). Detrital zircon age spectra in the western Munster Basin largely reflect input from Caledonian-aged igneous crustal input (400-480 Ma) and Laurentian sources. An Avalonian component is not detected in any of the samples from the western Munster Basin. In the central and eastern parts of the Munster Basin, detrital zircon age spectra indicate that the dominant sources of detritus are derived from Laurentia and from Caledonian igneous rocks. In contrast to the western part of the basin, age components around 600 Ma are present in some samples and represent an Avalonian source. These signals are echoed, at varying degrees, in detrital age spectra from Jurassic and Cretaceous samples of the central North Celtic Sea Basin. These age spectra also indicate a significant contribution of detritus from Avalonian terrane. The Avalonian signature is completely absent from Jurassic

  20. Sedimentary processes in High Arctic lakes (Cape Bounty, Melville Island, Canada): What do sediments really record?

    Science.gov (United States)

    Normandeau, Alexandre; Lamoureux, Scott; Lajeunesse, Patrick; Francus, Pierre

    2016-04-01

    Lacustrine sedimentary sequences can hold a substantial amount of information regarding paleoenvironments, hydroclimate variability and extreme events, providing critical insights into past climate change. The study of lacustrine sediments is often limited to the analysis of sediment cores from which past changes are inferred. However, studies have provided evidence that the accumulation of sediments in lacustrine basins and their distribution can be affected by a wide range of internal and external forcing mechanisms. It is therefore crucial to have a good knowledge of the factors controlling the transport and distribution of sediments in lakes prior to investigating paleoenvironmental archives. To address this knowledge gap, the Cape Bounty Arctic Watershed Observatory (CBAWO), located on southern Melville Island in the Canadian High Arctic, was initiated in 2003 as a long term monitoring site with the aim of understanding the controls over sediment transport within similar paired watersheds and lakes. The East and West lakes have been monitored each year since 2003 to document the role of hydro-climate variability on water column processes and sediment deposition. Moorings recording water electrical conductivity, temperature, density, dissolved oxygen and turbidity, as well as sediment traps were deployed during the active hydrological period (generally May-July). These data were analyzed in combination with hydrological and climatic data from the watersheds. Additionally, a high-resolution bathymetric and sub-bottom survey was completed in 2015 and allowed imaging the lake floor and sub-surface in great detail. This combination of process and lake morphological data are unique in the Arctic. The morphostratigraphic analysis reveals two highly disturbed lake floors, being widely affected by subaqueous mass movements that were triggered during the last 2000 years. Backscatter intensity maps and the presence of bedforms on each delta foresets indicate that

  1. Realistic modelling of observed seismic motion in compIex sedimentary basins

    Directory of Open Access Journals (Sweden)

    G. F. Panza

    1994-06-01

    Full Text Available Three applications of a numerical technique are illustrated to model realistically the seismic ground motion for complex two-dimensional structures. First we consider a sedimentary basin in the Friuli region, and we model strong motion records from an aftershock of the 1976 earthquake. Then we simulate the ground motion caused in Rome by the 1915, Fucino (Italy earthquake, and we compare our modelling with the damage distribution observed in the town. Finally we deal with the interpretation of ground motion recorded in Mexico City, as a consequence of earthquakes in the Mexican subduction zone. The synthetic signals explain the major characteristics (relative amplitudes, spectral amplification, frequency content of the considered seismograms, and the space distribution of the available macroseismic data. For the sedimentary basin in the Friuli area, parametric studies demonstrate the relevant sensitivity of the computed ground motion to small changes in the subsurface topography of the sedimentary basin, and in the velocity and quality factor of the sediments. The relative Arias Intensity, determined from our numerical simulation in Rome, is in very good agreoment with the distribution of damage observed during the Fucino earthquake. For epicentral distances in the range 50 km-100 km, the source location and not only the local soil conditions control the local effects. For Mexico City, the observed ground motion can be explained as resonance effects and as excitation of local surface waves, and the theoretical and the observed maximum spectral amplifications are very similar. In general, our numerical simulations estimate the maximum and average spectral amplification for specific sites, i.e. they are a very powerful tool for accurate micro-zonation

  2. An examination of recharge mound decay and fossil gradients in arid regional sedimentary basins

    International Nuclear Information System (INIS)

    In many of the vast arid sedimentary basins of the world, groundwater gradients exist that appear to be anomalous in the context of the probable modern recharge potential. The possibility that such gradients are in fact remnant fossil conditions representing the decay of ancient recharge mounds is examined. An example of decay condition is represented using a resistor-network analogue model in which the time control is based on 14C ages. The decay hypothesis is found to be plausible with realistic aquifer characteristics but a non-homogeneous flow is indicated from the 14C data. (author)

  3. The petroleum habitat in the post-rift sequences in the Brazilian sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    De Figueiredo, A.M.F.D.; Fernandes, G.J.F.; Guimaraes, P.T.M. (Petrobras, Rio de Janeiro (Brazil))

    1991-03-01

    The post-rift sedimentary strata of the Brazilian coastal basins are made of two main sequences: the evaporite and carbonatic Albian-Aptian sequence, and the open-marine Late Albian to Recent sequence, both related to the opening of the South Atlantic Ocean. More than 40 billion barrels of oil-equivalent in place has been found in these sequences, mostly in siliciclastic reservoirs above and below the Aptian salt beds. The productive basins are Campos, Espirito Santo, Sergipe-Alagoas, Potiguar, Ceara, and Santos, but the first one is responsible for more than 60% of the original oil in place discovered in these basins. The hydrocarbon origin, migration, and accumulation models in these sequences are discussed and exemplified by some giant oil fields of Campos and Sergipe-Alagoas basins, where oil is trapped in Aptian conglomerates, Albian carbonates, and Upper Cretaceous to Tertiary turbidite sandstones. The cumulative production in these sequences reaches 958.6 million barrels and the proved exploitable reserve amounts reach 2.7 billion barrels of oil-equivalent. Petrobras' exploratory forecast indicates that the post-rift sequences are the most prolific ones in the Brazilian marginal basins. The oil-equivalent that is expected to be discovered, particularly in deep water areas, where giant oil fields (as the Marlim field) have been found, exceeds the amount that has been discovered until now.

  4. Sedimentology of cores recovered from the Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Edwards, B. D.; Saint-Ange, F.; Pohlman, J.; Higgins, J.; Mosher, D. C.; Lorenson, T. D.; Hart, P.

    2011-12-01

    Researchers from the United States and Canada are collaborating to understand the tectonic and sedimentary history of the Arctic Ocean between Canada and Alaska. As part of this on-going study, a joint US-Canadian ice breaker expedition operated in parts of the Canada Basin during August 2010. Occasional interruptions of the seismic data acquisition provided the ship time to collect gravity and piston cores at five sites-of-opportunity throughout the basin. High-resolution multibeam bathymetry and chirp sub-bottom profiler data collected immediately prior to coring reveal the fine-scale morphology of each site. Core photographs, X-ray radiographs, and physical property data support the following descriptions. Two piston cores were collected from the Beaufort Sea continental margin in a region of known bottom simulating reflectors (BSRs). Site 1 (2538 m water depth): This core recovered 5.72 m of gas-charged, gray sticky clay and silty-clay from an approximately 1100 m diameter, 130 m high conical mound overlying the crest of a buried anticline. Gas hydrate recovered in the core catcher combined with cracks and voids, methane and other hydrocarbon gasses, pyrite concretions, chemosynthetic clams, carbonate nodules, and soft carbonate masses indicate the likely upward migration of deep-seated fluids. Site 2 (1157 m water depth): This core, positioned 40 km upslope from the gas hydrate core, recovered 3 m of gray sticky silty clay and clayey silt near the base of an erosional scarp. Some voids and fracturing are apparent but carbonate masses and pyrite concretions are absent. Site 3 (3070 m water depth): This core from the top of a seamount discovered in 2009 in the north-central part of the Canada Basin recovered 4.94 m of sediment. More than 3 m of dark brown to yellowish brown, massive interbedded silty clays with sands and matrix-supported gravels (ice rafted debris [IRD]) occur in abrupt contact with underlying reddish yellow to brownish yellow silty clay and

  5. Triassic rift-related sedimentary basins in northern Chile (24° 29°S)

    Science.gov (United States)

    Suarez, M.; Bell, C. M.

    1992-10-01

    Triassic rocks in northern Chile (latitude 24°-29°S) include marine and continental rift-related sedimentary deposits, associated with basaltic, andesitic, and silicic volcanic rocks. Five main successions include the deposits of two marine basins (Profeta and San Félix) separated by three continental basins (Cifuncho, La Ternera, and La Coipa). The marine strata include turbidites and debris flow deposits interpreted as coarse-grained fan-delta sediments. The continental sediments include lacustrine fan delta, open lake, braided river, alluvial fan, and sabkha deposits. The widespread fan-delta systems (both marine and lacustrine), together with abrupt lateral and vertical facies discontinuities and large-scale depositional cycles, are indicative of rift-controlled sedimentation. The associated magmatic activity indicates that this rifting was the product of subduction-related extension or strike-slip movement on the active plate margin. Triassic rifting was followed in Late Triassic to Early Jurassic times by widespread thermotectonic subsidence.

  6. Discussion of gas enrichment mechanism and natural gas origin in marine sedimentary basin, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    There are abundant natural gas resources in Chinese marine sedimentary basin. The exploration hot shots of natural gas are the Palaeozoic marine strata here in recent years, and several large scale gas fields have been discovered. Chinese Palaeozoic high-post matured and coal measure hydrocarbon source rocks are mainly prone to gas generation in the present. This research considered that gas source rocks and TSR are the key cause of gas enrichment of marine strata. High-quality argillaceous and coal measure hydrocarbon rocks are distributed widely in the Palaeozoic marine strata, which have been in highly matured phase in the present. The argillaceous source rock generally contains various sulfates that could accelerate crude oil cracking to gas for TSR occurrence, and coal measure source rock mainly generates gas, so Chinese marine basin gives priority to accumulating gas. Marine strata have not founded oil reservoirs in the Sichuan Basin and Ordos Basin, and they consist mainly of dry gas. Marine natural gases are the mixed gases of oil cracking gas and coal-formed gas in a general way,oil cracking gases contain usually some H2S and CO2. Hydrocarbon carbon isotopes are very complicated, and methane and ethane isotopic values bear apparent reversal caused by thermal evolution and mixing among different genetic types of natural gas. Coal-formed gases are the main component of Chinese marine natural gas. The Upper Permian of the Sichuan Basin and the Carboniferous-Permian of the Ordos Basin coal measure hydrocarbon source rock present large hydrocarbon generation potential, which are the prospecting highlight of marine natural gas hereafter. Oil cracking gas exploration will be paid much attention to in the Tarim Basin because of the lack of coal measure hydrocarbon source rock.

  7. Natural gas origins of large and medium-scale gas fields in China sedimentary basins

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas.

  8. STRATIGRAPHY AND SEDIMENTARY HISTORY OF THE PLIO-PLEISTOCENE SANT'ARCANGELO BASIN, OUTHERN APENNINES, ITALY

    Directory of Open Access Journals (Sweden)

    CARLOS ZAVALA

    2000-11-01

    Full Text Available Defined as a piggyback basin, the Plio-Pleistocene Sant'Arcangelo basin is one of the more recent onshore sedimentary basin of the Southern Apennines. Extensive field studies allow to reinterpret the whole stratigraphy of the basin in a more simple and significant way. Five unconformity-bounded units ("groups" have been recognised : The (1 Catarozzo Group (late Pliocene unconformably overlies pre-Miocene units, and it is composed of a flood-dominated fan-delta marine (C1 and restricted-marine (C2 systems bounded by a sharp contact with a total thickness up to 650 meters. The (2 Aliano Group (late Pliocene - early Pleistocene includes an up to 1,400 meters thick succession of flood-dominated fan-delta systems, with facies ranging from poorly organised alluvial conglomerates in the west to massive marine mudstones in the east. Two sub-units have been recognised, bounded by a regional unconformity, which shows an abrupt passage from marine (A1 to restricted-marine (A2 conditions. The (3 Tursi Group (early-middle Pleistocene reaches a thickness of 500 meters. It is composed of two sub-units, corresponding to alluvial fan (T1 and fan-delta (T2 systems. The alluvial facies of T2 (conglomerates outcrop extensively in the Sant'Arcangelo basin, with equivalent flood-dominated shelfal sandstone lobes broadly developed in the Tursi area (Metaponto basin. The (4 Profico and (5 Montalbano Jonico groups (middle Pleistocene are partially time equivalents, and were developed in both sides of the Valsinni structure, which divided an early, broader Sant'Arcangelo basin into two sub-basins, the present "Sant'Arcangelo" and "Metaponto" basins. The Profico Group has a thickness of up to 300 m and consists of lacustrine strata overlying in angular unconformity the Tursi Allogroup in the "Sant'Arcangelo basin". The Montalbano Jonico Group on the other hand is made up of up to 300 m of fine-grained marine strata unconformably overlying the Tursi Group in the "Metaponto

  9. Tectonic and climatic control on geomorphological and sedimentary evolution of the Mercure basin, southern Apennines, Italy

    Science.gov (United States)

    Robustelli, Gaetano; Ermolli, Elda Russo; Petrosino, Paola; Jicha, Brian; Sardella, Raffaele; Donato, Paola

    2014-06-01

    The morpho-tectonic and sedimentary evolution of the Mercure intramontane basin (Calabria-Lucania boundary, southern Apennines) has been assessed through facies analysis, morphostratigraphy and geomorphological correlation with adjacent areas. The Mercure basin, one of the most active seismogenic zones of the southern Apennines, is a favorable area for reconstructing the main stages of landscape evolution of the axial zone because of its capability to record changes in base level during the Quaternary. In addition, the presence of both erosional and depositional Palaeosurfaces is a useful marker for reconstructing tectonic and morphogenetic events, and hence to detect the role played by tectonics and climate in its genesis, evolution and extinction. The present study identifies the key role of tectonics and denudation, combined with high-frequency floods, as mechanisms controlling alluvial sedimentation in the study area. During endorheic conditions, denudational processes driven by pulses of extensional deformation of the basin margin caused strong alluvial inputs that resulted in the development of alluvial fans. Alluvial facies are mainly characterized by turbulent, subaerial, hyperconcentrated flood flows deposited during the glacial, semi-arid conditions of MIS 14. The retrogradational stacking pattern of the alluvial system indicates decreasing rates of tectonic activity along with declining river gradients. The Mercure coalescing alluvial fans were inundated by lake transgression during MIS 13 in response to (i) abrupt tectonic subsidence at the basin margins and (ii) large decrease of coarse sediment supply due to the interplay among climate, tectonics and catchment size changes. In this regard, it is suggested that tectonic control on the drainage network along with climate and long-term slope evolution may have caused marked pulses in sediment supply, thus influencing the arrangement of facies associations in the sedimentary succession. In addition, the

  10. Shelf-edge sedimentary systems off Rio de Janeiro State, northern Santos basin-Brazil

    Science.gov (United States)

    Maia, R. M. C.; Dos Reis, A. T.; Gorini, C.; Silva, C. G.; Rabineau, M.; Granjeon, D.

    2012-04-01

    elements provide a hint at a prevailing subsidence regime and effective sediment supply into the basin that clearly contrast with the conveyed idea of a sediment-starved and tectonic stable shelf. They naturally raise questions about the nature and origin of sediment supply, since no significant point siliciclastic fluvial source flows directly into the shelf. Stemming from that, we are forced to speculate about: (A) the role of neotectonic movements involving the Serra do Mar coastal mountain ranges to potentially source clastic influx into the basin during the Quaternary, or about the real importance of secondary drainage basins debouching today; and (B) the mechanical nature of a supposed subsidence during the Pliocene and the Quaternary time span (overloading ? sediment compaction ? thermal cooling ?). The interpretation of industrial seismic lines can provide the answers of many of these questions. The next step of this work is to make a stratigraphy model of the sedimentary systems of Santos basin to understand how the ancient creation of accommodation space can influence the recent sedimentary architecture and how is the change in sedimentary influx and the sedimentary records of different orders of cyclicity.

  11. Physical and chemical environments of abnormal vitrinite reflectance evolution in the sedimentary basins

    Institute of Scientific and Technical Information of China (English)

    QIU Nansheng; WANG Weixiao; XIE Mingju

    2007-01-01

    Based on the tested data of pressure and vitrinitere flectance of some wells in sedimentary basins, abnormal high pressure is regarded as not the only factor to retard the increase of vitrinite reflectance (Ro). Apart from the types of the organic matter, the physical environment (temperature and pressure) and chemical environment (fluid compositionand inorganic elements) will result in the abnormal vitrinite reflectance values in the sedimentary basins. This paper tested trace elements and vitrinite reflectance data from the the abnormal high pressure and normal pressure strata pro-files, respectively, and found that the acidic and lower salinity starta are favorable for the increase of Ro. By discussing the corresponding relationship between the contents of some trace elements in the mudstone and the vitrinite reflectance values, the typical trace elements were found to suppress and/or catalyze the vitrinite reflectance of organic matter, while the elements of Ca, Mn, Sr, B, Ba and P may result in the retardation of Ro. However, elements of Fe, Co, Zn, Ni and Rb may catalyze the organic matter maturation. This study is conductive to the organic maturation correction, oil and gas assessment and thermal history reconstruction by the paleothermometry.

  12. Geodynamic evolution and sedimentary infill of the northern Levant Basin: A source to sink-perspective

    Science.gov (United States)

    Hawie, N.

    2013-12-01

    Nicolas Hawie a,b,c (nicolas.hawie@upmc.fr) Didier Granjeon c (didier.granjeon@ifpen.fr) Christian Gorini a,b (christian.gorini@upmc.fr) Remy Deschamps c (remy.deschamps@ifpen.fr) Fadi H. Nader c (fadi-henri.nader@ifpen.fr) Carla Müller Delphine Desmares f (delphine.desmares@upmc.fr) Lucien Montadert e (lucien.montadert@beicip.com) François Baudin a (francois.baudin@upmc.fr) a UMR 7193 Institut des Sciences de la Terre de Paris, Université Pierre et Marie Curie/ Univ. Paris 06, case 117. 4, place Jussieu 75252 Paris Cedex 05, France b iSTEP, UMR 7193, CNRS, F-75005, Paris, France c IFP Energies nouvelles, 1-4 avenue du Bois Préau 92852 Rueil Malmaison Cedex, France d UMR 7207, Centre de Recherche sur la Paleobiodiversité et les Paleoenvironnements. Université Pierre et Marie Curie, Tour 46-56 5ème. 4, place Jussieu 75252 Paris Cedex 05, France e Beicip Franlab, 232 Av. Napoléon Bonaparte, 95502 Rueil-Malmaison, France Sedimentological and biostratigraphic investigations onshore Lebanon coupled with 2D offshore reflection seismic data allowed proposing a new Mesozoic-Present tectono-stratigraphic framework for the northern Levant Margin and Basin. The seismic interpretation supported by in-depth facies analysis permitted to depict the potential depositional environments offshore Lebanon as no well has yet been drilled. The Levant region has been affected by successive geodynamic events that modified the architecture of its margin and basin from a Late Triassic to Middle Jurassic rift into a Late Cretaceous subduction followed by collision and Miocene-Present strike slip motion. The interplay between major geodynamic events as well as sea level fluctuations impacted on the sedimentary infill of the basin. During Jurassic and Cretaceous, the Levant Margin is dominated by the aggradation of a carbonate platform while deepwater mixed-systems prevailed in the basin. During the Oligo-Miocene, three major sedimentary pathways are expected to drive important

  13. Depositional tracts and stratigraphic architecture of the Itajaí Basin sedimentary sucessions (Neoproterozoic, northeastern Santa Catarina, Brazil

    Directory of Open Access Journals (Sweden)

    Michel Silva Costa

    2015-06-01

    Full Text Available Neoproterozoic sedimentary successions of the Itajaí Basin show depositional trends and a stratigraphic framework characteristics of foreland basin system. The sedimentary environments have developed in basin conditions ranging from deep marine context, transitional shallow marine, to continental. Stratigraphic architecture comprises three depositional tracts (DT: DTI - submarine fans system that records the initial basin sedimentation and involves frontal and distal turbiditic deposits; DTII - transitional to shallow marine depositional system that represents the efective infill fase of basin, and includes deltaic succession with braided channels dominated plain; and DTIII - fluvial braided and alluvial fan depositional system that comprises the final stage of basin sedimentation. Arkoses and greywacke of the DTI present paleocurrent unimodals patterns and general trend to south-southeast, suggesting source area from Santa Catarina Granulitic Complex. The sandstones and conglomerates of DTII and DTIII have opposite paleocurrent pattern, indicating source area from both Metamorphic Brusque Complex and Florianópolis Batolith. Integration of paleoenvironmental and stratigraphic data, with previous information (U-Pb in detrital zircon, allowed a consistent interpretation on the sedimentary evolution and detrital sources of the basin and represent a progress on the discussions on the knowledge of the Itajaí Basin and its significance in the evolutionary context of the Dom Feliciano Belt.

  14. Distribution and Origin of Underground Water Chemical Fields in Songliao Continental Oil—Bearing Sedimentary Basin

    Institute of Scientific and Technical Information of China (English)

    楼章华; 张秉坚; 等

    1999-01-01

    There are many factors affecting ungerground water chemistry of an oil-bearing sedimentary basin.The properties of underground water show variations in the vertical direction, giving rise to a vertical zonation with respect to underground water chemistry,Five zones could be divided downwards,including 1)The freshening zone due to meteoric water leaching (A):2)the evaporation-concentration zone near the surface(B);3) the freshening zone due to stratum compaction-released water(C1)-infiltration-concentration zone during the mudstone compaction and water releasing(C2);4) the freshening zone for clay mineral dehydration(D);and 5)the seepage-concentration zone(E).The hydrodynamic fields in the Songliao Basin are obviously asymmetrical,with the characteristics of gravity-induced centripetal flow recharged by meteoric water along the edge to the inner part of the basin mainly in its northern and eastern regions,centrifugal flow and crossformational flow in the center of the basin,as well as the cross-formation flow-evaporation discharge area in its southern area.Hydrodynamics controls the planar distribution of underground-water chemical fields;1)the freshening area due to penetrating meteoric water generally at the basin edges;2)the freshening area for mudstone compaction-released water at the center of the basin;3) the cross-formational area as the transitional aqrea;and 4)the concentration area by cross-formational flow and evaporation.The mineralization degree and the concentrations of Na+ and Cl- and their salinity coefficeents tend to increase,while the concentrations of(CO32-+HCO3-) and SO42- and the metamorphism and desulfuration coefficients tend to decrease along the centrifugal flow direction caused by mudstone compaction in the depression area.But all of them tend to increase along the gravity-induced centripetal flow direction.

  15. Evidence for an important tectonostratigraphic seismic marker across Canada Basin and southern Alpha Ridge of the Arctic Ocean

    Science.gov (United States)

    Shimeld, J.; Chian, D.; Jackson, R.; Hutchinson, D. R.; Mosher, D. C.; Wade, J.; Chapman, B.

    2010-12-01

    Using a modern ice-strengthened seismic acquisition system, more than 12,000 km of high quality 16-channel, vertical incidence seismic reflection and wide-angle sonobuoy data, along with single- and multibeam bathymetric soundings and gravimetric profiles have been acquired across Canada Basin and the southern flank of Alpha Ridge. These datasets are being used to determine the crustal types, rifting processes, subsidence history, and sedimentary sequences of this poorly known region. More than a dozen regional seismostratigraphic units are identified, exceeding ~6.5 km in total sediment thickness in the south, thinning northward toward Alpha Ridge. The oldest regionally mappable unit is informally named “bisque” and is characterized by high-amplitude, continuous, parallel and subparallel internal reflections. The bisque unit averages ~600 m thick, with significant local variability. Along southern Alpha Ridge, the base of the bisque unit is marked by a prominent angular unconformity which can be traced southwards into Canada Basin before becoming obscured by thick overlying units. Though affected by faulting and compaction drape, the bisque unit appears to be concordant with the topography of the underlying acoustic basement. It is also spatially and temporally associated with large structures that are interpreted to be volcanic edifices. Most of the 129 available sonobuoy records show clear wide-angle refractions/reflections from sedimentary and upper and lower crustal layers, which can be ray-traced and velocity modeled using constraints from coincident reflection profiles. Slight ray angle dependent anisotropy is found to best describe these observed data, and is used for conversion between two-way travel time and vertical depth domains. Two distinct features are identified for the bisque layer: 1) a wide-angle reflection observed on nearly all sonobuoy data; and 2) S waves (named PsP), doubly converted at the bisque layer. P-wave refractors from bisque

  16. Radiogenic heat production in sedimentary rocks of the Gulf of Mexico Basin, south Texas

    Science.gov (United States)

    McKenna, T.E.; Sharp, J.M.

    1998-01-01

    Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we calculate radiogenic heat production for Stuart City (Lower Cretaceous) limestones, Wilcox (Eocene) sandstones and mudrocks, and Frio (Oligocene) sandstones and mudrocks from south Texas. Heat production rates range from a low of 0.07 ?? 0.01 ??W/m3 in clean Stuart City limestones to 2.21 ?? 0.24??W/m3 in Frio mudrocks. Mean heat production rates for Wilcox sandstones, Frio sandstones, Wilcox mudrocks, and Frio mudrocks are 0.88, 1.19, 1.50, and 1.72 ??W/m3, respectively. In general, the mudrocks produce about 30-40% more heat than stratigraphically equivalent sandstones. Frio rocks produce about 15% more heat than Wilcox rocks per unit volume of clastic rock (sandstone/mudrock). A one-dimensional heat-conduction model indicates that this radiogenic heat source has a significant effect on subsurface temperatures. If a thermal model were calibrated to observed temperatures by optimizing basal heat-flow density and ignoring sediment heat production, the extrapolated present-day temperature of a deeply buried source rock would be overestimated.Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we

  17. Sedimentary and diagenetic markers of the restriction in a marine basin: the Lorca Basin (SE Spain) during the Messinian

    Science.gov (United States)

    Rouchy, J. M.; Taberner, C.; Blanc-Valleron, M.-M.; Sprovieri, R.; Russell, M.; Pierre, C.; Di Stefano, E.; Pueyo, J. J.; Caruso, A.; Dinarès-Turell, J.; Gomis-Coll, E.; Wolff, G. A.; Cespuglio, G.; Ditchfield, P.; Pestrea, S.; Combourieu-Nebout, N.; Santisteban, C.; Grimalt, J. O.

    1998-10-01

    The Lorca Basin (southeastern Spain) is part of a chain of small marginal Neogene basins located in the structurally active Betic area. The Upper Miocene (Messinian) sequence is composed of a thick diatomite-bearing series (Tripoli Unit) overlain by the Main Evaporites, analogous to the classical succession that records the main events during the Salinity Crisis in the Mediterranean region. The shallow restricted conditions of this region amplified the sedimentary responses to local and global forcings. An integrated approach using sedimentology, micropalaeontology, stable isotope geochemistry and organic geochemistry has been applied to the Tortonian/Messinian succession of the Lorca Basin, in order to obtain a continuous record of the environmental changes. The sediments record two major events which affected the whole Mediterranean: (1) high levels of productivity that led to the formation of the diatomite-bearing deposits in the early Messinian (Tripoli); and (2) the Messinian Salinity Crisis with its two major stages, represented by the Halite and Gypsum Units, both mainly precipitated from marine-derived brines. The rapid reflooding of the Mediterranean by normal marine waters at the base of the Pliocene did not reach the Lorca Basin, nor other basins of this part of the Betic area. Instead, continental sediments were deposited as a consequence of the regional uplift of SE Iberia, which started close to the Messinian/Pliocene boundary. The most prominent feature of this basin concerns the record of its restriction by the time of the deposition of the Tripoli Unit, which led to intercalations of precursor evaporitic layers, consisting of Ca-sulphate deposited in sub-aqueous and sabkha conditions, interbedded with diatomites. This alternation of evaporites and diatomites proves that the Lorca Basin was periodically restricted and reflooded by marine waters, a possible cause for this being relative sea-level fluctuations in the Mediterranean. This strengthens

  18. Sonobuoy-based velocity functions for sediment thickness calculation in the deep Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Lebedeva-Ivanova, N. N.; Hart, P. E.; Chian, D.; Shimeld, J.; Lizarralde, D.; Hutchinson, D. R.; Mosher, D. C.

    2012-12-01

    The deep Canada Basin, which occupies much of the western (Amerasian) Arctic Ocean, is one of the most unexplored and difficult areas on Earth for marine seismic acquisition due to permanent sea ice cover. It extends northward from the Alaskan and Canadian margins for ~500 km and is characterized by a remarkably flat sea floor at 3.6-3.8 km below sea level (bsl) and covers ~500,000 km^2. A set of 143 sonobuoy records were collected during 2007-2010 over the Canada Basin by US-Canada collaborative expeditions. The sonobuoys were deployed along short streamer multi-channel seismic (MCS) lines for estimating seismic velocities in the sediments. A spatial coverage of sonobuoys at every ~80 km on MCS lines provides data for robust average empirical time-depth conversion functions.Sediments are nearly sub-horizontal and sub-parallel, mostly undisturbed with maximum two-way travel time (TWTT)thicknesses of ~5 s, but not greater than ~2.5-3.0 s TWTT closer to the Alpha Ridge and the Chukchi Borderland. Semblance velocity analysis has been applied to the sonobuoy records to determine sediment thickness and depth using the Dix equation. Assuming flat-lying sediments, the normal-moveout (NMO) velocity is approximately equal to the root-mean-square (RMS) average velocity from the sea surface to the reflection horizon. A dip of 5 degrees effects velocity less than 0.5%. Semblance velocity analyses were completed for 128 of 143 sonobuoy records in the deep Canada Basin; 25 records were excluded from later analysis due to bad quality or location on the slope. Results were also converted to interval velocities and depths.The RMS velocities were consistently picked from clear high-coherency events to yield only increasing interval velocities.Picking stopped at or above the bright reflection interpreted as basement on the MCS. Velocities were not picked on dipping reflections surfaces, along the margins where the seafloor was dipping, nor for sedimentary horizons characterized by

  19. Sedimentary Characteristics and Evolution of Asri Basin, Indonesia, in Early Tertiary

    Institute of Scientific and Technical Information of China (English)

    Zhong Dakang; Zhu Xiaomin; Zhang Qin

    2006-01-01

    The Asri basin is a typical half-graben basin. The east side of the basin is a steep slope controlled by syn-rifting and the west side is a widespread gentle slope. In the early Tertiary, it was filled with terrigenous clastic sediments composed of the Banuwati and Talang Akar formations from bottom to top. The latter is further divided into the Zelda member (lower part) and the Gita member (upper part). The previous studies suggested that the early tertiary sediments are alluvial, fluvial and swamp deposits. In this paper, based on the core lithology, well logs and seismic data, the sediments should be alluvial, fluvial and lacustrine systems. The lacustrine system includes subaqeous fan, fan delta and delta, shore-shallow lake, deep lake and turbidite fan deposition. Alluvial fan, subaqeous fan and fan delta sediments were deposited in the early stage and located on the steep slope adjacent. The deltaic sedimentary system was usually distributed on the gentle slope of the basin. In the early Tertiary, the basin evolution could be divided into four stages: initial subsidence (matching Banuwati formation), rapid subsidence (matching low Zelda member), steady subsidence or fluctuation (matching middle Zelda) and uplifting (matching upper Zelda). At the first stage, the alluvial fan, flood plain, braided stream sediments were deposited first with thick brown conglomerate and pebble sandstones, and then subaqeous fan sediments were interbedded with the thick lacustrine mudstones. At the second stage, shore-shallow lake and deep lake and turbidite fan sediments were deposited, with thin fine sandstones and siltstones interbedded with thick mudstones. At the third stage, thick fan delta and delta sandstones were deposited. At last came fluvial meandering, anastomosed and swamp sediments. Sediment supply was mainly from the west and the east, partly from the north.

  20. Palynostratigraphy and sedimentary facies of Middle Miocene fluvial deposits of the Amazonas Basin, Brazil

    Science.gov (United States)

    Dino, Rodolfo; Soares, Emílio Alberto Amaral; Antonioli, Luzia; Riccomini, Claudio; Nogueira, Afonso César Rodrigues

    2012-03-01

    Palynostratigraphic and sedimentary facies analyses were made on sedimentary deposits from the left bank of the Solimões River, southwest of Manaus, State of Amazonas, Brazil. These provided the age-dating and subdivision of a post-Cretaceous stratigraphic succession in the Amazonas Basin. The Novo Remanso Formation is subdivided into upper and lower units, and delineated by discontinuous surfaces at its top and bottom. The formation consists primarily of sandstones and minor mudstones and conglomerates, reflecting fluvial channel, point bar and floodplain facies of a fluvial meandering paleosystem. Fairly well-preserved palynoflora was recovered from four palynologically productive samples collected in a local irregular concentration of gray clay deposits, rich in organic material and fossilized wood, at the top of the Novo Remanso Formation upper unit. The palynoflora is dominated by terrestrial spores and pollen grains, and is characterized by abundant angiosperm pollen grains ( Tricolpites, Grimsdalea, Perisyncolporites, Tricolporites and Malvacearumpollis). Trilete spores are almost as abundant as the angiosperm pollen, and are represented mainly by the genera Deltoidospora, Verrutriletes, and Hamulatisporis. Gymnosperm pollen is scarce. The presence of the index species Grimsdalea magnaclavata Germeraad et al. (1968) indicates that these deposits belong to the Middle Miocene homonymous palynozone (Lorente, 1986; Hoorn, 1993; Jaramillo et al., 2011). Sedimentological characteristics (poorly sorted, angular to sub-angular, fine to very-coarse quartz sands facies) are typical of the Novo Remanso Formation upper part. These are associated with a paleoflow to the NE-E and SE-E, and with an entirely lowland-derived palinofloristic content with no Andean ferns and gymnosperms representatives. All together, this suggests a cratonic origin for this Middle Miocene fluvial paleosystem, which was probably born in the Purus Arch eastern flank and areas surrounding the

  1. Facies pattern of the middle Permian Barren Measures Formation, Jharia basin, India: The sedimentary response to basin tectonics

    Indian Academy of Sciences (India)

    Prabir Dasgupta

    2005-06-01

    In the Lower Gondwana succession of the Jharia basin of eastern India, the Barren Measures Formation is characterized by the cyclic disposition of fine-grained lacustrine deposits and relatively coarse-grained fluvial deposits. The cyclic variation in the rate of coarse clastic input is attributed to the sedimentary response to basin tectonics. The sandstone–shale alternations of the Barren Measures succession can be correlated with the tectonic cyclothems developed on the hangingwall dip-slope and adjoining trough in a continental half-graben setting. Enhancement of the gradient of the hangingwall dip-slope during reactivation of the basin margin faults led to progradation of the existing fluvial system towards the half-graben trough and deposition of the coarser clastics on the fine-grained lacustrine deposits of the trough. Peneplanation of the hangingwall slope and slow increase in the lake level caused lacustrine transgression and retrogration of the fluvial system on the hangingwall block. The fluvial sediments were onlapped by the fine-grained lacustrine deposits. Episodic rejuvenation of the basin margin faults thus caused development of tectonic cyclothem on the hangingwall block. The paleocurrent pattern indicates that a persistent northward paleoslope was maintained during Barren Measures sedimentation. The inferred depositional settings were much more extensive than the present limit of the outcrop. The faults, presently defining the northern limit of the Barren Measures Formation, were possibly emplaced after Barren Measures sedimentation. The final movement along these fault planes caused preservation of the downthrown hangingwall block and the Barren Measures sediments on the footwall block were eroded during subsequent denudation. The Southern Boundary Fault came into existence after the deposition of the Barren Measures sediments.

  2. Understanding the subsurface thermal structure of deep sedimentary basins in Denmark - measurements and modelling results

    DEFF Research Database (Denmark)

    Balling, N.; Poulsen, Søren Erbs; Bording, Thue Sylvester;

    2015-01-01

    Most of the Danish area is characterized by deep sedimentary basins with a great potential for exploitation of geothermal energy. Geothermal reservoirs are present at various depths and temperatures. Currently, three geothermal plants are operating producing warm water for district heating purposes...... of different conductivity. Mean geothermal gradients from surface to depths of 1000 to 3000 m are generally between 20 and 35 °C/km. The subsurface thermal structure is clearly dominated by conduction. Advection by groundwater migration is generally insignificant. Heat flow increases significantly with depth...... due to perturbation from long-term palaeoclimatic surface temperature variations. Examples of modelled temperature distribution for selected geothermal reservoir are shown. In the Gassum Formation, which is present in most of the Danish area, temperatures are largely between 35 and 90 °C for depths...

  3. Norway and adjacent sedimentary basins during Cenozoic times - sediment fluxes, accumulation rates and mass balance

    DEFF Research Database (Denmark)

    Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

    2011-01-01

    stable Eocene epoch. Furthermore, histograms of depositional rates in the study area show a common feature with global patterns, that is a few-fold increase in sediment production during last 3-4 million years. This correlates well with the climate cooling, increased frequency of climate change and...... use offshore data from adjacent sedimentary basins (the North Sea and the Norwegian shelf) to calculate the amount of erosion. We have used a broad dataset of seismic 2D lines to map depositional units and a well dataset for the stratigraphic control and the velocity distribution in the sediments. We...... have therefore obtained accumulation rates in meters per million years for 5 depositional units in three areas - Southern North Sea, Central and Northern North Sea and the Norwegian shelf. Furthermore, taking into account the decay of porosity in sediments with burial depth, we have estimated the...

  4. A sedimentary paleomagnetic record of the upper Jaramillo transition from the Lantian Basin in China

    Science.gov (United States)

    Wu, Yi; Ouyang, Tingping; Qiu, Shifan; Rao, Zhiguo; Zhu, Zhaoyu

    2015-10-01

    The termination of the Jaramillo (normal to reverse) subchron is a key chronostratigraphic marker for dating global Pleistocene sedimentary sequences. However, the stratigraphic position of the geomagnetic polarity reversal varies greatly across the Chinese Loess Plateau (CLP), from near the bottom of paleosol unit S9 to the middle-upper part of S10. Here, we present paleomagnetic and rock magnetic results from high-resolution sampling of the Yushan loess section of the Lantian Basin located within the southern CLP. Our combined analyses determine that the polarity reversal is located in the middle-lower part of the paleosol unit S10. This stratigraphic position is lower than most of other studies conducted throughout the CLP. We attribute the difference in the location of the reversal to a deeper lock-in depth of remanence acquisition, which may have occurred from postdepositional processes under favorable hydrothermal conditions along the southern margin of CLP. It is important to note that age determinations through magnetic stratigraphy on sedimentary sections, particularly in discontinuous and/or imperfect sequences, should be treated with caution; there are significant differences with respect to the location of the polarity reversal throughout the CLP.

  5. A non-tectonic origin for the present day stress field in the sedimentary Paris Basin

    Science.gov (United States)

    Cornet, Francois; Magnenet, Vincent

    2016-04-01

    The large scale stress patterns observed in intraplate area is generally considered to result from far-field boundary forces that drive plate tectonics. However, no present day deformation has been detected in the Paris Basin, yet significant deviatoric stresses are measured in limestone formations observed above soft argillite layers encountered in this region at depths close to 500m. Further, the pore pressure measured in the argillite is larger than that measured in the surrounding permeable zones. These observations suggest a presently active source of stress in this sedimentary system. We propose that this stress is not related to tectonics but to pressure solution effects activated by pore pressure transients. These transients develop in the natural fracture system that affects the limestone formations. They are linked to climatic variations and involve periods that range from thousands to hundreds of thousands years. This mechanism generates time-dependent shear stresses in soft formations and explains overpressures observed in the very low permeability argillite. This mechanism may be modeled by different visco-elastic behaviors for the various formations. It outlines the influence of time dependent material properties on the present day stress field. These results imply that the viscoelastic properties of sedimentary formations raise a strong difficulty for extrapolating measured surface deformations to basement rocks in domains of very slow tectonics.

  6. Compound-specific radiocarbon dating of the varved Holocene sedimentary record of Saanich Inlet, Canada

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Smittenberg, R.H.; Hopmans, E.C.; Schouten, S.; Hayes, J.M.; Eglinton, T.I.

    2004-01-01

    The radiocarbon contents of various biomarkers extracted from the varve-counted sediments of Saanich Inlet, Canada, were determined to assess their applicability for dating purposes. Calibrated ages obtained from the marine planktonic archaeal biomarker crenarchaeol compared favorably with varve-cou

  7. Lithospheric flexure and sedimentary basin evolution: depositional cycles in the steer's head model

    Science.gov (United States)

    Moore, James; Watts, Tony

    2016-04-01

    Backstripping studies of biostratigraphic data from deep wells show that sediment loading is one of the main factors controlling the subsidence and uplift history of sedimentary basins. Previous studies based on single layer models of elastic and viscoelastic plates overlying an inviscid fluid have shown that sediment loading, together with a tectonic subsidence that decreases exponentially with time, can explain the large-scale 'architecture' of rift-type basins and, in some cases, details of their internal stratigraphy such as onlap and offlap patterns. One problem with these so-called 'steer's head' models is that they were based on a simple rheological model in which the long-term strength of the lithosphere increased with thermal age. Recent oceanic flexure studies, however, reveal that the long-term strength of the lithosphere depends not only on thermal age, but also load age. We have used the thermal structure based on plate cooling models, together with recent experimentally-derived flow laws, to compute the viscosity structure of the lithosphere and a new analytical model to compute the flexure of a multilayer viscoelastic plate by a trapezoid-shaped sediment load at different times since basin initiation. The combination of basin subsidence and viscoelastic flexural response results in the fluctuation of the depositional surface with time. If we define the nondimensional number Dw= τm/τt, where τm is the Maxwell time constant and τt is the thermal time constant, we find that for Dw>1 the flexure approximates that of a viscoelastic plate and is dominated by "offlapping" stratigraphy, with the basin edges evolving through shallow marine facies; though erosion late in the basin formation prevents much of this from being recorded in the stratigraphy. Interestingly Dw~1 produces a basin in which onlap dominates its early evolution while offlap dominates its later evolution with an unconformity separating the two different stratal patterns. This case lends

  8. South China connected to north India in Gondwana: sedimentary basin and detrital provenance analyses

    Science.gov (United States)

    Yao, W.; Li, Z. X.; Li, W. X.; Li, X. H.; Yang, J. H.

    2015-12-01

    The paleoposition of South China during the Ediacaran-Silurian is important for understanding the assembly of Gondwana. We report here the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua foreland basin in South China, and discuss South China's connection with Gondwana and potential tectonic triggers for both the Wuyi-Yunkai orogeny in South China and the Bhimphedian orogeny in north India. The Nanhua basin was involved in a three-stage evolution, which are: Stage 1 (the Ediacaran-Cambrian) recording the start of tectonic subsidence with turbiditic marine clastic deposition, fed by exotic orogens outboard South China; Stage 2 (the Ordovician to earliest-Silurian) featured by migrating depocentres with dominant shallow marine to deltaic clastic deposition, fed by the local Wuyi-Yunkai orogen; and Stage 3 (the Silurian) showing the arrival of depocentre in the Yangtze Block during the waning stage of the Wuyi-Yunkai orogeny with deltaic deposition in the remanent foreland basin. Detrital zircon analyses of the Ediacaran-Silurian sandstones across the Nanhua basin reveal a prominent age population of 1100-900 Ma (with a peak age at ~980 Ma) and moderate populations of Archean-Paleozoic ages, grossly matching that of crystalline and sedimentary rocks in northern India. Zircon isotopes of the Stage 1 samples suggest three Precambrian episodes of juvenile crustal growth at 3.0 Ga, 2.5 Ga and 1.0 Ga, and a major crustal reworking at 580-500 Ma for the source areas, which are constraint to be northwestern India and its surrounding orogens. Together with other evidence, we propose that South China likely collided with northwestern India during the Gondwana assembly, generated the Bhimphedian orogeny in north India and formed two foreland basins on both the north India and South China sides. Far-field stress of the collision triggered the Ordovician-Silurian Wuyi-Yunkai orogeny in South China. The Stage 2-3 samples in the Nanhua basin of South China were shed

  9. Basin-floor fans in the North Sea: Sequence stratigraphic models vs. sedimentary facies

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, G.; Bloch, R.B. [Mobil Research and Development Corp., Dallas, TX (United States); Mitchell, S.M. [Mobil Exploration and Producing US, Inc., Dallas, TX (United States); Beamish, G.W.J.; Shields, K.E. [Mobil North Sea Ltd., London (United Kingdom); Hodgkinson, R.J.; Straume, T.; Syvertsen, S.E. [Mobil Exploration Norway, Inc., Stavanger (Norway); Damuth, J.E. [Univ. of Texas, Arlington, TX (United States)

    1995-04-01

    Examination of nearly 12,000 feet (3658m) of conventional core from Paleogene and Cretaceous deep-water sandstone reservoirs cored in 50 wells in 10 different areas or fields in the North Sea and adjacent regions reveals that these reservoirs are predominantly composed of mass-transport deposits, mainly sandy slumps and sandy debris flows. Sedimentary features indicating slump and debris-flow origin include sand units with sharp upper contacts; slump folds; discordant, steeply dipping layers (up to 60{degrees}); glide planes; shear zones; brecciated clasts; clastic injections; floating mudstone clasts; planar clast fabric; inverse grading of clasts; and moderate-to-high matrix content (5-30%). This model predicts that basin-floor fans are predominantly composed of sand-rich turbidites with laterally extensive, sheetlike geometries. However, calibration of sedimentary facies in our long (400-700 feet) cores with seismic and wire-line-log signatures through several of these basin-floor fans (including the Gryphon-Forth, Frigg, and Faeroe areas) shows that these features are actually composed almost exclusively of mass-transport deposits consisting mainly of slumps and debris flows. Distinguishing deposits of mass-transport processes, such as debris flows, from those of turbidity currents has important implications for predicting reservoir geometry. Debris flows, which have plastic flow rheology, can form discontinuous, disconnected sand bodies that are harder to delineate and less economical to develop than deposits of fluidal turbidity currents, which potentially produce more laterally continuous, interconnected sand bodies. Process sedimentological interpretation of conventional core is commonly critical for determining the true origin and distribution of reservoir sands.

  10. Magnetostratigraphy of the middle-upper Jurassic sedimentary sequences at Yanshiping, Qiangtang Basin, China

    Science.gov (United States)

    Song, Chunhui; Zeng, Yongyao; Yan, Maodu; Wu, Song; Fang, Xiaomin; Bao, Jing; Zan, Jinbo; Liu, Xifang

    2016-09-01

    A series of important geological events occurred in the Tibetan Plateau area during the Jurassic, such as the collision of the Lhasa and Qiangtang Terranes, the closure of the Meso-Tethyan Ocean, the opening of the Neo-Tethyan Ocean and the cessation of the mega-monsoon. The ˜3000 m thick Jurassic sedimentary sequence in the Qiangtang Basin on the central Tibetan Plateau, which is called the Yanshiping (YSP) Group, recorded these geological events. However, the chronology of the sequence is surprisingly poorly constrained. Here, we perform a detailed palaeomagnetic analysis on the ˜1060 m thick middle and upper portions of the YSP Group (the Xiali and Suowa Formations) in the YSP section of the eastern Qiangtang Basin. Three bivalve zones at stratigraphic intervals of ˜40-140, 640-800 and 940-1040 m are identified, which yield a Bathonian-Callovian age for the Lower Xiali Fm., a Callovian-Oxfordian age for the Lower Suowa Fm. and an Oxfordian-Kimmeridgian age for the Upper Suowa Fm. A total of 544 oriented palaeomagnetic samples were collected from the section. By combining thermal and alternating field demagnetizations, clear characteristic remanent magnetization (ChRM) directions are isolated for most of the samples. The robust ChRM directions pass fold and reversals tests, which support the primary nature of the ChRMs and yield a palaeopole at 76.8°N/297.2°E (dp = 2.2°, dm = 3.7°). A total of 27 normal and 26 reversed polarity zones were successfully recorded in the section. Combined with fossil age constraints, results suggest that the section is plausibly composed of a Callovian-Early Kimmeridgian age sedimentary sequence.

  11. Sedimentology and Sedimentary Dynamics of the Desmoinesian Cherokee Group, Deep Anadarko Basin, Texas Panhandle

    Science.gov (United States)

    Hu, N.; Loucks, R.; Frebourg, G.

    2015-12-01

    Understanding the spatial variability of deep-water facies is critical to deep-water research because of its revealing information about the relationship between desity flow processes and their resultant sedimentary sequences. The Cherokee Group in the Anadarko Basin, northeastern Texas Panhandle, provides an opportunity to investigate an icehouse-greenhouse Pennsylvanian hybrid system that well demonstrates the intricacies of vertical and lateral facies relationships in an unconfined fan-delta fed deep-water slope to basinal setting. The stratigraphic section ranges in thickness from 150 to 460 m. The cyclic sedimentation and foreland basin tectonics resulted in a complex stratal architecture that was sourced by multiple areas of sediment input. This investigation consists of wireline-log and core data. Five-thousand wireline logs were correlated in an area of over 9500 sq km to map out six depositional sequences that are separated by major flooding events. These events are correlative over the whole area of study. Six cores, that sample nearly the complete section, were described for lithofacies. Lithofacies are recognized based on depositional features and mineralogy:(1) Subarkose, (2) Lithicarkoses, (3) Sandy siliciclastic conglomerate, (4) Muddy calcareous conglomerate, (5) Crinoidal packstone, (6) Oodic grainstone, (7)Pelodic grainstone, (8) Ripple laminated mudrock, (9) faint laminated mudrock. The integration of isopachs of depositional sequences with the lithofacies has allowed the delineation of the spatial and temporal evolution of the slope to basin-floor system. Thin-to-thick bedded turbidites, hyperconcentrated density flow deposits (slurry beds), and debris and mud flow deposits were observed and can be used to better predicte lithofacies distributions in areas that have less data control. These mixed siliciclastic and carbonate deposits can be carrier beds for the hydrocarbons generated from the enclosing organic-rich (TOC ranges from 0.55 to 6.77wt

  12. A comparison of burial, maturity and temperature histories of selected wells from sedimentary basins in The Netherlands

    NARCIS (Netherlands)

    Nelskamp, S.; David, P.; Littke, R.

    2008-01-01

    Sedimentary basins in The Netherlands contain significant amounts of hydrocarbon resources, which developed in response to temperature and pressure history during Mesozoic and Cenozoic times. Quantification and modelling of burial, maturity and temperature histories are the major goals of this study

  13. Sedimentary basins and continental margin processes - from modern hyper-extended margins to deformed ancient analogues : An introduction

    NARCIS (Netherlands)

    Gibson, George M.; Roure, Francois; Manatschal, Gianreto

    2015-01-01

    Continental margins and their fossilized analogues are important repositories of natural resources. With better processing techniques and increased availability of high-resolution seismic and potential field data, imaging of present-day continental margins and their embedded sedimentary basins, in w

  14. Geothermal Regime, Thermal History and Hydrocarbon Generation Types of Sedimentary Basins in the Continental Area of China

    Institute of Scientific and Technical Information of China (English)

    QiuNansheng; JamesPuckette; JinZhijun; WangJiyang

    2005-01-01

    The thermal regimes in sedimentary basins in the continental area of China are varied and reflect differences in geological settings. As a result of these variable thermal regimes, the history of hydrocarbon generation in each basin is also different. An east-west profile of the thermal threshold across the continental basins of China, like the Liaohe Basin, the North China Basin, the Ordos Basin, the Qaidam Basin and the Tarim Basin, was constructed using large numbers of heat flow measurements, temperature data and rock thermophysical parameters. Isotherms, surface heat flow, mantle heat flow and Moho temperature beneath the basins are shown in the profile, which illustrates changes in some thermal characteristics between basins in east China and those in west China. Thermal evolution histories in basins were reconstructed using Easy%Ro method, apatite fission track annealing and other paleothermometers. Typical hydrocarbon generation histories of the primary source rocks were modeled by referring to the thermal evolution data. Thermal stages controlled source rocks maturation and oil and gas generation, and influenced the type of hydrocarbon (oil and gas) production in the basins.

  15. Evolution of deepwater sedimentary environments and its implication for hydrocarbon exploration in Qiongdongnan Basin, northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; JIANG Tao; ZHANG Daojun; WANG Yahui; ZUO Qianmei; HE Weijun

    2015-01-01

    Over the past several years, a number of hydrocarbon reservoirs have been discovered in the deepwater area of Qiongdongnan Basin, northwestern South China Sea. These oil/gas fields demonstrate that the evolution of the deepwater sedimentary environment are controlling the formation and distribution of large-scale clastic reservoirs. Integration between seismic and borehole data were necessary to best clarify the distribution and quality of these deepwater reservoirs. Geochemical and paleobiological evidence from discrete samples was also applied to document specific information regarding the sedimentary environment. Results show that the Qiongdongnan Basin has existed as a thriving marine environment since Oligocene, when several rifting depressions developed throughout the entire Qiongdongnan Basin. Triggered by the faults activities, several distinct provenances supplied the coarse sediments, transporting and depositing them in deep parts of the rifting depressions. A fan delta system then formed nearby the source in the deeper area of these rifting depressions. The sedimentary environment of Qiongdongnan gradiationally became deepwater since early Miocene. Consequently, abundances of sediments were transported from Hainan Island and Southern Uplift, and then sunk into the basin center. The submarine fans revealed by many boreholes in this area verified them as good reservoir. Because the area reached its lowest sea level at late Miocene and the Southern Uplift subsidenced under sea level, not providing any sediment, so that the carbonate mesa and biorhythms characteristic of this area also developed during this period. In the west part of Qiongdongnan Basin, sediments transported from Vietnam increased in response to the Tibetan Uplift. Consequently, a central canyon developed along the center of Qiongdongnan Basin, which has been confirmed by several boreholes as a favorable hydrocarbon reservoir. The clarification of the deepwater sedimentary environment

  16. Basin Dynamics and Sedimentary Infilling of Miocene Sandstone Reservoir Systems In Eastern Tunisian African Margin

    Science.gov (United States)

    Bédir, Mourad; Khomsi, Sami

    2015-04-01

    Most of hydrocarbon accumulations and aquifers within the Cap Bon, Gulf of Hammamet and Sahel basins in eastern tunisian foreland are reservoired within the Upper Miocene Birsa and Saouaf sandstones and shales Formations. In the gulf of Hammamet, these sandstones constitutes oil and gas fields and are exploited on anticline highs and described as varying from shoreface to shallow marine and typically exhibit excellent reservoir quality of 30% to 35% porosity and good permeability from 500 to 1100 md. In addition, the fracturing of faults enhanced the reservoir quality potential. In contrary, the same hydrocarbon reservoirs are important hydrogeologic ones in the Cap Bon and Sahel basins with huge amount of hundred millions of cubic meters of water only partially exploited. Integrated wire line logging correlations, seismic sequence stratigraphic, tectonics and outcrop geologic analogue studies had permitted to highlight the basin structuring and sedimentary environments of sequence deposits infilling of the reservoir distribution between high platforms to subsiding graben and syncline basins bounded by deep-seated transtensive and transpressive flower faults. Seven third order sequence deposits limited by downlap prograding and onlap/toplap aggrading/retrograding system tracts extend along the eastern margin around the three basins by facies and thickness variances. System tracts exhibit around high horst and graben a channelized and levee infillings extending from 100 meters to more than a kilometer of width. They present a stacked single story and multistory channels types showing space lateral and vertical migrations along NE-SW, E-W and N-S directions. Paleogeographic depositional reservoir fair maps distribution highlight deltaic horst domain with floodplain and incised valley of fluvial amalgamed and braided sandstones distributary channels that occupy the high folded horsts. Whereas folded horst-graben and syncline borders domain of Shelf prodelta are

  17. Measurements of frequency dependent shear wave attenuation in sedimentary basins using induced earthquakes

    Science.gov (United States)

    Richter, Tom; Wegler, Ulrich

    2015-04-01

    Modeling of peak ground velocity caused by induced earthquakes requires detailed knowledge about seismic attenuation properties of the subsurface. Especially shear wave attenuation is important, because shear waves usually show the largest amplitude in high frequency seismograms. We report intrinsic and scattering attenuation coefficients of shear waves near three geothermal reservoirs in Germany for frequencies between 2 Hz and 50 Hz. The geothermal plants are located in the sedimentary basins of the upper Rhine graben (Insheim and Landau) and the Molasse basin (Unterhaching). The method optimizes the fit between Green's functions for the acoustic, isotropic radiative transfer theory and observed energy densities of induced earthquakes. The inversion allows the determination of scattering and intrinsic attenuation, site corrections, and spectral source energies for the investigated frequency bands. We performed the inversion at the three sites for events with a magnitude between 0.7 and 2. We determined a transport mean free path of 70 km for Unterhaching. For Landau and Insheim the transport mean free path depends on frequency. It ranges from 2 km (at 2 Hz) to 30 km (at 40 Hz) for Landau and from 9 km to 50 km for Insheim. The quality factor for intrinsic attenuation is constant for frequencies smaller than 10 Hz at all three sites. It is around 100 for Unterhaching and 200 for Landau and Insheim with higher values above 10 Hz.

  18. Magmatism in the brazilian sedimentary basins and the petroleum geology; Magmatismo nas bacias sedimentares brasileiras e sua influencia na geologia do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Thomaz Filho, Antonio; Antonioli, Luzia [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Faculdade de Geologia]. E-mails: antoniothomaz@globo.com; antonioli@novanet.com.br; Mizusaki, Ana Maria Pimentel [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias]. E-mail: ana.mizusaki@ufrgs.br

    2008-06-15

    In the recent years, the researches on the magmatic events that occurred in the Brazilian sedimentary basins had shown the importance of these episodes for the hydrocarbons exploration. The generation (heating), migration (structural and petrographic alterations), accumulation (basalt fractures) and migrations barriers (sills and dykes) of the hydrocarbons, produced for these rocks, are cited in the marginal and intra continental Brazilian basins. The magmatism produce the temperature increase in the sedimentary basin, around its intrusion, and this propitiate the maturation of the organic matter contained in the hydrocarbons generating rocks of the basin. At the same time, has been verified that the contacts dykes/sedimentary rocks can represent important ways for the hydrocarbons migrations. Recent studies have shown that the magmatism, in its extrusive manifestations, can be analyzed in view of the possibility of having acted as effective hydrocarbon seals and, in consequence, making possible the accumulation of hydrocarbons generated in the underlying sediments. The magmatism of predominantly basic to intermediary character is generated in the asthenosphere, that is, below the lithosphere. The dykes that had introduced in the basement of our sedimentary basins are good heat conductors and we can expect the geothermal gradients increase in the overlapped sedimentary deposits. The more detailed study of the magmatic processes in the Brazilian sedimentary basins must lead to new forms of hydrocarbons exploration in our sedimentary basins, also in those basins where the traditional exploration activities have not occasioned the waited expected successes. (author)

  19. Characterizing long period (1--10 sec) ground motions for base isolated structures located in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Graves, R.W.; Somerville, P.G. [Woodward-Clyde Federal Services, Pasadena, CA (United States)

    1995-12-01

    Many urban regions, including Los Angeles, Portland and Seattle in the United States and Tokyo in Japan, are located above deep sedimentary basins. The conventional approach of estimating ground motions in these environments is to assume that the geology can be characterized by a horizontally stratified medium, and that only the shallowest few tens of meters influence the ground motion characteristics. However, the trapping and amplification of long period (1-10 sec) waves by sedimentary basins can generate amplitudes that are significantly larger than those calculated from simple 1D models of site resonance. This may be of particular concern for base isolated structures which are most sensitive to ground motions in this period range. The recent development of efficient computational methods for modeling seismic wave, propagation in laterally varying geological structure enable the authors to model the effects of sedimentary basins on earthquake generated ground motions. They are now applying this calculation procedure to characterize the ground motions that may be generated in the Puget Trough and the Portland Basin due to large earthquakes on the Cascadia subduction zone, and in the Los Angeles region due to large earthquakes on blind thrust faults beneath the Los Angeles basin.

  20. Prominent bacterial heterotrophy and sources of 13C-depleted fatty acids to the interior Canada Basin

    Directory of Open Access Journals (Sweden)

    S. R. Shah

    2013-04-01

    Full Text Available In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to depth, particularly as our baseline understanding of organic carbon cycling in the deep basin is limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC, are more concentrated under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ13C values that are similar to suspended POC at all depths and are 13C-enriched compared to even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. A source of saturated even-numbered fatty acids is also suggested below surface waters which could represent contributions from laterally advected organic carbon or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C20–24, branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon on benthic particulate matter. At these deep depths, two individual fatty acids (C12 and iso-C17 are significantly depleted in 13C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin.

  1. Framework for the assessment of interaction between CO2 geological storage and other sedimentary basin resources.

    Science.gov (United States)

    Michael, K; Whittaker, S; Varma, S; Bekele, E; Langhi, L; Hodgkinson, J; Harris, B

    2016-02-01

    Sedimentary basins around the world considered suitable for carbon storage usually contain other natural resources such as petroleum, coal, geothermal energy and groundwater. Storing carbon dioxide in geological formations in the basins adds to the competition for access to the subsurface and the use of pore space where other resource-based industries also operate. Managing potential impacts that industrial-scale injection of carbon dioxide may have on other resource development must be focused to prevent potential conflicts and enhance synergies where possible. Such a sustainable coexistence of various resource developments can be accomplished by implementing a Framework for Basin Resource Management strategy (FBRM). The FBRM strategy utilizes the concept of an Area of Review (AOR) for guiding development and regulation of CO2 geological storage projects and for assessing their potential impact on other resources. The AOR is determined by the expected physical distribution of the CO2 plume in the subsurface and the modelled extent of reservoir pressure increase resulting from the injection of the CO2. This information is used to define the region to be characterised and monitored for a CO2 injection project. The geological characterisation and risk- and performance-based monitoring will be most comprehensive within the region of the reservoir containing the carbon dioxide plume and should consider geological features and wells continuously above the plume through to its surface projection; this region defines where increases in reservoir pressure will be greatest and where potential for unplanned migration of carbon dioxide is highest. Beyond the expanse of the carbon dioxide plume, geological characterisation and monitoring should focus only on identified features that could be a potential migration conduit for either formation water or carbon dioxide.

  2. Drainage architecture and sediment routing in erosive catchments within the Ebro Eiver sedimentary basin (NE Iberian Peninsula)

    Science.gov (United States)

    Castelltort, Xavier; Colombo, Ferran; Carles Balasch Solanes, Josep

    2016-04-01

    The Ebro Basin (EB) is the result of filling a foreland basin located between active mountain ranges during the Paleogene compressive phases, and later affected by phases of distension in the Neogene. The arrangement of filler material is monocline in the eastern margin and in the contact with the Catalan Coastal Range (CCR). This has repercussions on the model of emptying the erosive basins and in the drainage that took place in the margins of the original sedimentary basin. One can speak of a drainage architecture and sediment routing associated to a monocline erosive basin model. The monocline topography in the original margin of EB encouraged the formation of a string of erosive basins around the contact with CCR, which are the result of headward erosion towards the center of the EB of the rivers draining the CCR towards the Valencia Trough. At the time, the transition from the EB in its initial condition of endorheic to exorheic was through one of these monocline erosive basins. The erosive basins emptied by means of two vectors. On the one hand, growth in surface of the basin by deepening anaclinal streams through resistant beds of monocline stratigraphic succession that empty and link small depressions that increase laterally on the less resistant lithologic member. Moreover, the new drainage system entrenches as the exit point of the basin does, thanks to gradients created by distensional movements of the Neogene Valencia Trough. Growth and entrenchment model of river basins, as well as, sedimentary deposits and landforms generated by these processes are described and analyzed.

  3. Late Paleozoic paleofjord in the southernmost Parana Basin (Brazil): Geomorphology and sedimentary fill

    Science.gov (United States)

    Tedesco, Julia; Cagliari, Joice; Coitinho, Julia dos Reis; da Cunha Lopes, Ricardo; Lavina, Ernesto Luiz Correa

    2016-09-01

    In the southernmost part of the Parana Basin, records of the late Paleozoic glaciation occur in a discontinuous form preserved in paleovalley systems excavated in the crystalline basement. This paper addresses one of these paleovalleys, the Mariana Pimentel, which extends over 60 km with NW-SE valley direction and a constant width of 2.5 km. With the objective of demonstrating that the paleovalley worked as a fjord during the glaciation period, its origin as well as sedimentary fill and morphology were analyzed. The paleovalley morphology was obtained through electrical resistivity (electrical sounding and lateral mapping) and mathematical modeling in four transverse sections. The morphology of the paleovalley documented by the U-shape, steady width, and high depth reaching up to 400 m are typical features of modern glacial valleys. The sedimentary facies that fill the base of the paleovalley, such as rhythmites and dropstones with thickness up to 70 m and diamictites with faceted pebbles (up to 5 m thick) are signs of its glacial origin. During the glaciation period, the paleovalley had a connection to the epicontinental sea located to the northwest, extended toward Namibia, and was excavated by glaciers from the highlands of this region. Thus, the evidence attests that the Mariana Pimentel paleovalley was a fjord during the late Paleozoic glaciation. The duration of the late Paleozoic glaciation (which is longer than the Quaternary glaciation), the apatite fission track that suggests erosion up to 4 km thick in the study area, and the lack of preserved hanging valleys in the Mariana Pimentel indicate that the paleovalley once featured a higher dimension. Furthermore, the existence of paleofjords excavated in the border of the basement corroborates the idea of small ice centers controlled by topography during the late Paleozoic glaciation.

  4. A comparison of burial, maturity and temperature histories of selected wells from sedimentary basins in The Netherlands

    Science.gov (United States)

    Nelskamp, S.; David, P.; Littke, R.

    2008-09-01

    Sedimentary basins in The Netherlands contain significant amounts of hydrocarbon resources, which developed in response to temperature and pressure history during Mesozoic and Cenozoic times. Quantification and modelling of burial, maturity and temperature histories are the major goals of this study, allowing for a better understanding of the general geological evolution of the different basins as well as petroleum generation. All major basins in The Netherlands encountered at least one time of inversion and therefore moderate to high amounts of erosion. In order to determine the amount of inversion the basins have experienced, a 1D study was performed on 20 wells within three basins (West Netherlands, Central Netherlands and Lower Saxony Basins). New vitrinite reflectance values were obtained and existing data re-evaluated to gain a good data base. The burial histories of six wells, two for each studied basin, are presented here, to demonstrate the differences in basin evolution that led to their present shape and petroleum potential. The Permo-Triassic subsidence phase can be recognized in all three basins, but with varying intensity. In the Jurassic, the basins experienced different relative movements that culminated in the Cretaceous when the influence of the inversion caused erosion of up to 2,500 m. Most wells show deepest burial at present-day, whereas the timing of maximum temperature differs significantly.

  5. Regional hydrogeology of the Silurian and Ordovician sedimentary rock underlying Niagara Falls, Ontario, Canada

    Science.gov (United States)

    Novakowski, Kentner S.; Lapcevic, Patricia A.

    1988-12-01

    Due to concern over the potential for widespread groundwater contamination in the sedimentary rock underlying the Niagara Falls area, this study was done to investigate the hydrogeology of the Silurian and Ordovician stratigraphy underlying the Upper Niagara River and the Eastern Niagara Peninsula. Seven boreholes (up to 150 m deep) were drilled, instrumented with multiple packer casing, tested for permeability, sampled for inorganic and organic solutes and monitored for hydraulic head to provide data for a conceptual model of regional groundwater flow. Results show that there are at least three distinct groundwater flow regimes in the bedrock. The uppermost regime consists of fracture zones in the Guelph and Lockport Formations, within which hydraulic conductivity, hydraulic head measurements and geochemical analyses indicate active groundwater circulation primarily discharging towards the Niagara Gorge and Escarpment. Underlying the Lockport Formation are an overpressured (high hydraulic head) regime in the Clinton-Upper Cataract-Lower Queenston Formation and an underpressured (low hydraulic head) regime in the Lower Cataract-Upper Queenston Formation. In both regimes, geochemical analyses and permeability measurements indicate very old and saline groundwater which probably has undergone minimal migration since pre-Pleistocene time. The implication based on the study so far, is that potential groundwater contamination below the bottom of the Lockport Formation is probably not significant in the Niagara Falls area except adjacent to the Niagara Gorge where vertical permeability in the lower flow regimes may be enhanced.

  6. Derivation of S and Pb in phanerozoic intrusion-related metal deposits from neoproterozoic sedimentary pyrite, Great Basin, United States

    Science.gov (United States)

    Vikre, P.G.; Poulson, S.R.; Koenig, A.E.

    2011-01-01

    The thick (???8 km), regionally extensive section of Neoproterozoic siliciclastic strata (terrigenous detrital succession, TDS) in the central and eastern Great Basin contains sedimentary pyrite characterized by mostly high d34S values (-11.6 to 40.8%, isotopes ( 207Pb/204Pb Precambrian cratonal rocks to the east-southeast. In the overlying Paleozoic section, Pb-Zn-Cu-Ag-Au deposits associated with Jurassic, Cretaceous, and Tertiary granitic intrusions (intrusion-related metal deposits) contain galena and other sulfide minerals with S and Pb isotope compositions similar to those of TDS sedimentary pyrite, consistent with derivation of deposit S and Pb from TDS pyrite. Minor element abundances in TDS pyrite (e.g., Pb, Zn, Cu, Ag, and Au) compared to sedimentary and hydrothermal pyrite elsewhere are not noticeably elevated, implying that enrichment in source minerals is not a precondition for intrusion-related metal deposits. Three mechanisms for transferring components of TDS sedimentary pyrite to intrusion-related metal deposits are qualitatively evaluated. One mechanism involves (1) decomposition of TDS pyrite in thermal aureoles of intruding magmas, and (2) aqueous transport and precipitation in thermal or fluid mixing gradients of isotopically heavy S, radiogenic Pb, and possibly other sedimentary pyrite and detrital mineral components, as sulfide minerals in intrusion-related metal deposits. A second mechanism invokes mixing and S isotope exchange in thermal aureoles of Pb and S exsolved from magma and derived from decomposition of sedimentary pyrite. A third mechanism entails melting of TDS strata or assimilation of TDS strata by crustal or mantle magmas. TDS-derived or assimilated magmas ascend, decompress, and exsolve a mixture of TDS volatiles, including isotopically heavy S and radiogenic Pb from sedimentary pyrite, and volatiles acquired from deeper crustal or mantle sources. In the central and eastern Great Basin, the wide distribution and high density

  7. Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

    Science.gov (United States)

    Sobrinho, R. L.; Bernardes, M. C.; Abril, G.; Kim, J.-H.; Zell, C. I.; Mortillaro, J.-M.; Meziane, T.; Moreira-Turcq, P.; Sinninghe Damsté, J. S.

    2016-01-01

    In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Mirituba and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as the C : N ratio and the stable isotopic composition of organic carbon (δ13Corg). These results were compared with lignin phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the crenarchaeol as an indicator of aquatic (rivers and lakes) OM. Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C3 plant-derived OM. However, a downstream increase in C4 macrophyte-derived OM contribution was observed along the gradient of increasing open waters - i.e., from upstream to downstream. Accordingly, we attribute the temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.

  8. Fracture systems in normal fault zones crosscutting sedimentary rocks, Northwest German Basin

    Science.gov (United States)

    Reyer, Dorothea; Bauer, Johanna F.; Philipp, Sonja L.

    2012-12-01

    Field studies of fracture systems associated with 58 normal fault zones crosscutting sedimentary rocks were performed in the Northwest German Basin. Fracture orientations, densities, apertures and lengths, as well as fault zone structural indices, were analysed separately for fault damage zones and host rocks. The results show a pronounced difference between carbonate and clastic rocks: mainly in carbonate rocks we found presence of clear damage zones, characterized by higher fracture densities than in the host rocks. While the maximum aperture is similar for both units, the percentage of fractures with large apertures is much higher in the damage zones than in the host rocks. Based on laboratory measurements of Young's moduli and field measurements of fracture densities, we calculate effective stiffnesses Ee, that is the Young's moduli of the in situ rock masses, within the normal fault zones. Compared with carbonate rocks, Ee computed for clastic-rock damage zones decreases significantly less due to lower fracture densities. We conclude that normal fault zones in carbonate rocks have more profound effects on enhancing permeability in fluid reservoirs than those in clastic rocks. The results are of great importance for modelling the hydromechanical behaviour of normal fault zones in subsurface fluid reservoirs.

  9. SEDIMENTARY PATTERN OF PROTOTYPE BASIN IN THE DEPOSITION PERIOD OF LAIYANG FORMATION AND THE ADVANTAGEOUS AREAS FOR OIL AND GAS EXPLORATION OF JIAOLAI BASIN

    Institute of Scientific and Technical Information of China (English)

    WU Zhiping; LI Ling; LI Wei; ZHOU Yaoqi

    2004-01-01

    Laiyang formation of Jiaolai Basin is the target stratum for oil and gas exploration. By measuring several field sections, the authors find that Laiyang formation reveals the whole processes from development to death of the lake basin and its sedimentary facies differ in different structural locations.Analyses about sedimentary facies and paleocurrent orientations in association with researches about the positive tectonic units such as Dayetou horseback and Chaigou horst indicate that Laiyang sag is a relatively independent sedimentary unit that shows great water depth typical of deep lake or semideep lake and was controlled by Wulongcun fault during the deposition period of Laiyang formation. Its sediments mainly originated from Jiaobei uplift area and Dayetou horseback. Gaomi-Zhucheng sag was a fast-filled basin controlled by Wurong fault and Yishu fault zone, being high in the northeast and low in the northwest and characterized by the development of pluvial facies and fluvial facies in most areas, and with the development of lake facies being limited to local low-lying regions. Selection of advantageous hydrocarbon reservoir areas for exploration purpose mainly relies on the sedimentation pattern of prototype basin and conservation conditions. The central-west area of Laiyang sag covered by overlying Laiyang formation is the most advantageous exploration area.

  10. The control of syndepositional faulting on the Eogene sedimentary basin fills of the Dongying and Zhanhua sags,Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    LIN Changsong; ZHENG Herong; REN Jianye; LIU Jingyan; Qiu Yigang

    2004-01-01

    The Dongying and Zhanhua sags are the major hydrocarbon exploration and production subbasins in the Bohai Bay Basin. Integrated analysis of the sedimentary basin fills has shown that the syndepositional faults and their arrangement styles exerted an important influence on the development and distribution of the Eogene depositional systems. The sedimentary filling evolution of the subbasins reflects the general control of the episodic rifting process. The major long-term active normal faults formed a series of paleogeomorphic accident or slopebreak zones that commonly delineated the subsidiary palaeostructural units and the depositional facies tracts and constrained the general distribution of sedimentary facies zones. The central sag boundary fault slopebreak zones usually determined the distribution of the depocenters of terrestrial clastic depositional systems, particularly the Iowstand fans or deltaic depositional systems, and have proven to be the economically important targets for the exploration of subtle sandstone reservoirs. A variety of syndepositional fault arrangement patterns, including the parallel, en echelon, combo-like, broom-like fault systems and the fault overlap or transfer zones,have been recognized in the subbasins. They generated distinctive geomorphic features and exerted a direct influence on sediment dispersal and sandbody distribution during the Eogene synrift stage. It is the key for the prediction of depositional systems tracts and reservoir sandstones to investigate the activity and distribution of the fault slopebreak zones and reconstruct the structural paleogeomorphy in different basin filling stages of the basin evolution.

  11. Sedimentary pyrite δ34S differs from porewater sulfide in Santa Barbara Basin: Proposed role of organic sulfur

    Science.gov (United States)

    Raven, Morgan Reed; Sessions, Alex L.; Fischer, Woodward W.; Adkins, Jess F.

    2016-08-01

    Santa Barbara Basin sediments host a complex network of abiotic and metabolic chemical reactions that knit together the carbon, sulfur, and iron cycles. From a 2.1-m sediment core collected in the center of the basin, we present high-resolution profiles of the concentrations and isotopic compositions of all the major species in this system: sulfate, sulfide (∑H2S), elemental sulfur (S0), pyrite, extractable organic sulfur (OS), proto-kerogen S, total organic and dissolved inorganic carbon, and total and reducible iron. Below 10 cm depth, the core is characterized by low apparent sulfate reduction rates (biogeochemical cycles and redox structure in sedimentary paleoenvironments.

  12. Chapter 50 Geology and tectonic development of the Amerasia and Canada Basins, Arctic Ocean

    Science.gov (United States)

    Grantz, Arthur; Hart, Patrick E.; Childers, Vicki A

    2011-01-01

    Amerasia Basin is the product of two phases of counterclockwise rotational opening about a pole in the lower Mackenzie Valley of NW Canada. Phase 1 opening brought ocean–continent transition crust (serpentinized peridotite?) to near the seafloor of the proto-Amerasia Basin, created detachment on the Eskimo Lakes Fault Zone of the Canadian Arctic margin and thinned the continental crust between the fault zone and the proto-Amerasia Basin to the west, beginning about 195 Ma and ending prior to perhaps about 160 Ma. The symmetry of the proto-Amerasia Basin was disrupted by clockwise rotation of the Chukchi Microcontinent into the basin from an original position along the Eurasia margin about a pole near 72°N, 165 W about 145.5–140 Ma. Phase 2 opening enlarged the proto-Amerasia Basin by intrusion of mid-ocean ridge basalt along its axis between about 131 and 127.5 Ma. Following intrusion of the Phase 2 crust an oceanic volcanic plateau, the Alpha–Mendeleev Ridge LIP (large igneous province), was extruded over the northern Amerasia Basin from about 127 to 89–75 Ma. Emplacement of the LIP halved the area of the Amerasia Basin, and the area lying south of the LIP became the Canada Basin.

  13. Chapter 50: Geology and tectonic development of the Amerasia and Canada Basins, Arctic Ocean

    Science.gov (United States)

    Grantz, A.; Hart, P.E.; Childers, V.A.

    2011-01-01

    Amerasia Basin is the product of two phases of counterclockwise rotational opening about a pole in the lower Mackenzie Valley of NW Canada. Phase 1 opening brought ocean-continent transition crust (serpentinized peridotite?) to near the seafloor of the proto-Amerasia Basin, created detachment on the Eskimo Lakes Fault Zone of the Canadian Arctic margin and thinned the continental crust between the fault zone and the proto-Amerasia Basin to the west, beginning about 195 Ma and ending prior to perhaps about 160 Ma. The symmetry of the proto-Amerasia Basin was disrupted by clockwise rotation of the Chukchi Microcontinent into the basin from an original position along the Eurasia margin about a pole near 72??N, 165 Wabout 145.5-140 Ma. Phase 2 opening enlarged the proto-Amerasia Basin by intrusion of mid-ocean ridge basalt along its axis between about 131 and 127.5 Ma. Following intrusion of the Phase 2 crust an oceanic volcanic plateau, the Alpha-Mendeleev Ridge LIP (large igneous province), was extruded over the northern Amerasia Basin from about 127 to 89-75 Ma. Emplacement of the LIP halved the area of the Amerasia Basin, and the area lying south of the LIP became the Canada Basin. ?? 2011 The Geological Society of London.

  14. Seismic stratigraphy of sedimentary cover in Amerasian Basin based on the results of Russian High Arctic expeditions

    Science.gov (United States)

    Poselov, Viktor; Kireev, Artem; Smirnov, Oleg; Butsenko, Viktor; Zholondz, Sergey; Savin, Vasily

    2016-04-01

    Massive amount of multichannel seismic (MCS) data were obtained by Russian High Arct ic expeditions "Arctica-2011", "Acrtica-2012" and "Arctica-2014". More than 40 MCS lines are located in the Amerasian basin and help to substantiate the seismic stratigraphy model of its sedimentary cover. The proposed seismic stratigraphy model was successively determined for the Cenozoic and pre-Cenozoic parts of the sedimentary section and was based on correlation of the Russian MCS data and seismic data documented by boreholes. Cenozoic part of the sedimentary cover is based on correlation of the Russian MCS data and AWI91090 section calibrated by ACEX-2004 boreholes on the Lomonosov Ridge. Two major unconformities are traced. The upper regional unconformity (RU) is associated with a major pre-Miocene hiatus. Another major hiatus is recorded in the borehole section between the Campanian and the Upper Paleocene units. It is recognized as the post-Campanian unconformity (pCU) in the seismic sections. Formation of the regional unconformities is associated with a fundamental change in depositional environment. Formation of RU was initiated by opening of the Fram Strait gateway at the Paleogene/Neogene boundary. Post-Campanian unconformity is linked with the initial stage of the Eurasian Basin opening between the Cretaceous and the Paleogene. Cenozoic sedimentary units are continuously traced from the East-Siberian and Chukchi sea shelves across the transit zone to the Amerasian basin. Paleogene unit (between pCU and RU) is formed under the neritic depositional environment and it is characterized by an extremely small thickness on the Lomonosov Ridge (less than 200 m), on the Mendeleev Rise and in the Podvodnikov Basin (not more than 300-400 m). Neogene unit (above RU) consists of hemipelagic deposits and occupies the essential part of thickness of the Cenozoic section in Podvodnikov and Makarov Basins. Interval velocities in the Paleogene unit vary within 2.8-3.2 km/s, in the

  15. Behaviour of lithium and its isotopes during weathering in the Mackenzie Basin, Canada

    OpenAIRE

    Millot, Romain; Vigier, Nathalie; Gaillardet, Jérôme

    2010-01-01

    International audience; We report Li isotopic compositions, for river waters and suspended sediments, of about 40 rivers sampled within the Mackenzie River Basin in northwestern Canada. The aim of this study is to characterize the behaviour of Li and its isotopes during weathering at the scale of a large mixed lithology basin. The Mackenzie River waters display systematically heavier Li isotopic compositions relative to source rocks and suspended sediments. The range in delta Li-7 is larger i...

  16. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    Directory of Open Access Journals (Sweden)

    Ziliang Liu

    Full Text Available A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km. The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front

  17. Jurassic sedimentary evolution of southern Junggar Basin:Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region, China

    Institute of Scientific and Technical Information of China (English)

    Shun-Li Li; Xing-He Yu; Cheng-Peng Tan; Ronald Steel

    2014-01-01

    Junggar Basin, located in northern Xinjiang, presents continuous and multi-kilometer-thick strata of the Jurassic deposits. The Jurassic was entirely terrestrial lfuvial and lacustrine deltaic sedimentation. Eight outcrop sections across the Jurassic strata were meas-ured at a resolution of meters in southern Junggar Basin. Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology, fossils and tectonic setting. In the Early to Middle Jurassic, the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent, and provided adequate moisture for Junggar Basin. Coal-bearing strata of the Badaowan, Sangonghe, and Xishanyao Formations were developed under warm and humid palaeocli-mate in Junggar Basin. In the late Middle Jurassic, Junggar Basin was in a semi-humid and semi-arid environment due to global warming event. Stratigraphy in the upper part of the Mid-dle Jurassic with less plant fossils became multicolor or reddish from dark color sediments. During the Late Jurassic, collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea. A major change in climate from semi-humid and semi-arid to arid conditions took place, and reddish strata of the Upper Jurassic were developed across Junggar Basin.

  18. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2015-04-01

    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  19. Subsurface plumbing and fluid expulsion from sedimentary basins: evidence from the sedimentary record offshore West Africa (Invited)

    Science.gov (United States)

    Huuse, M.

    2010-12-01

    Many petroliferous basins around the world show evidence for fluid expulsion and seepage on the land surface or seafloor. However, not all fluid expulsion features are evidence of a working hydrocarbon systems and one needs to carefully evaluate fluid expulsion features and their associated geology and in particular their plumbing systems before inferring the nature of the expelled fluids. Geochemical fingerprinting of the migrating fluids may be sampled directly or via carbonate cements secreted in association with focus fluid conduits and may help determine the nature of the expelled fluids including their stratigraphic origin. When such evidence is unavailable, one may have to rely on remote sensing, including 3D seismic characterization in order to assess the nature of expelled fluids and links with hydrocarbon migration and/or ‘normal’ diagenetic fluid expulsion. This paper presents 3D seismic case studies of pockmarks, fluid flow pipes and polygonal fault systems which show evidence of both deep and shallow sources of expelled fluids and discuss the different controls on their occurrence and significance. Importantly, there is evidence of both conducting and sealing behaviours of polygonal fault sytems. Bottom-Simulating Reflections from interfaces between free gas and overlying gas hydrate occur in a variety of manifestations and may be linked with both deep and shallow sources of methane. Their depth of occurrence relative to seafloor depth may be used to infer local geothermal gradients and it is shown that underlying salt causes BSRs to shallow, indicative of a doubling of the geothermal gradient above salt structures compared to the adjacent salt mini basins. It is further suggested that salt structures on the middle slope serve a dual purpose as trap and leak-forming features, with traps focused on the down-dip side of overhanging diapirs and leaks located on the updip side and flanks. Associated leakage phenomena include gas and gas hydrate

  20. Cyclicity recorded in the provenance sandstones in the sedimentary in fill of the Cameros basin (N. Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Acebron, L.; Arribas, J.; Omodeo-Sale, S.; Arribas, E.; Le Pera, E.; Mas, R.; Lopez-Elorza, M.; Fernandez-Diaz, P. R.

    2013-06-01

    The intra plate Cameros rift basin in the north of Spain was formed came into being between the Tithonian and the Early Albian and contains 9 000 m of mostly continental sediments. This basin is a good example of cyclicity of different depositional sequences (DSs) in sedimentary environments, which show clear repetition in their sandstone composition (petrofacies) and diagenetic patterns. The DSs are arranged in two mega sequences (MSs) separated by a tectonic unconformity. A similar vertical sandstone compositional evolution, subdivided into two stages that repeat cyclically, has been recognised in both MSs: the first comprises quartzo-sedimentolithic petrofacies and the second is made up of several quartzo-feldspathic petrofacies. This was caused by a progression from the recycling of the pre-rift sedimentary cover to the erosion of the mainly plutonic and metamorphic crystalline basement. These changes in the erosion of the different source areas were conditioned by the tectonics of the basin. Furthermore, the original sandstone framework composition conditioned the diagenetic pattern of the two stages: quartzo-sedimentolithic sandstones containing large amounts of very pervasive carbonate cement that reduce their original porosity considerably, and quartzo-feldspathic petrofacies with a rigid framework that maintained the original pores during burial diagenesis. This compositional and diagenetic pattern is probably applicable to other non-volcanic rifted basins, depending upon the original amount of carbonate rock fragments present. (Author)

  1. Discussions on the sedimentary-tectonic event and tectonic setting of the North Tarim Basin in Cryogenian-Cambrian

    Science.gov (United States)

    Zhou, X. B.; Li, J. H.; Li, W. S.

    2012-04-01

    Across the Tarim Basin, limited surface outcrops of Cryogenian to Cambrian sedimentary succession are completely exposed in the vicinity of Aksu area(Northwest Tarim), Kuruktag(Northeast Tarim)and Southwest Tarim, thus provides a unique, well preserved and accessible means by which to study the early development of the north Tarim Basin. Based on the field geological investigation in the northwestern and northeastern of Tarim Basin, with the referencing of paleomagnetism mapping and previous research, basin evolution process in Cryogenian-Cambrian is discussed according to sedimentary-tectonic event and other evidences. The major lithological types of Cryogenian-Cambrian system in Northeast Tarim are: tillite, clastic rocks(rich in organic matter) and carbonate ,with interbeds of volcanic rocks while in Northwest Tarim, the calstic rocks and carbonate are the common rock type, with tillite and volcanic interbeds in a small amount. The north margin of Tarim Block, which was a part of Rodinia supercontinent, neighboring the northwestern margin of Australia, was deeply rifted in Cryogenian-Ediacaran and developed into two rifts in the northwestern and northeastern margin, while formed a thick layer of the rift-passive margin deposits and the layer in the northwestern rift was not completely developed as the northeastern. The deepest rift-passive magin sediment which can be observed is Cryogenian-Middle Ordovician strata, and the period can be divided into Cryogenian faulted period (supercontinent rifting stage) and Ediacaran-Middle Ordovician subsidence period (plate drifting stage).

  2. Freshwater budget of the Canada Basin, Arctic Ocean, from salinity, δ18O, and nutrients

    Science.gov (United States)

    Yamamoto-Kawai, M.; McLaughlin, F. A.; Carmack, E. C.; Nishino, S.; Shimada, K.

    2008-01-01

    The contribution of freshwater components (e.g., meteoric, sea ice, and Pacific water) in the Canada Basin is quantified using salinity, δ18O, and nutrient data collected in 2003 and 2004. The penetration depth of sea ice meltwater is limited to the upper 30 m, and brine, rejected during sea ice formation, is observed from 30 to 250 m depth. The fraction of meteoric water is high in the upper 50 m and decreases with depth. Pacific water entering via Bering Strait is the main source of freshwater below 50 m depth. Bering Strait throughflow, which transports Pacific water with salinity 32.5 together with meteoric water supplied upstream of the Bering Strait, contributes up to 75% of freshwater input (>3200 km3 a-1) to the Canada Basin. The mean residence time of Pacific water in the Canada Basin is estimated to be 11 years. Precipitation and river runoff from both North American and Eurasian continents add >800 km3 a-1 and sea ice formation removes export of ice and liquid fresh water from the Canada Basin contributes ˜40% of the freshwater flux from the Arctic Ocean to the North Atlantic Ocean.

  3. Contrasting patterns of river runoff and sea-ice melted water in the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    TONG Jinlu; CHEN Min; QIU Yusheng; LI Yanping; CAO Jianping

    2014-01-01

    The fractions of river runoff and sea-ice melted water in the Canada Basin in summer 2003 were determined by the salinity-δ18O system. The fraction of river runoff (fR) was high in the upper 50 m of the water column and decreased with depth and latitude. The signals of the river runoff were confined to water depths above 200 m. The total amount of river runoff in the Canada Basin was higher than that in other arctic seas, indi-cating that the Canada Basin is a main storage region for river runoff. The penetration depth of the sea-ice melted water was less than 50 m to the south of 78°N, while it was about 150 m to the north of 78°N. The total amount of sea-ice melted water was much higher to the north of 78°N than to the south of 78°N, indicating the sea-ice melted waters accumulated on the ice edge. The abundant sea-ice melted water on the ice edge was attributed to the earlier melted water in the southern Canada Basin and transported by the Beaufort Gyre or the reinforced melting of sea ice by solar radiation in the polynya.

  4. Extensional deformation of the Guadalquivir Basin: rate of WSW-ward tectonic displacement from Upper Tortonian sedimentary rocks

    Science.gov (United States)

    Roldán, Francisco J.; Azañón, Jose Miguel; Rodríguez-Fernández, Jose; María Mateos, Rosa

    2016-04-01

    The Guadalquivir Basin (Upper Tortonian-Quaternary sedimentary infilling) has been considered the foreland basin of the Betic Orogen built up during its collision with the Sudiberian margin. The basin is currently restricted to its westernmost sector, in the Cadiz Gulf, because the Neogene-Quaternary uplift of the Betic Cordillera has produced the emersion of their central and eastern parts. The upper Tortonian chronostratigraphic unit is the oldest one and it was indistinctly deposited on the South Iberian paleomargin and the External units from the Betic Cordillera. However, these rocks are undeformed on the Sudiberian paleomargin while they are deeply affected by brittle deformation on the External Betic Zone. Outcrops of Upper Tortonian sedimentary rocks on External Betic Zone are severely fragmented showing allocthonous characters with regard to those located on the Sudiberian paleomargin. This post- Upper Tortonian deformation is not well known in the External Zones of the Cordillera where the most prominent feature is the ubiquity of a highly deformed tecto-sedimentary unit outcropping at the basement of the Guadalquivir sedimentary infilling. This tecto-sedimentary unit belongs to the Mass Wasting Extensional Complex (Rodríguez-Fernández, 2014) formed during the collision and westward migration of the Internal Zone of the Betic Cordillera (15-8,5 Ma). In the present work, we show an ensemble of tectonic, geophysical and cartographic data in order to characterize the post-Upper Tortonian deformation. For this, seismic reflection profiles have been interpreted with the help of hidrocarbon boreholes to define the thickness of the Upper Tortonian sedimentary sequence. All these data provide an estimation of the geometrical and kinematic characteristics of the extensional faults, direction of movement and rate of displacement of these rocks during Messinian/Pliocene times. References Rodríguez-Fernández, J., Roldan, F. J., J.M. Azañón y Garcia-Cortes, A

  5. Basin-Scale Sand Deposition in the Upper Triassic Xujiahe Formation of the Sichuan Basin, Southwest China: Sedimentary Framework and Conceptual Model

    Institute of Scientific and Technical Information of China (English)

    Xiucheng Tan; Qingsong Xia; Jingshan Chen; Ling Li; Hong Liu; Bing Luo; Jiwen Xia; Jiajing Yang

    2013-01-01

    The Upper Triassic Xujiahe(须家河) Formation in the Sichuan (四川) Basin,Southwes China is distinctive for the basin-scale sand deposition.This relatively rare sedimentary phenomenon has not been well interpreted.Here we addressed this issue by discussing sedimentary framework and conceptual model.Analysis of sedimentary setting implied that the basin received transgression during the deposition.It had multiple provenance supplies and river networks,as being surrounded by oldlands in multiple directions including the north,east and south.Thus,the basin was generally characterized by coastal and widely open and shallow lacustrine deposition during the Late Triassic Xujiahe period.This is similar to the modern well-known Poyang(鄱阳) Lake.Therefore,we investigated the framework and conceptual model of the Sichuan Basin during the Xujiahe period with an analogue to the Poyang Lake.Results show that the conceptual model of the deposition can be divided into transgressive and regressive stages.The first,third and fifth members of the formation are in transgressive stage and the deposits are dominated by shore and shallow lacustrine mud.In contrast,the deposition is mainly of braided river channel sand deposits during the regressive stage,mainly including the second,fourth and sixth members of the formation.The sand deposited in almost the entire basin because of the lateral migration and forward moving of the cross networks of the braided rivers.The multiple alternations of short and rapid transgression and relatively long regression are beneficial to the basin-scale sand deposition.Thus,the main channel of the braided river and its extensional areas are favorable for the development of hydrocarbon reservoir.This provides practical significance to the reservoir evaluation and exploration.In addition,the results also justify the relatively distinctive sedimentary phenomenon in the study area and may also have implications for understanding the large

  6. Tectono-sedimentary evolution of an extensional basin revealed by a combined photo-geological and field-mapping approach. The Montefalco Basin (Northern Apennines, Italy)

    Science.gov (United States)

    Bucci, Francesco; Mirabella, Francesco; Santangelo, Michele; Cardinali, Mauro; Guzzetti, Fausto

    2016-04-01

    Active extensional basins are important since their sedimentary infills and bounding tectonic structures provide: i) sinks with preservation potential for sedimentary and fossil records of past changes in climate and sediment/water supply, ii) information on the growth, activity, decay and death of normal faults, iii) vast economic reserves of hydrocarbons, water and minerals. Unfortunately, quaternary extensional basins, especially if located in humid and temperate climate environments, are often characterized by extensively cultivated areas, homogeneous terrains and quite flat morphologies. Furthermore, they commonly host human settlements, together with roads, economic and industrial infrastructures, with a consequent limited availability of good outcrops. Such a limitation can (often severely) hamper an adequate mapping of the sedimentary infill. Therefore alternative methodological approaches (such as aerial photographs interpretation, API) are needed to integrate heterogeneous and incomplete datasets. This contribution presents an updated photo-geological map of a Quaternary extensional basin in Central Italy, the Montefalco Basin. This basin developed in a continental environment characterized by clayey-sandy lacustrine and fluvial sequences (late Pliocene - early Pleistocene) underlying more recent coarse grained deposits related to alluvial fan environment (early-to-late Pleistocene) and younger palustrine deposits (late Pleistocene). Since the late Pleistocene, regional uplift and local tectonics led to the end of deposition in the Montefalco basin, which experienced a diffuse incision and the modification of the drainage network, in response to the W-to-E migration of active faulting and tectonic subsidence. The new photo-geological map represents an important improvement compared to the existing data, since it provides unprecedented and spatially distributed information on the geometry of the continental deposits and on the tectonic structures affecting

  7. Sedimentary cyclicity in early Pleistocene, evaporitic, playa-lake lacustrine deposits in the Guadix-Baza basin (Betic Cordillera, Spain)

    International Nuclear Information System (INIS)

    The Guadix-Baza basin (Betic Cordillera, southern Spain) contains in its eastern sector an early Pleistocene (Gelasian and lowermost Calabrian) sedimentary unit that was deposited in a shallow lacustrine environment. Given that the chronological limits of this unit lie between 2.5 and 1.6 Ma BP, the thickness of its preserved sediments (400 m) and high sedimentation rate (44.4 cm/ka) are remarkable. Numerous sedimentary cycles marked by an alternation of marls and sands are commonly found in the marginal sectors and marls and gypsum in the central sector, which would owe their origins to permanent flooding and evaporation/ re-flooding phases due to global climatic changes. Spectral analyses carried out using Fourier transform have revealed the existence of temporary frequencies associated with sedimentary cycles of between 0.2 and 5.2 ka. The origin of these cycles may be associated with variations in solar radiation and oscillations in the Moons orbital position, which would induce global climatic changes resulting in the rise and fall of the water table of the lake. Autocorrelation analyses conducted separately on the marly and evaporitic levels support this conclusion, as they indicate the existence of significant direct correlations between about 4 to 12 sedimentary cycles, which would correspond to repetitions of the stratigraphic series over a time span of 1.3 to 4 ka. (Author)

  8. Lower Paleozoic oil relationships within Williston Basin, Canada

    Institute of Scientific and Technical Information of China (English)

    Stephen L.Bend; Mauri C.Smith

    2004-01-01

    The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.

  9. Differences in sedimentary filling and its controlling factors in rift lacustrine basins, East China: A case study from Qikou and Nanpu sags

    Institute of Scientific and Technical Information of China (English)

    Hua WANG; Shu JIANG; Chuanyan HUANG; Hua JIANG; Huajun GAN

    2011-01-01

    The riff lacustrine basin is characterized by a variety of sediment sources, multiple sedimentary systems,and complex filling, and its sediment supply is largely influenced by climate change. The sedimentary filling and its controlling factors have always been the focuses in basin analysis. This paper first reviews the recent advancement in riff lacustrine basin investigations with an emphasis on the structural controlling on lacustrine configuration, accommodation, and directly structural controlling on basin filling characteristics. The paleogeography resulted from spatial configuration of structural styles, and the sediment supplies synergically determine the types and distribution of depositional systems. The sedimentary filling characteristics of the fourth-order sequence record the evolution of cyclic climate. The case studies are followed on the basis of the sedimentary filling analysis in typical Nanpu sag and Qikou sag in Huanghua riff lacustrine basins in East China. The comparison of sedimentary fillings within sequence stratigraphic frameworks in the two sags shows the different episodic tectonic activities, and their resulting structural frameworks mainly controlled the different sequence stratigraphic developments, their internal architectures, and depositional systems distribution. Qikou sag has more complicate sedimentary filling controlled by episodic activities of boundary and intrabasin secondary faults and sediment supplies. Based on the studies from our own and the formers, we suggest that the sedimentary filling study in rift lacustrine basin should be under the guidance of sequence stratigraphy, use high resolution seismic and all available geological data, combine tectonic evolution and structural styles to build the sequence framework, and then reconstruct the paleo-structure and paleogeography. Studying the relationship between paleogeography and paleosedimentary filling can favor the understanding of the characteristics of sedimentary

  10. Well-log based prediction of thermal conductivity of sedimentary successions: a case study from the North German Basin

    DEFF Research Database (Denmark)

    Fuchs, Sven; Förster, Andrea

    2014-01-01

    Data on rock thermal conductivity (TC) are important for the quantification of the subsurface temperature regime and for the determination of heat flow. If drill core is not retrieved from boreholes and thus no laboratory measurement of TC can be made, other methods are desired to determine TC. One...... German Basin. The theoretical approach comprised the calculation of TC from well-log response values for artificial sets of mineral assemblages consisting of variable contents of 15 rock-forming minerals typical for sedimentary rocks. The analysis shows different correlation trends between TC...... and the theoretical well-log response in dependence on the mineral content, affecting the rock matrix TC, and on porosity. The analysis suggests the development of empirical equations for the prediction of matrix TC separately for different groups of sedimentary rocks. The most valuable input parameters...

  11. EGS in sedimentary basins: sensitivity of early-flowback tracer signals to induced-fracture parameters

    Science.gov (United States)

    Karmakar, Shyamal; Ghergut, Julia; Sauter, Martin

    2015-04-01

    -effective aperture, in a water fracture (WF), or - fracture thickness and porosity, for a gel-proppant fracture (GPF). We find that parameter determination from SW early signals can significantly be improved by concomitantly using a number of solute tracers with different transport and retardation behaviour. We considered tracers of different sorptivity to proppant coatings, and to matrix rock surfaces, for GPF, as well as contrasting-diffusivity or -sorptivity tracers, for WF. An advantage of this SW approach is that it requires only small chaser volumes (few times the fracture volume), not relying on advective penetration into the rock matrix. Thus, selected tracer species are to be injected during the very last stage of the fracturing process, when fracture sizes and thus target parameters are supposed to attain more or less stable values. We illustrate the application of these tracer test design principles using hydro- and lithostratigraphy data from the Geothermal Research Platform at Groß Schönebeck [4], targeting a multi-layer reservoir (sedimentary and crystalline formations in 4-5 km depth) in the NE-German Sedimentary Basin. Acknowledgments: This work benefited from long-term support from Baker Hughes (Celle) and from the Lower-Saxonian Science and Culture Ministry (MWK Niedersachsen) within the applied research project gebo (Geothermal Energy and High-Performance Drilling, 2009-2014). The first author gratefully acknowledges continued financial support from the DAAD (German Academic Exchange Service) to pursuing Ph. D. work. References: [1] http://www.sciencedirect.com/science/article/pii/S1876610214017391 [2] http://www.geothermal-energy.org/cpdb/record_detail.php?id=7215 [3] http://www.geothermal-energy.org/cpdb/record_detail.php?id=19034 [4] http://www.gfz-potsdam.de/en/scientific-services/laboratories/gross-schoenebeck/

  12. The geology and hydrocarbon possibilities of the Triassic-Jurassic Fundy Basin, eastern Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wade, J.A.; Fensome, R.A. [Geological Survey of Canada, Dartmouth, NS (Canada). Atlantic Geoscience Centre; Brown, D.E. [Canada-Nova Scotia Offshore Petroleum Board, Halifax, NS (Canada)

    1997-09-01

    The development of the Mesozoic sedimentary basins beneath the waters of the eastern coast of North America was discussed. These basins have been linked to the rifting of the central part of Pangaea during Mid and Late Triassic time that ended in the formation of a series of grabens extending from Florida to The Grand Banks of Newfoundland, one of them being the Bay of Fundy Basin which is about 16,500 square kilometres in size. Onshore and offshore geologic mapping and seismic interpretations have shown their age range to be from the Mid Triassic Anisian or Ladinian to Mid Jurassic. Up to 12 km of Mesozoic rocks were deposited in the basin with up to 9 km still present. The depositional history of the area was described. The two areas with greatest hydrocarbon potential are the Bay of Fundy and the Chignecto subbasins.

  13. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    Science.gov (United States)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  14. Sedimentary response to orogenic exhumation in the northern rocky mountain basin and range province, flint creek basin, west-central Montana

    Science.gov (United States)

    Portner, R.A.; Hendrix, M.S.; Stalker, J.C.; Miggins, D.P.; Sheriff, S.D.

    2011-01-01

    Middle Eocene through Upper Miocene sedimentary and volcanic rocks of the Flint Creek basin in western Montana accumulated during a period of significant paleoclimatic change and extension across the northern Rocky Mountain Basin and Range province. Gravity modelling, borehole data, and geologic mapping from the Flint Creek basin indicate that subsidence was focused along an extensionally reactivated Sevier thrust fault, which accommodated up to 800 m of basin fill while relaying stress between the dextral transtensional Lewis and Clark lineament to the north and the Anaconda core complex to the south. Northwesterly paleocurrent indicators, foliated metamorphic lithics, 64 Ma (40Ar/39Ar) muscovite grains, and 76 Ma (U-Pb) zircons in a ca. 27 Ma arkosic sandstone are consistent with Oligocene exhumation and erosion of the Anaconda core complex. The core complex and volcanic and magmatic rocks in its hangingwall created an important drainage divide during the Paleogene shedding detritus to the NNW and ESE. Following a major period of Early Miocene tectonism and erosion, regional drainage networks were reorganized such that paleoflow in the Flint Creek basin flowed east into an internally drained saline lake system. Renewed tectonism during Middle to Late Miocene time reestablished a west-directed drainage that is recorded by fluvial strata within a Late Miocene paleovalley. These tectonic reorganizations and associated drainage divide explain observed discrepancies in provenance studies across the province. Regional correlation of unconformities and lithofacies mapping in the Flint Creek basin suggest that localized tectonism and relative base level fluctuations controlled lithostratigraphic architecture.

  15. Tectono-sedimentary evolution of the Tertiary Piedmont Basin (NW Italy) within the Oligo-Miocene central Mediterranean geodynamics

    Science.gov (United States)

    Maino, Matteo; Decarlis, Alessandro; Felletti, Fabrizio; Seno, Silvio

    2013-06-01

    analyze the tectono-sedimentary and thermochronometric constraints of the Tertiary Piedmont Basin (TPB) and its adjoining orogen, the Ligurian Alps, providing new insights on the basin evolution in response to a changing geodynamic setting. The geometry of the post-metamorphic faults of the Ligurian belt as well as the fault network that controlled the Oligo-Miocene TPB deposition has been characterized through a detailed structural analysis. Three main faulting stages have been distinguished and dated thanks to the relationships among faults and basin stratigraphy and thermochronometric data. The first stage (F1, Rupelian-Early Chattian) is related to the development of extensional NNW-directed faults, which controlled the exhumation of the orogen and the deposition of nearshore clastics. During the Late Chattian, the basin drowning is marked by mudstones and turbidites, which deposition was influenced by the second faulting stage (F2). This phase was mainly characterized by NE- to ENE-striking faults developed within a transtensional zone. Since the Miocene, the whole area was dominated by transpressive tectonics. The sedimentation was represented by a condensed succession followed by a very thick, turbiditic complex. At the regional scale, this succession of events reflects the major geodynamic reorganization in the central Mediterranean region during the Oligo-Miocene times, induced by the late-collisional processes of the Alps, by the eastward migration of the Apennines subduction and by the opening of extensional basins (i. e., the Liguro-Provençal Ocean).

  16. Cooperative and adaptive transboundary water governance in Canada's Mackenzie River Basin: status and prospects

    Directory of Open Access Journals (Sweden)

    Michelle Morris

    2016-03-01

    Full Text Available Canada's Mackenzie River Basin (MRB is one of the largest relatively pristine ecosystems in North America. Home to indigenous peoples for millennia, the basin is also the site of increasing resource development, notably fossil fuels, hydroelectric power resources, minerals, and forests. Three provinces, three territories, the Canadian federal government, and Aboriginal governments (under Canada's constitution, indigenous peoples are referred to as "Aboriginal" have responsibilities for water in the basin, making the MRB a significant setting for cooperative, transboundary water governance. A framework agreement that provides broad principles and establishes a river basin organization, the MRB Board, has been in place since 1997. However, significant progress on completing bilateral agreements under the 1997 Mackenzie River Basin Transboundary Waters Master Agreement has only occurred since 2010. We considered the performance of the MRB Board relative to its coordination function, accountability, legitimacy, and overall environmental effectiveness. This allowed us to address the extent to which governance based on river basin boundaries, a bioregional approach, could contribute to adaptive governance in the MRB. Insights were based on analysis of key documents and published studies, 19 key informant interviews, and additional interactions with parties involved in basin governance. We found that the MRB Board's composition, its lack of funding and staffing, and the unwillingness of the governments to empower it to play the role envisioned in the Master Agreement mean that as constituted, the board faces challenges in implementing a basin-wide vision. This appears to be by design. The MRB governments have instead used the bilateral agreements under the Master Agreement as the primary mechanism through which transboundary governance will occur. A commitment to coordinating across the bilateral agreements is needed to enhance the prospects for

  17. Tectonic Setting and Nature of the Provenance of Sedimentary Rocks in Lanping Mesozoic-Cenozoic Basin: Evidence from Geochemistry of Sandstones

    Institute of Scientific and Technical Information of China (English)

    李志明; 刘家军; 胡瑞忠; 何明勤; 刘玉平; 李朝阳

    2003-01-01

    The geochemical composition of sandstones in the sedimentary basin is controlled mainly by the tectonic setting of the provenance,and it is therefore possible to reveal the tectonic setting of the provenance and the nature of source rocks in terms of the geochemical composition of sandstones. The major elements,rare-earth elements and trace elements of the MesozoicCenozoic sandstones in the Lanping Basin are studied in this paper,revealing that the tectonic settings of the provenance for Mesozoic-Cenozoic sedimentary rocks in the Lanping Basin belong to a passive continental margin and a continental island arc. Combined with the data on sedimentary facies and palaeogeography,it is referred that the eastern part of the basin is located mainly at the tectonic setting of the passive continental margin before Mesozoic,whereas the western part may be represented by a continental island arc. This is compatible with the regional geology data. The protoliths of sedimentary rocks should be derived from the upper continental crust,and are composed mainly of felsic rocks,mixed with some andesitic rocks and old sediment components. Therefore,the Lanping Mesozoic-Cenozoic Basin is a typical continental-type basin. This provides strong geochemical evidence for the evolution of the paleo-Tethys and the basin-range transition.

  18. The Feature of Sedimentary, Structure and the Laws of Hydrocarbon Distribution in Erlian Basin

    Institute of Scientific and Technical Information of China (English)

    Zhang Wenchao; Du Jinhu; Xu Wenbin; Wang Hongsheng; He Shuping

    1996-01-01

    @@ Introduction Erlian Basin is one of the ten biggest oil/gas-bearing basins in China. It is a faulted lake basin developed in Early Cretaceous on the basement of Paleozoic fold. The total area is 100 000 km2, There are altogether 49 sags bulging alternatively, totaling about 55 000 km2 (Fig. 1).

  19. New seismo-stratigraphic data of the Volturno Basin (northern Campania, Tyrrhenian margin, southern Italy: implications for tectono-stratigraphy of the Campania and Latium sedimentary basins

    Directory of Open Access Journals (Sweden)

    Ennio Marsella

    2011-07-01

    Full Text Available A geological section of the Volturno Basin (northern Campania, continental margin, Italy has been constructed based on new multi-channel seismic data, to show the stratigraphic relationships between the filling in the Quaternary basin and the Meso-Cenozoic acoustic basement. The new seismic sections presented here outline the underlying structures of the basin and their relationships to the filling in the Quaternary basin. Deep exploration wells in Campania and Latium on the Tyrrhenian margin have gathered litho-stratigraphic and commercial multi-channel seismic data that can be used for better integration of the geological data for the area under study. The trending of the seismic units is controlled by the Massico Structural High, which forms the boundary of the Volturno Basin towards the north-west. This produces a geometry that is characteristic of a fan complex, with NE-SW trending. This qualitative calibration of the seismic sequences that fill the sedimentary basin was carried out through the litho-stratigraphic data of the «Castelvolturno 2» well, which highlights the pyroclastic layers and conglomeratic strata of the lagoon and delta environments as they evolve upwards towards marine sediments. Seismo-stratigraphic analysis shows the complex depositional geometries of the filling in the Volturno Basin, which overlie the Meso-Cenozoic carbonatic basement and the related flysch deposits. Coupled with regional geological evidence, the data interpretation here suggests that the Volturno Basin represents a half-graben structure that is characterized by down-thrown blocks along normal faults.

  20. Spectral gamma-ray evaluation of Lower Jurassic basalts and lacustrine sediments from the Fundy Basin (Nova Scotia, Canada)

    Science.gov (United States)

    Silva, Ricardo L.; Wach, Grant; Wong, Carlos

    2014-05-01

    In the Fundy Basin (Nova Scotia, Canada), the McCoy Brook Formation corresponds to the first sedimentary unit of Early Jurassic (Hettangian-Pliensbachian) age deposited after the North Mountain basalts, part of the Central Atlantic Magmatic Province (CAMP). The McCoy Brook Formation includes at its base the Scots Bay Member, comprising red and green lutites, silicified limestones, cherts, stromatolites and sandstones. Deposition of the Scots Bay Member occurred in a shallow and oxygenated lake, where the trophic state varied from oligotrophic to eutrophic. The McCoy Brook Formation is less than 100ky younger than the end-Triassic extinction event (Olsen and Et-Touhami, 2008 and references therein). We analysed the spectral gamma-ray (GR) response of the top of the North Mountain basalts and base of the Scots Bay member at Broad Cove (Kings County, Nova Scotia, Canada) in order to calibrate outcrop with borehole wireline data and test uranium as a proxy for organic matter richness. The North Mountain basalts have a constant and low GR profile, varying from 58-92 cts. Potassium varies from 0.5-1.3%, U from 0-3.1ppm and Th from 0-5.1ppm. Average content of these elements are 1.0 %, 1.9ppm and 2.5ppm, respectively. The Scots Bay Member presents more variation, from 162 cts at the base to 68 cts at the top. Potassium varies from 0.4-2.3%, U from 0-6.4ppm and Th from 0-10.0ppm. Average content of these elements are 1.2%, 3.4ppm and 4.1ppm, respectively. The use of U contents to estimate TOC (see for example, Correia et al., 2012) generates non-significant results, where limestones have TOC of 11wt%. Olsen and Et-Touhami (2008) report that these outcrops are organically lean, with TOC lower that 1wt%. It is apparent that the high U contents and the overestimation of authigenic U is linked with U mineralization due the stromatolites and microbial activity, highlighting that lithological and mineralogical components are critical to accurate petrophysical interpretation of

  1. The first deep heat flow determination in crystalline basement rocks beneath the Western Canadian Sedimentary Basin

    Science.gov (United States)

    Majorowicz, Jacek; Chan, Judith; Crowell, James; Gosnold, Will; Heaman, Larry M.; Kück, Jochem; Nieuwenhuis, Greg; Schmitt, Douglas R.; Unsworth, Martyn; Walsh, Nathaniel; Weides, Simon

    2014-05-01

    Heat flow (Q) determined from bottom-hole temperatures measured in oil and gas wells in Alberta show a large scatter with values ranging from 40 to 90 mW m-2. Only two precise measurements of heat flow were previously reported in Alberta, and were made more than half a century ago. These were made in wells located near Edmonton, Alberta, and penetrated the upper kilometre of clastic sedimentary rocks yielding heat flows values of 61 and 67 mW m-2 (Garland & Lennox). Here, we report a new precise heat flow determination from a 2363-m deep well drilled into basement granite rocks just west of Fort McMurray, Alberta (the Hunt Well). Temperature logs acquired in 2010-2011 show a significant increase in the thermal gradient in the granite due to palaeoclimatic effects. In the case of the Hunt Well, heat flow at depths >2200 m is beyond the influence of the glacial-interglacial surface temperatures. Thermal conductivity and temperature measurements in the Hunt Well have shown that the heat flow below 2.2 km is 51 mW m-2 (±3 mW m-2), thermal conductivity measured by the divided bar method under bottom of the well in situ like condition is 2.5 W m-1 K-1, and 2.7 W m-1 K-1 in ambient conditions), and the geothermal gradient was measured as 20.4 mK m-1. The palaeoclimatic effect causes an underestimate of heat flow derived from measurements collected at depths shallower than 2200 m, meaning other heat flow estimates calculated from basin measurements have likely been underestimated. Heat production (A) was calculated from spectral gamma recorded in the Hunt Well granites to a depth of 1880 m and give an average A of 3.4 and 2.9 μW m-3 for the whole depth range of granites down to 2263 m, based on both gamma and spectral logs. This high A explains the relatively high heat flow measured within the Precambrian basement intersected by the Hunt Well; the Taltson Magmatic Zone. Heat flow and related heat generation from the Hunt Well fits the heat flow-heat generation

  2. Radon and its decay product activities in the magmatic area and the adjacent volcano-sedimentary Intrasudetic Basin

    Directory of Open Access Journals (Sweden)

    D. Tchorz

    2007-06-01

    Full Text Available In the magmatic area of Sudetes covering the Karkonosze granite and adjacent volcano-sedimentary Intrasudetic Basin a study of atmospheric radon activity was performed by means of SSNTD Kodak LR-115. The study was completed by gamma spectrometric survey of eU and eTh determined by gamma activity of radon decay products 214Bi and 208Tl respectively. In the case of the western part of the Karkonosze granite area the radon decay products activity in the granitic basement was found to be as high as 343 Bq/kg for 214Bi and 496 Bq/kg for 208Tl respectively. Atmospheric radon content measured by means of Kodak LR115 track detector at the height of 1.5 m was found as high as 70 Bq/m3 in the regions, where no mining activities took place. However in the eastern part of the granitic massif in the proximity of abandoned uranium mine atmospheric radon content was found to be 6000 Bq/m3. In the case of sedimentary basin where sedimentary sequence of Carboniferous rocks has been penetrated by younger gases and fluids of volcanic origin uranium mineralization developed. The region known from its CO2 outburst during coal mining activity is characterized by good ventilation of the uranium enriched geological basement resulting in increased atmospheric radon activity being in average 72 Bq/m3. In the vicinity of coal mine tailing an increase up to 125 Bq/m3 can be observed. Seasonal variations of atmospheric radon content are influenced in agricultural areas by cyclic cultivation works (plough on soils of increased uranium content and in the case of post-industrial brownfields varying rates of radon exhalation from tailings due to different meteorological conditions.

  3. Regional MT survey across an archaean craton in south Australia. Influence of sedimentary basins and plate boundaries

    International Nuclear Information System (INIS)

    Complete text of publication follows. Long-period MT data at more than 200 stations have been collected across the Late Archaean - Early Proterozoic Gawler Craton, South Australia, during numerous field campaigns between 2002 and 2009. The total site coverage spans an area of approximately 800x500 km providing a unique dataset to image one of the oldest cratons in the world. The Gawler Craton is known for its mineral exploration potential, i.e. the IOCG Olympic Dam deposit (Heinson et al, 2006). MT data can help constrain the position of lithospheric structures which could provide clues to the genesis of mineral deposits throughout the region. Moreover, large parts of the craton are covered with sediments ranging from tens to thousands of meters in thickness. The sedimentary basins have a significant influence on the MT responses and if not taken into account can lead to erroneous results in a smooth inversion scheme due to their high conductances. We present 3D inversion models using a subset of sites in the period range of 10-10000s in order to image the subsurface resistivity distribution of the Gawler Craton. Initial 2D and 3D inversions of a subset of MT sites indicates an electrically resistive Archaean core. The thick sedimentary basins surrounding most of the Gawler Craton are taken into account by using starting models with the basins included as a priori information. Together with the inclusion of bathymetry data of the Southern Sea the inverse procedure has more constraints and is able to produce better results than an unconstrained inversion. The results provide additional constrains to the understanding of the evolution of the Archaean-Proterozoic Gawler Craton by imaging the crust and upper mantle. Tectonic models are largely based on limited outcrop due to thick regolith cover and domain boundaries inferred from potential field data. These can now be validated with the use of large-scale MT modelling.

  4. Sedimentary fluxes and different dispersion mechanism of the clay sediments in the Adriatic Basin; Flussi sedimentari e differenti meccanismi di dispersione dei sedimenti argillosi nel Bacino Adriatico

    Energy Technology Data Exchange (ETDEWEB)

    Tomadin, L. [Urbino Univ., Urbino (Italy). Ist. di Geodinamica e Sedimentologia

    2000-07-01

    Investigating the composition and the distribution of the muds deposited in the Adriatic, a typical shelf basin, numerous evidences of the variable provenance and dispersal of the clay sediments have been observed. The clay minerals behave, in fact, as excellent natural tracers. The distribution maps of illite and smectite (the most abundant components of the Adriatic clays) and of their crystallinity indices, show a prevailing longitudinal dispersion of the clay sediments, which is connected with the general cyclonic circulation of the marine currents. Two main fluxes toward SE have been recognised in the bottom sediments along the Italian peninsula: one Apennine flux close to the western coasts and one parallel Padane flux in the open sea. On the contrary, one subordinate Albanian flux conveys clay sediments toward NW along the eastern coasts of the basin. Also other transport mechanisms play an important role in the different areas of the Adriatic. In the shallow northern Adriatic, the clay sedimentation is controlled by a superficial dispersion of the fine suspended load carried by the large plume of the Po River. By increasing depth of the waters, gradient currents of variable provenance favour the longitudinal flows of the clay sediments. In the deepest Southern Adriatic, besides the NS-oriented fluxes, turbidity currents flow transversely to the basin and carry clay sediments from the Apulian shelf and from the Albanian-Montenegrin shelf into the bathyal basin. [Italian] La composizione e la distribuzione dei fanghi di un tipico bacino di piattaforma come l'Adriatico hanno fornito molteplici indicazioni sulla provenienza e la dispersione dei sedimenti argillosi. I minerali argillosi che li compongono, si comportano infatti da eccellenti traccianti naturali. Mappe di distribuzione di illite e smectite (i piu' abbondanti minerali presenti nei sedimenti argillosi adriatici) e dei loro indici di cristallinita', mettono in evidenza la prevalente

  5. Regional groundwater flow and geochemical processes within an intercratonic sedimentary basin affected by long-term episodes of freshwater

    Science.gov (United States)

    Bea, S. A.; Mayer, K. U.; Macquarrie, K. T.

    2009-12-01

    Present-day regional groundwater flow systems in intercratonic sedimentary basins are mainly driven by water table topographic gradients and recharge derived from precipitation. During a glaciation-deglaciation event; however, the migration and melting of ice sheets may alter the patterns of freshwater ingress into these basins. Under such conditions water fluxes in aquifers can be expected to be significantly modified as a result of the high hydraulic gradients beneath wet-based ice sheets. In fact, present-day hydrogeological and geochemical conditions across formerly glaciated areas may still reflect the impact of the last glaciation (around 10 ka B.P., e.g. anomalous fluid pressures in deep hydrogeologic units, changes in oxygen isotope composition, etc.). Reactive transport modeling can be used to understand the evolution of geochemical conditions of these formations and assess their suitability for hosting a deep geologic repository for used nuclear fuel. In this work, we will shed light on the effect of long-term perturbations over geologic time scales (e.g. glaciation-deglaciation events) on the hydrogeological and geochemical processes in a hypothetical sedimentary basin. Processes included in the model are density-driven flow and transport, as well as chemical reactions (aqueous complexation, mineral dissolution and precipitation including evaporites, sulfates and carbonates, cation-exchange, redox processes involving the decomposition of organic matter, and the oxidation of ferrous iron and sulfide). Transient boundary conditions are imposed in the upper part of the model to mimic ice sheet advance and retreat. Modeling hydrodynamic and geochemical processes in these basins is complex due to the presence of dense brines, hydraulic heterogeneities, continental-basin scale, permafrost and the formation of taliks., requiring robust numeric capabilities. Our preliminary results suggest that low velocities, in regions containing dense brines, are maintained

  6. Application of Seismic Interferometry Method by Using Portable Seismometer for Delineating the Sedimentary Structure of Pohang Basin, Korea

    Science.gov (United States)

    Kim, H.; Li, X.; So, Y.

    2012-12-01

    Pohang Basin consisting of non-marine to deep-marine strata, occurs along the southeastern coast of the Korean Peninsula and the basin is believed to have the potential of carbon dioxide sequestration. We have applied the seismic interferometry method by using portable 72 channels seismometer with normal velocity geophones for delineating the sedimentary structure of the basin and for checking the preliminary feasibility of geological storage of carbon dioxide. Comparing with the surface wave, reflected and refracted waves have low energy and it is difficult to retrieve the reflected and refracted waves from the ambient seismic noise by using interferometry method. So it is more challenging to delineate the seismic reflection and refraction signals by the interferometry method for seismic section or travel time curve. The reflection and refraction signals were retrieved from 100 ambient seismic noise data by bandpass filtering, crosscorrelation and stacking. The preliminary reflection seismic sections and travel time curves were prepared by using interferometry method and the sections and curves were compared with those of obtained by active sources using sledge hammer in the same lines. The results do not show clear reflection and refraction signals but some parts give comparable signals similar with the signals obtained by active sources. This implies the possibility of seismic interferomety method to retrieve the reflection and refraction signals by portable seismometer in near surface mapping.

  7. The structure and sedimentary sequence of intracratonic rift from Late Sinian to Early Cambrian in the Sichuan Basin, South China

    Science.gov (United States)

    Gu, Zhidong; Zhang, Baomin; Lu, Weihu; Zhai, Xiufen; Jiang, Hua

    2016-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze craton of South China, and there is developed an intracratonic rift from Late Sinian to Early Cambrian in the middle of Sichuan Basin, and the paper systematically discusses the structure and sedimentary sequence of the intracratonic rift based on the fields, drilling and seismic data, and so on. Detailed structural interpretation of 2D and 3D seismic profiles displays the development of two stages of intracratonic rift due to regional extension with the depth of 2000m, and plane distribution of intracratonic rift presents the V-pattern from the northwest to the southeast in the middle of Sichuan Basin with the width from 100km to 20km. The drilling data from the intracratonic rift shows the obvious thinning of Upper Sinian and thickening of Lower Cambrian. And field outcrops situated in the intracratonic rift reveal that the Upper Sinian is mainly composed of siliceous rock, shale and carbonate, with the thickness of less than 100m, but the thickness of Upper Sinian on the platform reaches 1000m by contrast; They also reveals that Lower Cambrian is mainly composed of shale, mudstone, and siltstone with the development of gravity current, and the thickness of Lower Cambrian reaches 2000m. The formation of intracratonic rift may be initiated by pre-existing basement weakness zone and deep mantle dynamics.

  8. The Cenozoic growth of the Qilian Shan in the northeastern Tibetan Plateau: A sedimentary archive from the Jiuxi Basin

    Science.gov (United States)

    Wang, Weitao; Zhang, Peizhen; Pang, Jianzhang; Garzione, Carmala; Zhang, Huiping; Liu, Caicai; Zheng, Dewen; Zheng, Wenjun; Yu, Jingxing

    2016-04-01

    Sedimentary deposits in Tibetan Basins archive the spatial-temporal patterns of the deformation and surface uplift processes that created the area's high topography during the Cenozoic India-Asia collision. In this study, new stratigraphic investigation of the Caogou section from the Jiuxi Basin in the northeasternmost part of Tibetan Plateau provides chronologic constraints on the deformation and northward growth of the plateau. Magnetostratigraphic analysis results suggest that the age of the studied ~1000 m thick section spans from ~24.2 Ma to 2.8 Ma. Detailed sedimentology and apatite fission track (AFT) analyses reveal that variations in the clast provenance, lithofacies, sediment accumulation rates, and AFT lag times occurred at ~13.5-10.5 Ma. We interpret these changes as in response to the initial uplift of the North Qilian Shan. In addition, paleomagnetic declination results from the section indicate a clockwise rotation of the Jiuxi Basin before ~13.5 Ma, which was followed by a subsequent counterclockwise rotation during 13.5-9 Ma. This reversal in rotation direction may be directly related to left-lateral strike-slip activity along the easternmost segment of the Altyn Tagh Fault. Combined with previous studies, we suggest that movement on the western part of the Altyn Tagh Fault was probably initiated during the Oligocene (>30 Ma) and that fault propagation to its eastern tip occurred during the middle-late Miocene.

  9. Tectono-sedimentary evolution of the Neuquén basin (Argentina) between 39°S and 41°S during the Neogene

    Science.gov (United States)

    Huyghe, D.; Bonnel, C.; Nivière, B.; Messager, G.; Dhont, D.; Fasentieux, B.; Hervouët, Y.; Xavier, J.-P.

    2012-04-01

    Sedimentary rocks deposited in foreland basins are of primary interest, because they record the interactions between the growth of the orogenic wedge, the isostatic readjustment of the lithosphere, the variations of base-level and earth surface process. The Neuquén basin (32°S - 41°S) is a triangular shape foreland basin located on the eastern flank of the Andes. Its filling began during the late Triassic, first as back arc basin context and as compressive foreland basin since the upper Cretaceous. The structural inheritance is thus important and old basement structures, like the Huincul Ridge, generate significant variations of both deformation and shortening. Its Mesozoic history is well constrained due to its hydrocarbon potential. In comparison, its Cenozoic history remains poorly documented. The modern configuration of this basin results from several successive compressive tectonic phases. The last one is dated from the Miocene (Quechua phase) and has conditioned the segmentation of the foreland basin in several intra-mountainous sub-basins, whose sedimentary filling could reach several hundred meters. In this work, we document the relative chronology of the geological events and the sedimentary processes that have governed the Cenozoic history of the southern part of the Neuquen basin, to discriminate the relative rules of climatic and structural controlling factors on the evolution of the depocentres. Several NNW-SSE oriented intra-mountainous basins exist in this part of the Andes (Collon Cura basin and Catan Lil basin). On the contrary the associated foreland basin (Picun Leufu basin) is relatively underformed and is bounded to the North by the Huincul ridge and the North Patagonian massif to the South. Fifteen sedimentary sections have been studied along the Rio Limay River in the southern border of the basin, from the range to the external part of the foreland. The sedimentation is discontinuous in time and important retrogradations of the depocentres

  10. Petroleum geological investigations in East greenland: project `Resources of the sedimentary basins of North and East Greenland`

    Energy Technology Data Exchange (ETDEWEB)

    Stemmerik, L.; Clausen, O.R.; Larsen, M.; Piasecki, S.; Therkelsen, J. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark); Korstgaard, J. [Univ. of Aarhus, Geological Inst., Aarhus (Denmark); Seidler, L.; Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1997-12-31

    The multidisciplinary research project `Resources of the sedimentary basins of North and East Greenland` was initiated in 1995. The 1996 field work in East Greenland concentrated on integrated structural, sedimentological and biostratigraphical studies of the Upper Permian and Mesozoic successions. The most important new results arising from the 1996 field work are: 1) Re-interpretation of the Upper Permian Schuchert Dal Formation as a low stand turbidite unit within the Ravnefjeld Formation; 2) Recognition of Middle Jurassic deposits and thick lowermost Cretaceous sandstones on Hold with Hope; 3) Interpretation of a full spectrum of scarp-derived coarse-clastic mass movement deposits inter-bedded with Cretaceous shales on eastern Traill Oe; 4) The presence of a thick sand-rich Cretaceous turbidite succession on eastern Traill Oe; 5) Re-interpretation of the Mesozoic-Cenozoic fault systems on Traill Oe and Geographical Society Oe. (EG) 24 refs.

  11. Paleotemperatures of Upper Carboniferous sedimentary rocks in the NW part of the Upper Silesian coal basin, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Krystian Probierz; Malgorzata Lewandowska [Silesian University of Technology, Gliwice (Poland). Faculty of Mining and Geology, Institute of Applied Geology

    2004-07-01

    Paleothermal conditions of Upper Carboniferous sedimentary rocks in the strongly folded north-western part of the Upper Silesian Coal Basin (USCB) are characterized in this paper. NS-oriented narrow folds predominate, with amplitudes ranging from 100 to 800 m, often dislocated by axial faults. The paleothermal conditions, i.e. maximum paleotemperatures and paleothermal gradient were calculated according to Bostick's nomogram and Barker and Pawlewicz's method on the basis of studies of 115 samples of coal taken from depths between +17 and -368 m b.s.l. The paleotemperatures range from 135 to 220{degree}C and the paleothermal gradients from 2.4 to 5.9{degree}C/100 m. The coalification process probably has a synorogenic character. 11 refs., 5 figs., 2 tabs.

  12. Porous media of the Red River Formation, Williston Basin, North Dakota: a possible Sedimentary Enhanced Geothermal System

    Science.gov (United States)

    Hartig, Caitlin M.

    2016-09-01

    Fracture-stimulated enhanced geothermal systems (EGS) can be developed in both crystalline rocks and sedimentary basins. The Red River Formation (Ordovician) is a viable site for development of a sedimentary EGS (SEGS) because the formation temperatures exceed 140 °C and the permeability is 0.1-38 mD; fracture stimulation can be utilized to improve permeability. The spatial variations of the properties of the Red River Formation were analyzed across the study area in order to understand the distribution of subsurface formation temperatures. Maps of the properties of the Red River Formation-including depth to the top of the formation, depth to the bottom of the formation, porosity, geothermal gradient, heat flow, and temperature-were produced by the Kriging interpolation method in ArcGIS. In the future, these results may be utilized to create a reservoir simulation model of an SEGS in the Red River Formation; the purpose of this model would be to ascertain the thermal response of the reservoir to fracture stimulation.

  13. Sequence Stratigraphy and Sedimentary Facies in the Lower Member of the Permian Shanxi Formation, Northeastern Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    Wei Du; Zaixing Jiang; Ying Zhang; Jie Xu

    2013-01-01

    The Lower Permian Shanxi(山西) Formation is one of the main gas-bearing stratigraphic units in northeastern Ordos(鄂尔多斯) Basin,China.Based on an integrated investigation of well logs,cores,and outcrop,we delineated the sedimentary facies of the lower member of the Shanxi Formation and divided the succession into three third-order sequences from base to top as SQ1,SQ2,and SQ3.The lower region of Shanxi Formation was deposited in the following sedimentary facies or subfacies: subaqueous braided channel,subaqueous interdistributary,mouth bar,swamp and shelf in the Daniudi(大牛地)Gas Field and braided channel,and shelf and lake at Heidaigou(黑岱沟)outcrop.Braided-river deposits form the lowstand systems tract (LST) in each sequence.Braided channels mark the sequence boundaries at Heidaigou outcrop.A shelf and lake depositional environment with dark gray mudstone forms the transgressive systems tract (TST).The location where dark gray mudstone first appears above the braided channel marks the first flooding surface (FFS),and the end of that marks the maximum flooding surface (MFS).The highstand systems tract (HST) deposits are fine-grained sediments with an aggradational parasequence at Heidaigou outcrop and swamp coalbed in the Daniudi Gas Field.Mouth-bar sand bodies in braided delta front,which form the LST in each sequence,form excellent reservoirs in the Daniudi Gas Field.

  14. Origin of New Faculty in Sedimentary Petrology at Ph.D.-Granting Universities in the United States and Canada.

    Science.gov (United States)

    Thornton, Scott E.

    1981-01-01

    To aid prospective graduate students in sedimentary petrology who wish to teach at colleges or universities, 121 doctoral graduates in this field are traced to their present appointments in higher education. Only 31 percent of these graduates attained this career goal. (Author/WB)

  15. Tectonics and sedimentary evolution of the Sandino forearc basin off Nicaragua, Central America

    Science.gov (United States)

    Costa Pisani, P.; Silver, E.; McIntosh, K.; Ahmed, I.; Ranero, C. R.; Taylor, B.

    2003-04-01

    The Sandino basin is the Nicaragua sector of the Central American forearc, where the Cocos plate subducts beneath the Middle America trench. Recently, Ranero et al. have interpreted a seismic section across the margin and proposed a history of formation of the forearc which is constrained by industry drilling in the basin. They suggested a late Cretaceous to Paleocene accretion event, followed by later subduction erosion processes. The margin wedge consists of the ophiolitic Nicoya complex. The seismic units, unconformities and tectonic features record a rich history of both local and regional vertical movements occurring since the Middle Eocene, which are linked to the evolution of the Pacific convergent margin. During June, 2000, 2800 kms of multichannel seismic reflection data were collected on the R/V Ewing off Nicaragua. Analysis of the 240 channels dataset indicates rapid changes along strike in the Sandino basin. The basin is relatively thin in the southern part, thinning quite rapidly southward against the Nicoya complex of the Santa Elena peninsula of Costa Rica. The forearc sediments thickness approaches and locally exceeds 10 kms in the central and northern parts of the Sandino basin. The oldest units (Upper Cretaceous-Middle Eocene) are very thick off northern Nicaragua, with relatively thin middle to late Cenozoic deposits. However, off central Nicaragua the latter units (Middle-Upper Miocene) attain great thicknesses and the older units appear to thin. This pattern suggests a history of successive deepening of the basin from north to south, after the convergent system evolved from accretion to subduction erosion processes. Present efforts are devoted to quantifying this change in development and using it to understand the dynamics of forearc basin evolution offshore of Central America.

  16. Organic carbon export to the deep Canada Basin: Importance of lateral supply

    Science.gov (United States)

    Hwang, J.; Eglinton, T. I.; Manganini, S. J.; Krishfield, R. A.; Griffith, D. R.; Honjo, S.; McLaughlin, F. A.; MacDonald, R. W.

    2010-12-01

    Understanding the processes driving the carbon cycle in the Arctic Ocean is of fundamental importance for assessing the impacts of the predicted climate change in this critical region. We analyzed sinking particle samples intercepted below the marginal ice zone of the Beaufort Sea at a depth of 3067m (Station A, 75N, 150W) in the Canada Basin from 2004 to 2005 and from 2007 to 2009, in order to examine interannual variability in carbon export to the bathypelagic zone. Sinking particles were also collected at other depths-2000m and 3750m- at Station A and from other locations (Station B-78N, 150W, and Station D-74N, 140W) within the basin for the latter time period. Prior observations from the 2004-5 study revealed that mass flux variations were temporally decoupled from the cycle of primary productivity in surface waters, and that sinking particle composition was characterized by old organic carbon (mean 14C age = ~ 1900 14C years) and abundant lithogenic material (~80%), implying supply via lateral advection from the surrounding margins (Hwang et al., 2008). Observations at Station A from 2007-9 reveal a similar mode of particle supply suggesting that lateral advection of resuspended sediment is a persistent feature in the southwest Canada Basin. Particle fluxes at three depths at Station A were similar with only slightly higher values at 50 m above the bottom, implying that lateral transport occurs throughout the lower water column. Particle flux and Δ14C values exhibited a negative correlation. Particle flux and Δ14C results also reveal interannual variability and spatial heterogeneity. A marked particle flux maximum was observed at Station A in August 2008 that was not seen in the prior deployments of 2004 and 2007. Extremely low Δ14C values for this late summer flux maximum implies that sediment resuspension and lateral advection, instead of enhanced summer time primary production in the overlying water column, was responsible. Particle flux was the highest

  17. The Efficacy and Potential of Renewable Energy from Carbon Dioxide that is Sequestered in Sedimentary Basin Geothermal Resources

    Science.gov (United States)

    Bielicki, J. M.; Adams, B. M.; Choi, H.; Saar, M. O.; Taff, S. J.; Jamiyansuren, B.; Buscheck, T. A.; Ogland-Hand, J.

    2015-12-01

    Mitigating climate change requires increasing the amount of electricity that is generated from renewable energy technologies and while simultaneously reducing the amount of carbon dioxide (CO2) that is emitted to the atmosphere from present energy and industrial facilities. We investigated the efficacy of generating electricity using renewable geothermal heat that is extracted by CO2 that is sequestered in sedimentary basins. To determine the efficacy of CO2-Geothermal power production in the United States, we conducted a geospatial resource assessment of the combination of subsurface CO2 storage capacity and heat flow in sedimentary basins and developed an integrated systems model that combines reservoir modeling with power plant modeling and economic costs. The geospatial resource assessment estimates the potential resource base for CO2-Geothermal power plants, and the integrated systems model estimates the physical (e.g., net power) and economic (e.g., levelized cost of electricity, capital cost) performance of an individual CO2-Geothermal power plant for a range of reservoir characteristics (permeability, depth, geothermal temperature gradient). Using coupled inverted five-spot injection patterns that are common in CO2-enhanced oil recovery operations, we determined the well pattern size that best leveraged physical and economic economies of scale for the integrated system. Our results indicate that CO2-Geothermal plants can be cost-effectively deployed in a much larger region of the United States than typical approaches to geothermal electricity production. These cost-effective CO2-Geothermal electricity facilities can also be capacity-competitive with many existing baseload and renewable energy technologies over a range of reservoir parameters. For example, our results suggest that, given the right combination of reservoir parameters, LCOEs can be as low as $25/MWh and capacities can be as high as a few hundred MW.

  18. Age and paleoenvironmental reconstruction of partially remagnetized lacustrine sedimentary rocks (Oligocene Aktoprak basin, central Anatolia, Turkey)

    Science.gov (United States)

    Meijers, Maud J. M.; Strauss, Becky E.; Özkaptan, Murat; Feinberg, Joshua M.; Mulch, Andreas; Whitney, Donna L.; Kaymakçı, Nuretdin

    2016-03-01

    The age and paleoenvironmental record of lacustrine deposits in the Aktoprak basin of south-central Turkey provides information about the evolution of topography, including the timing of development of an orographic rain shadow caused by uplift of the mountain ranges fringing the Central Anatolian Plateau. New magnetostratigraphy-based age estimates, in combination with existing biostratigraphic ages, suggest that the partially remagnetized Kurtulmuş Tepe section of the basin is Chattian (Upper Oligocene). The mean carbon and oxygen stable isotope ratios (δ18O= 24.6 ± 2.0 ‰, δ13C= -4.9 ± 1.1‰) are largely constant through the section and indicative of a subtropical, open freshwater lake. These isotopic values are also similar to those of the Chattian Mut basin to the south, on the Mediterranean side of the modern orographic barrier (Tauride Mountains), and indicate absence of an orographic barrier during Late Oligocene basin deposition. Post-depositional partial remagnetization occurred after tilting of the basin sequence and was mineralogically controlled, affecting grey, carbonate-rich rocks (average %CaCO3= 82), whereas interlayered pink carbonate-poor rocks (average %CaCO3= 38) carry a primary, pretilt magnetization. The pink rocks are rich in clay minerals that may have reduced the permeability of these rocks that carry a primary magnetization, concentrating basinal fluid flow in the carbonate-rich grey layers and leading to the removal and reprecipitation of magnetic minerals. The normal and reverse polarities recorded by the remagnetized rocks suggest that remagnetization occurred over a protracted period of time.

  19. A review of seismicity, siting and design criteria in Canada and Pacific Basin countries

    International Nuclear Information System (INIS)

    This paper provides a brief review of the earthquake history of the Pacific Basin region. Three different types of plate boundary fault system occurs at different parts of the Pacific Rim. This accounts for the relative levels of seismicity in the Pacific Rim countries. Canada, Western USA, Mexico, Colombia, Ecuador, Peru, Chile, Japan, China, Taiwan, Indonesia and New Zealand are relatively active areas, while Korea, Thailand, Malaysia, Singapore and Australia are less active. A brief review of the trends in development of seismic design criteria for 'critical facilities' in Canada is given. This indicates an effort to provide consistent levels of seismic design for a full range of facilities in addition to nuclear power plants. The rigorous methods developed for nuclear power plants may be of benefit in the development of design codes for other facilities

  20. Rayleigh-wave ellipticity and shallow structure in sedimentary basins: the Po Plain (northern Italy)

    Science.gov (United States)

    Berbellini, A.; Morelli, A.; Ferreira, A. M. G.

    2015-12-01

    The amplitude ratio between horizontal and vertical components of Rayleigh waves (also known as ellipticity) is in principle uniquely sensitive to local earth structure beneath each recording station. Rayleigh wave ellipticity is mostly influenced by the shallowest layers, so it can be effectively used to infer the structure of the uppermost crust, with particular relevance for sedimentary environments. We implement an automatic method to measure Rayleigh wave ellipticity, and extensively apply it to teleseismic records from the northern part of Italy, for a period range between 10s and 130s. As expected, no appreciable correlation with epicenter distance or azimuth can be seen, but rather a strong correlation with local structure: generally high horizontal to vertical amplitude ratios are seen in sedimentary settings, with respect to Alpine and Apenninic crystalline-rock terrains. We verify that shortest usable period may be limited by very low shear-wave velocity in shallow sediments, when the assumed retrograde elliptical particle motion polarisation for the fundamental mode breaks off. The highly non-linear sensitivity of frequency-dependent ellipticity curves can then be inverted using a direct search method to infer shear wave velocity profiles below stations. By comparing our results with local a priori geological information we show that robust information can indeed be retrieved.

  1. Sedimentary Environments of the Cangfanggou Group in Junggar Basin, Xinjiang, in Response to Climate and Tectonic Regime

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Detailed studies of petrology, palaeocurrent direction, palaeogeomorphology and palaeohydrodynamics have been conducted for the Permian-Triassic Cangfanggou Group in the foredeep of the Bogda Mountains in the southeastern Junggar Basin, Xinjiang. Sedimentary environments and facies of alluvial fans and pebbly braided rivers, sandy braided rivers, meandering rivers, low-sinuosity rivers, swamps and fresh-water lakes are recognized in the group. Climate and tectonics of source areas strongly controlled the evolution of the sedimentary environments and facies in the foredeep. The block faulting in the Bogda Mountains increased the ground slope, which led to a drastic increase in the grain size of the sediments.Humid climate, being beneficial to plant growth, would provide protection of channel banks and at the same time weaken chemical weathering in the source area,thus large amounts of clay materials are available for the formation of clay plugs. As a resuit, stable banks and meandering river belts are formed. Conversely, increasing aridity would strengthen mechanical weathering and reduce the mumber of clay plugs.Besides, plants would diminish gradually and channels would become more mobile. In this casc the decrease of transported clay materials would reduce the stability of the bank and result in a wider and shallower channel. Therefore, humid climate is beneficial to the formation of meandering rivers even if there is strong block faulting in the source areas and the ground slope is very large. As aridity further increases, plants would diminish and vanish at last,the meandering rivers prevalent under humid climate conditions would be transformed to low-sinuosity rivers even if the ground is gentle and the land is tectonically stable. And as the climate became more arid and the source area uplifted intensively to provide more sedimentary materials, low-sinuosity' rivers would be transformed to braided ones quickly, and wedge-like sedimentary bodies of the braided

  2. Mineralogical and geochemical aspects of the sedimentary zeolite occurrences in the Parnaiba Basin

    International Nuclear Information System (INIS)

    The paper presents the petrographical and mineralogical analysis by X-ray diffraction and chemical analysis through electronic microprobe realized in zeolites contained in the Corda Formation sandstones, in the northwestern portion of the Parnaiba Basin, Brazil. The data presented here update and complete the information propagated by Rezende and Angelica (1995) and Angelica et al. (1995)

  3. A review of stratigraphy and sedimentary environments of the Karoo Basin of South Africa

    Science.gov (United States)

    Smith, R. M. H.

    The Karoo Supergroup covers almost two thirds of the present land surface of southern Africa. Its strata record an almost continuous sequence of continental sedimentation that began in the Permo-Carboniferous (280 Ma) and terminated in the early Jurassic 100 million years later. The glacio-marine to terrestrial sequence accumulated in a variety of tectonically controlled depositories under progressively more arid climatic conditions. Numerous vertebrate fossils are preserved in these rocks, including fish, amphibians, primitive aquatic reptiles, primitive land reptiles, more advanced mammal-like reptiles, dinosaurs and even the earliest mammals. Palaeoenvironmental analysis of the major stratigraphic units of the Karoo sequence demonstrates the effects of more localised tectonic basins in influencing depositional style. These are superimposed on a basinwide trend of progressive aridification attributed to the gradual northward migration of southwestern Gondwanaland out of polar climes and accentuated by the meteoric drying effect of the surrounding land masses. Combined with progressive climatic drying was a gradual shrinking of the basin brought about by the northward migration of the subducting palaeo-Pacific margin to the south. Following deposition of the Cape Supergroup in the pre-Karoo basin there was a period of uplift and erosion. At the same time the southern part of Gondwana migrated over the South Pole resulting in a major ice-sheet over the early Karoo basin and surrounding highlands. Glacial sedimentation in both upland valley and shelf depositories resulted in the basal Karoo Dwyka Formation. After glaciation, an extensive shallow sea remained over the gently subsiding shelf fed by large volumes of meltwater. Black clays and muds accumulated under relatively cool climatic conditions (Lower Ecca) with perhaps a warmer "interglacial" during which the distinctive Mesosaurus-bearing, carbonaceous shales of the Whitehill Formation were deposited

  4. Volcano-sedimentary processes operating on a marginal continental arc: the Archean Raquette Lake Formation, Slave Province, Canada

    Science.gov (United States)

    Mueller, W. U.; Corcoran, P. L.

    2001-06-01

    The 200-m thick, volcano-sedimentary Raquette Lake Formation, located in the south-central Archean Slave Province, represents a remnant arc segment floored by continental crust. The formation overlies the gneissic Sleepy Dragon Complex unconformably, is laterally interstratified with subaqueous mafic basalts of the Cameron River volcanic belt, and is considered the proximal equivalent of the turbidite-dominated Burwash Formation. A continuum of events associated with volcanism and sedimentation, and controlled by extensional tectonics, is advocated. A complex stratigraphy with three volcanic and three sedimentary lithofacies constitute the volcano-sedimentary succession. The volcanic lithofacies include: (1) a mafic volcanic lithofacies composed of subaqueous pillow-pillow breccia, and subaerial massive to blocky flows, (2) a felsic volcanic lithofacies representing felsic flows that were deposited in a subaerial environment, and (3) a felsic volcanic sandstone lithofacies interpreted as shallow-water, wave- and storm-reworked pyroclastic debris derived from explosive eruptions. The sedimentary lithofacies are represented by: (1) a conglomerate-sandstone lithofacies consistent with unconfined debris flow, hyperconcentrated flood flow and talus scree deposits, as well as minor high-energy stream flow conglomerates that formed coalescing, steep-sloped, coarse-clastic fan deltas, (2) a sandstone lithofacies, interpreted as hyperconcentrated flood flow deposits that accumulated at the subaerial-subaqueous interface, and (3) a mudstone lithofacies consistent with suspension sedimentation in a small restricted lagoon-type setting. The Raquette Lake Formation is interpreted as a fringing continental arc that displays both high-energy clastic sedimentation and contemporaneous effusive and explosive mafic and felsic volcanism. Modern analogues that develop along active plate margins in which continental crust plays a significant role include Japan and the Baja California

  5. Phylogenetic analysis of bacteria in sea ice brine sampled from the Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bacterial diversity in sea ice brine samples which collected from four stations located at the Canada Basin, Arctic Ocean was analyzed by PCR-DGGE. Twenty-three 16S rDNA sequences of bacteria obtained from DGGE bands were cloned and sequenced. Phylogenetic analysis clustered these sequences within γ-proteobacteria, Cytophaga-Flexibacter-Bacteroides (CFB) group, Firmicutes and Actinobacteria. The phylotype of Pseudoalteromonas in the γ-proteobacteria was predominant and members of the CFB group and γ-proteobacteria were highly abundant in studied sea ice brine samples.

  6. A double-halocline structure in the Canada Basin of the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    SHI Jiuxin; ZHAO Jinping; LI Shujiang; CAO Yong; QU Ping

    2005-01-01

    A year-round halocline is a particular hydrographic structure in the upper Arctic Ocean. On the basis of an analysis of the hydrographic data collected in the Arctic Ocean, it is found that a double-halocline structure exists in the upper layer of the southern Canada Basin,which is absolutely different from the Cold Halocline Layer (CHL) in the Eurasian Basin. The Pacific-origin water is the primary factor in the formation of the double-halocline structure. The upper halocline lies between the summer modification and the winter modification of the Pacific-origin water while the lower halocline results from the Pacific-origin water overlying upon the Atlantic-origin water. Both haloclines are all the year-round although seasonal and interannual variations have been detected in the historical data.

  7. The Sedimentary System and Evolution of the Early Tertiary in the Sunda Basin, Indonesia

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Sunda basin is located at the north of the Sunda Strait situated between Sumatra and Java islands, Indonesia. It is an early Tertiary typical half-graben basin, in which developed a series of terrigenous clastic sedimentation. Previous work suggested that the early Tertiary sediments were alluvial, fluvial, lacustrine and swamp deposits, of which the Banuwati formation was alluvial and lacustrine deposits, the Zelda member fluvial deposits, and Gita member fluvial and swamp deposits. In this paper, based on the integrated research on core lithology (including lithology succession and structure), well log shape, and seismic reflection characteristics, a more detailed sedimentation system was set up as follows: 1) In addition to the alluvial, lacustrine, fluvial and the swamp deposits presented in previous work, subaqeous fan, shore-shallow lacustrine, deep lacustrine and turbidite fan, fan delta and delta deposits also developed in this basin. 2) Alluvial fan, subaqeous fan and fan delta deposits occurred on the steep slope adjacent to the synrift boundary fault; while the deltaic depositional system usually distributed on the gentle slope of the basins. 3) The Zelda member that was interpreted as a fluvial deposit in previous work is now interpreted as a subaqueous fan, fan delta, delta and lacustrine deposit system. 4) From the point of view of sedimentology, the evolution of basin could be divided into four stages: the initial subsidence (matching the Banuwati formation), the rapid subsidence (matching the low Zelda member of Talang Akar formation), the steady subsidence or fluctuation (matching the middle Zelda member of Talang Akar formation), and the uplifting (matching the upper Zelda member and the Gita member of Talang Akar formation). At the initial subsidence stage, the alluvial fan, flood plain, braided stream deposits developed, and then subaqeous fan sedimentation; at the rapid subsidence stage, shore-shallow lacustrine and deep lacustrine deposits

  8. The Hei River Basin in northwestern China - tectonics, sedimentary processes and pathways

    Science.gov (United States)

    Rudersdorf, Andreas; Nottebaum, Veit; Schimpf, Stefan; Yu, Kaifeng; Hartmann, Kai; Stauch, Georg; Wünnemann, Bernd; Reicherter, Klaus; Diekmann, Bernhard; Lehmkuhl, Frank

    2014-05-01

    The Hei River Basin (catchment area of c. 130,000 km²) is situated at the transition between the northern margin of the Tibetan Plateau and the southern slopes of Gobi-Tien-Shan. As part of the northwestern Chinese deserts, the Ejina Basin (Gaxun Nur Basin) constitutes the endorheic erosion base of the drainage system. The basin - hosting the second largest continental alluvial fans in the world, is tectonically strongly shaped by the Gobi belt of left-lateral transpression. The tectonic setting in combination with competing climatic driving forces (Westerlies and summer/winter monsoon currents) has supported the formation of a valuable long-time sediment archive comprises at least the last 250,000 yrs. of deposition. It is composed by the interplay of eolian, fluvial and lacustrine sedimentation cycles and today is dominated by widespread (gravel) gobi surfaces, insular dune fields and shallow evaporitic playa areas. Thus, it provides excellent conditions to investigate tectonic evolution and Quaternary environmental changes. Recently, geomorphological, geophysical, neotectonic and mineralogical studies have enhanced the understanding of the environmental history and the modern depositional environment. Moreover, the role of the Hei River Basin as an important source area of silt particles which were later deposited on the Chinese Loess Plateau is evaluated. Therefore, a 230 m long drill core, sediment sections and ca. 700 surface samples throughout the whole catchment and basin were analyzed. Instrumental and historical seismicity are very low, but the proximity to active fault zones and dating irregularities in earlier publications indicate evidence for deformation in the study area. Despite flat topography, indications of active tectonics such as fault-related large-scale lineations can be observed. Seismically deformed unconsolidated lacustrine deposits (seismites), presumably of Holocene age, are evident and must be related to the nearby faults. The upper

  9. Processes in Environmental Depositional Systems and Deformation in Sedimentary Basins: Goals for Exoloration in Mexico

    Science.gov (United States)

    Sandoval-Ochoa, J.

    2005-05-01

    Among the recent needs to establish new goals in the mexican energy industry to increase the petroleum reserves, has been necessary to recapitulate on some academic an operative concepts and definitions applied to the Petroliferous Basins Exploration; first of all, in order to understand the Petroleum System in given tectonophysical framework. The tectonophysical environment experienced by the petroliferous basin in the southwestern Gulf of Mexico, merely in the Campeche Sound and adjacent terrestrial regions (Figure 1); has been the result of interaction among the tectonic plates, the Coco's Plate with impingement and subduction beneath the Northamerican Plate and the Yucatán Microplate and even in very deep connection with the oceanic crust of southwesternmost portion of the Gulf of Mexico and the one of the Caribbean sea beneath the gulf of Belize-Honduras. The tectonosedimentary effects in the Campeche Bay starting with the skeleton formed for the Cenozoic Era, kept simultaneous conditions in depositions and deformations because of strain, stress and collapse fields, acted through this Era up to the present day, as observed in the surface Aguayo et al, 1999 and Sandoval, 2000. The involved portions of the crust and its boundaries have also been performing the relative sinking of the mere southwestern centre of the Gulf of Mexico, and the rising of the southeastern lands of Mexico. In the middle contiguity are found the productive Tertiary basins of: Comalcalco, Macuspana, Salina del Itsmo, Campeche-Champoton and other in deep waters; all of them, in an arrangement of basins among distensive faulted blocks in echelon, falling down to the deep centre of the Gulf Sandoval, op cit. With this scenario and that ones of other basins, a recapitulation on concepts and definitions, has been made on the regional natural processes of the environmental depositional systems and on the basins analysis in the tectonophysical framework, in order to reflect on the

  10. EVIDENCE OF NEOTECTONIC IMPACT ON A LARGE SEDIMENTARY BASIN BETWEEN TIBETAN PLATEAU AND GOBI ALTAY,NW CHINA

    Institute of Scientific and Technical Information of China (English)

    K.ttartmann; B.Wünnemann; Hucai Zhang

    2009-01-01

    The Ejina(Gaxun Nur)Basin-enclosed by the Tibetan Plateau in the south and the Gobi Altay in the north has continuously evolved as a strong continental endorheic depositional environment.Medium scale geomorphological mapping by Landsat-and Corona-Images as well as SRTM-topographic data,combined with field-surveys and geophysical investigation provides evidence for tectonic impact on sedimentary processes during the Late Quaternary.Analyses of SRTM-Data and Landsat-Images reveal a system of up to 20m high inverted channels developed on the inactive eastern part of the large Hei river drainage delta south of the ancient lake Juyanze.The complex evolution of these landforms requires a relative lowering of the lake basin at least two times since the last 40ka.A 26m high cliff section of gravel-covered lake sediments within the Juyanze paleolake indicates a strong subsidence of the lake bottom of 10m/1000yrs since 18kaB.P.North of Ejina river oasis a distinct north-south striking scarp up to 13m high constitutes the eastern margin of the Gaxun Nur.Palaeodrainage channels derived from the Gobi Altay.They display a sinistral offset of some decametres along a set of WE-trending faults.The rhombic shape of the modern dry Gaxun Nur,fossil cliffs,well preserved beach ridges along the margins of the palaeolake system as well as gravel covered topsets of lacustrine sediments indicate local displacements of morphological features.The displacements of lake sediments at the southern margin of the modern Gaxun Nut Basin imply a subsidence of at least 0.81m/1000 yrs since 25kaB.P.as a result of a pull-apart development due to the left stepping faults in a sinistral system.

  11. Flow-Through, Low Retention Hydrocarbon Generation in Active Sedimentary Basins

    Science.gov (United States)

    Cathles, L. M.

    2002-12-01

    Hydrocarbons are typically generated when thin (consumption of oil to date, from a 100 x 200 km portion of one basin in a relatively short timespan (about 20 Ma) provides an interesting geologic context for human production and consumption. The rapid venting also has potentially important implications for the fisheries food chain in the northern Gulf of Mexico. The venting rate is fast enough that hydrocarbons could be a significant aquatic food source.

  12. The supra-detachment tectono-sedimentary record of rifted margins: the example of the Los Barriles Basin, SE Baja California Sur.

    Science.gov (United States)

    Masini, Emmanuel; Robin, Cécile; Geoffroy, Laurent; Strzerzynski, Pierre

    2010-05-01

    The study of rifted margins have shown that the main controlling structures are changing from classical high-angle faults to low-angle detachment fault dominated extension when the crust thins to less than 10 km, which is the case in hyper-extended, magma-poor rifted margins. While the stratigraphic record related to classical high-angle faulting is well constrained, little is known about the tectono-sedimentary evolution of hyper-extended rift systems. A major question remains, how supra-detachment tectono-sedimentary systems are recorded in the stratigraphic record? This remains largely unexplored and must be better constrained by observations. In our poster, we present preliminary results from our study of a rift basin floored by a low-angle detachment system exposed at the southeastern edge of the Baja California Peninsula in the so-called Los Barriles area in the Gulf of California. This area represents one of the best examples of an active transtensional rift system from which the tectono-sedimentary evolution of the rift to drift transition can be studied in the field. The syn-tectonic sedimentary sequence is floored by a detachment fault and is limited oceanward by an extensional allochthon. The syn- to post-tectonic stratigraphy can be summarized into 4 main formations: (1) The Pescadero fluvial fm. (no available ages) evolves upsection from poorly organized polymictic in components and faulted breccias to more granitic and stratified conglomerates. It overlies the extensional allochthon and is tilted continentwards. The channel incisions show EW paleoflows and the upper Pescadero fm. is transitional to the following Refugio fm. (2) The overlying Refugio fm. (Lower Pliocene) occurs as thick marine sandy deposits within the basin axis, is granitic in composition and has average paleocurrents directions trending N-S. The upper part of the fm. is transitional to the following Barriles fm. (3) The Barriles fm. (Upper Miocene - Lower Pleistocene) occurs as very

  13. Tectonic uplift and sedimentary evolution of the Jiuxi Basin in the northern margin of the Tibetan Plateau since 13 Ma BP

    Institute of Scientific and Technical Information of China (English)

    宋春晖; 方小敏; 李吉均; 高军平; 赵志军; 范马洁

    2001-01-01

    Sediments shed from the northern margin of the Tibetan Plateau, the Qilian Mountains, are widely deposited in the foreland basin, the Jiuxi Basin, archiving plenty of information about the mountain surface uplift and erosion history. The Laojunmiao section, 1960 m thick, representing the upper sequence of the Cenozoic basin sediments, is paleomagnetically dated to about 13-0 Ma BP. Detailed sedimentary study of this sequence has revealed five sedimentary fades associations which determine four stages of sedimentary environment evolution. They are: (I) the half-deep lake system before 12.18 Ma BP, (Ⅱ) the shallow lake system between 12.18 and 8.26 Ma BP, (Ⅲ) the fan delta dominated sedimentary system in dry climate between 8.26 and 6.57 Ma BP, and (IV) alluvial fan system since 6.57 Ma BP. The associated mountain erosion and uplift are suggested to have experienced three phases, that is, tectonic stable (13-8.26 Ma BP), gradual uplift (8.26-<4.96 Ma BP), and rapid intermittent uplift (>3.66-0 Ma BP). Th

  14. Fluvial-aeolian interactions in sediment routing and sedimentary signal buffering: an example from the Indus Basin and Thar Desert

    Science.gov (United States)

    East, Amy E.; Clift, Peter D.; Carter, Andrew; Alizai, Anwar; VanLaningham, Sam

    2015-01-01

    Sediment production and its subsequent preservation in the marine stratigraphic record offshore of large rivers are linked by complex sediment-transfer systems. To interpret the stratigraphic record it is critical to understand how environmental signals transfer from sedimentary source regions to depositional sinks, and in particular to understand the role of buffering in obscuring climatic or tectonic signals. In dryland regions, signal buffering can include sediment cycling through linked fluvial and eolian systems. We investigate sediment-routing connectivity between the Indus River and the Thar Desert, where fluvial and eolian systems exchanged sediment over large spatial scales (hundreds of kilometers). Summer monsoon winds recycle sediment from the lower Indus River and delta northeastward, i.e., downwind and upstream, into the desert. Far-field eolian recycling of Indus sediment is important enough to control sediment provenance at the downwind end of the desert substantially, although the proportion of Indus sediment of various ages varies regionally within the desert; dune sands in the northwestern Thar Desert resemble the Late Holocene–Recent Indus delta, requiring short transport and reworking times. On smaller spatial scales (1–10 m) along fluvial channels in the northern Thar Desert, there is also stratigraphic evidence of fluvial and eolian sediment reworking from local rivers. In terms of sediment volume, we estimate that the Thar Desert could be a more substantial sedimentary store than all other known buffer regions in the Indus basin combined. Thus, since the mid-Holocene, when the desert expanded as the summer monsoon rainfall decreased, fluvial-eolian recycling has been an important but little recognized process buffering sediment flux to the ocean. Similar fluvial-eolian connectivity likely also affects sediment routing and signal transfer in other dryland regions globally.

  15. A sub-surface eddy at inertial current layer in the Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An Arctic Ocean eddy in sub-surface layer is analyzed in this paper by use of temperature, salinity and current profiles data obtained at an ice camp in the Canada Basin during the second Chinese Arctic Expedition in summer of 2003.In the vertical temperature section, the eddy shows itself as an isolated cold water block at depth of 60 m with a minimum temperature of-1.5℃, about 0.5℃ colder than the ambient water.Isopycnals in the eddy form a pattern of convex, which indicates the eddy is anticyclonic.Although maximum velocity near O.4 m s-1 occurs in the current records observed synchronously, the current pattern is far away from a typical eddy.By further analysis, inertial frequency oscillations with amplitudes comparable with the eddy velocity are found in the sub-surface layer currents.After filter the inertial current and mean current, an axisymmetric current pattern of an eddy with maximum velocity radius of 5 km is obtained.The analysis of the T-S characteristics of the eddy core water and its ambient waters supports the conclusion that the eddy was formed on the Chukchi Shelf and migrated northeastward into the northern Canada Basin.

  16. Sedimentary facies and depositional model of shallow water delta dominated by fluvial for Chang 8 oil-bearing group of Yanchang Formation in southwestern Ordos Basin, China

    Institute of Scientific and Technical Information of China (English)

    陈林; 陆永潮; 吴吉元; 邢凤存; 刘璐; 马义权; 饶丹; 彭丽

    2015-01-01

    A systematic analysis of southwestern Ordos Basin’s sedimentary characteristics, internal architectural element association styles and depositional model was illustrated through core statistics, well logging data and outcrop observations in Chang 8 oil-bearing group. This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin. Four microfacies with fine grain sizes are identified: distributary channels, sheet sandstone, mouth bar and interdistributary fines. According to the sandbody’s spatial distribution and internal architecture, two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone. In this sedimentary system, net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front. The mouth bar is largely absent in this system. By analyzing the palaeogeomorphology, the palaeostructure background, sedimentary characteristics, sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period, a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established, which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain, net-like distributary channels frequently diverting and converging in the proximal delta front, sheet sandstones with dispersing contiguous lobate shapes in the distal delta front, and prodelta or shallow lake mudstones.

  17. Interpretation of Refraction Data From the San Fernando Valley Sedimentary Basin

    Science.gov (United States)

    Thygesen, K.; Fuis, G. S.; Simila, G.; Thybo, H.; Murphy, J. M.; Okaya, D. A.

    2001-12-01

    In the second phase of the Los Angeles Region Seismic Experiment (Oct. 1999, LARSE II), two auxiliary seismic profiles (line 3 & 4) were recorded in the San Fernando Valley (SFV). The lines are 11.5/22.5 km long and recorded 4/6 inline shots. The lines were designed to constrain the basin geometry and geology of the SFV in an effort to identify areas of potentially high seismic hazard. Line 3 is located in the southern part of the SFV and strikes NW-SE through the Sepulveda flood control basin. Line 4 is located in the northern part of the Valley and strikes E-W from Hansen Dam to a point north of Chatsworth reservoir, crossing the Verdugo fault, the Northridge Hills blind thrust fault, and the Chatsworth reservoir fault. The seismic velocity model for line 3 is based on tomographic inversion and has useful ray coverage to 2.2 km in depth. It shows a constant velocity gradient down to 1.5 km were the velocity reach 4.0 km/s. In the southeast part of the line at 1.7 km depth, velocities of 4.5-5.5 km/s may identify crystalline rocks, as also reported from well data. The velocity model for line 4 has adequate ray coverage down to 4.2 km. It defines a basin which deepens gradually from west to east, and terminates at a sub-vertical boundary in the east. This boundary is interpreted as the Verdugo fault. Velocity contours in the deeper western part of the profile, could represent the Chatsworth reservoir fault, but the ray coverage is relatively low. There is no evidence of the Northridge Hills fault, with the tomographic inversion. This could be because the profile crosses the fault at an oblique angle.

  18. Preliminary Paleomagnetic Results From Tertiary Rocks of Sedimentary Basins in Northern Vietnam and Tectonic Implications

    Science.gov (United States)

    Zhao, X.; Liu, Z.; Le, K.; Zhao, Y.; Hoang, V.; Phan, D.

    2013-12-01

    The South China Sea (SCS) is a classical representative of western Pacific marginal seas and contains records of Cenozoic tectonic events of SE Asia. The SCS has been at the center stage of many first-order tectonic and paleoclimatic events since the Mesozoic. One clear way to evaluate the relationship between tectonic uplift and climate is to study the resulting changes in marginal sea strata. To this end, we will conduct an integrated paleomagnetic and stratigraphic investigation on Tertiary strata from Phu Tho and Yen Bai provinces, northern Vietnam to help understand the causal linkages among geological and tectonic events and their consequences related to the SCS evolution. We will collect paleomagnetic samples at sections where the most continuous, complete, and best preserved Eocene-Miocene successions. Standard paleomagnetic field tests, such as the fold, reversal, and conglomerate tests will be used to determine the relative age of the magnetization. In addition to detailed thermal and alternating field demagnetization and analysis, selected samples will also be subjected to several rock magnetic analyses to identify magnetic carriers in the rocks. In particular, the hysteresis parameters Jrs/Js and Hcr /Hc ratios will enable us to apply techniques for detecting low-temperature remagnetization of sedimentary rocks. Preliminary finding of this ongoing project will be presented.

  19. Investigating Controls on Sedimentation Through Interpretation of the Syntectonic Cretaceous-Paleogene Sedimentary Record in the San Juan Basin (New Mexico, U.S.A.)

    Science.gov (United States)

    Hobbs, K.; Weissmann, G. S.; Fawcett, P. J.

    2015-12-01

    The Cretaceous/Paleogene boundary in the southwestern San Juan Basin is bracketed by the mudstone-dominated Cretaceous Kirtland Formation, the sandstone-dominated Paleocene Ojo Alamo Sandstone, and the mudstone-dominated Paleocene lower Nacimiento Formation. Geochemical trends of fluvial mudstones from these units indicate changing sedimentary source areas through time. While the Kirtland and Nacimiento Formations represent periods of high accommodation within the San Juan Basin, the Ojo Alamo Sandstone represents a period of low accommodation and general reworking and transport by southeast-flowing paleorivers. The Kirtland and Nacimiento Formations thin and fine away from their interpreted source area whereas the Ojo Alamo Sandstone thickens and fines away from the source area. Here we investigate the enigmatic sedimentary architecture of the Ojo Alamo Sandstone, geochemical evidence for a changing source area through this time period, and the complex relationships between sedimentation, source area, accommodation, and basin tectonic evolution. Incorporating new measured sections, petrographic analyses, geochemical trends, and stratigraphic relationships, we propose that the Ojo Alamo Sandstone represents an anomalous short period of low accommodation in the San Juan Basin during the early Laramide Orogeny and explore possible intra- and extra-basinal tectonic, climatic, and sedimentologic explanations as well as implications for understanding the evolution of the basin.

  20. Canada

    International Nuclear Information System (INIS)

    Nuclear research and development in Canada started in the 1940s as a responsibility of the federal government. An engineering design team was established at Chalk River, Ontario, to carry out research on heavy water moderated lattices. A zero-energy heavy water moderated research reactor, ZEEP, was built and achieved criticality in September 1945; it was in fact the first human-made operating reactor outside the USA. In 1947, the 20 MW heavy water moderated national research experimental reactor (NRX) started up. It served as one of the most valuable research reactors in the world, and provided the basis for Canada's development of the very successful CANDU series of pressurised heavy water reactors (PHWR) for power generation. Atomic Energy of Canada Limited (AECL) was established in 1952 as a federal Crown Corporation. It has both a public and a commercial mandate. AECL has overall responsibility for Canada's nuclear research and development programme (its public mandate) as well as for the Canadian reactor design (CANDU), engineering and marketing programme (its commercial mandate). Nuclear energy in Canada is a $5 billion per-year industry, representing about 150 firms, 21 000 direct jobs and 10 000 indirect jobs, and ∼$1.2 billion in exports - the value to the country's economy is much higher than the research and development funding provided by the federal government. The CANDU nuclear reactor system was developed by AECL in close collaboration with the Canadian nuclear industry, and in particular with Ontario Hydro (now Ontario Power Generation). Currently, Canada operates 17 CANDU reactors, which contribute 16% of the country's current electricity consumption. There are also 12 CANDU reactors operating abroad (in Argentina, China, India, the Republic of Korea, Pakistan and Romania). AECL is now developing the 'third generation plus' Advanced CANDU Reactor (ACR-1000), and also has the leading role internationally in developing the Generation IV

  1. The structure and stratigraphy of the sedimentary succession in the Swedish sector of the Baltic Basin: New insights from vintage 2D marine seismic data

    Science.gov (United States)

    Sopher, Daniel; Erlström, Mikael; Bell, Nicholas; Juhlin, Christopher

    2016-04-01

    We present five interpreted regional seismic profiles, describing the full sedimentary sequence across the Swedish sector of the Baltic Sea. The data for the study are part of an extensive and largely unpublished 2D seismic dataset acquired between 1970 and 1990 by the Swedish Oil Prospecting Company (OPAB). The Baltic Basin is an intracratonic basin located in northern Europe. Most of the Swedish sector of the basin constitutes the NW flank of a broad synclinal depression, the Baltic Basin. In the SW of the Swedish sector lies the Hanö Bay Basin, formed by subsidence associated with inversion of the Tornquist Zone during the Late Cretaceous. The geological history presented here is broadly consistent with previously published works. We observe an area between the Hanö Bay and the Baltic Basin where the Palaeozoic strata has been affected by transpression and subsequent inversion, associated with the Tornquist Zone during the late Carboniferous-Early Permian and Late Cretaceous, respectively. We propose that the Christiansø High was a structural low during the Late Jurassic, which was later inverted in the Late Cretaceous. We suggest that a fan shaped feature in the seismic data, adjacent to the Christiansø Fault within the Hanö Bay Basin, represents rapidly deposited, coarse-grained sediments eroded from the inverted Christiansø High during the Late Cretaceous. We identify a number of faults within the deeper part of the Baltic Basin, which we also interpret to be transpressional in nature, formed during the Caledonian Orogeny in the Late Silurian-Early Devonian. East of Gotland a number of sedimentary structures consisting of Silurian carbonate reefs and Ordovician carbonate mounds, as well as a large Quaternary glacial feature are observed. Finally, we use the seismic interpretation to infer the structural and stratigraphic history of the Baltic and Hanö Bay basins within the Swedish sector.

  2. The Beaufort Gyre variation and its impacts on the Canada Basin in 2003-2012

    Institute of Scientific and Technical Information of China (English)

    ZHONG Wenli; ZHAO Jinping; SHI Jiuxin; CAO Yong

    2015-01-01

    The Beaufort Gyre (BG) was spun up in the last decade which is an important factor in regulating the variation of the upper ocean. The heat content and freshwater content of the upper ocean increased gradually in the Canada Basin, as did momentum input. Both the geostrophic wind curl and freshwater content could contribute to the spin-up of BG. However, even though there is no change of the wind field the increasing freshwater alone could result in the spin-up of BG. In this study we show that the Pacific Water is difficult to flow into the central basin as the BG spins up and the maximum temperature of the Pacific Summer Water (PSW) experienced a dramatic decrease inside the BG in 2005 and 2009 due to a change of flow pathway of PSW. The enhancement of Ekman Pumping (EP) contributed to the deepening of the Pacific Winter Water by piling up more freshwater. This change of water column dynamics has also contributed to the deepening ofthe Atlantic Water core after 2007. The EP decreased significantly in 2012 (indicating a spin down of BG) and the direction of Ekman transport turned to the north, which favoured the release of freshwater that had resided in the basin for years.

  3. Basic Types and Structural Characteristics of Uplifts: An Overview of Sedimentary Basins in China

    Institute of Scientific and Technical Information of China (English)

    HE Dengfa; LI Desheng; WU Xiaozhi; WEN Zhu

    2009-01-01

    The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19-3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types--the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can he subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The

  4. Report on the research so far carried out in the sedimentary basin situated east of Potamoi village, Drama Department

    International Nuclear Information System (INIS)

    This report refers to the small sedimentary basin of about 40 km2 situated east of Potamoi village (north of Drama department) within the crystalline massive of Rhodope. The results of the first phase stream sediment sampling have been very promising. The localization of a great number of radiometric anomalous horizons, mainly of arkosic composition, very rich in hematite-limonite, and with small amounts of carbonaceous material was the result of a first recognizing geological and radiometric research carried out within the area concerned. The geological formation of interest consists of alternating tough beds of different composition (fine-, medium-, course-grained arkoses, conglomerates and siltstone). The strike of these beds is about E-W and their dip about 70 deg northerly. The probable age of this formation is eocenic-oligocenic. A pair of assays from horizons with high γ-radiation have shown concentrations of easily extractable uranium between 100 and 300 ppm. The results from the research so far conducted within the area concerned lead us to the conclusion that this is a very promising area and the possibilities of localization of payable concentrations of uranium in it are very high. (author)

  5. Measurement of intrinsic and scattering attenuation of shear waves in two sedimentary basins and comparison to crystalline sites in Germany

    Science.gov (United States)

    Eulenfeld, Tom; Wegler, Ulrich

    2016-05-01

    We developed an improved method for the separation of intrinsic and scattering attenuation of seismic shear waves by envelope inversion called Qopen. The method optimizes the fit between Green's functions for the acoustic, isotropic radiative transfer theory and observed energy densities of earthquakes. The inversion allows the determination of scattering and intrinsic attenuation, site corrections and spectral source energies for the investigated frequency bands. Source displacement spectrum and the seismic moment of the analysed events can be estimated from the obtained spectral source energies. We report intrinsic and scattering attenuation coefficients of shear waves near three geothermal reservoirs in Germany for frequencies between 1 and 70 Hz. The geothermal reservoirs are located in Insheim, Landau (both Upper Rhine Graben) and Unterhaching (Molasse basin). We compare these three sedimentary sites to two sites located in crystalline rock with respect to scattering and intrinsic attenuation. The inverse quality factor for intrinsic attenuation is constant in sediments for frequencies smaller than 10 Hz and decreasing for higher frequencies. For crystalline rock, it is on a lower level and strictly monotonic decreasing with frequency. Intrinsic attenuation dominates scattering except for the Upper Rhine Graben, where scattering is dominant for frequencies below 10 Hz. Observed source displacement spectra show a high-frequency fall-off greater than or equal to 3.

  6. Aliphatic biomarkers and their signal from two hydrogeochemically differing sedimentary environments of the Tertiary Krepoljin Coal Basin (Serbia)

    Science.gov (United States)

    Dević, Gordana J.; Popovic, Zoran

    2010-05-01

    The sediments of the coal-bearing series of the Tertiary Krepoljin Brown Coal Basin have been investigated and presented in this manuscript. The samples of the intercalated mixed sediments (pieces of coal in clays, sandstones and shales) originate from two hydrogeochemically differing sedimentary environments: the illite-montmorillonitic (IM), and the calcitic (Ct) environment. The characteristics of the early diagenetic processes which influenced the composition of the organic matter of this sediment were assessed by the statistical correlation analysis and multivariate principal component analysis. The precursor material of higher plants gymnosperms had a significant influence on the overall organic matter of mixed sediments in both hydrochemical environments. A weak effect of N/C ratios on the specific diagenetic transformations of hopanoid molecules is noticed in the samples of the calcite environment. Sterane maturation transformations are not marked as significant for the samples of mixed sediments by the component analysis. The samples of I-M environments show a strong inhibitory effect on the processes of diastereoisomerization.

  7. Sedimentary Basin Analysis and Petroleum Potential of the Cretaceous Yuchon Group In Haenam Depression, SW Korea

    Institute of Scientific and Technical Information of China (English)

    Son Jin-Dam

    2000-01-01

    The Yuchon Group in the Late Cretaceous of Haenam and Mokpo area on the southwest coast of Korea peninsula can be divided into two Formations: (1) the intermediate volcanic Formation (Hwawon Formation), about 500m thick, (2)the acidic volcanic Formation (Hwangsan Formation), about 400m thick in ascending order.The former comprises intermediate volcaniclastics interlayered with volcanic rocks, and red mudrock and tuffaceous sandstone indicating fluvial deposits. The latter is subdivided into the upper part (Hwangsan Tuff Member) consisting of subaerial pyroclastics and intercalated rhyolites, and the lower part (Byeongonri Member) including subaqueous volcaniclastics, lake deltaic sandstone and gravelstone, lacustrine black shale and limestone and chert, and lake turbidite sandstone.The Late Cretaceous basin including Haenam subbasin in southwest Korea was largely formed of extensional nonmarine depressions (volcano- tectonic) bounded by NE- SW sinistral fault system.The thermal maturation based on geochemical and mineralogical studies for the black shales and tuffaceous sandstones reached the late stage of oil generation zone or gas generation stage. It seems that black shales and limestones are fairly good as source rock. The porosity of potential reservoir sandstone and tuff ranges from 5 % to 11%, but their permeability except the fractured rocks is very low ( <1md) because of fine pore throats reduced by diagenetic cementation of tuffaceous sandstones. Numerous potential traps might have been formed by the later folding and faulting along with lateral facies change and abundant mudrocks and volcaniclastics should make excellent seals.

  8. Geology of the Cenozoic Indus Basin sedimentary rocks: Paleoenvironmental interpretation of sedimentation from the western Himalaya during the early phases of India-Eurasia collision

    OpenAIRE

    Henderson, Alexandra L.; Najman, Yani; Parrish, Randall; BouDagher‐Fadel, Marcelle; Barford, Dan; Garzanti, Eduardo; Andò, Sergio

    2010-01-01

    This study reassesses the stratigraphy, sedimentology, and provenance of the Indus Basin sedimentary rocks, deposited within the Indus Tsangpo Suture Zone (ITSZ) during the early phases of India-Eurasia collision. Using field observations, biostratigraphy, and petrographic and isotopic analyses we create a paleodepositional reconstruction within the paleotectonic setting of the early phases of India-Eurasia collision. We then re-examine existing constraints to the timing of India-Eurasia coll...

  9. Sequence Stratigraphy and Sedimentary Facies of Lower Oligocene Yacheng Formation in Deepwater Area of Qiongdongnan Basin, Northern South China Sea:Implications for Coal-Bearing Source Rocks

    Institute of Scientific and Technical Information of China (English)

    Jinfeng Ren; Hua Wang; Ming Sun; Huajun Gan; Guangzeng Song; Zhipeng Sun

    2014-01-01

    For unveiling coal-bearing source rocks in terrestrial-marine transitional sequences, the sequence stratigraphic framework and sedimentary facies of Lower Oligocene Yacheng Formation of Qiongdongnan Basin were investigated using seismic profiles, complemented by well bores and cores. Three third-order sequences are identified on the basis of unconformities on basin margins and cor-relative conformities in the basin center, namely SQYC3, SQYC2 and SQYC1 from bottom to top. Coal measure in Yacheng Formation of Qiongdongnan Basin were deposited within a range of facies asso-ciations from delta plain/tidal zone to neritic sea, and three types of favourable sedimentary facies as-sociations for coal measure were established within the sequence stratigraphic framework, including braided delta plain and alluvial fan, lagoon and tidal flat, and fan delta and coastal plain facies associa-tions. Results shown that, in the third-order sequences, coal accumulation in landward areas (such as delta plain) of the study area predominantly correlates with the early transgressive systems tract (TST) to middle highstand systems tract (HST), while in seaward areas (such as tidal flat-lagoon) it correlates with the early TST and middle HST. The most potential coal-bearing source rocks formed where the accommodation creation rate (Ra) and the peat-accumulation rate (Rp) could reach a state of balance, which varied among different sedimentary settings. Furthermore, intense tectonic subsidence and fre-quent alternative marine-continental changes of Yacheng Formation during the middle rift stage were the main reasons why the coal beds shown the characteristics of multi-beds, thin single-bed, and rapidly lateral changes. The proposed sedimentary facies associations may aid in predicting distribution of coal-bearing source rocks. This study also demonstrates that controlling factors analysis using sequence stratigraphy and sedimentology may serve as an effective approach for coal

  10. Factors controlling the sedimentary evolution of the Kimmeridgian ramp in the north Iberian Basin (NE Spain

    Directory of Open Access Journals (Sweden)

    Bádenas, B.

    1994-04-01

    Full Text Available The aim of this paper is to summarize the present knowledge reached by the authors on the carbonate ramp which developed in the iberian basin during Kimmeridgian times. Our results were obtained from a combined field analysis and computer modelling carried out in the north Iberian Chain (NE Spain. Extensive field analysis in the Ricia area (Zaragoza, NE Spain, resulted in a detailed mapping of the transition from inner to outerramp facies on this carbonate rampo Three facies belts may be distinguished in this rampo The outer ramp facies consists of marls and mudstones rhythmic facies. The inner ramp facies, located aboye fair-weather wave base, are dominated by coral patch reef growing. The middle ramp facies are represented by marls and micrites bearing skeletal and oolitic tempestite levels which sharply grade into high-amplitude o'olitic sandwave. Factors such as resedimentation by storms, carbonate production and relative variation of sea level acting in the Kimmeridgian ramp are also quantiphied and discussed. Most of the mud accumulated in outer-ramp areas was produced in the coral «carbonate factory» located in inner areas. Off-shore resedimentation by storm was the main agent of basinward transport of this mudo The deduced accommodation curve consists of three elements: a linear rise which satisfactorily matches the normal subsidence figures observed in intracratonic basins; a third-order cycle, that may have a regional cause and higher order cycles in the Milanckovich band, that may be eustatic in origin.La sedimentación en la cuenca ibérica septentrional durante el Kimmeridgiense tuvo lugar en una extensa rampa carbonatada de bajo ángulo. Las facies de rampa externa, acumuladas por debajo del nivel de base del oleaje debido a tormentas (i.e., C. 50 to 80 m de profundidad, están formadas por una ritmita de margas y calizas (i.e., Fm Loriguilla. Las facies de rampa interna, localizadas por encima del nivel de base del oleaje de

  11. Nutrient maximums related to low oxygen concentrations in the southern Canada Basin

    Institute of Scientific and Technical Information of China (English)

    JIN Ming-ming; SHI Jiuxin; LU Yong; CHEN Jianfang; GAO Guoping; WU Jingfeng; ZHANG Haisheng

    2005-01-01

    The phenomenon of nutrient maximums at 70~200 m occurred only in the region of the Canada Basin among the world oceans. The prevailing hypothesis was that the direct injection of the low-temperature high-nutrient brines from the Chukchi Sea shelf (<50 m) in winter provided the nutrient maximums. However, we found that there are five problems in the direct injection process. Formerly Jin et al. considered that the formation of nutrient maximums can be a process of locally long-term regeneration. Here we propose a regeneration-mixture process. Data of temperature, salinity, oxygen and nutrients were collected at three stations in the southern Canada Basin during the summer 1999 cruise. We identified the cores of the surface, near-surface, potential temperature maximum waters and Arctic Bottom Water by the diagrams and vertical profiles of salinity, potential temperature, oxygen and nutrients. The historical 129Ⅰ data indicated that the surface and near-surface waters were Pacific-origin, but the waters below the potential temperature maximum core depth was Atlantic-origin. Along with the correlation of nutrient maximums and very low oxygen contents in the near-surface water, we hypothesize that, the putative organic matter was decomposed to inorganic nutrients; and the Pacific water was mixed with the Atlantic water in the transition zone. The idea of the regeneration-mixture process agrees with the historical observations of no apparent seasonal changes, the smooth nutrient profiles, the lowest saturation of CaCO3 above 400 m, low rate of CFC-11 ventilation and 3H-3He ages of 8~18 a around the nutrient maximum depths.

  12. A new look at Northwind Ridge: implications for the history of the Canada Basin

    Science.gov (United States)

    Hutchinson, D. R.; Mosher, D. C.; Shimeld, J.; Jackson, R.; Chian, D.; Edwards, B. D.; Hart, P. E.; Mayer, L. A.

    2010-12-01

    Researchers from the US and Canada are conducting collaborative seismic, multibeam, and sampling studies in the mostly ice-covered regions of the Canada Basin (CB) of the Arctic Ocean. Recently acquired data sets, together with older acoustic and coring data, yield new details about the stratigraphic and structural history of CB, particularly regarding its boundary with Northwind Ridge (NR). As previously interpreted, NR represents the eastern edge of a rifted, submerged continental block known as Chukchi Borderland. Gradients along the remarkably linear slope are generally between 10o and 30o, but can be locally as high as ~70o. Water depths across the ridge vary from ~1000 m to ~3800 m. The new data reveal perched half grabens within the escarpment, and numerous complex reflection packages, including at least one possible talus deposit. These deeper reflection packages continue east for ~ 100 km (off northern NR) to ~200 km (off central NR) beneath the oldest on-lapping deposits of CB. This continuity suggests that the shallow basement extending east of NR consists of rocks that may be similar to those on NR, but more highly stretched and therefore more deeply subsided. A low-amplitude positive gravity anomaly coincides with this inferred continental-basement remnant. The profound unconformity at the top of these oldest reflection packages is generally highly reflective, gently sloping, and low relief. This reflection character of basement changes abruptly to high-relief and minimally reflective adjacent to and beneath a distinctive curvilinear gravity low that extends most of the length of CB, previously interpreted as a possible seafloor spreading center. The transition in basement reflection character can be mapped on multiple seismic lines and may represent the basement expression of the final breakup position of the continent (west) to ocean (east) boundary. Two consequences of this possible buried and subsided continental-basement fragment are that (1

  13. Current and future water issues in the Oldman River Basin of Alberta, Canada.

    Science.gov (United States)

    Byrne, J; Kienzle, S; Johnson, D; Duke, G; Gannon, V; Selinger, B; Thomas, J

    2006-01-01

    Long-term trends in alpine and prairie snow pack accumulation and melt are affecting streamflow within the Oldman River Basin in southern Alberta, Canada. Unchecked rural and urban development also has contributed to changes in water quality, including enhanced microbial populations and increased waterborne pathogen occurrence. In this study we look at changing environment within the Oldman River Basin and its impact on water quality and quantity. The cumulative effects include a decline in net water supplies, and declining quality resulting in increased risk of disease. Our data indicates that decreases in the rate of flow of water can result in sedimentation of bacterial contaminants within the water column. Water for ecosystems, urban consumption, recreation and distribution through irrigation is often drawn from waterholding facilities such as dams and weirs, and concern must be expressed over the potential for contaminate build-up and disproportionate potential of these structures to pose a risk to human and animal health. With disruption of natural flow rates for water resulting from environmental change such as global warming and/or human intervention, increased attention needs to be paid to use of best management practices to protect source water supplies.

  14. Observational analysis of the double-diffusive convection in the deep Canada Basin

    Institute of Scientific and Technical Information of China (English)

    XIE Lingling; LI Mingming; LI Min

    2015-01-01

    The Canada Basin (CB) is the largest sub-basin in the Arctic, with the deepest abyssal plain of 3 850 m. The double-diffusive process is the possible passage through which the geothermal energy affects the above isolated deep waters. With the temperature-salinity-pressure observations in 2003, 500-m-thick transition layers and lower 1 000-m-thick bottom homogenous layers were found below 2 400 m in the central deep CB. Staircases with downward-increasing temperature and salinity are prominent in the transition layers, suggesting the double-diffusive convection in deep CB. The interface of the stairs is about 10 m thick with 0.001–0.002°C temperature difference, while the thicknesses of the homogenous layers in the steps decrease upward from about 60 to 20 m. The density ratio in the deep central CB is generally smaller than 2, indicating stronger double-diffusive convection than that in the upper ocean of 200–400 m. The heat flux through the deepest staircases in the deep CB varies between 0.014 and 0.031 W/m2, which is one-two orders smaller than the upper double-diffusive heat flux, but comparable to the estimates of geothermal heat flux.

  15. Geochemical behavior and dissolved species control in acid sand pit lakes, Sepetiba sedimentary basin, Rio de Janeiro, SE - Brazil

    Science.gov (United States)

    Marques, Eduardo D.; Sella, Sílvia M.; Bidone, Edison D.; Silva-Filho, Emmanoel V.

    2010-12-01

    This work shows the influence of pluvial waters on dissolved components and mineral equilibrium of four sand pit lakes, located in the Sepetiba sedimentary basin, SE Brazil. The sand mining activities promote sediment oxidation, lowering pH and increasing SO 4 contents. The relatively high acidity of these waters, similar to ore pit lakes environment and associated acid mine drainage, increases weathering rate, especially of silicate minerals, which produces high Al concentrations, the limiting factor for fish aquaculture. During the dry season, basic cations (Ca, Mg, K and Na), SiO 2 and Al show their higher values due to evapoconcentration and pH are buffered. In the beginning of the wet season, the dilution factor by rainwater increases SO 4 and decreases pH values. The aluminum monomeric forms (Al(OH) 2+ and Al(OH) 2+), the most toxic species for aquatic organisms, occur during the dry season, while AlSO 4+ species predominate during the wet season. Gibbsite, allophane, alunite and jurbanite are the reactive mineral phases indicated by PHREEQC modeling. During the dry season, hydroxialuminosilicate allophane is the main phase in equilibrium with the solution, while the sulphate salts alunite and jurbanite predominate in the rainy season due to the increasing of SO 4 values. Gibbsite is also in equilibrium with sand pit lakes waters, pointing out that hydrolysis reaction is a constant process in the system. Comparing to SiO 2, sulphate is the main Al retriever in the pit waters because the most samples (alunite and jurbanite) are in equilibrium with the solution in both seasons. This Al hydrochemical control allied to some precaution, like pH correction and fertilization of these waters, allows the conditions for fishpond culture. Equilibrium of the majority samples with kaolinite (Ca, Mg, Na diagrams) and primary minerals (K diagram) points to moderate weathering rate in sand pit sediments, which cannot be considered for the whole basin due to the anomalous

  16. Connections between sedimentary basins during continental collision: how tectonic, surface and sedimentary processes shaped the Paratethys (Utrecht Studies in Earth Sciences 045)

    NARCIS (Netherlands)

    ter Borgh, M.M.

    2013-01-01

    The aim of this thesis is to improve the understanding of source to sink systems in general and the Danube River Basin - Black Sea source to sink system in particular. The sediment sources of this system are formed by a number of mountain chains, including the Alps, Dinarides and Carpathians; a numb

  17. Chronology and tectono-sedimentary evolution of the Upper Pliocene to Quaternary deposits of the lower Guadalquivir foreland basin, SW Spain

    Science.gov (United States)

    Salvany, Josep Maria; Larrasoaña, Juan Cruz; Mediavilla, Carlos; Rebollo, Ana

    2011-11-01

    This paper presents new litho, chrono and magnetostratigraphic data from cores of 23 exploratory boreholes drilled in the Abalario and marshlands areas of the lower Guadalquivir basin (the western sector of the Guadalquivir foreland basin, SW of Spain). The lithologic logs of these boreholes identify four main sedimentary formations, namely: Almonte Sand and Gravel, Lebrija Clay and Gravel, Marismas Clay and Abalario Sand, respectively interpreted as proximal-alluvial, distal-alluvial, alluvial-estuarine and aeolian. From radiocarbon and magnetostratigraphic data, these formations were dated as Upper Pliocene to Holocene. In the marshlands area, three main sedimentary sequences are present: an Upper Pliocene to Lower Pleistocene sequence of the Almonte and Lebrija (lower unit) formations, a Pleistocene sequence of the Lebrija (upper unit) and the lower Marismas formations, and a latest Pleistocene to present-day sequence of the upper Marismas Formation. The three sequences began as a rapid alluvial progradation on a previously eroded surface, and a subsequent alluvial retrogradation. In the third sequence, estuarine and marsh sediments accumulated on top of the alluvial sediments. The aeolian sands of the Abalario topographic high developed coeval to alluvial and estuarine sedimentation after the first alluvial progradation, and continuously until the present. Correlation with the surrounding areas show that the sequences are the result of the forebulge uplift of the northern margin of the basin (Sierra Morena) and the adjacent Neogene oldest sediments of their northern fringe, both form the main source area of the study formations. This uplift occurred simultaneous to the flexural subsidence (SSE tilting) of the southern part of the basin, where sedimentary aggradation dominated.

  18. Canada

    International Nuclear Information System (INIS)

    This paper reports that the Canadian oil and natural gas sector is in for another grim year in 1992. Further streamlining to enhance operating efficiencies and control costs is the first order of the day. About $4 billion worth of producing properties remains on the market, as corporate focus continues to shift to core properties. New management structures put in place in the last two years will be severely tested to improve the sector's financial performance. Massive write-downs in 1990 and 1991 have put balance sheets in much better shape for improved financial performance in the future. Although new long-term debt exceeded redemptions in 1991, largely because of debt- financing of major capital projects, individually most companies are in better shape through significant debt repayment or restructuring. The substantial reductions in interest rates will also help to enhance discretionary cash flow. At this stage, everything appears to be in place to expect that 1992 will represent the bottom of the down-cycle for Canada

  19. Origin and time-space distribution of hydrothermal systems in east-central Australian sedimentary basins: Constraints from illite geochronology and isotope geochemistry.

    Science.gov (United States)

    Uysal, I. Tonguç

    2016-04-01

    Some well-known precious mineral deposits and hydrocarbon resources occur extensively in east-central Australian sedimentary Basins. The metal occurrences are abundant in northwestern and eastern part of Queensland, whereas no significant deposits are known in large areas further south, which may, however, be hidden beneath the Jurassic-Cretaceous sedimentary basins. Important hydrocarbon resources exist within the Jurassic-Cretaceous sedimentary rocks at relatively shallow depths, of which the distribution represent zones of high paleo-geothermal gradients. This study examines the time-space distribution in relation to the regional tectonic history of concealed metal deposits and areas of high paleo-geothermal gradient leading to hydrocarbon maturation. To this end, authigenic illitic clay minerals representing various locations and stratigraphic depths in east-central Australia were investigated, of which the Rb-Sr and Ar-Ar geochronology and stable isotope geochemistry assist in delineating zones of hydrothermal systems responsible for hydro-carbon maturation/migration and potentially ore deposition. The Late Carboniferous - Early Permian crustal extension that affected large areas of eastern Australia and led to the epithermal mineralisations (e.g., the Drummond Basin) is also recorded in northern South Australia and southwest Queensland. A Late Triassic - Early Jurassic tectonic event being responsible for coal maturation and gas generation in the Bowen Basin and the epithermal mineralisation in the North Arm goldfield in SE Queensland likewise affected the areas much further west in Queensland. Some illites from the basement in outback Queensland and fault gouges from the Demon Fault in NE New South Wales yield younger Rb-Sr and Ar-Ar ages indicating the effect of hydrothermal processes as a result of a Middle-Upper Jurassic tectonic event. The majority of illite samples from the crystalline basement rocks, Permian Cooper Basin, and Jurassic

  20. Sea Level and Paleoenvironment Control on Late Ordovician Source Rocks, Hudson Bay Basin, Canada

    Science.gov (United States)

    Zhang, S.; Hefter, J.

    2009-05-01

    Hudson Bay Basin is one of the largest Paleozoic sedimentary basins in North America, with Southampton Island on its north margin. The lower part of the basin succession comprises approximately 180 to 300 m of Upper Ordovician strata including Bad Cache Rapids and Churchill River groups and Red Head Rapids Formation. These units mainly comprise carbonate rocks consisting of alternating fossiliferous limestone, evaporitic and reefal dolostone, and minor shale. Shale units containing extremely high TOC, and interpreted to have potential as petroleum source rocks, were found at three levels in the lower Red Head Rapids Formation on Southampton Island, and were also recognized in exploration wells from the Hudson Bay offshore area. A study of conodonts from 390 conodont-bearing samples from continuous cores and well cuttings from six exploration wells in the Hudson Bay Lowlands and offshore area (Comeault Province No. 1, Kaskattama Province No. 1, Pen Island No. 1, Walrus A-71, Polar Bear C-11 and Narwhal South O-58), and about 250 conodont-bearing samples collected from outcrops on Southampton Island allows recognition of three conodont zones in the Upper Ordovician sequence, namely (in ascendant sequence) Belodina confluens, Amorphognathus ordovicicus, and Rhipidognathus symmetricus zones. The three conodont zones suggest a cycle of sea level changes of rising, reaching the highest level, and then falling during the Late Ordovician. Three intervals of petroleum potential source rock are within the Rhipidognathus symmetricus Zone in Red Head Rapids Formation, and formed in a restricted anoxic and hypersaline condition during a period of sea level falling. This is supported by the following data: 1) The conodont Rhipidognathus symmetricus represents the shallowest Late Ordovician conodont biofacies and very shallow subtidal to intertidal and hypersaline condition. This species has the greatest richness within the three oil shale intervals to compare other parts of Red

  1. Discriminating sediment archives and sedimentary processes in the arid endorheic Ejina Basin, NW China using a robust geochemical approach

    Science.gov (United States)

    Yu, Kaifeng; Hartmann, Kai; Nottebaum, Veit; Stauch, Georg; Lu, Huayu; Zeeden, Christian; Yi, Shuangwen; Wünnemann, Bernd; Lehmkuhl, Frank

    2016-04-01

    Geochemical characteristics have been intensively used to assign sediment properties to paleoclimate and provenance. Nonetheless, in particular concerning the arid context, bulk geochemistry of different sediment archives and corresponding process interpretations are hitherto elusive. The Ejina Basin, with its suite of different sediment archives, is known as one of the main sources for the loess accumulation on the Chinese Loess Plateau. In order to understand mechanisms along this supra-regional sediment cascade, it is crucial to decipher the archive characteristics and formation processes. To address these issues, five profiles in different geomorphological contexts were selected. Analyses of X-ray fluorescence and diffraction, grain size, optically stimulated luminescence and radiocarbon dating were performed. Robust factor analysis was applied to reduce the attribute space to the process space of sedimentation history. Five sediment archives from three lithologic units exhibit geochemical characteristics as follows: (i) aeolian sands have high contents of Zr and Hf, whereas only Hf can be regarded as a valuable indicator to discriminate the coarse sand proportion; (ii) sandy loess has high Ca and Sr contents which both exhibit broad correlations with the medium to coarse silt proportions; (iii) lacustrine clays have high contents of felsic, ferromagnesian and mica source elements e.g., K, Fe, Ti, V, and Ni; (iv) fluvial sands have high contents of Mg, Cl and Na which may be enriched in evaporite minerals; (v) alluvial gravels have high contents of Cr which may originate from nearby Cr-rich bedrock. Temporal variations can be illustrated by four robust factors: weathering intensity, silicate-bearing mineral abundance, saline/alkaline magnitude and quasi-constant aeolian input. In summary, the bulk-composition of the late Quaternary sediments in this arid context is governed by the nature of the source terrain, weak chemical weathering, authigenic minerals

  2. TECTONIC ZONING OF THE SEDIMENTARY COVER IN THE DERYUGIN BASIN OF THE SEA OF OKHOTSK BASED ON STRUCTURAL-MATERIAL (LITHOPHYSICAL INDICATORS

    Directory of Open Access Journals (Sweden)

    V. P. Semakin

    2015-09-01

    Full Text Available In terms of tectonics, the Deryugin basin (Fig. 1 is a part of the epi-Mesozoic Okhotsk plate comprising the heterogeneous basement that is mainly pre-Cenozoic (the lower structural stage and the sedimentary cover that is mainly represented by the Paleogenic-Neogenic-Quaternary deposits with the Upper Cretaceous sedimentary rocks observed locally without a visible hiatus (the upper structural stage.The acoustic basement (AB is composed of the metamorphosed Upper Cretaceous-Paleogenic silty-clayey-siliceous deposits (the western part of the region, amphibolites, gneisses, crystalline schists, weakly metamorphosed sandstones, siltstones, and mudstones (often siliceous, as well as intrusive and effusive rocks of basic, intermediate, and rarely persilic composition (the eastern part of the region. AB is generally dated as Mesozoic–Paleozoic.Results of tectonic zoning of the sedimentary cover based on material (lithophysical indicators (Fig. 2 are represented in the format of maps showing lithophysical complexes (LC within the limits of four regional seismo-stratigraphic complexes/structural layers (RSSC I-IV corresponding to the following time intervals: the pre-Oligocene К2–P1-2 (RSSC I, the Oligocene – Lower Miocene P3–N11 (RSSC II, the Lower – Mid Miocene N11–2 (RSSC III, and the Upper Miocene – Pliocene N13–N2 (RSSC IV. Diverse lithological-facies associations composing the RSSCs are grouped into the following lithophysical complexes (LC: 1 - coal-bearing silty-clayey-sandy terrigenous, 2 - sandy-silty-clayey terrigenous, 3 - silty-clayey-siliceous, and 4 - sandy-silty-clayey volcanic [Sergeyev, 2006]. In the studied area (Fig. 2, the deposits of the pre-Oligocene RSSC are identified in limited areas within its northern, northwestern, and southwestern parts; they are represented by coal-bearing silty-clayey-sandy terrigenous and silty-clayey-siliceous LCs. Other RSSCs (II, III, and IV in this area represented mostly by sandy

  3. The Great Basin Canada goose in southcentral Washington: A 40-year nesting history

    Energy Technology Data Exchange (ETDEWEB)

    Fitzner, R.E.; Rickard, W.H.; Eberhardt, L.E.; Gray, R.H.

    1991-04-01

    Overall, the nesting population of Great Basin Canada geese (Branta canadensis moffitti) on the Hanford Site in southcentral Washington State is doing well and appears to be increasing. The average annual total nests for the period 1981 through 1990 was 215 nests, which is slightly above the average reported for the period 1950 through 1970. The nesting population has shifted its nucleus from upriver islands (1--10) to the lower river islands (11--20) with over 70% of the present-day nesting occurring on Islands 17, 18, 19, 20. The annual percent-successful nests from 1981 through 1990 was 80%. This is above the 71% reported for 1950 to 1970, but is below the 82% reported for 1971 to 1980. Average annual clutch size for 1981 to 1990 was 6.05, which is above the 1971-to-1980 average of 5.6 and the 1950-to-70 average of 5.5. Next desertions for 1981 to 1990 averaged 8%. This rate is well below the 14% reported for 1950 to 1970. Predators were responsible for an annual predation rate of 9% from 1981 to 1990. This is below the 1950-to-1970 annual average predation rate of 14%. Flooding losses to nests were low during the 1980s, except for 1989 and 1990 when 6% and 9% of the total nests, respectively, were destroyed by flooding. 9 refs., 4 figs., 1 tab.

  4. Characterization of the summer pack ice biotic community of Canada Basin

    Institute of Scientific and Technical Information of China (English)

    HE Ji anfeng; CAI Minghong; JIANG Xiaodong; CHEN Bo; YU Yong

    2005-01-01

    Summer pack ice biotic community of the Canada Basin was characterized during the Second Chinese National Arctic Research Expedition (CHINARE-2003, 20 August-5 September 2003). Bacteria, ice algae (diatoms and autotrophic flagellates) and protozoa (mainly heterotrophic flagellates) were observed throughout the whole ice column. The vertical distribufon of biotic taxa varied among sites.The integrated biomass ranged from 48.4 and 58.1 mg/m2, with an average of 55.2 mg/m2. Bacteria were the dominant of the assem-blage in pack ice, accounted for 84.1% of the integrated, and ice algae, which usually dominate the ice biotic community, constituted only 3.5% of the total. Considering the quick environmental changes of the Arctic Ocean in recent years, we suggested that quick melting of pack ice in summer was suggested, which caused such change of pack ice biotic community. The low salinity throughout the whole ice column and the continuous melting of the pack ice cumbered the formation of ice algae bloom in summer, finally resulting in the dominance of microbial food web with bacteria and heterotrophic flagellates as the most obvious characteristics. Considering the high ratio of pack ice primary production to the total found in previous studies, the quick change of pack ice community structure in summer would deeply influence the marine ecosystem of the high Arctic Ocean.

  5. Seasonal variations in sea ice motion and effects on sea ice concentration in the Canada Basin

    Science.gov (United States)

    Serreze, Mark C.; Barry, Roger G.; McLaren, Alfred S.

    1989-08-01

    Drifting buoy data, surface pressure, and geostrophic wind analyses from the Arctic Ocean Buoy Program are used to examine seasonal features of the sea ice motion in the Canada Basin for 1979-1985. Although the 7-year annual mean motion in this region is clockwise, the month-to-month motion is highly variable. In late summer to early autumn, the circulation can become net anticlockwise for periods lasting at least 30 days. Results from a linear model demonstrate that these "reversals" of ice motion in the Beaufort Gyre are a wind-driven response to persistent cyclonic activity that contrasts sharply with the predominantly anticyclonic regimes of spring, late autumn, and winter. Model-predicted ice divergences of 0.5% or more per day which can occur during periods of anticlockwise ice motion are in good agreement with values calculated from optimally interpolated velocity gradient fields. Visible band imagery and passive microwave data confirm associated large areal reductions in ice concentration of approximately 20%. Data from under-ice submarine sonar transects and surface pressure records prior to the study period point to frequent recurrences of these late summer to early autumn ice conditions.

  6. Isotopic Assessment of Sources of Surface Water Nitrate within the Oldman River Basin, Southern Alberta, Canada

    International Nuclear Information System (INIS)

    Concentrations and isotopic compositions of NO3- from the Oldman River (OMR) and some of its tributaries (Alberta, Canada) have been determined on a monthly basis since December 2000 to assess temporal and spatial variations of riverine NO3- sources within the OMR basin. For the OMR sites, NO3--N concentrations reached up to 0.34 mg L-1, δ15N-NO3- values varied between -0.3 and +13.8 per mille , and δ18O-NO3- values ranged from -10.0 to +5.7 per mille . For the tributary sites, NO3--N concentrations were as high as 8.81 mg L-1, δ15N-NO3- values varied between -2.5 and +23.4 per mille , and δ18O-NO3- values ranged from -15.2 to +3.4 per mille . Tributaries in the western, relatively pristine forested part of the watershed add predominantlyNO3- to the OMR with δ15N-NO3- values near +2 per mille indicative of soil nitrification. In contrast, tributaries in the eastern agriculturally-urban-industrially-used part of the basin contribute NO3- with δ15N-NO3- values of about +16 per mille indicative of manure and/or sewage derived NO3-. This difference in δ15N-NO3- values of tributaries was found to be independent of the season, but rather indicates a spatial change in the NO3- source, which correlates with land use changes within the OMR basin. As a consequence of tributary influx, δ15N-NO3- values in the Oldman River increased from +6 per mille in the downstream direction (W to E), although [NO3--N] increased only moderately (generally -1). This study demonstrates the usefulness of δ15N-NO3- and δ18O-NO3- values in identifying the addition of anthropogenic NO3- to riverine systems

  7. Hydrogeologic controls imposed by mechanical stratigraphy in layered rocks of the Chateauguay River Basin, a U.S.-Canada transborder aquifer

    Science.gov (United States)

    Morin, Roger H.; Godin, Rejean; Nastev, Miroslav; Rouleau, Alain

    2007-01-01

    [1] The Châteauguay River Basin delineates a transborder watershed with roughly half of its surface area located in northern New York State and half in southern Québec Province, Canada. As part of a multidisciplinary study designed to characterize the hydrogeologic properties of this basin, geophysical logs were obtained in 12 wells strategically located to penetrate the four major sedimentary rock formations that constitute the regional aquifers. The layered rocks were classified according to their elastic properties into three primary units: soft sandstone, hard sandstone, and dolostone. Downhole measurements were analyzed to identify fracture patterns associated with each unit and to evaluate their role in controlling groundwater flow. Fracture networks are composed of orthogonal sets of laterally extensive, subhorizontal bedding plane partings and bed-delimited, subvertical joints with spacings that are consistent with rock mechanics principles and stress models. The vertical distribution of transmissive zones is confined to a few select bedding plane fractures, with soft sandstone having the fewest (one per 70-m depth) and hard sandstone the most (five per 70-m depth). Bed-normal permeability is examined using a probabilistic model that considers the lengths of flow paths winding along joints and bedding plane fractures. Soft sandstone has the smallest bed-normal permeability primarily because of its wide, geomechanically undersaturated joint spacing. Results indicate that the three formations have similar values of bulk transmissivity, within roughly an order of magnitude, but that each rock unit has its own unique system of groundwater flow paths that constitute that transmissivity.

  8. Crustal structures across Canada Basin and southern Alpha Ridge of the Arctic Ocean from P- and S-wave sonobuoy wide-angle studies

    Science.gov (United States)

    Chian, D.; Shimeld, J.; Jackson, R.; Hutchinson, D. R.; Mosher, D. C.

    2010-12-01

    During 2007-2009, a total of 127 expendable sonobuoys (SB) were deployed across Canada Basin and southern Alpha Ridge to record wide-angle reflections and refractions from more than 10,000 km of inline, short-offset seismic reflection surveying. Most of the SB data show clear wide-angle refractions/reflections from various sedimentary and crustal layers at offsets up to 35 km. Source-receiver offsets are calculated using direct water waves. Subsequent processing includes compensation for spherical divergence and attenuation, despiking, filtering, deconvolution, and NMO correction. During wide-angle modeling, inline reflection data are converted to depth using velocity models/interpretations, iteratively updated based on wide-angle raytracing. Slight ray angle dependent anisotropy is found to best describe observed data, and is used for time-depth conversions. Clear deep refractions from upper, middle and lower crusts are recorded by most SB. Across southern Canada Basin, a regionally consistent velocity structure exists: velocities of ~4.5 km/s overlie a sub-basement layer of 5.5-5.8 km/s at depths of 12-13 km which, in turn, overlie a lower crust of 6.7-7.2 km/s. This structure is intersected by a central gravity low (previously interpreted to be an extinct spreading center), west of which the basement and sub-basement layers are consistently shallower by >1 km than the eastern side. Further northward, significant velocity variations exist. For example, the southern Alpha Ridge has a lower crust of 6.0-6.6 km/s or 6.8-7.0 km/s. Volcanic intrusions, inferred from high basement velocities of ~5.7 km/s at unusually shallow depths (~5 km), exist at discrete locations along southern Alpha Ridge. Between Northwind Ridge and Alpha Ridge, a typical continent-type crustal structure is observed. PmP is occasionally observed, modeling of which results in a Moho depth of 12-15 km. Velocities of 4.2-4.5 km/s in the northern study area are associated with a regional

  9. Fluids preserved in variably altered graphitic pelitic schists in the Dufferin Lake Zone, south-central Athabasca Basin, Canada: implications for graphite loss and uranium deposition

    Science.gov (United States)

    Pascal, Marjolaine; Boiron, Marie-Christine; Ansdell, Kevin; Annesley, Irvine R.; Kotzer, Tom; Jiricka, Dan; Cuney, Michel

    2016-06-01

    The Athabasca Basin (Canada) contains the highest grade unconformity-type uranium deposits in the world. Underlying the Athabasca Group sedimentary rocks of the Dufferin Lake Zone are variably graphitic, pelitic schists (VGPS), altered to chlorite and hematite (Red/Green Zone: RGZ). They were locally bleached near the unconformity during paleoweathering and/or later fluid interaction. Overall, graphite was lost from the RGZ and the bleached zone relative to the original VGPS. Fluid inclusions were examined in different generations of quartz veins, using microthermometry and Raman spectroscopy, to characterize and compare the different fluids that interacted with the RGZ and the VGPS. In the VGPS, CH4-, and N2-rich fluid inclusions, which homogenize into the vapor phase between -100 and -74 °C, and -152 and -125 °C, respectively, and CO2-rich fluid inclusions, homogenizing either into vapor or liquid between 20 and 28 °C, are present. Carbonic fluids could be the result of the breakdown of graphite to CH4 + CO2, whereas N2-rich fluid is interpreted to be the result of breakdown of feldspars/micas to NH4 ++N2. In the RGZ, the presence of fluid inclusions with low ice melting temperature (-38 to -16 °C) reflect the presence of CaCl2, and fluid inclusions with halite daughter minerals that dissolve between 190 and 240 °C indicate the presence of highly saline fluids. These fluids are interpreted to be derived from the Athabasca Basin. The circulation of carbonic fluids and brines occurred during two different events related to different P-T conditions of trapping. The carbonic fluids interacted with basement rocks during retrograde metamorphism of the basement rocks before deposition of the Athabasca Basin, whereas the brines circulated after the deposition of the Athabasca Basin. These latter fluids are similar to brines related to uranium mineralization at McArthur River and thus, in addition to possibly being related to graphite depletion in the RGZ, they could

  10. Spreading Dynamics and Sedimentary Process of the Southwest Sub-basin, South China Sea: Constraints from multi-channel seismic data and IODP Expedition 349

    Science.gov (United States)

    Ding, Weiwei; Li, Jiabiao; Clift, Peter

    2016-04-01

    Neotectonic and sedimentary processes in the South China Sea abyssal basin are still debated because of the lack of drilling evidence to test competing models. In this study, we interpreted four multi-channel seismic profiles across the Southwest Sub-basin (SWSB) and achieved stratigraphic correlation with new drilling data from Integrated Ocean Discovery Program (IODP) Expedition 349. Neogene sediments are divided into four stratigraphic units, each with distinctive seismic character. Sedimentation rate and lithology variations suggest climate-controlled sedimentation. In the late Miocene winter monsoon strength and increased aridity in the limited accumulation rates in the SWSB. Since the Pliocene summer monsoons and a variable glacial-interglacial climate since have enhanced accumulation rates. Terrigeneous sediments in the SWSB are most likely derived from the southwest. Three basement domains are classified with different sedimentary architectures and basement structures, including hyper-stretched crust, exhumed subcontinental mantle, and steady state oceanic crust. The SWSB has an asymmetric geometry and experienced detachment faulting in the final stage of continental rifting and exhumation of continental mantle lithosphere. Mantle lithospheric breakup post-dates crustal separation, delaying the establishment of oceanic spreading and steady state crust production.

  11. Sedimentary Characteristics and Model of Gravity Flow Depositional System for the First Member of Upper Miocene Huangliu Formation in Dongfang Area, Yinggehai Basin, Northwestern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Ming Sun; Hua Wang; Jihua Liao; Huajun Gan; Jun Xiao; Jinfeng Ren; Shue Zhao

    2014-01-01

    The gravity flow deposit were mainly developed in the lowstand systems tract (LST) of the first member of Upper Miocene Huangliu Formation (Ehl1) in Dongfang area, Yinggehai Basin, has become a valuable target for gas exploration and production. The gravity flow sedimentary character-istics of lithofacies associations, sedimentary texture, seismic facies and logging facies were described in detail on the basis of integrated analysis of cores, logging and seismic data. The sedimentary microfacies types composed of neritic sandbar, continental shelf mud, main channel, bifurcated or cross-cutting distributary channel, overspill, and natural levee are revealed under the constraint of high resolution sequence stratigraphic framework in the Ehl1. The gravity flow deposit system in the LST is divided into three evolution stages corresponding to periods of three parasequence sets. The gravity flow deposit was induced in the early LST, expanded rapidly in the middle LST and decreased slightly in the late LST. But its developing scale decreased sharply in the transgression systems tract (TST) and finally vanished in the highstand systems tract (HST). This spatial evolution rule is constrained by the integrated function of sediments supply of the Vietnam Blue River in the LST, the development of local gradient change in sea floor (micro-topography, i.e., flexure slope break), and the fall in relative sea lev-el. On the basics of the deep study of the coupling relationship among the three main control factors, the sedimentary model is established as an optimal component of “source-channel-sink” for shallow marine turbidite submarine fan.

  12. Possible Origin of High-Amplitude Reflection Packages (HARPs) in the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Lebedeva-Ivanova, Nina; Hutchinson, Deborah; Shimeld, John; Chian, Deping; Hart, Patrick; Jackson, Ruth; Saltus, Richard; Mosher, David

    2013-04-01

    The Canada Basin (CB) of the Arctic Ocean is a semi-enclosed ocean basin surrounded by the Alaskan and Canadian margins to the south and east, the Alpha-Mendeleev Large Igneous Province (AMLIP) to the north and the subsided continental Chukchi Borderland (ChB) to the west. During 2007-2011, US-Canada expeditions collected ~15,000 km multichannel seismic data and sonobuoy reflection and refraction seismic data with average spacing of ~80 km mostly over the CB and AMLIP. High-amplitude reflective packages (HARPs) underlie the mostly flat-lying sediments of CB. Although HARPs are discontinuous in the central CB, they become more continuous toward ChB and AMLIP. HARPs are often the most reflective events in the seismic section, exceeding even the seafloor reflection. Only rarely are reflections seen beneath HARPs. Where best developed, HARPs are ~100-300 ms TWTT, consisting of several high-amplitude wavelets with a pronounced narrow frequency band within the limits of ~10-30 Hz. This character of HARPs is consistent with patterns produced by constructive interference of thin beds (Widess, 1973). Forward modeling of sonobuoy data, synthetic tests, and frequency analysis of the tuning effect suggest that HARPs are composed of a series of alternating high- and low-velocity layers. The high-velocity layers are ~100-200 m thick with P-velocities of ~3.5-4.5 km/s. The low-velocity layers are about half as thick with velocities of ~2-3 km/s. A broad range of possible interpretations of rock composition exists from these velocities, e.g. sandstone and interbedded shale (Prince Patrick Island, Harrison and Brent, 2005); or tholeiitic basalts flows and sediments (Voring volcanic margin, Olanke and Eldholm, 1994); or sills and sediments (Newfoundland margin, Peron-Pinvidic et all, 2010). HARP can be associated with several origins. In the central and southern CB, where oceanic spreading is interpreted, HARPs are discontinuous among high-relief, but otherwise low

  13. Discrete kinematic modeling of the 3-D deformation of sedimentary basins; Modelisation cinematique discrete de la deformation 3D des bassins sedimentaires

    Energy Technology Data Exchange (ETDEWEB)

    Cornu, T.

    2001-01-01

    The present work deals with three-dimensional deformation of sedimentary basins. The main goal of the work was to propose new ways to study tectonic deformation and to insert it into basin-modeling environment for hydrocarbon migration applications. To handle the complexity of the deformation, the model uses kinematic laws, a discrete approach, and the construction of a code that allows the greatest diversity in the deformation mechanisms we can take into account. The 3-D-volume deformation is obtained through the calculation of the behavior of the neutral surface of each basin layer. The main idea is to deform the neutral surface of each layer with the help of geometrical laws and to use the result to rebuild the volume deformation of the basin. The constitutive algorithm includes three characteristic features. The first one deals with the mathematical operator we use to describe the flexural-slip mechanism which is a combination of the translation of the neutral surface nodes and the rotation of the vertical edges attached to these nodes. This performs the reversibility that was required for the basin modeling. The second one is about. the use of a discrete approach, which gives a better description of the global deformation and offers to locally control volume evolutions. The knowledge of volume variations can become a powerful tool in structural geology analysis and the perfect complement for a field study. The last one concerns the modularity of the developed code. Indeed, the proposed model uses three main mechanisms of deformation. But the architecture of the code allows the insertion of new mechanisms or a better interaction between them. The model has been validated first with 2-D cases, then with 3-D natural cases. They give good results from a qualitative point of view. They also show the capacity of the model to provide a deformation path that is geologically acceptable, and its ability to control the volume variations of the basin through the

  14. Sedimentary records of environmental evolution in the Sanmen Lake Basin and the Yellow River running through the Sanmenxia Gorge eastward into the sea

    Institute of Scientific and Technical Information of China (English)

    王苏民; 吴锡浩; 张振克; 蒋复初; 薛滨; 童国榜; 田国强

    2002-01-01

    A series of independent faulted basins developed in the present middle reaches of the Yellow River during late Cenozoic, among which the Sanmen Lake Basin is located in the east edge of the Loess Plateau, a transitional zone between the second and third macromorphological step of China. The thick strata of the Sanmen Group deposited in the large basin. The Sanmen Group is a perfect place for the study on paleoenvironmental change, tectono-climatic cycles as well as the formation and evolution of the Yellow River. In this paper, the paleoenvironmental changes, regional tectonic movement and the evolutionary process of the Sanmen Lake Basin during the past 5 Ma were reconstructed based on the analysis of paleomagnetic stratigraphy, pollen, TOC and carbonate content from the Huangdigou outcrop near the Sanmenxia Reservoir, Pinglu County, Shanxi Province. The sedimentary records from the outcrop indicate that the basin was first formated by fault activity at about 5.4 MaBP, and after the strong tectonic movement at 3.6 MaBP the lake enlarged and the rainfall of summer monsoon increased. There was no great climatic transition near 2.6 MaBP, corresponding to the bottom age of loess in the Loess Plateau. After Olduvai event (about 1.77 MaBP) the Picea and Abies were presented in the sediments, which indicates a colder climate. The tectonic movement at 1.2 MaBP caused the light angular discordance between the upper and lower Sanmen Group. The sedimentary records show a cold and wet climate during the prosperous periods of loess accumulation such as L15, L9, L6. The tectonic intensification periods of the Sanmen Basin correspond with the tectonic movements in the Qinghai-Xizang Plateau chronologically. The earliest age of the outflow from the Paleo-Sanmen Lake or the partly cutting off of the Sanmenxia Gorge was about 0.41- 0.35 MaBP. The age of cutting thoroughly the Sanmenxia Gorge by the Yellow River and the disappearance of the Paleo-Sanmen Lake was about 0.15 Ma

  15. The formation and evolution of Chepaizi-Mosuowan paleo-uplift and its control on the distributions of sedimentary facies in the Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Chepaizi-Mosuowan paleo-uplift is a large-scale uplift stretching across the Junggar Basin formed during the Yanshanian. It has experienced four evolutionary stages: the initial forming stage (J1), the intense development stage (J2+3), the waning and burial stage (K-E), and the tilting and extinction stage (N-Q). The most intense period of activities is the Middle Jurassic. Dur-ing the Early Jurassic, the Chepaizi-Mosuowan paleo-structure was a low amplitude uplift. Because of the subsequent strong uplifting during Middle-Late Jurassic, the Middle and Upper Jurassic were eroded. With the evolution of the Chepaizi-Mosuowan paleo-uplift, the sedimentary pattern of the basin changed, and the paleo-uplift separated the northern depositional systems from those in the south side. As a result, the basin tectonics controlled the distribution and evolution of the depositional systems. During Early Jurassic, while the paleo-uplift was low, its controlling effect on depositional systems was limited and sediments coming from the northwest could reach the central and southern parts of the basin. With the strong uplifting of the Chepaizi-Mosuowan paleo-structure during Middle-Late Jurassic, sediments from the northwest provenance could only deposit in the northern graben of the paleo-uplift. The intense erosion of the Middle-Upper Jurassic also changed the former sedimentary center of the basin into a source area, supplying sediments for grabens on both sides of the paleo-uplift. In the Cretaceous, regional subsidence caused the paleo-uplift to be buried again and subsequently sediments accumulated on top of it. The depositional facies are dominated by fluvial in the Early Cretaceous and shallow lacustrine to deltaic in the Late Cretaceous. In the history of the long-lasting development of this paleo-uplift, large-scale erosions of the paleohigh not only provided sufficient sediments to the center of the Junggar Basin, but also created favorable conditions for the formation

  16. The sources of the upper and lower halocline water in the Canada Basin derived from isotopic tracers

    Institute of Scientific and Technical Information of China (English)

    陈敏; 黄奕普; 金明明; 邱雨生

    2003-01-01

    Seawater samples were collected in the water column from the Canada Basin aboard RV Xuelong in August 1999. Concentrations of δ D, δ 18O, nutrients (NO3-, PO43-, SiO32-) and dissolved oxygen were measured, along with hydrographic parameters (salinity and temperature). Our results showed that the upper layer of the water column was characterized by the occurrence of the upper halocline water (UHW) and the lower halocline water (LHW). The UHW was associated with a salinity of 33.1 (~150m depth) and maximums of nutrients, NO and PO*, whereas minimums of NO and PO* (PO* = PO43- + O2/175-1.95 (mol/dm3) occurred at the depth of LHW (~300m depth). Two tracer systems, S-δ 18O-PO* and S-δ D-SiO32-, were used to estimate the fractions of the Atlantic water, Pacific water, river runoff and sea ice meltwater in water samples. Combined with the nutrient ratio NO/PO, it was suggested that the UHW was derived from the inflow of the Pacific water through the Bering Strait. These waters were modified to obtain the high salinity and nutrients in the Chukchi shelf or/and the east Siberian shelf. The LHW was maintained by inflow of the Atlantic water through Barents Sea and subsequent mixing with freshwater in the shelf region to produce the signals of NO and PO* minimums. In study basin, the river runoff signals were confined to water depths less than 300 m and the fractions of river runoff decreased with the increasing depth. Water column inventories of river runoff and sea ice meltwater were calculated between the surface and 300m. The river runoff inventories in the Canada Basin were higher than those in other sea areas, suggesting that the Canada basin is a major storage region for Arctic river water. The sea ice meltwater signals suggested that the Canada Basin is a region of net sea ice formation and the inventories of net sea ice in the upper water column increasing from the south to the north.

  17. Research on the bio-stratigraphy. Stratigraphy and paleontology of the Cretaceous sedimentary strata in the Youngdong basin

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sung Ja; Kim, Yoo Bong; Kim, Bok Chul [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-01

    The Youngdong Basin developed at the eastern margin of the Okcheon Orogenic Belt is in contact with the Yongnam Massif by the Youngdong Fault. This study deals with tectonic setting, sedimentological, pale-ontological study of the Youngdong Basin. Concerned with the formation of the basin, left lateral movement of the Ogdong and Youngdong faults gave a major role for the development of the Youngdong Basin. The Youngdong Basin is tectonically subdivided into three parts (north, center, and south) on the basis of bedding form line and fracture patterns. Sedimentological study is concentrated in the southern part of the basin in order to establish stratigraphy in this area. The Mangyeri Formation is characterized by the deposit of debris flow and hyper-concentrated flow deposits developed at the steep gradient fan-delta slope and on alluvial fan along the southern basin margin. On the other hand, the formation in northern part of the basin is deposited in alluvial fan and braided rivers. The Gadongri Formation is mostly deposited by the process of turbidity current and density under current in lacustrine environment, and the Dongjongri Formation comprises alluvial fan and braided river sediments which mostly deposited by debris flow, hyper-concentrated flood flow, sheet flood and stream flow. For paleontology, ostracodes and charophytes are yielded from the Gadongri, Dongjongri and Sonyoudong formations. On the basis of fossils, the Dongjongri formation is correlated with the Iljig Formation of the Euisung basin, the Sonyoudong formation is correlated with the Songnaedong and Geonchunri formations of the Milyang basin. Consequently, the Mangyeri and Gadongri formations are correlated with the Sindong Group, the Dongjongri and Sonyoudong formations are correlated with the Hayang Group. (author). 47 refs., 5 tabs.

  18. Tectonic and paleoenvironmental evolution of Mesozoic sedimentary basins along the Andean foothills of Argentina (32°-54°S)

    Science.gov (United States)

    Franzese, Juan; Spalletti, Luis; Pérez, Irene Gómez; Macdonald, David

    2003-05-01

    Chronoenvironmental and tectonic charts are presented for Mesozoic basins located along the Andean foothills of the South American plate. On the basis of the main tectonic events, pre-Andean basins, break-up-related basins, extensional back-arc basins, and Andean foreland basins are recognized. The pre-Andean basins were formed by continental extension and strike-slip movement before the development of the Mesozoic-Cenozoic Andean magmatic arc. Upper Permian to Middle Triassic extension along Palaeozoic terrane sutures resulted in rifting, bimodal magmatism (Choiyoi group), and continental deposition (Cuyo basin). From the Late Triassic to the Early Jurassic, continental extension related to the collapse of the Gondwana orogen initiated a series of long, narrow half-grabens that filled with continental volcaniclastic deposits. These depocenters were later integrated into the Neuquén basin. Coeval development of the shallow marine Pampa de Agnia basin (42-44°S) is related to short-lived extension, probably driven by dextral displacement along major strike-slip faults (e.g. the Gastre fault system). Widespread extension related to the Gondwana breakup (180-165 Ma) and the opening of the Weddell Sea reached the western margin of the South American plate. As a result, wide areas of Patagonia were affected by intraplate volcanism (Chon Aike province), and early rifting occurred in the Magallanes basin. The Andean magmatic arc was almost fully developed by Late Jurassic times. A transgressive stage with starvation and anoxia characterized the Neuquén basin. In western Patagonia, back-arc and intra-arc extension produced the opening of several grabens associated with explosive volcanism and lava flows (e.g. Rı´o Mayo, El Quemado). To the south, a deep marginal basin floored by oceanic crust (Rocas Verdes) developed along the back-arc axis. In mid-to late Cretaceous times, Andean compressional tectonics related to South Atlantic spreading caused the inversion of

  19. Subsidence, stress regime and rotation(s) of a tectonically active sedimentary basin within the western Alpine Orogen: the Tertiary Piedmont Basin (Alpine domain, NW Italy)

    OpenAIRE

    Carrapa, B.; Bertotti, G.; Krijgsman, W.

    2003-01-01

    The Oligocene to Miocene Tertiary Piedmont Basin (TPB) is located in the NW part of Italy at the junction between the Apennine and the Alpine thrust belts. The position of the TPB on top of the Alpine/Apennine Orogen poses fundamental questions as to the tectonics of the basin subsidence. Having undergone little deformation, the TPB sediments provide an insight into the stress regime and rotations in the kinematically very complex area surrounding the basin itself. In this study we integrate ...

  20. Neogene sedimentary history of the Outer Cilicia Basin, eastern Mediterranean: a contribution to the TopoEurope VAMP project

    Science.gov (United States)

    Piercey, Tiffany; Akhun, Selin; Hall, Jeremy; Aksu, Ali; Ćifçi, Günay

    2010-05-01

    The Vertical Anatolian Movements Project (VAMP) addresses the Neogene uplift of the Taurides and the Central Anatolian Plateau. While terrestrial studies are focussed on erosion in the sediment source area, and deposition within the Turkish landmass, our marine work is intended to provide a history of deposition in one of the ultimate sinks: the eastern Mediterranean. In particular, we are mapping the distribution in space and time of sediment deposited from the Göksu River into the Cilicia Basin. In 2008 we obtained km of high-resolution marine multi-channel seismic profiles radiating out from the river delta across the basin. Many of the profiles are processed and images of the data are presented. Interpretation of the available industry seismic reflection profiles show that during the the Miocene the northeastern Mediterranean, including the Cilicia Basin, experienced regional compression, which resulted in the formation of a broad and arcuate fold-thrust belt extending from the Taurides in the north, across the Troodos ophiolite complex into the Cyprus Arc in the south. Two prominent culminations were developed: one was located along the Misis-Kyrenia Fault Zone, another developed in the Amanos-Larnaka-Troodos Fault Zone. Stratigraphic and structural relationships demonstrated that the late Pliocene-Quaternary Cilicia-Adana Basin complex evolved as an asymmetric piggyback basin on the hanging-wall of the south-verging Misis-Kyrenia thrust culmination. Detailed mapping demonstrated that the S/SE-directed contraction culminated in the latest Miocene, and is followed in the early Pliocene by a progressive transition to partitioned contraction and extension related to the initiation of strike slip along the eastern Anatolian Transform Fault and its marine extensions. The shift in kinematics is expressed by the development of major NE-SW trending (Inner Cilicia Basin) and E-W trending (Outer Cilicia Basin) steep faults with extensional separations bounding the

  1. Evolution of Sedimentary Basins in the Upper Yangtze during Mesozoic%上扬子地区中生代沉积盆地演化

    Institute of Scientific and Technical Information of China (English)

    韦一; 张宗言; 何卫红; 吴年文; 杨兵

    2014-01-01

    The geotectonic environments are reconstructed and presented in this paper.Firstly,the Mesozoic sedimentary for-mation of the Upper Yangtze is studied in detail,then the basin features are analyzed based on the lithology of each unit (for-mation)and the space distribution framework of basins is established.Eventually,three stages of tectonic evolution of the Up-per Yangtze are summarized by means of detailed analysis of chronostratigraphic and biostratigraphic correlations,paleogeogra-phy of biology,lithofacies and tectonics.The Upper Yangtze region rose continuously,water of which became shallow,and a series of clastic-carbonate epeiric sea and platform-interplatform basin sedimentary basin formed because of Indosinian orogeny during Early-Middle Triassic.When it came to Late Triassic to Early Jurassic,the Upper Yangtze collided with the Tethys do-main block or arc-basin collisional zone in its west,the paleogeographic environments in the southwest and north of which turned to foreland basin and peripheral foreland basin,while the Xuefeng uplift turned orogeny.After middle Jurassic,with the subduction of paleo-Pacific plate to Asia plate,the south Upper Yangtze came into continental orogenic stage that mainly devel-oped a series of downwarped basins to the east of Xuefeng Mountain and a large-scale depressional basin to the west.%以地层分区为单位对上扬子地区中生代沉积建造进行了详细分析,对盆地原型进行了初步划分,建立了中生代上扬子陆块沉积盆地时空分布格架。结合年代地层和生物地层划分对比、生物古地理、岩相古地理和构造演化规律的综合分析,对上扬子地区中生代3个阶段的盆地演化过程进行生动刻画,并以此为依据分析了盆地形成演化的大地构造环境。早三叠世上扬子陆块受印支造山运动的影响不断抬升,海相盆地水体变浅,形成一系列混积陆表海、台盆-台地构造相;晚三叠世-早侏罗世上

  2. Tectono-sedimentary evolution of the peripheral basins of the Alboran Sea in the arc of Gibraltar during the latest Messinian-Pliocene

    Science.gov (United States)

    Guerra-Merchán, Antonio; Serrano, Francisco; Hlila, Rachid; El Kadiri, Khalil; Sanz de Galdeano, Carlos; Garcés, Miguel

    2014-07-01

    In the peripheral basins of the Alboran Sea, five stratigraphic units (latest Messinian-Pliocene) separated by discontinuities and representing transgressive-regressive cycles have been recognized. The first unit (LM) is latest Messinian in age and precisely characterizes the Lago-Mare event at the end of the Messinian Salinity Crisis, i.e. just before the opening of the Strait of Gibraltar at the beginning of the Pliocene. The three following units (Pl-1, Pl-2 and Pl-3) are Zanclean in age, whereas the last one (Pl-4) is Piacenzian. These four Pliocene units consist of alluvial, deltaic, and littoral deposits in the marginal areas, changing to open marine deposits with planktonic components in the basinal areas, although their extension varies in each basin. Regionally, these units do not necessarily stack in a single stratigraphic succession because of tectonics that controlled their hosting basins. Thus, the LM and Pl-1 units occur only in the Malaga and Estepona-Marbella basins, revealing that the onset of the sedimentation after the Messinian evaporitic stage and the Pliocene transgression was not a single and synchronous event in the western Alboran Sea. Moreover, the Pl-3 and Pl-4 units do not appear in all basins, so that the subsequent continentalization process of these Alboran peripheral areas during the Pliocene was also diachronous. The sedimentary evolution of the peripheral basins was controlled mainly by tectonics. During the latest Messinian-early Pliocene, the sedimentation took place in a context marked by a NNW-SSE compression and ENE-WSW perpendicular tension. The onset of the sedimentation (LM and Pl-1 units) could be linked to preexisting E-W faults that mark part of the borders of the Malaga basin and the Estepona-Marbella sector. During the deposition of the Pl-2 unit, the movements of E-W, NW-SE, and NE-SW normal faults determined a continuous subsidence in several basins, resulting in the accumulation of thick clastic marine sequences (i

  3. Subsidence, stress regime and rotation(s) of a tectonically active sedimentary basin within the western Alpine Orogen: the Tertiary Piedmont Basin (Alpine domain, NW Italy)

    NARCIS (Netherlands)

    Carrapa, B.; Bertotti, G.; Krijgsman, W.

    2003-01-01

    The Oligocene to Miocene Tertiary Piedmont Basin (TPB) is located in the NW part of Italy at the junction between the Apennine and the Alpine thrust belts. The position of the TPB on top of the Alpine/Apennine Orogen poses fundamental questions as to the tectonics of the basin subsidence. Having und

  4. Tectono-sedimentary evolution of the peripheral basins of the Alboran Sea in the arc of Gibraltar during the latest Messinian-Pliocene

    Science.gov (United States)

    Guerra-Merchán, Antonio; Serrano, Francisco; Hlila, Rachid; El Kadiri, Khalil; Sanz de Galdeano, Carlos; Garcés, Miguel

    2014-07-01

    In the peripheral basins of the Alboran Sea, five stratigraphic units (latest Messinian-Pliocene) separated by discontinuities and representing transgressive-regressive cycles have been recognized. The first unit (LM) is latest Messinian in age and precisely characterizes the Lago-Mare event at the end of the Messinian Salinity Crisis, i.e. just before the opening of the Strait of Gibraltar at the beginning of the Pliocene. The three following units (Pl-1, Pl-2 and Pl-3) are Zanclean in age, whereas the last one (Pl-4) is Piacenzian. These four Pliocene units consist of alluvial, deltaic, and littoral deposits in the marginal areas, changing to open marine deposits with planktonic components in the basinal areas, although their extension varies in each basin. Regionally, these units do not necessarily stack in a single stratigraphic succession because of tectonics that controlled their hosting basins. Thus, the LM and Pl-1 units occur only in the Malaga and Estepona-Marbella basins, revealing that the onset of the sedimentation after the Messinian evaporitic stage and the Pliocene transgression was not a single and synchronous event in the western Alboran Sea. Moreover, the Pl-3 and Pl-4 units do not appear in all basins, so that the subsequent continentalization process of these Alboran peripheral areas during the Pliocene was also diachronous. The sedimentary evolution of the peripheral basins was controlled mainly by tectonics. During the latest Messinian-early Pliocene, the sedimentation took place in a context marked by a NNW-SSE compression and ENE-WSW perpendicular tension. The onset of the sedimentation (LM and Pl-1 units) could be linked to preexisting E-W faults that mark part of the borders of the Malaga basin and the Estepona-Marbella sector. During the deposition of the Pl-2 unit, the movements of E-W, NW-SE, and NE-SW normal faults determined a continuous subsidence in several basins, resulting in the accumulation of thick clastic marine sequences (i

  5. Sedimentary deposition and reflux of phosphorus (P in the Eastern Gotland Basin and their coupling with P concentrations in the water column

    Directory of Open Access Journals (Sweden)

    Sven Hille

    2005-12-01

    Full Text Available In order to describe the role of sedimentary processes for the phosphorus (P cycle in the open Baltic Proper, P deposition and reflux were quantified for the predominately anoxic sediments of the Eastern Gotland Basin. The study is based on investigations of 53 surface sediment samples and pore water samples from 8 sediment cores. The average P deposition rate was estimated at 0.20 g ± 0.18 g -2 yr-1, the fluctuation being due to variable bulk sediment deposition rates. P refluxes were estimated by applying Fick's First Law of Diffusion. A fairly good positive correlation between sedimentary P deposition and P release was obtained. P release from sediments by diffusion exceeds net P deposition by a factor of 2. This suggests that 2/3 of the deposited gross P is recycled in the sediments and released back into the water column; only 1/3 remains in the sediment permanently. A budget calculation demonstrates that the released dissolved inorganic phosphorus (DIP accounts for the observed increase in DIP concentrations in the deep water during periods of stagnation, which is noticeable even at the surface P concentrations. Under such conditions and with the present remediation conditions it is not possible to freely manage P concentrations in the water column on short time scales.

  6. Reserves' potential of sedimentary basin: modeling and estimation; Potentiel de reserves d'un bassin petrolier: modelisation et estimation

    Energy Technology Data Exchange (ETDEWEB)

    Lepez, V.

    2002-12-01

    The aim of this thesis is to build a statistical model of oil and gas fields' sizes distribution in a given sedimentary basin, for both the fields that exist in:the subsoil and those which have already been discovered. The estimation of all the parameters of the model via estimation of the density of the observations by model selection of piecewise polynomials by penalized maximum likelihood techniques enables to provide estimates of the total number of fields which are yet to be discovered, by class of size. We assume that the set of underground fields' sizes is an i.i.d. sample of unknown population with Levy-Pareto law with unknown parameter. The set of already discovered fields is a sub-sample without replacement from the previous which is 'size-biased'. The associated inclusion probabilities are to be estimated. We prove that the probability density of the observations is the product of the underlying density and of an unknown weighting function representing the sampling bias. An arbitrary partition of the sizes' interval being set (called a model), the analytical solutions of likelihood maximization enables to estimate both the parameter of the underlying Levy-Pareto law and the weighting function, which is assumed to be piecewise constant and based upon the partition. We shall add a monotonousness constraint over the latter, taking into account the fact that the bigger a field, the higher its probability of being discovered. Horvitz-Thompson-like estimators finally give the conclusion. We then allow our partitions to vary inside several classes of models and prove a model selection theorem which aims at selecting the best partition within a class, in terms of both Kuilback and Hellinger risk of the associated estimator. We conclude by simulations and various applications to real data from sedimentary basins of four continents, in order to illustrate theoretical as well as practical aspects of our model. (author)

  7. New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

    Science.gov (United States)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2016-04-01

    Numerical temperature models generated for geodynamic studies as well as for geothermal energy solutions heavily depend on rock thermal properties. Best practice for the determination of those parameters is the measurement of rock samples in the laboratory. Given the necessity to enlarge databases of subsurface rock parameters beyond drill core measurements an approach for the indirect determination of these parameters is developed, for rocks as well a for geological formations. We present new and universally applicable prediction equations for thermal conductivity, thermal diffusivity and specific heat capacity in sedimentary rocks derived from data provided by standard geophysical well logs. The approach is based on a data set of synthetic sedimentary rocks (clastic rocks, carbonates and evaporates) composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities varying between 0 and 30%. Petrophysical properties are assigned to both the rock-forming minerals and the pore-filling fluids. Using multivariate statistics, relationships then were explored between each thermal property and well-logged petrophysical parameters (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) on a regression sub set of data (70% of data) (Fuchs et al., 2015). Prediction quality was quantified on the remaining test sub set (30% of data). The combination of three to five well-log parameters results in predictions on the order of Andrea (2015): Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs, Geophysical Journal International 203, 1977-2000, doi: 10.1093/gji/ggv403

  8. TransCanada PipeLines Limited 1998 annual report : TransCanada energy solutions

    International Nuclear Information System (INIS)

    Financial information from TransCanada PipeLines Limited and a review of the company's 1998 operations was made available for the benefit of shareholders. TransCanada's pipeline system transports natural gas and crude oil from Western Canada Sedimentary Basin to North America's major energy markets. Net earnings from continuing operations for 1998, before unusual charges, were $575 million ($ 355 million after unusual charges) compared to $522 million for 1997. Solid performances from the energy transmission and international business, when compared to 1997, were more than offset by a decreased contribution from energy processing. TransCanada recorded integration costs of $166 million, after tax, related to the merger with NOVA in 1998, which was the major operational accomplishment during the year, creating a seamless economic energy delivery, processing and marketing system from the wellhead to the market. tabs., figs

  9. Sedimentary environments for the massive formation of the lacustrine organic rich petroleum source rocks of late Cretaceous from Songliao Basin, China

    Science.gov (United States)

    Zhiguang, S.

    2009-12-01

    Songliao Basin is the major oil-bearing and production basin in China and containing two major sets of excellent organic matter rich source rocks developed during the two related short periods of later Cretaceous time. For a long time, these source rocks were considered unquestionably being formed under fresh or brackish lacustrine environment. However, increasing evidence and studies suggest that this may be not the case anymore, as possible marine transgression and much high salinity lacustrine environment has been suggested or implied from a number of recent studies for Songliao Basin. Here, we show our recent extensive organic geochemical studies carried out on the core samples of Nenjiang formation from a newly drilled scientific exploration well of No. 1 in Songliao Basin. The overall evidence of organic matter and biomarkers suggest that: 1) the main source rocks were likely formed under a much saline(even mesosaline) lacustrine environment, as the existence of a number high saline related biomarkers and their ratios such Pr/Ph, MTTCI, α-MTTC/δ-MTTC, α-MTTC /γ-MTTC, Gammacerane/C30hop are in favor of a mesosaline to saline environments; 2) during the major source rocks formation periods, a photic zone oxygen depletion and stratified water column was suggested by the strong occurrence of a series of aryl isoprenoids and Isorenieratane; 3) a general mild to strong reduced sedimentary environments were concluded from the consistent of a number of index. Fig 1 Correlation between MTTCI vs Pr/Ph ratios with indication of salinity fields (after SCHWARK et al., 1998)

  10. Preliminary integration study of Precambrian with tectonic events in Brazilian sedimentary basins (Republication); Estudo preliminar de integracao do Pre-Cambriano com os eventos tectonicos das bacias sedimentares brasileiras (Republicacao)

    Energy Technology Data Exchange (ETDEWEB)

    Cordani, Umberto G.; Neves, Benjamim B. Brito; Fuck, Reinhard A.; Porto, Roberto; Thomaz Filho, Antonio; Cunha, Francisco M. Bezerra da

    2008-11-15

    The various successive episodes of vertical cratogenic evolution modelling the geo tectonic features of the basement were correlated with the internal structure, shape, origin and geologic evolution of the sedimentary basin. A systematic petrologic and geochronological investigation of all available drill core samples was carried out, and the pertinent geophysical data regarding basement structure were taken into consideration. Specific geo tectonic analyses, were carried out along the borders of the sedimentary basins, within the adjacent basement. The main boundaries between Precambrian tectonic provinces, the main tectonic sutures with polycyclic evolution, and the ancient intracratonic rifts were identified wherever possible. Their extensions under the sedimentary basins were inferred, corroboration being sought from structural information and data obtained from the drill core samples. It was found that many of the identified basement discontinuities had a direct influence on the depositional history of each of the sedimentary basins, demonstrating the distinct tectonic inheritance. The subject was treated on a reconnaissance scale, 1:1.000.000 or smaller,owing to its complexity. (author)

  11. Neogene sedimentary history of the Inner Cilicia Basin, eastern Mediterranean: a contribution to the TopoEurope VAMP project

    Science.gov (United States)

    Walsh, Susan; Kurtboǧan, Bahar; Akhun, Selin; Aksu, Ali; Hall, Jeremy; Ćifçi, Günay

    2010-05-01

    The Vertical Anatolian Movements Project (VAMP) addresses the Neogene uplift of the Taurides and the Central Anatolian Plateau. While terrestrial studies are focused on erosion in the sediment source area and deposition within the Turkish landmass, our marine work is focused to provide a history of deposition in one of the ultimate sinks: the eastern Mediterranean. In particular, we are mapping the distribution in space and time of sediment deposited from the Göksu River into the Cilicia Basin. In 2008 we collected ~2000 km of high-resolution marine multi-channel seismic reflection profiles radiating out from the present-day mouth of the Göksu River across the basin. The Göksu River delta is located on a narrow shelf at the junction of the Inner and Outer Cilicia Basins. The Inner Cilicia Basin consists of a 40 km-wide shelf linking to the onshore Adana Basin and a slope down to the deeper water (~ 1 km) of the Outer Cilicia Basin. The shelf is built out of a >2.5 km-thick sequence of Pliocene-Quaternary sediment overlying Messinian evaporites or older Miocene sediments. The evaporites have been mobilised to move down slope during the Pliocene-Quaternary so that the shelf is located above an extensional fault fan, complemented by a salt-cored fold/thrust belt in deeper water (see poster by Piercey et al., this meeting). The 2008 seismic reflection profiles show that the western margin of the Inner Cilicia Basin seaward of the mouth of the Göksu River is constructed by numerous vertically stacked and east-prograded delta successions. Detailed mapping in this region revealed that the sediment input from the Göksu River can be readily distinguished from the larger influxes from the coalescing Tarsus, Seyhan and Ceyhan Rivers to the north. The bases of major delta packages supplied by the Göksu River are marked by strong reflections, defining shelf-crossing unconformities, which can be correlated across the Inner Cilicia Basin. Industry exploration wells in the

  12. Late Pleistocene sedimentary sequences and paleoclimate changes in Xunhua basin in the upper reach of Yellow River in China

    Institute of Scientific and Technical Information of China (English)

    Fang HAN; Kexin ZHANG; Junliang JI; Yadong XU; Fenning CHEN; Xiaohu KOU

    2012-01-01

    The third terrace of the Yellow River was well developed in Xunhua basin in the north-east margin of the Tibetan Plateau.The terrace was formed at ca 75 ka as dated by the optically stimulated luminescence (OSL) method.On the basis of grain size,magnetic susceptibility and palynological data,six episodes of the climatic change were identified in Xunhua basin; they include very warm and humid period during 120-114 ka,cool and dry period during 114-105 ka,warm and humid period during 105-98 ka,gradually cooling period during 98-85 ka,warm and humid period during 85-75 ka,very cold and dry period during 75-63 ka.The six stages of climatic change recorded in Xunhua basin correspond to the marine oxygen isotope stages (MIS) of 5e,5d,5c,5b,5a and 4,respectively.

  13. 中国大陆地区沉积盆地的热状况、热历史和生烃史%Geothermal Regime, Thermal History and Hydrocarbon Generation Types of Sedimentary Basins in the Continental Area of China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The thermal regimes in sedimentary basins in the continental area of China are varied and reflect differences in geological settings. As a result of these variable thermal regimes, the history of hydrocarbon generation in each basin is also different. An east-west profile of the thermal threshold across the continental basins of China, like the Liaohe Basin, the North China Basin, the Ordos Basin, the Qaidam Basin and the Tarim Basin, was constructed using large numbers of heat flow measurements, temperature data and rock thermophysical parameters. Isotherms, surface heat flow,mantle heat flow and Moho temperature beneath the basins are shown in the profile, which illustrates changes in some thermal characteristics between basins in east China and those in west China. Thermal evolution histories in basins were reconstructed using Easy%Ro method, apatite fission track annealing and other paleothermometers. Typical hydrocarbon generation histories of the primary source rocks were modeled by referring to the thermal evolution data. Thermal stages controlled source rocks maturation and oil and gas generation, and influenced the type of hydrocarbon (oil and gas)production in the basins.

  14. Stochastic joint inversion of temperature and self-potential data to determine the permeability of geological units in sedimentary basins

    Science.gov (United States)

    Revil, A.; Jardani, A.

    2008-12-01

    The flow of the ground water is responsible for both thermal and self-potential anomalies. We will first reviewed the basic equations for these two problems and we will address the forward model using the finite eement code Comsol Multiphysics. Then we are interested by inverting jointly the temperature and self- potential responses associated with ground water flow. Note that their sampling are complementary as the temperature is recorded in boreholes while the self-potential data are usually recorded at the ground surface of the Earth. We use the "Adaptive Metropolis Algorithm" (AMA) to invert the material properties of the different geological units (sedimentary formations and faults). We demonstrate that the joint inversion problem yields a better estimate of the material properties than using the thermal or the self-potential data independently. The algorithm is tested using a synthetic case corresponding to a pile of sedimentary layers overlying a very impermeable substratum. The flow of the ground water is mainly localized into two faults both acting as preferential fluid flow pathways. The first fault is discharging warmed ground water while the second fault acts as a recharge zone of cold water. We found that we can recover the permeability of the different geological units including faults.

  15. Application of the authigenic 10Be/9Be dating method to Late Miocene-Pliocene sequences in the northern Danube Basin (Pannonian Basin System): Confirmation of heterochronous evolution of sedimentary environments

    Science.gov (United States)

    Šujan, Michal; Braucher, Régis; Kováč, Michal; Bourlès, Didier L.; Rybár, Samuel; Guillou, Valéry; Hudáčková, Natália

    2016-02-01

    Authigenic 10Be/9Be dating method was applied to lacustrine, deltaic and alluvial sequences of the northern Danube Basin (Pannonian Basin System), to bridge the insufficiency of geochronological data for the Late Miocene to Pliocene period. The measurements of 51 samples (both lacustrine and floodplain), ranging from 11.6 to 0.95 Ma are consistent with the existing magnetostratigraphic and biostratigraphic data standing mainly on the evolution degree of endemic mollusk fauna, mammals and dinocysts. This agreement confirms our assumption that the incoming beryllium fluxes remained constant over the studied time period and thus that the two initial 10Be/9Be ratios determined in actual Holocene/Late Pleistocene sediments (lacustrine and floodplain) are valid for these environments. The obtained ages indicate gradual progradation of the deltaic depositional systems across the Danube Basin with a clear time-transgressional character, replacing basin floor and shelfal environments. Deltaic sedimentation occurred firstly in the north at foothills of the Western Carpathians from 11.0 Ma, and changed to the alluvial environment after 10.5 Ma. At the same time (~ 10.5 Ma), the paleo-Danube deltaic system draining the Eastern Alps entered the study area from the Vienna Basin situated on the West. Later, the deltaic systems were merged in the central part of the basin and reached its southeastern margin at ~ 9.4 Ma. Regression of the Lake Pannon from the southernmost part of the study area is evidenced after 8.7 Ma. Alluvial deposition of meandering rivers lasting until 6.0-5.0 Ma followed and was interrupted by the early Pliocene basin inversion. Sedimentation of braided streams took place during the late Pliocene and Pleistocene, reflecting uplift of mountains surrounding the basin margins. This study documents the powerful potential of the authigenic 10Be/9Be dating method and its reliability in a basin with complicated tectonic and sedimentary history. It demonstrates that

  16. Evolution of Mesozoic Sedimentary Basins in Wuyi-Yunkai Area%武夷-云开中生代沉积盆地演化

    Institute of Scientific and Technical Information of China (English)

    唐婷婷; 何卫红; 王成刚; 纪星星; 郝奕玮; 邹亚锐

    2014-01-01

    In order to study the sendimentary basin evolution of the Wuyi-Yunkai area,in this paper the area is divided into 5 stratigraphic regions.Based on the previous studies on the lithostritagraphy combinations,fossil assemblages,isotopic geochro-nology and tectonics of this area,types of sedimentary basin in the Wuyi-Yunkai area are identified,and their formation and evolution are investigated.The evolutional history of the sedimentary and tectonic features of the study area shows that the ba-sin and structure have experienced three major evolutionary stages in Mesozoic.In the Early-Middle Triassic,the research area entered the marine-continental alternating epicontinental sea stage because of transgressions with the crust uplifting,the main sea level dropping and the sea gradually receding to the west or southwest.In the Middle Jurassic-Cretaceous,a series of sub-duction-accretionary complex belt formed in Taiwan,and inland areas were bounded by the Zhenghe-Dapu fracture,with fault basin (including volcanoes)developed in the west and its east entering evolutionary stage of intra-arc graben basin whose late stage was fault basin evolution,mainly influenced by the low subduction of the Pacific plate.%将武夷-云开地层大区分为5个地层区,通过综合分析前人对该地区中生代岩石地层、生物地层、同位素年代学及构造等研究,对研究区中生代沉积盆地类型进行划分,并探讨该区沉积盆地-大地构造演化史。研究区中生代共经历了3个重要演化阶段:早-中三叠世,该区地壳抬升,海平面总体下降,海水向西-西南方向逐渐退出,形成混积陆表海;晚三叠世-早侏罗世,该区发生海侵,形成海陆交互陆表海;中侏罗世-白垩纪,由于受古太平洋板块西北低俯冲的影响,台湾地区形成了一系列俯冲增生杂岩带,内陆地区以政和-大浦断裂为界,西部发育(火山)断陷盆地;东部发育弧内裂陷盆地,晚期形成断陷盆地。

  17. A review of the stratigraphy and sedimentary environments of the Karoo-aged basins of Southern Africa

    Science.gov (United States)

    Smith, R. M. H.; Eriksson, P. G.; Botha, W. J.

    1993-02-01

    The Karoo Basin of South Africa was one of several contemporaneous intracratonic basins in southwestern Gondwana that became active in the Permo-Carboniferous (280 Ma) and continued to accumulate sediments until the earliest Jurassic, 100 million years later. At their maximum areal extent, during the early Permian, these basins covered some 4.5 million km 2. The present outcrop area of Karoo rocks in southern Africa is about 300 000 km 2 with a maximum thickness of some 8000 m. The economic importance of these sediments lies in the vast reserves of coal within the Ecca Group rocks of northern and eastern Transvaal and Natal, South Africa. Large reserves of sandstone-hosted uranium and molybdenum have been proven within the Beaufort Group rocks of the southern Karoo trough, although they are not mineable in the present market conditions. Palaeoenvironmental analysis of the major stratigraphic units of the Karoo succession in South Africa demonstrates the changes in depositional style caused by regional and localized tectonism within the basin. These depocentres were influenced by a progressive aridification of climate which was primarily caused by the northward drift of southwestern Gondwana out of a polar climate and accentuated by the meteoric drying effect of the surrounding land masses. Changing palaeoenvironments clearly influenced the rate and direction of vertebrate evolution in southern Gondwana as evidenced by the numerous reptile fossils, including dinosaurs, which are found in the Karoo strata of South Africa, Lesotho, Namibia and Zimbabwe. During the Late Carboniferous the southern part of Gondwana migrated over the South Pole resulting in a major ice sheet over the early Karoo basin and surrounding highlands. Glacial sedimentation in upland valleys and on the lowland shelf resulted in the Dwyka Formation at the base of the Karoo Sequence. After glaciation, an extensive shallow sea covered the gently subsiding shelf, fed by large volumes of meltwater

  18. Constraints to the timing of India-Eurasia collision; a re-evaluation of evidence from the Indus Basin sedimentary rocks of the Indus-Tsangpo Suture Zone, Ladakh, India

    Science.gov (United States)

    Henderson, Alexandra L.; Najman, Yani; Parrish, Randall; Mark, Darren F.; Foster, Gavin L.

    2011-06-01

    Deposited within the Indus-Tsangpo suture zone, the Cenozoic Indus Basin sedimentary rocks have been interpreted to hold evidence that may constrain the timing of India-Eurasia collision, a conclusion challenged by data presented here. The Eurasian derived 50.8-51 Ma Chogdo Formation was previously considered to overlie Indian Plate marine sedimentary rocks in sedimentary contact, thus constraining the timing of collision as having occurred by this time. Using isotopic analysis (U-Pb dating on detrital zircons, Ar-Ar dating on detrital white mica, Sm-Nd analyses on detrital apatite), sandstone and conglomerate petrography, mudstone geochemistry, facies analysis and geological mapping to characterize and correlate the formations of the Indus Basin Sedimentary rocks, we review the nature of these contacts and the identification and correlation of the formations. Our results reveal that previously interpreted stratigraphic contacts identifying Chogdo Formation unconformably overlying Indian plate sedimentary rocks are incorrect. Rather, we suggest that the inaccuracy of previous interpretations is most likely a result of Formation misidentification and thus cannot be used to constrain the timing of India-Asia collision.

  19. Investigating traces of early life in the oldest tectono-sedimentary basin of the 3.5 - 3.1 Ga Barberton greenstone belt, South Africa

    Science.gov (United States)

    Grosch, Eugene

    2014-05-01

    temperature and redox conditions surrounding the candidate titanite biotextures. New carbon stable isotope data from pillow cores and rims are presented. U-Pb dating of the alteration in the pillow metabasites determined by laser-ablation ICP-MS, places new constraints on the timing of alteration locally in parts of the pillow lava sequence. A U-Pb detrital zircon provenance study of clastic sediments in the Noisy formation that unconformably overlies the Hooggenoeg pillow lavas, provides evidence for the earliest tectono-sedimentary basin in the BGB at ca. 3.432 Ga (Grosch et al., 2011). Petrological characterization of altered and deformed mafic-ultramafic rocks of the structurally overlying Kromberg type-section indicates a mid-Archean convergent margin setting at 3.23 Ga, similar to modern-day ophiolite terrains. On the basis of SIMS sulfur isotope data, it is proposed that sulfur-metabolizing bacteria and possibly methanogenic microbes may have thrived in the shallow-marine subsurface of this tectono-sedimentary basin as early as ca. 3.432 Ga (Grosch & Mcloughlin, 2013). Collectively, the new field mapping and petrological data allows for a better understanding of the early geologic evolution of the Barberton greenstone belt and the potential habitats that may once have been available for early life. The candidate titanite biotextures are thus placed in better metamorphic and geological context. As such their syngenicity and biogenicity are evaluated particularly in light of an early 'bioalteration' subseafloor model.

  20. Deep versus shallow controlling factors of the regional thermal field in the Beaufort-Mackenzie Basin (Arctic Canada)

    Science.gov (United States)

    Scheck-Wenderoth, M.; Sippel, J.; Lewerenz, B.

    2011-12-01

    important process. We discuss the predicted temperature variations with respect to the structure of the basin including stratigraphic and tectonic domains, the inferred depth of the lithosphere-asthenosphere boundary, and the distribution of permafrost. Chen, Z., Osadetz, K.G., Issler, D.R., Grasby, S.E., 2008. Hydrocarbon migration detected by regional temperature field variations, Beaufort-Mackenzie Basin, Canada. AAPG Bulletin, 92(12): 1639-1653.

  1. Transport of trace metals (Mn, Fe, Ni, Zn and Cd) in the western Arctic Ocean (Chukchi Sea and Canada Basin) in late summer 2012

    Science.gov (United States)

    Kondo, Yoshiko; Obata, Hajime.; Hioki, Nanako; Ooki, Atsushi; Nishino, Shigeto; Kikuchi, Takashi; Kuma, Kenshi

    2016-10-01

    Distributions of trace metals (Mn, Fe, Ni, Zn and Cd) in the western Arctic Ocean (Chukchi Sea and Canada Basin) in September 2012 were investigated to elucidate the mechanisms behind the transport of these metals from the Chukchi Shelf to the Canada Basin. Filtered (biogeochemical cycles of the ocean interior. Based on the findings of studies that have previously evaluated the concentration maxima of Ni, Zn and Cd within the halocline layer in the Canada Basin near the Canadian Arctic Archipelago, the elevated Ni, Zn and Cd concentrations in the halocline layer may extend across the Canada Basin from the Chukchi Sea shelf-break area. The determination coefficients for correlations with phosphate concentration varied between the concentrations of Ni, Zn and Cd, which suggest that the sources of these trace metals, such as sediments and sea-ice melting, affected their patterns of distributions differently. Our findings reveal the importance and impact of the halocline layer for the transport of trace metals in the western Arctic Ocean during the late summer. The existence of rich and various sources likely sustained the high concentrations of trace metals and their unique profiles in this region.

  2. Tectonostratigraphy and depositional history of the Neoproterozoic volcano-sedimentary sequences in Kid area, southeastern Sinai, Egypt: Implications for intra-arc to foreland basin in the northern Arabian-Nubian Shield

    Science.gov (United States)

    Khalaf, E. A.; Obeid, M. A.

    2013-09-01

    This paper presents a stratigraphic and sedimentary study of Neoproterozoic successions of the South Sinai, at the northernmost segment of the Arabian-Nubian Shield (ANS), including the Kid complex. This complex is composed predominantly of thick volcano-sedimentary successions representing different depositional and tectonic environments, followed by four deformational phases including folding and brittle faults (D1-D4). The whole Kid area is divisible from north to south into the lower, middle, and upper rock sequences. The higher metamorphic grade and extensive deformational styles of the lower sequence distinguishes them from the middle and upper sequences. Principal lithofacies in the lower sequence include thrust-imbricated tectonic slice of metasediments and metavolcanics, whereas the middle and upper sequences are made up of clastic sediments, intermediate-felsic lavas, volcaniclastics, and dike swarms. Two distinct Paleo- depositional environments are observed: deep-marine and alluvial fan regime. The former occurred mainly during the lower sequence, whereas the latter developed during the other two sequences. These alternations of depositional conditions in the volcano-sedimentary deposits suggest that the Kid area may have formed under a transitional climate regime fluctuating gradually from warm and dry to warm and humid conditions. Geochemical and petrographical data, in conjunction with field relationships, suggest that the investigated volcano-sedimentary rocks were built from detritus derived from a wide range of sources, ranging from Paleoproterozoic to Neoproterozoic continental crust. Deposition within the ancient Kid basin reflects a complete basin cycle from rifting and passive margin development, to intra-arc and foreland basin development and, finally, basin closure. The early phase of basin evolution is similar to various basins in the Taupo volcanics, whereas the later phases are similar to the Cordilleran-type foreland basin. The

  3. Sedimentary input of trace metals from the Chukchi Shelf

    Science.gov (United States)

    Aguilar-Islas, A. M.; Seguré, M.; Rember, R.; Nishino, S.

    2014-12-01

    The distribution of trace metals in the Arctic Ocean has implications for their global cycles, yet until recently few trace metal observations were available from this rapidly changing ocean. Profiles of dissolved Fe from recent Japanese field efforts in the Western Canada Basin (2008, 2010) indicate the broad Chukchi Shelf as a source of Fe to the halocline of the Western Canada Basin. Here we present dissolved and particulate data for crustal (Al, Mn, Fe) and non-crustal elements (Co, Cu, Zn) from the productive Chukchi Sea to characterize the sedimentary input of these metals to shelf waters contributing to the halocline layer of the Canada Basin. Water column profiles were collected in late summer 2013 onboard the R/V Mirai at 10 stations from the Bering Strait to the slope, and at a time-series (10 days) station located over the outer shelf. A narrow and variable (5-10 m) benthic boundary layer was sampled at the time-series station with highly elevated dissolved and suspended particulate metal concentrations. High metal concentrations were also observed in the subsurface at a station over Barrow Canyon where mixing is enhanced. Reactivity of suspended particulate metals was determined by the leachable vs. refractory fractions. Metal concentrations were determined by ICP-MS. Trace metal transport from the shelf to the interior will be discussed in context with shelf mechanisms contributing to this export, and to expected future changes in the Arctic Ocean.

  4. Molecular genetic diversity of bacteria in the bottom section of arctic sea ice from the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    LI Huirong; YU Yong; CHEN Bo; ZENG Yinxin; REN Daming

    2005-01-01

    PCR-DGGE approach was used to analyze bacterial diversity in the bottom section of seven arctic sea ice samples colleted from the Canada Basin. Thirty-two 16S rDNA sequences were obtained from prominent DGGE bands. The closest relatives of these sequences are found to be those of cultivated or uncultured bacteria from antarctic or arctic sea ice. Phylogenetic analysis clustered these sequences or phylotypes within α- proteobacteria, γ-proteobacteria and CFB (cytophaga-flexibacter-bacteroides) group. Sequences belonging to γ-proteobacteria were dominant and members of the CFB group were highly abundant. It was suggested that the CFB group was the representative of the bottom section of sea ice samples.

  5. Carbonate rock classification applied to brazilian sedimentary basins; Classificacao de rochas carbonaticas aplicavel as bacias sedimentares brasileiras

    Energy Technology Data Exchange (ETDEWEB)

    Terra, Gerson Jose Salamoni [Universidade Petrobras, Rio de Janeiro, RJ (Brazil). Escola de Ciencias e Tecnologias de Exploracao e Producao], E-mail: gersonterra@petrobras.com.br; Spadini, Adali Ricardo [Petrobras E e P, Rio de Janeiro, RJ (Brazil). Exploracao], E-mail: spadini@petrobras.com.br; Franca, Almerio Barros [Centro de Pesquisa e Desenvolvimento Leopoldo A. Miguez de Mello (CENPES), Rio de Janeiro, RJ (Brazil). Sedimentologia e Petrologia] (and others)

    2009-11-15

    A new classification of carbonate rocks is proposed seeking to cover the entire spectrum of their occurrence in Brazilian basins. Emphasis is given to those in oil exploration and production locations, especially since the discovery of giant oil fields in the so called Pre-Salt section. This classification is a synergy between the various existing classifications adapting or modifying some terms and introducing new names. The carbonate rocks were divided into four groups according to their depositional texture: 1) elements not bound during deposition (mudstone, wackestone, packstone, grainstone, floatstone, rudstone, bioaccumulated, breccia), 2) elements bound during deposition, or in situ (boundstone, stromatolite, arborescent stromatolite, arbustiform stromatolite, dendriform stromatolite, thrombolite, dendrolite, leiolite, spherulitite, travertine and tufa), 3) elements bound or not bound during deposition (laminite, smooth laminite, crenulated laminite); 4) unrecognized depositional texture (crystalline limestone, dolomite). (author)

  6. The depositional setting of the Late Quaternary sedimentary fill in southern Bannu basin, Northwest Himalayan fold and thrust belt, Pakistan

    KAUST Repository

    Farid, Asam M.

    2014-07-10

    Geostatistical variogram and inversion techniques combined with modern visualization tools have made it possible to re-model one-dimensional electrical resistivity data into two-dimensional (2D) models of the near subsurface. The resultant models are capable of extending the original interpretation of the data to depict alluvium layers as individual lithological units within the 2D space. By tuning the variogram parameters used in this approach, it is then possible to visualize individual lithofacies and geomorphological features for these lithologic units. The study re-examines an electrical resistivity dataset collected as part of a groundwater study in an area of the Bannu basin in Pakistan. Additional lithological logs from boreholes throughout the area have been combined with the existing resistivity data for calibration. Tectonic activity during the Himalayan orogeny uplifted and generated significant faulting in the rocks resulting in the formation of a depression which subsequently has been filled with clay-silt and dirty sand facies typical of lacustrine and flood plain environments. Streams arising from adjacent mountains have reworked these facies which have been eroded and replaced by gravel-sand facies along channels. It is concluded that the sediments have been deposited as prograding fan shaped bodies, flood plain, and lacustrine deposits. Clay-silt facies mark the locations of paleo depressions or lake environments, which have changed position over time due to local tectonic activity and sedimentation. The Lakki plain alluvial system has thus formed as a result of local tectonic activity with fluvial erosion and deposition characterized by coarse sediments with high electrical resistivities near the mountain ranges and fine sediments with medium to low electrical resistivities towards the basin center. © 2014 Springer International Publishing Switzerland.

  7. A singular spectrum analysis on Holocene climatic oscillation from lake sedimentary record in Minqin Basin,China

    Institute of Scientific and Technical Information of China (English)

    JIN Liya; CHEN Fahu; DING Xiaojun; ZHU Yah

    2007-01-01

    The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57'-104°57'E, 37°48'-39°17'N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20'25"E, 39°00'38"N),which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7-6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth's climate systems.

  8. Natural CO2 migrations in the South-Eastern Basin of France: implications for the CO2 storage in sedimentary formations

    International Nuclear Information System (INIS)

    Study of natural CO2 analogues brings key informations on the factors governing the long term stability/instability of future anthropogenic CO2 storages. The main objective of this work, through the study of cores from V.Mo.2 well crosscutting the Montmiral natural reservoir (Valence Basin, France), is to trace the deep CO2 migrations in fractures. Petrographic, geochemical and micro-thermometric studies of the V.Mo.2 cores were thus performed in order: 1) to describe the reservoir filling conditions and 2) to detect possible CO2-leakage through the sediments overlying the reservoir. Fluid inclusions from the Paleozoic crystalline basement record the progressive unmixing of a hot homogeneous aquo-carbonic fluid. The Montmiral reservoir was therefore probably fed by a CO2-enriched gas component at the Late Cretaceous-Paleogene. The study of the sedimentary column in V.Mo.2 well, demonstrates that the CO2 did not migrate towards the surface through the thick marly unit (Domerian-Middle Oxfordian). These marls have acted as an impermeable barrier that prevented the upward migration of fluids. Two main stages of fluid circulation have been recognized: 1) an ante- Callovian one related to the Tethysian extension 2) a tertiary stage during which the upper units underwent a karstification, with CO2 leakage related but which remained confined into the deeper parts of the Valence Basin. Since the Paleogene, the Montmiral reservoir has apparently remained stable, despite the Pyrenean and alpine orogeneses. This is mainly due to the efficient seal formed by the thick marly levels and also to the local structuration in faulted blocks which apparently acted as efficient lateral barriers. (author)

  9. Three-dimensional Magnetotelluric Inversion and Model Validation with Potential Field Data and Seismics for the Central Portion of Parana Sedimentary Basin in Brazil

    Science.gov (United States)

    La Terra, E. F.; Fontes, S. L.; Taveira, D. T.; Miquelutti, L. G.

    2015-12-01

    The Paraná basin, on the central-south region of the South American Plate, is one of the biggest South American intracratonic basins. It is composed by Paleozoic and Mesozoic sediments, which were covered by the enormous Cretaceous flood basalts, associated with the rifting of Gondwana and the opening of the South Atlantic Ocean. Its depocenter region, with a maximum estimated depth of just over 7000 m, was crossed by three magnetotelluric - MT profiles proposed by the Brazilian Petroleum Agency (ANP) aimed at better characterizing its geological structure, as the seismic images are very poor. The data include about 350 MT broadband soundings spanning from 1000 Hz down to 2,000 s. The MT data were processed using robust techniques and remote reference. Static shift observed in some stations were corrected based on Transient Electromagnetic - TEM measurements at each site. These models were integrated to existent gravity, magnetic and seismic data for a more comprehensive interpretation of the region. A pilot 3D model has also been constructed on a crustal scale covering the study area using four frequencies per decade in the 3D inversion scheme proposed by Siripunvaraporn et al. (2005). The inversion scheme produced a reliable model and the observations were adequately reproduced, with observed fitting particularly better for the deeper structures related to basement compared to the 2D results. The main features in the conductivity model correspond to known geological features. These included the conductivity structures obtained for the upper crust, i.e. the sedimentary sequences, underlain by more resistive material, assumed to be basement. Local resistive features in the near-surface are associated to volcanic basalts covering the sediments. Some highly resistivity horizontal and vertical bodies were associated to volcanic intrusion like dikes and sills. We observed depressions on basement consistent with half-graben structures possibly filled with sandstones.

  10. Use of beta regression for statistical downscaling of precipitation in the Campbell River basin, British Columbia, Canada

    Science.gov (United States)

    Mandal, Sohom; Srivastav, Roshan K.; Simonovic, Slobodan P.

    2016-07-01

    Impacts of global climate change on water resources systems are assessed by downscaling coarse scale climate variables into regional scale hydro-climate variables. In this study, a new multisite statistical downscaling method based on beta regression (BR) is developed for generating synthetic precipitation series, which can preserve temporal and spatial dependence along with other historical statistics. The beta regression based downscaling method includes two main steps: (1) prediction of precipitation states for the study area using classification and regression trees, and (2) generation of precipitation at different stations in the study area conditioned on the precipitation states. Daily precipitation data for 53 years from the ANUSPLIN data set is used to predict precipitation states of the study area where predictor variables are extracted from the NCEP/NCAR reanalysis data set for the same interval. The proposed model is applied to downscaling daily precipitation at ten different stations in the Campbell River basin, British Columbia, Canada. Results show that the proposed downscaling model can capture spatial and temporal variability of local precipitation very well at various locations. The performance of the model is compared with a recently developed non-parametric kernel regression based downscaling model. The BR model performs better regarding extrapolation compared to the non-parametric kernel regression model. Future precipitation changes under different GHG (greenhouse gas) emission scenarios also projected with the developed downscaling model that reveals a significant amount of changes in future seasonal precipitation and number of wet days in the river basin.

  11. Comparison of isotopic time-series partitioning analysis with an evaporative enrichment model in lake- and wetland-dominated river basins, Mackenzie basin, Canada

    International Nuclear Information System (INIS)

    The use of the water isotope tracers oxygen-18 and deuterium to partition the streamflow components into snowmelt, surface water and groundwater can provide fundamental information about the factors that influence water balance and runoff generation in cold regions. Defining the isotopic composition of surface water (lakes and wetlands) is a challenge with the partitioning strategy, since the surface water contribution to streamflow, which is influenced seasonally by inputs of snowpack in spring and evaporative enrichment in summer, is a mixture from different water sources. Furthermore, the isotopic composition of streams in cold climates, particularly in subarctic wetlands, is often skewed because of non-contributing water balance compartments that undergo evaporative enrichment. That is, streams tend to reflect lower isotopic enrichment, especially in wetland-dominated basins. The streamflow partitioning strategy relies on 'set points' of low flow during late winter and fall leading to the development of a conceptual model for the isotopic variations in streamflow, which allow closure of the water balance over complete annual cycles. The isotopic variation in source waters for five subarctic basins near Fort Simpson, Northwest Territories, Canada is shown. The temporal changes in the volume of snowmelt, surface water, and groundwater contributions to streamflow from each river basin are displayed. Evaporation/inflow (E/I) ratios are obtained from isotope-mass balance calculations and the results are presented in the table below. Correspondingly, runoff contributions are calculated based on the water balance equation. The lowest level of the drainage hierarchy collects the maximum surface water accumulation, representing the corresponding isotopic signal (a value close to summer low-flow signal) integrated over the catchment area, and reflects the total water loss by evaporation. Hence, the evaporative enrichment model for E/I can be used to predict the net

  12. Evaluation of Groundwater Recharge Estimates in a Partially Metamorphosed Sedimentary Basin in a Tropical Environment: Application of Natural Tracers

    Science.gov (United States)

    Oteng Mensah, Felix; Alo, Clement

    2014-01-01

    This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB) method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests that annual groundwater recharge rates in the area ranges between 0.9% and 21% of annual precipitation. These estimates are consistent with evaporation rates computed from stable isotope data of groundwater and surface water in the Voltaian Basin. Moreover, estimates of groundwater recharge through numerical model calibration in other parts of the terrain appear to be consistent with the current data in this study. A spatial distribution of groundwater recharge in the area based on the estimated data takes a pattern akin to the spatial pattern of distribution of the hydraulic head, the local topography, and geology of the terrain. This suggests that the estimates at least qualitatively predicts the local recharge and discharge locations in the terrain. PMID:24772021

  13. The origin of groundwater arsenic and fluorine in a volcanic sedimentary basin in central Mexico: a hydrochemistry hypothesis

    Science.gov (United States)

    Morales-Arredondo, Iván; Rodríguez, Ramiro; Armienta, Maria Aurora; Villanueva-Estrada, Ruth Esther

    2016-06-01

    A groundwater sampling campaign was carried out in the summer of 2013 in a low-temperature geothermal system located in Juventino Rosas (JR) municipality, Guanajuato State, Mexico. This groundwater presents high concentrations of As and F- and high Rn counts, mainly in wells with relatively higher temperature. The chemistry of major elements was interpreted with different methods, like Piper and D'Amore diagrams. These diagrams allowed for classification of four groundwater types located in three hydrogeological environments. The aquifers are hosted mainly in alluvial-lacustrine sediments and volcanic rocks in interaction with fault and fracture systems. The subsidence, faults and fractures observed in the study area can act as preferential channels for recharge and also for the transport of deep fluids to the surface, especially in the basin plain. The formation of a piezometric dome and the observed hydrochemical behavior of groundwater suggest a possible origin of the As and F-. Geochemical processes occurring during water-rock interaction are related to high concentrations of As and F-. High temperatures and alteration processes (like rock weathering) induce dissolution of As and F--bearing minerals, increasing the content of these elements in groundwater.

  14. Evaluation of Groundwater Recharge Estimates in a Partially Metamorphosed Sedimentary Basin in a Tropical Environment: Application of Natural Tracers

    Directory of Open Access Journals (Sweden)

    Felix Oteng Mensah

    2014-01-01

    Full Text Available This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests that annual groundwater recharge rates in the area ranges between 0.9% and 21% of annual precipitation. These estimates are consistent with evaporation rates computed from stable isotope data of groundwater and surface water in the Voltaian Basin. Moreover, estimates of groundwater recharge through numerical model calibration in other parts of the terrain appear to be consistent with the current data in this study. A spatial distribution of groundwater recharge in the area based on the estimated data takes a pattern akin to the spatial pattern of distribution of the hydraulic head, the local topography, and geology of the terrain. This suggests that the estimates at least qualitatively predicts the local recharge and discharge locations in the terrain.

  15. MODTOHAFSD — A GUI based JAVA code for gravity analysis of strike limited sedimentary basins by means of growing bodies with exponential density contrast-depth variation: A space domain approach

    Science.gov (United States)

    Chakravarthi, V.; Sastry, S. Rajeswara; Ramamma, B.

    2013-07-01

    Based on the principles of modeling and inversion, two interpretation methods are developed in the space domain along with a GUI based JAVA code, MODTOHAFSD, to analyze the gravity anomalies of strike limited sedimentary basins using a prescribed exponential density contrast-depth function. A stack of vertical prisms all having equal widths, but each one possesses its own limited strike length and thickness, describes the structure of a sedimentary basin above the basement complex. The thicknesses of prisms represent the depths to the basement and are the unknown parameters to be estimated from the observed gravity anomalies. Forward modeling is realized in the space domain using a combination of analytical and numerical approaches. The algorithm estimates the initial depths of a sedimentary basin and improves them, iteratively, based on the differences between the observed and modeled gravity anomalies within the specified convergence criteria. The present code, works on Model-View-Controller (MVC) pattern, reads the Bouguer gravity anomalies, constructs/modifies regional gravity background in an interactive approach, estimates residual gravity anomalies and performs automatic modeling or inversion based on user specification for basement topography. Besides generating output in both ASCII and graphical forms, the code displays (i) the changes in the depth structure, (ii) nature of fit between the observed and modeled gravity anomalies, (iii) changes in misfit, and (iv) variation of density contrast with iteration in animated forms. The code is used to analyze both synthetic and real field gravity anomalies. The proposed technique yielded information that is consistent with the assumed parameters in case of synthetic structure and with available drilling depths in case of field example. The advantage of the code is that it can be used to analyze the gravity anomalies of sedimentary basins even when the profile along which the interpretation is intended fails to

  16. Comment on “Stratigraphy, petrography and dispersion of the lower Permian syn-eruptive deposits in the Viar Basin, Spain” by S. Sierra, C. Moreno and E. Pascual [Sedimentary Geology 217 (2009) 1-29

    Science.gov (United States)

    Wagner, R. H.; Mayoral, E.

    2010-07-01

    Comments are provided on a published paper on "Lower Permian" strata in SW Spain [S. Sierra, C. Moreno and E. Pascual, Stratigraphy, petrography and dispersion of the lower Permian syn-eruptive deposits in the Viar Basin, Spain, Sedimentary Geology 217 (2009) 1-29], which failed to take into account up-to-date information on this most southerly occurrence in western Europe. This generally lacustrine basin commenced with valley fill deposits in a deeply incised palaeotopography and contains mainly red beds with two basaltic intervals and a major acidic volcanic episode linked to a nearby volcanic centre to the Northeast. The stratigraphic succession shows southeasterly onlap. Although a syn-sedimentary fault has been postulated on the NE basin margin, the field evidence disproves this notion as well as the assumption that this "Early Permian" basin would have been controlled by a rejuvenated Ossa-Morena/South Portuguese boundary fault. In fact, this basin lies within the (former) area of Ossa-Morena.

  17. Analysis of tectonic-controlled fluvial morphology and sedimentary processes of the western Amazon Basin: an approach using satellite images and digital elevation model

    Directory of Open Access Journals (Sweden)

    Clauzionor L. Silva

    2007-12-01

    Full Text Available An investigation of the tectonic controls of the fluvial morphology and sedimentary processes of an area located southwest of Manaus in the Amazon Basin was conducted using orbital remote sensing data. In this region, low topographic gradients represent a major obstacle for morphotectonic analysis using conventional methods. The use of remote sensing data can contribute significantly to overcome this limitation. In this instance, remote sensing data comprised digital elevation model (DEM acquired by the Shuttle Radar Topographic Mission (SRTM and Landsat Thematic Mapper images. Advanced image processing techniques were employed for enhancing the topographic textures and providing a three-dimensional visualization, hence allowing interpretation of the morphotectonic elements. This led to the recognition of main tectonic compartments and several morphostructural features and landforms related to the neotectonic evolution of this portion of the Amazon Basin. Features such as fault scarps, anomalous drainage patterns, aligned ridges, spurs and valleys, are expressed in the enhanced images as conspicuous lineaments along NE-SW, NW-SE, E-W and N-S directions. These features are associated to the geometry of alternated horst and graben structures, the latter filled by recent sedimentary units. Morphotectonic interpretation using this approach has proven to be efficient and permitted to recognize new tectonic features that were named Asymmetric Ariaú Graben, Rombohedral Manacapuru Basin and Castanho-Mamori Graben.Uma investigação do controle tectônico da morfologia fluvial e dos processos sedimentares de uma área localizada a sudoeste da cidade de Manaus, na Bacia do Amazonas, foi conduzida a partir do uso de dados de sensores remotos orbitais. Nessa região, o baixo gradiente topográfico representa o principal obstáculo para a análise morfotectônica usando métodos convencionais. O uso de dados de sensores remotos pode contribuir

  18. Integrated stratigraphy of the Smirra Coring: a new reference sedimentary record for the early Paleogene from the Umbria-Marche Basin (Northern Apennines, Italy)

    Science.gov (United States)

    Turtù, Antonio; Lauretano, Vittoria; Catanzariti, Rita; Galeotti, Simone; Lanci, Luca; Moretti, Matteo; Lourens, Lucas J.

    2016-04-01

    The early Paleogene represents a critical time interval in Earth's history characterized by prolonged greenhouse conditions, culminating in a series of extreme global warming events (i.e. hyperthermals), as well as large uncertainties in the Geological Time Scale. Therefore new, high-resolution, geological records are crucial in providing novel constraints on these topics. The Paleogene Umbria-Marche sections of the Northern Apennines (Italy) have shown to be suitable for integrated stratigraphy allowing regional-to-global correlations and environmental reconstructions across this time interval. Among several well-known sections, a new sedimentary record is provided by the Smirra Coring, which recovered an undisturbed sequence of rocks (~120 m from 4 overlapping holes) spanning the upper Scaglia Fms. (early Paleocene - middle Eocene) of the Umbria-Marche pelagic succession. Here we present a new, high-resolution, integrated stratigraphic framework (magnetostratigraphy, calcareous nannofossil biostratigraphy, physical properties, calibrated XRF core scanning and cyclostratigraphy) of the ~93 m composite section drilled in Smirra Holes 1 and 2. The succession extends almost continuously, with modest tectonic disturbance affecting its lowermost part with minor faulting. The resulting magnetic stratigraphy defines a succession of normal and reversed polarity magnetozones. The correlation of the paleomagnetic polarity sequence with the latest Geomagnetic Polarity Timescales (GPTSs; e.g. CK95, GTS 2004 and 2012), also constrained through nannofossil biostratigraphy, shows that the section spans the late Paleocene - middle Eocene from chrons C21n (~46 Ma) to C26r (~60 Ma). The overall sedimentation rates computed at Smirra are fully comparable with those from coeval sections from the Umbria-Marche Basin, ranging from ~10 m/Ma, between chrons C21n and C22n, to ~6 m/Ma, between chrons C22r and the base of the section. However, the sedimentation rates vary considerably

  19. Sedimentary Records of Hyperpycnal Flows and the Influence of River Damming on Sediment Dynamics of Estuaries: Examples from the Nelson, Churchill, Moisie and Sainte-Marguerite Rivers (Canada)

    Science.gov (United States)

    St-Onge, G.; Duboc, Q.; Boyer-Villemaire, U.; Lajeunesse, P.; Bernatchez, P.

    2015-12-01

    Sediment cores were sampled in the estuary of the Nelson and Churchill Rivers in western Hudson Bay, as well as in the estuary of the Moisie and Sainte-Marguerite Rivers in Gulf of St. Lawrence in order to evaluate the impact of hydroelectric dams on the sedimentary regime of these estuaries. The gravity cores at the mouth of the Nelson River recorded several cm-thick rapidly deposited layers with a reverse to normal grading sequence, indicating the occurrence of hyperpycnal flows generated by major floods during the last few centuries. These hyperpycnal flows were probably caused by ice-jam formation, which can increase both the flow and the sediment concentration following the breaching of such natural dams. Following the construction of hydroelectric dams since the 1960s, the regulation of river discharge prevented the formation of hyperpycnal flows, and hence the deposition of hyperpycnites in the upper part of the cores. In the core sampled in the estuary of the Churchill River, only one hyperpycnite was recorded. This lower frequency may be due to the enclosed estuary of the Churchill River, its weaker discharge and the more distal location of the coring site.In the Gulf of St. Lawrence, grain size measurements allowed the identification of a major flood around AD 1844±4 years in box cores from both the Sainte-Marguerite and Moisie Rivers, whereas a drastic decrease in variations in the median grain size occurred around AD ~1900 in the estuary of the Sainte-Marguerite River, highlighting the offshore impact of the SM1 dam construction in the early 1900s. Furthermore, sedimentological variations in the box cores from both estuaries have been investigated by wavelet analysis and the sharp disappearance of high frequencies around AD 1900 in the estuary of the dammed river (Sainte-Marguerite River), but not in the estuary of the natural river (Moisie River), also provides evidence of the influence of dams on the sedimentary regime of estuaries.

  20. Hydraulic Fracturing At Sedimentary Basin Scale Fracturation hydraulique à l'échelle des bassins sédimentaires

    Directory of Open Access Journals (Sweden)

    Schneider F.

    2006-12-01

    Full Text Available One key point for simulating the hydraulic fracturing at basin scale, is to be able to compute the stress tensor. This is generally not addressed in basin model because of the complexity of this problem. In order to get access to the stress tensor we have to assume that:- one of the principal stress is vertical and equals the overburden weight;- the horizontal stress is deduced from the vertical stress with the K0 coefficient that is a function of depth and of the tectonical setting. Consolidation is considered here as the combined effect of the mechanical compaction and the chemical compaction. The mechanical compaction is mainly caused by the rearrangement of grains during burial and could be represented at the macroscopical scale by an elastoplastic rheology. The chemical compaction is considered here as resulting from dissolution-precipitation mechanisms, generally induced by stress (pressure-solution. The chemical compaction could be represented at the macroscopical scale by a viscoplastic rheology. The complete elastoplastic yield is defined by the union of the consolidation elastoplastic yield and of the different failure criteria that could be seen as elastobrittle yields. Thus, the elastoplastic yield is composed of six elementary elastoplastic yields which define the onset of vertical compaction, horizontal compaction, vertical tensile fracturing, horizontal tensile fracturing, subvertical shear fracturing, and subhorizontal shear fracturing. Due to the consolidation, most of the parameters that describe the physical properties of the sediments evolve with the geological times. One difficulty is to quantify the degree of evolution of the porous medium during its geological history. Here, we have chosen to measure the evolution of the sediments by their porosity. The local simulations showed that fracturing may occur is numerous configurations. Some of these configurations indicate that the sediments can reach the limit of its elastic

  1. Integrated biostratigraphy and stage boundaries of the Abderaz Formation, east of the Kopeh-Dagh sedimentary basin, NE Iran

    Science.gov (United States)

    Vahidinia, Mohammad; Youssef, Mohamed; Shafiee Ardestani, Meysam; Sadeghi, Abbas; Dochev, Docho

    2014-02-01

    The foraminiferal content of the well-known, foraminifera-rich Abderaz Formation of the Kopeh-Dagh basin in northeastern Iran was analyzed to determine biostratigraphy, age dating, chronostratigraphy and evolutionary trends. The Abderaz Formation was sampled at the following four sections: the Qarehso section, the Abderaz village section, the Muzduran section and the Shorab section. The Qarehso section is approximately 540 m thick and consists of 77 planktonic foraminifera species belonging to 18 genera in 5 biozones, 10 echinoid species belonging to 4 genera and 8 inoceramid species belonging to 5 genera. Based on this fossil content, the Qarehso section was dated to the lowermost Turonian to the upper Santonian. Based on the first occurrence datums of Cremnoceramus walterdorfensis walterdorfensis and Cremnoceramus deformis deformis and on the FODs of Micraster cortestudinarium and Dicarinella concavata, the Turonian-Conician boundary was detected in this section. In addition, based on the FODs of Echinocorys gr. scutata forma vulgaris, Echinocorys gr. scutata forma vulgaris-planodama and Di. Asymetrica, the base of the Santonian stage was also detected in the Qarehso section. The Abderaz village section is 556.5 m thick and contains 17 genera and 68 species of planktonic foraminifera that have been identified in 9 biozones and 7 genera and 15 species of invertebrates. The lowermost Turonian to the lowermost Campanian ages have been established in the Abderaz Formation. In the Abderaz village section, 3 boundaries were identified. Based on the FODs of Cremnoceramus walterdorfensis walterdorfensis, C. deformis deformis and C. crassus crassus and on the FODs of Contusotruncana fornicata and C. pateliformis, the base of the Coniacian stage was identified. Based on the FODs of Di. asymetrica and Macroglobigerinelloides alvarezi, the Coniacian-Santonian boundary was identified. Additionally, based on the extinction of the Marginotruncanid group and on the LOD of

  2. Biomarker characterization of the record of the OAE1a (early Aptian) in Betic and Cantabrian basins (Spain)-Sedimentary implications

    Science.gov (United States)

    Quijano, María. Luisa; Castro, José Manuel; Pancost, Richard D.; de Gea, Ginés. A.; Najarro, María.; Aguado, Roque; Rosales, Idoia; Martín-Chivelet, Javier

    2010-05-01

    Molecular analyses of sedimentary organic matter are powerful tools in assessing the origin of organic matter and its thermal maturity as well as constraining ancient environmental conditions, such as as marine productivity, anoxia in bottom waters or the photic zone and sea surface temperatures. This communication presents the study of four sections recording the OAE1a (early Aptian) in Spain, which are located in two broad basins respectively located in the South and the North of Iberia: the Southern Iberian Palaeomargin (Carbonero - CAB, La Frontera - XF and Cau - CAU sections) and the Cantabrian Basin (Puente Nansa - PN section). These sections represent depositional settings ranging from platform (CAU, PN) to pelagic environments (CAB, XF). C-isotope profiles and biostratigraphic data are used to define the interval corresponding to the OAE 1a. Here we focus on the biomarker composition of the organic-rich facies, and the integration of these data with the sedimentology, stratigraphy and paleogeography. The study has been based mainly upon the analysis of samples with Gas Chromatography-Mass Spectrometry (GCMS). Four main groups of compounds are present in all sections: n-alkanes, isoprenoids, hopanes and steranes. n-Alkanes and isoprenoids (pristane and phytane) are dominant in most samples. To facilitate interpretation of these distributions, we have calculated the TAR (terrestrial aquatic ratio derived from the ratio of long to short chain compounds) and also the OEP (odd over even predominance of n-alkanes). The ratio of pristane to phytane and various isoprenoid/n-alkanes ratios have also been calculated. The hopanes are represented by a range of C27 to C35 components, with the specific isomers varying amongst the sections due to differences in thermal maturity. Steranes occur as a range of C27, C28 and C29 isomers, whereas diasteranes only occur in the most thermally mature section (CAB). Other compounds of interest include gammacerane and dinosterane

  3. Sequence stratigraphic significance of sedimentary cycles and shell concentrations in the Aitamir Formation (Albian-Cenomanian), Kopet-Dagh Basin, northeastern Iran

    Science.gov (United States)

    Sharafi, M.; Mahboubi, A.; Moussavi-Harami, R.; Ashuri, M.; Rahimi, B.

    2013-05-01

    Albian-Cenomanian siliciclastic shallow marine sediments of the Aitamir Formation, Kopet-Dagh Basin, northeastern Iran, form strongly asymmetric fining-coarsening-upward cycles, which are interpreted as recording changes in relative sea level (deepening-shallowing cycles). These cycles correspond to depositional sequences, in which deposits of the lowstand systems tract are not present, the sequence boundary coinciding with the transgressive surface. Shell concentrations are found in distinct positions within the depositional sequence: as transgressive lags at the base of the transgressive systems tract (TST), in the maximum flooding zone (MFZ), and at or close to the top of the highstand systems tract (HST). They are dominated by bivalves (mainly oysters) and/or ammonites and differ from each other in a number of stratigraphic, sedimentologic, palaeoecological and taphonomic features, such as species diversity, preservation quality, orientation, percentage of disarticulation, and degree of biogenic alteration. Characteristic features of concentrations at the base of the TSTs are moderate time-averaging, distinct basal erosional surface, sorting, a chaotic to preferred convex-up orientation, and nearly total disarticulation of shells. They are suggestive of an environment in which reworking and local transport was frequent events. Similar features are shown by concentrations near the tops of the HSTs, except that the shells were largely concentrated in lenses rather than in beds as in the transgressive lags. Associated sedimentary structures indicate deposition above fair weather wave base in a high-energy environment. Concentrations occurring in the MFZ, in contrast, are autochthonous and highly time-averaged, having accumulated during times of low rates of sedimentation below storm wave base. This is supported by their high preservation quality (comparatively high percentage of articulated shells, shells of infaunal organisms commonly preserved in life position

  4. Kinetic modeling of the thermal evolution of crude oils in sedimentary basins; Modelisation cinetique de l'evolution thermique des petroles dans les gisements

    Energy Technology Data Exchange (ETDEWEB)

    Bounaceur, R.

    2001-01-15

    The aim of this work is to obtain a better understanding of the reactions involved in the thermal cracking of crude oil in sedimentary basins, and to study its kinetics as a function of temperature and pressure. We study the kinetics of pyrolysis of alkanes at low temperature, high pressure and high conversion and we propose three methods of reduction of the corresponding mechanisms. Several compounds having an inhibiting or accelerating effect on the rate of decomposition of alkanes were also studied. This research led to the construction of a general kinetic model of 5200 elementary steps representing the pyrolysis of a complex mixture of 52 molecules belonging to various chemical families: 30 linear alkanes (from CH{sub 4} to C{sub 30}H{sub 62}), 10 branched-chain alkanes (including pristane and phytane), 2 naphthenes (propyl-cyclo-pentane and propyl-cyclohexane), tetralin, 1-methyl-indan, 4 aromatics (benzene, toluene, butyl-benzene and decyl-benzene), 3 hetero-atomic compounds (a disulfide, a mercaptan and H{sub 2}S). This model is compared to experimental data coming from the pyrolysis of two oils: one from the North Sea and the other from Pematang. The results obtained show a good agreement between the experimental and simulated values. Then, we simulated the cracking of these two oils by using the following burial scenario: initial temperature of 160 degrees, 50 m per million years (ma) in a constant geothermal gradient of 30 degrees C/km, implying a heating rate of 1.5 degrees C/ma. Under these conditions, our model shows that these two oils start to crack only towards 210-220 degrees C and that their time of half-life corresponds to a temperature around 230-240 degrees C. The model also makes it possible to simulate the evolution of geochemical parameters such as the GOR, the API degree... (author)

  5. Organic geochemistry of the Callovo-Oxfordian argillo-carbonated sedimentary series of the East of the Paris basin and of England. Variabilities and paleo-environmental implications

    International Nuclear Information System (INIS)

    The Callovo-Oxfordian clay-stones from the East of the Paris basin are studied by ANDRA in order to test the feasibility of a possible storage of radioactive waste. The molecular analysis of their organic matter indicates that they can be considered as homogenous from their organic content point of view because they are characterized by only one molecular facies. However, the transition to the surrounding limestones is underlined by a major evolution of the molecular facies indicating a change and an increase of the variability of the deposition and diagenesis conditions. The evolution of the distribution of the plant bio-markers indicates, at the end of the Lower Oxfordian, a paleo-floristic change characterized by the increase of the proportion of Pinaceae (a conifer family) or their forerunners on the London-Brabant massif. This paleo-floristic evolution reflects a paleo-climatic change characterized by the increase of aridity at the global scale. Other complementary results get on other sedimentary series of similar ages highlight the occurrence of a period of water anoxia during the Middle Callovian which certainly happened on the major part of the Western Europe. This event could be at the origin of the crisis of the carbonate production at the Dogger/Malm transition. On the other hand, an experimental technique based on artificial maturation of extant plants has been developed and will allow the acquisition of new palaeo-chemo-taxonomic data. These data will contribute to a better interpretation of plant bio-marker assemblages in terms of palaeo-floristic composition. (author)

  6. Intermediate crust (IC); its construction at continent edges, distinctive epeirogenic behaviour and identification as sedimentary basins within continents: new light on pre-oceanic plate motions

    Science.gov (United States)

    Osmaston, Miles F.

    2014-05-01

    Introduction. The plate tectonics paradigm currently posits that the Earth has only two kinds of crust - continental and oceanic - and that the former may be stretched to form sedimentary basins or the latter may be modified by arc or collision until it looks continental. But global analysis of the dynamics of actual plate motions for the past 150 Ma indicates [1 - 3] that continental tectospheres must be immensely thicker and rheologically stiffer than previously thought; almost certainly too thick to be stretched with the forces available. In the extreme case of cratons, these tectospheric keels evidently extend to 600 km or more [2, 3]. This thick-plate behaviour is attributable, not to cooling but to a petrological 'stiffening' effect, associated with a loss of water-weakening of the mineral crystals, which also applies to the hitherto supposedly mobile LVZ below MORs [4, 5]. The corresponding thick-plate version of the mid-ocean ridge (MOR) process [6 - 8], replacing the divergent mantle flow model, has a deep, narrow wall-accreting axial crack which not only provides the seismic anisotropy beneath the flanks but also brings two outstanding additional benefits:- (i) why, at medium to fast spreading rates, MOR axes become straight and orthogonally segmented [6], (ii) not being driven by body forces, it can achieve the sudden jumps of axis, spreading-rate and direction widely present in the ocean-floor record. Furthermore, as we will illustrate, the crack walls push themselves apart at depth by a thermodynamic mechanism, so the plates are not being pulled apart. So the presence of this process at a continental edge would not imply the application of extensional force to the margin. Intermediate Crust (IC). In seeking to resolve the paradox that superficially extensional structures are often seen at margins we will first consider how this MOR process would be affected by the heavy concurrent sedimentation to be expected when splitting a mature continent. I reason

  7. The Hydromedusae and its distribution in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    张金标; 林茂

    2001-01-01

    The present paper is based on materials collected in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean during the period from July to August 1999 on the icebreaker, the R/V “Xuelong”, by the Chinese First Arctic Scientific Expedition. Totally, 8 species of pelagic Hydromedusae were identified, of which 4 species belonged to Anthomedusae, 2 species to Leptomedusae, 1 species to Trachymedusae and 1 species to Narcomedusae, the Neoturris breviconis is recorded for the first time in Chukchi Sea. Their principal morphological characteristics are described and illustrated. The 8 species of Hydromedusae occurring in the Chukchi Sea were all cold water species, of which 6 species belong to neritic species and 2 species to ocean species. According to the geographic distribution of species, they may be divided into three groups: Arctic species, Arctic-boreal species and Boreal-temperate species. From the view-point of zoogeography, species from these waters belong to the Arctic fauna.The abundance of Hydromedusae in Chukchi Sea was generally low, with a mean value of 108 ind.*10-2*m-3. Rathkea octopunctata and Aglantha digitale were dominant species. From the view-point of vertical distribution Aglantha digitale is inhabiting in the depth of 0 300 m and with the maximum in the depth of 50 m to 100 m.

  8. Primary Analysis on Rock Salt Sedimentary Facies Area of Dawenkou Basin in Tai'an City%泰安市大汶口盆地岩盐沉积相区探析

    Institute of Scientific and Technical Information of China (English)

    张树淇; 郝瑞娥; 王浩

    2015-01-01

    Dongxiang depression Is a structural depression located in the west of Dawenkou basin.Favoura-ble structural conditions,ancient climate,geographical conditions,and the surrounding rich source formed rock salt deposit in the basin.Regional tectonic evolution caused sedimentary range and the concentration differences of brine.Thus,rock salt sedimentary facies have a certain evolution.The main tendency is a-long the direction of SWW from the northwest to the midwest of Dongxiang depression.The sedimentary thickness changes as well.%东向洼地是位于大汶口凹陷西部的构造洼地,有利的构造条件、古气候古地理条件、周边丰富的物源,形成了盆地内的岩盐矿床。区域构造演化,造成洼地内构造沉积幅度、卤水浓度差异,从而岩盐沉积相也有了一定的演化,主要趋势为沉积中心自沉积中心自东向洼地西北部沿走向 SWW 向向洼地中西部转移,沉积厚度也随之变化。

  9. Chemical evolution of groundwater in a drainage basin of Holocene age, east-central Alberta, Canada

    Science.gov (United States)

    Wallick, E. I.

    1981-12-01

    Chemical evolution of groundwater in a small drainage basin of glacial origin (10,250 yr. B.P., based on radiocarbon age dating of gyttja from a closed saline lake in the basin) was studied in order to understand the generation of salts in surface-mined areas on the interior plains of Alberta. The basin was considered to be a natural analogue of a surface-disturbed area because of the large volumes of rock that had been redistributed by glaciers with the resulting change in topography and drainage. The distributions of hydraulic head, total dissolved solids (TDS), and environmental isotopes essentially reflect the superimposition of groundwater flow systems associated with the post-glacial topography upon a regional bedrock flow system of older but undertermined age. In the glacial drift aquifers and aquitards (sands and till), the groundwater composition was typically Ca-Mg-bicarbonate type at depths less than 30 m, but at depths of 30-100 m, the composition was Na-bicarbonate-sulfate type. In the deeper bedrock aquifers (> 100 m), Nabicarbonate-sulfate and Na-bicarbonate-chloride types were present. TDS was as low as 400 mg/l in the shallow drift aquifer, generally constant at ˜1000 mg/l in the deep drift and shallow bedrock aquifer, and over 1700 mg/l in the deep bedrock aquifer system. Chemical evolution of groundwater in the area appears to be dominated by two depth zones having different types of water-rock interaction. In the shallow drift zone, the dissolution of soil CO 2 in infiltrating groundwater, oxidation of organic carbon, sulfur and pyrite result in the formation of carbonic and sulfuric acids that attack carbonate and silicate minerals. On the basis of X-ray diffraction analysis, these minerals were calcite, dolomite, plagioclase feldspar, and smectite clays. However, in the deep regional bedrock aquifer, conditions are reducing (presence of methane), groundwater is alkaline (pH 8.6-10.3), and the Na-bicarbonate-chloride composition of groundwater

  10. Estimating annual high-flow statistics and monthly and seasonal low-flow statistics for ungaged sites on streams in Alaska and conterminous basins in Canada

    Science.gov (United States)

    Wiley, Jeffrey B.; Curran, Janet H.

    2003-01-01

    Methods for estimating daily mean flow-duration statistics for seven regions in Alaska and low-flow frequencies for one region, southeastern Alaska, were developed from daily mean discharges for streamflow-gaging stations in Alaska and conterminous basins in Canada. The 15-, 10-, 9-, 8-, 7-, 6-, 5-, 4-, 3-, 2-, and 1-percent duration flows were computed for the October-through-September water year for 222 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the individual months of July, August, and September for 226 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the season July-through-September for 65 stations in southeastern Alaska. The 7-day, 10-year and 7-day, 2-year low-flow frequencies for the season July-through-September were computed for 65 stations for most of southeastern Alaska. Low-flow analyses were limited to particular months or seasons in order to omit winter low flows, when ice effects reduce the quality of the records and validity of statistical assumptions. Regression equations for estimating the selected high-flow and low-flow statistics for the selected months and seasons for ungaged sites were developed from an ordinary-least-squares regression model using basin characteristics as independent variables. Drainage area and precipitation were significant explanatory variables for high flows, and drainage area, precipitation, mean basin elevation, and area of glaciers were significant explanatory variables for low flows. The estimating equations can be used at ungaged sites in Alaska and conterminous basins in Canada where streamflow regulation, streamflow diversion, urbanization, and natural damming and releasing of water do not affect the streamflow data for the given month or season. Standard errors of estimate ranged from 15 to 56 percent for high-duration flow

  11. Sedimentary thickness and velocity in the northeast boundary of the Parana Basin with Andean earthquakes and local events; Espessura e velocidade das camadas sedimentares na borda nordeste da Bacia do Parana utilizando telessismos da regiao andina e sismos locais

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Josimar A.; Souza, Luiz M. [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Geofisica; Assumpcao, Marcelo S. [Universidade de Sao Paulo (USP), SP (Brazil)

    2008-07-01

    Deep Andean earthquakes are a suitable source of high-frequency P-waves (with good signal to noise ratio up to {approx} 10 Hz) that can be used to obtain high-resolution receiver functions at stations in intra-cratonic basins in Brazil. Receiver functions (Gaussian width 20) at five stations in the Bebedouro seismic area (NE Parana Basin) were calculated using the time domain deconvolution of Ligorria and Ammon (1999). Inter-station Rayleigh wave phase velocities were measured using local earthquakes. Joint inversion of receiver functions and Rayleigh phase velocities provided reasonably well constrained S-wave velocity profiles. Shallow seismic refraction surveys were used to fix the velocities of the surface layers during the inversion. The area is characterized by a thin surface layer of sandstones ({approx}60 m), followed by a {approx}500 m thick basalt layer. Beneath the basalts, low-velocity layers define another sedimentary sequence. These features are consistent with the expected values based on well data at regional distances and confirm the usefulness of high-frequency receiver functions to study sedimentary basins. (author)

  12. An Assessment of the Influence of Orbital Forcing on Late Pliocene Global Sea-Level Using a Shallow-Marine Sedimentary Record from the Wanganui Basin, New Zealand.

    Science.gov (United States)

    Sefton, J.; Naish, T.; Mckay, R. M.; Turner, G. M.; Morgans, H. E. G.; Seward, D.; Alloway, B.

    2015-12-01

    Classical Milankovitch Theory suggests variance in the orbital cycles of precession (21 kyr) and obliquity (41 kyr) should have a profound influence on insolation and ice volume. However, the globally-integrated ice volume proxy record (benthic δ18O) during the Late Pliocene (3.0-2.6 Ma) is dominated by obliquity-paced cycles, and lacks a significant precession component. A number of hypotheses have been proposed to explain this phenomenon, but paleoclimate records independent of the benthic δ18O record are required to test these. The Wanganui Basin, New Zealand, contains a shallow-marine Neogene sedimentary succession that is widely recognised as an important site for examining sea-level/ice volume changes at orbital frequencies. Here, we present a record of paleobathymetric changes at an orbital resolution from the Late Pliocene Mangaweka Mudstone outcrop succession. Modern analogue-calibrated water-depth proxies of grainsize and benthic foraminifera census data were used to evaluate paleobathymetric changes. An integrated magneto-, bio- and tephrostratigraphy was developed that constrains the outcrop succession to between ~3.0 Ma and 2.58 Ma. Nine distinct cycles spanning ~400,000 years are identified in the grainsize and benthic foraminifera assemblages. Within the uncertainty of the age model, the Mangaweka Mudstone grainsize cycles can be matched one-for-one to the δ18O cycles, as they display a similar pattern of frequency and amplitude. The frequency of these cycles (and the corresponding interval in the δ18O record) are dominated by the 41 kyr year obliquity cycle, but with a subordinate eccentricity component. Therefore, the fluctuations in the grainsize and benthic foraminifera proxies likely represent an indirect response to global sea-level fluctuations via their effect on continental shelf sediment transport mechanisms. The implications for the orbital theory of the ice ages are that during the Late Pliocene, global ice volume changes responded

  13. Underground water and pollution vulnerability assessment of lower Imo sedimentary basin of South-eastern Nigeria: A case study of Nwangele Local Government Area of Imo state, Nigeria

    Directory of Open Access Journals (Sweden)

    Onunkwo – A, A

    2012-06-01

    Full Text Available Water exploitation and population explosion are two major problems facing Nwangele Local Government. This study was therefore predicated on these problems to assess the underground water and pollution vulnerability of the study area. The method of study involves literature survey of previous work done in Imo River sedimentary basin and other works considered necessary for the study. A total of ten (10 vertical electricity soundings (VES was conducted for data generation using terrameter 300 SAS employing Schlumberger configuration. Aquifer (sands from boreholes within three (3 communities and ten (10 water samples were collected and used for statistical and geochemical analysis. The result shows that the lithology is made of sand, silt sand, clay and shale. Three (3 aquifer systems exits in the area confined, semi confined and unconfined aquifers, these occur as upper (33.5m, middle (82m and lower (102 to 115m aquifers. The lithology comprises 4 to 6 layers with water bearing bed occurring at the fifth layer. Average aquifer thickness measured 38 metres. Multiaquifer system exists in some localities. Hydraulic conductivity values range from 25.6m/day to 28.9m/day, transmissivity ranges from 450.842/day to 111.7m2/day while the storativity values ranges from 0.468 x 10-5 to 1.13 x 10-5, all indicate aquifer of good yield. Aquifer thickness ranges from 12.5 to 45m. The water chemistry is neutral, mildly acidic to mildly alkaline. The underground water is of calcium by carbonate type (CaHCO3 fresh and ideal for consumption, irrigation and laundry industry. None of the constituents fell short of WHO (1984 standard . Environmental pollution is only confined to upper aquifer. It is recommended that the three aquifer horizons can be tapped at the depth range of 18 to 102 metres. Multiple screen should be employed where there are more than one aquifer horizon. It is advisable that down the hole electric logging be conducted prior to the installation of

  14. CO2 Saline Storage Demonstration in Colorado Sedimentary Basins. Applied Studies in Reservoir Assessment and Dynamic Processes Affecting Industrial Operations

    Energy Technology Data Exchange (ETDEWEB)

    Nummedal, Dag [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Doran, Kevin [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Sitchler, Alexis [Trustees Of The Colorado School Of Mines, Golden, CO (United States); McCray, John [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Mouzakis, Katherine [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Glossner, Andy [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Mandernack, Kevin [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Gutierrez, Marte [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Pranter, Matthew [Trustees Of The Colorado School Of Mines, Golden, CO (United States); Rybowiak, Chris [Trustees Of The Colorado School Of Mines, Golden, CO (United States)

    2012-09-30

    This multitask research project was conducted in anticipation of a possible future increase in industrial efforts at CO2 storage in Colorado sedimentary basins. Colorado is already the home to the oldest Rocky Mountain CO2 storage site, the Rangely Oil Field, where CO2-EOR has been underway since the 1980s. The Colorado Geological Survey has evaluated storage options statewide, and as part of the SW Carbon Sequestration Partnership the Survey, is deeply engaged in and committed to suitable underground CO2 storage. As a more sustainable energy industry is becoming a global priority, it is imperative to explore the range of technical options available to reduce emissions from fossil fuels. One such option is to store at least some emitted CO2 underground. In this NETL-sponsored CO2 sequestration project, the Colorado School of Mines and our partners at the University of Colorado have focused on a set of the major fundamental science and engineering issues surrounding geomechanics, mineralogy, geochemistry and reservoir architecture of possible CO2 storage sites (not limited to Colorado). Those are the central themes of this final report and reported below in Tasks 2, 3, 4, and 6. Closely related to these reservoir geoscience issues are also legal, environmental and public acceptance concerns about pore space accessibility—as a precondition for CO2 storage. These are addressed in Tasks 1, 5 and 7. Some debates about the future course of the energy industry can become acrimonius. It is true that the physics of combustion of hydrocarbons makes it impossible for fossil energy to attain a carbon footprint anywhere nearly as low as that of renewables. However, there are many offsetting benefits, not the least that fossil energy is still plentiful, it has a global and highly advanced distribution system in place, and the footprint that the fossil energy infrastructure occupies is

  15. Preliminary study of Precambrian integration with tectonic events in brazilian sedimentary basins (Updated); Estudo preliminar de integracao do Pre-Cambriano com os eventos tectonicos das bacias sedimentares brasileiras (Atualizacao)

    Energy Technology Data Exchange (ETDEWEB)

    Cordani, Umberto G. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Centro de Pesquisas Geocronologicas], Email: ucordani@usp.br; Neves, Benjamim Bley de Brito [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica], Email: bbleybn@usp.br; Thomaz Filho, Antonio [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Fac. de Geologia. Dept. de Estratigrafia e Paleontologia], Email: antoniothomaz@globo.com

    2008-11-15

    The article 'Preliminary study of Precambrian integration with tectonic events in Brazilian sedimentary basins,' by U. G. Cordani, B. B. Brito-Neves, R. A. Fuck, R. Porto, A. Thomaz-Filho and F. M. B. da Cunha, was published in PETROBRAS Petroleum Technical Science Series (Serie Ciencia Tecnica Petroleo da PETROBRAS) in 1984 and is being reissued by PETROBRAS Geosciences Bulletin. Naturally, the work requires many updates in the light of geosciences' progress in Brazil over the past 26 years. In these comments, numerous reflections have been addressed at short notice, but nevertheless considered appropriate, to occupy space conceded by the publishers for an assessment of the original work. In principle, only the latest summaries and newer published items on the topic have been consulted and commented. For this reason, it was decided to 'overlook' a number of important references on this issue, apologizing to the authors of omitted relevant works. The study, conducted in the early '80s, was based on the knowledge at the time regarding the tectonic evolution of the South American basement; an examination of PETROBRAS subsurface data in Brazilian sedimentary basins and the study of the Company's core samples obtained from perforations which reached the basement. Since then, great advances have been made in understanding the Brazilian territory tectonic evolution and important geophysical data collected regarding its sedimentary basins. On the other hand, there are virtually no recent perforations of the interior Cratonic basins. Moreover, in the marginal and offshore basins, many wells have not reached the basement. Therefore, in these comments, we sought to review the original study's interpretations and confirm the relevant geological knowledge added in recent decades, in the range of the original work. In this article, we try to follow the same structural sequence of the original text, giving the reader a better understanding

  16. Contributions of zircon U-Pb geochronology to understanding the volcanic and sedimentary history of some Purāna basins, India

    Science.gov (United States)

    Basu, Abhijit; Bickford, Marion. E.

    2014-09-01

    In this century, U-Pb ages of magmatic and detrital zircons, together with a few less accurate but fairly robust ages determined on monazite and baddeleyite, in the Purāna successions in India have established a few firm timelines that constrain the opening, closure, inversion, and provenance of the Purāna basins. The Cuddapah basin opened shortly before ca. 1900 Ma, the Vindhyan basin opened before ca. 1630 Ma, the Khariar basin likely opened ca. 1500 Ma, and the Chhattisgarh basin opened ca. 1400 Ma. The Marwar basin opened after ca. 750 Ma. The Chhattisgarh basin began to invert at ca. 1000 Ma and closed shortly thereafter. The Indravati and the Vindhyan basins closed ca. 1000 Ma. There are no other defensible geochronologic data to adequately constrain the opening and closure of other Purāna basins (e.g., Kaladgi, Badami, Bhima, Kurnool, Mallampalli, Albaka, Ampani, Sabari, and Kolhan). Neither the fossil record nor the biostratigraphy of these basins necessarily correspond to the chronology determined through radiometric measurements. The discovery of ca. 1000 Ma volcanic events in the Indravati and Chhattisgarh basins adds to the growing list of ca. 1000 Ma thermal disturbances in the Indian shield. Most of these events were likely the far field effects of the final assembly of Rodinia.

  17. Sedimentary Characteristics and Tectonic Setting of the Lower Cretaceous Strata in Jiuxi Basin,Gansu%酒西盆地下白垩统沉积特征及构造背景讨论

    Institute of Scientific and Technical Information of China (English)

    杨林; 朱利东; 郑荣才; 杨文光; 王成善

    2011-01-01

    Jiuquan Basin, located on the western part of the northern endge of Qilian orogenic belt, is a petroliferous basin on western end of the Corridor basin group. It is a subbasin of Jiuquan Basin. The exploration of several medium-to high-capacity industrial oil wells in the Lower Cretaceous strata indicates Jiuxi Basin the favourable geological conditions for hydrocarbon accumulation. People have never come to an agreement to the origin of the Jiuquan Basin. So, we studied the sedimentary facies of the Early Cretaceous strata at Hongliuxia Section of Jiuxi Basin and believe that sedimentary setting experienced four evolution stages are deep lake subfacies , pro fan-delta subfacies, fan-delta front subfacies, and fan-delta plain subfacies. Therefore the Jiuxi Basin can be divided into three evolutionary stage of embryonic rift,spread rift and basin shrinkage, having a bilayer structure of superposed sag and depression. By analyzing the exploration data and regional correlation, we propose that that tectonic setting of Cretaceous strata in Jiuxi Basin is similar to that of Mesozoic land facies basin in east China. Through comparing to the origin of early Cretaceous extensional rift basin group in east China, we think that the formation and evolution of the basin is affected by the subduction of Pacific Plate and the southward drift of Siberia Plate.%酒泉盆地位于祁连造山带北缘西部,是走廊盆地群西端的一个重要的富油气盆地,酒西盆地是酒泉盆地的次级盆地之一,下白垩统已钻获多口中、高产工业油井,显示具备优越的油气地质条件.白垩纪酒泉盆地的成因问题一直存在争议.对酒西盆地红柳峡早白垩世地层的实测剖面沉积相研究,得出当时的沉积环境具有由深湖亚相向前扇三角洲亚相、扇三角洲前缘亚相到扇三角洲平原亚相的演化序列,说明盆地发展经历了初始断陷阶段、断陷扩张阶段和坳陷阶段,是具有典型的断-坳双层

  18. Evidence for only minor contributions from bacteria to sedimentary organic carbon

    Science.gov (United States)

    Hartgers, W. A.; Sinninghe Damste, J. S.; Requejo, A. G.; Allan, J.; Hayes, J. M.; de Leeuw, J. W.

    1994-01-01

    Because their molecular signatures are often prominent in extracts of sediments, bacteria are thought to be important contributors to petroleum source beds. It has been shown recently, however, that abundances of biomarkers do not always reflect relative contributions to sedimentary organic carbon (Corg). The contribution of photosynthetic green sulphur bacteria to sediments can be assessed effectively because the diagenetic products of distinctive carotenoids from these organisms occur widely and their biomass is isotopically labelled, being enriched in 13C. We show here that, although sediments and oils from the Western Canada and Williston basins contain prominent biomarkers of photosynthetic bacteria, the absence of 13C enrichment in the total Corg requires that the bacterial contribution is in fact minimal. Although the importance of bacterial reworking of sedimentary debris cannot be doubted, we argue that our findings, when considered in conjunction with those from other settings, suggest that bacterial biomass may commonly represent only a minor component of total Corg in carbonaceous rocks.

  19. SEDIMENTARY PETROLOGY

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>20080229 Bai Guoping(Key Laboratory for Hydrocarbon Accumulation of Education Ministry,China University of Petroleum,Beijing 102249,China);John B.Keene Diagenesis and Fluid Flow History in Sandstones of the Upper Permian Black Jack Formation,Gunnedah Basin,Eastern Australia(Acta Geologica Sinica(English Edition)--Journal of the Geological Society of China,ISSN1000-9515,CN11-2001/P,81(3),2007,p.433-441,5 illus.,3 tables,21 refs.) Key words:sandstone,Australia

  20. Combined application of numerical simulation models and fission tracks analysis in order to determine the history of temperature, subsidence and lifting of sedimentary basins. A case study from the Ruhr Coal basin inWest Germany; Die kombinierte Anwendung numerischer Simulationsmodelle und Spaltspurenuntersuchungen zur Entschluesselung der Temperatur-, Subsidenz- und Hebungsgeschichte von Sedimentbecken - Ein Fallbeispiel aus dem Ruhrkohlenbecken Westdeutschlands

    Energy Technology Data Exchange (ETDEWEB)

    Karg, H. [Forschungszentrum Juelich (Germany). Inst. fuer Erdoel und organische Geochemie; Littke, R. [RWTH Aachen (Germany); Bueker, C. [Univ. Bern (Switzerland). Inst. fuer Geologie

    1998-12-31

    The Ruhr Coal basin is one of the globally best known sedimentary basins. According to classical, established the Ruhr Basin is a typical foreland molasse basins. The thermal history (heating and cooling) and the structural and sedimentary development since the formation of the basin, i.e. subsidence and lifting and erosion are of the first importance for the potential formation of hydrocarbons. In order to quantify these processes, two-dimensional numerical simulation models (based on geological and seismological sections) of the Ruhr basin were developed from which one could conclude the heat flow at the time of maximum basin depth after variscis orogenesis, maximum temperatures of individual strata sections and thickness of eroded strata. The PetroMod program package of the company IES/Juelich was used for these analyses. Finite-element-grids enable mathematican mapping and reconstruction of complex geological structures and processes. The models on temperature history are calibrated by comparing measured and calculated carbonification (vitrinite reflection) data. (orig./MSK). [Deutsch] Das Ruhrkohlenbecken stellt weltweit eines der am besten erforschten Sedimentbecken dar. Nach klassischen und etablierten Beckenmodellen kann das Ruhrbecken als typisches Vorlandmolassebecken angesehen werden. Besonders relevant fuer die potentielle Bildung von Kohlenwasserstoffen sind in erster Linie die thermische Geschichte (Aufheizung und Abkuehlung) sowie die strukturelle und sedimentaere Entwicklung seit der Beckenbildung, sprich Versenkungs-, Hebungs- und Erosionsprozesse. Um solche Prozesse zu quantifizieren, wurden im Ruhrbecken zweidimensionale (d.h. auf der Grundlage von geologischen und seismischen Sektionen) numerische Simulationsmodelle entwickelt, die Aufschluss ueber Waermefluesse zur Zeit der maximalen Beckeneintiefung im Anschluss an die variszische Orogenese, erreichte Maximaltemperaturen einzelner Schichtglieder sowie die Maechtigkeit erodierter Schichten im

  1. Further observations of a decreasing atmospheric CO2 uptake capacity in the Canada Basin (arctic Ocean) due to sea ice loss

    DEFF Research Database (Denmark)

    Else, B.G.T.; Galley, R.J.; Lansard, B.;

    2013-01-01

    ), considering that surface water temperatures were low and the influence of ice melt was strong. A simple model simulating melt of the remaining ice and exposure of the surface water for 100 days revealed a weak capacity for atmospheric CO2 uptake (mean flux: 2.4 mmol m2 d1), due largely to warming of the shallow......[1] Using data collected in 2009, we evaluated the potential for the southeastern Canada Basin (Arctic Ocean) to act as an atmospheric CO2 sink under the summertime ice-free conditions expected in the near future. Beneath a heavily decayed ice cover, we found surprisingly high pCO2sw (~290–320matm...... mixed layer. Our results confirm a previous finding that the Canada Basin is not a significant sink of atmospheric CO2 under summertime ice-free conditions and that increased ventilation of the surface mixed layer due to sea ice loss is weakening the sink even further. Citation: Else, B. G. T., R. J...

  2. Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

    Directory of Open Access Journals (Sweden)

    J. Majorowicz

    2012-03-01

    Full Text Available Atmospheric methane from episodic gas hydrate (GH destabilization, the "clathrate gun" hypothesis, is proposed to affect past climates, possibly since the Phanerozoic began or earlier. In the terrestrial Beaufort-Mackenzie Basin (BMB, GHs occur commonly below thick ice-bearing permafrost (IBP, but they are rare within it. Two end-member GH models, where gas is either trapped conventionally (Case 1 or where it is trapped dynamically by GH formation (Case 2, were simulated using profile (1-D models and a 14 Myr ground surface temperature (GST history based on marine isotopic data, adjusted to the study setting, constrained by deep heat flow, sedimentary succession conductivity, and observed IBP and Type I GH contacts in Mallik wells. Models consider latent heat effects throughout the IBP and GH intervals. Case 1 GHs formed at ~0.9 km depth only ~1 Myr ago by in situ transformation of conventionally trapped natural gas. Case 2 GHs begin to form at ~290–300 m ~6 Myr ago in the absence of lithological migration barriers. During glacial intervals Case 2 GH layers expand both downward and upward as the permafrost grows downward through and intercalated with GHs. The distinctive model results suggest that most BMB GHs resemble Case 1 models, based on the observed distinct and separate occurrences of GHs and IBP and the lack of observed GH intercalations in IBP. Case 2 GHs formed >255 m, below a persistent ice-filled permafrost layer that is as effective a seal to upward methane migration as are Case 1 lithological seals. All models respond to GST variations, but in a delayed and muted manner such that GH layers continue to grow even as the GST begins to increase. The models show that the GH stability zone history is buffered strongly by IBP during the interglacials. Thick IBP and GHs could have persisted since ~1.0 Myr ago and ~4.0 Myr ago for Cases 1 and 2, respectively. Offshore BMB IBP and GHs formed terrestrially during Pleistocene sea level low

  3. 新疆西天山伊犁地区石炭纪火山-沉积序列及盆地性质%Carboniferous Volcanic-Sedimentary Succession and Basin Properties in Ili Area,Western Tianshan,Xinjiang

    Institute of Scientific and Technical Information of China (English)

    白建科; 李智佩; 徐学义; 孙吉明; 牛亚卓

    2015-01-01

    新疆西天山伊犁地区作为中天山微板块的一部分,呈“倒三角形”被缝合带或断裂带所围限。其上广泛出露的石炭纪火山—沉积岩系,是研究西天山石炭纪盆地性质和天山古生代造山作用演化过程最为直接的载体。本文通过对石炭纪火山—沉积剖面的岩石组合、地层序列、构造环境及盆地演化过程研究表明:伊犁地区石炭纪火山—沉积岩与下伏地层(前寒武纪结晶基底或前石炭纪褶皱基底)之间呈广泛的区域性角度不整合接触;火山—沉积岩系由下到上可以划分为2个序列,分别对应于盆地伸展—裂陷演化的两个旋回:序列Ⅰ:大哈拉军山组底部扇三角洲相、向上出现2次爆发相—喷溢相的火山喷发旋回,阿克沙克组底部扇三角洲相,向上过渡为滨浅海相—开阔台地相;序列Ⅱ:伊什基里克组由下到上由3次爆发相—喷溢相的火山喷发旋回构成,东图津河组为浅海陆棚相。西天山伊犁地区石炭纪火山—沉积序列反映了后碰撞伸展环境下的裂谷盆地充填演化过程。%The Ili area,as a part of the Central Tianshan micro-continent,is a inverse-triangular area bordered by sutures and zones in the Tianshan belt.Carboniferous volcanic—sedimentary rocks widely outcropping in Ili area is the most direct carrier in the study of Carboniferous basin properties of western Tianshan and Paleozoic orogenic evolution of Tianshan.According to the rock assemblage,stratigraphic sequence,tectonic setting and basin evolution of the Carboniferous volcanic—sedimentary section,we can draw the following conclusions:there is a wide regional angular unconformity between the Lower Carboniferous and its underlying strata (the Precambrian crystalline basemen or pre-Carboniferous folded basement ). From bottom to top, Carboniferous volcanic—sedimentary rocks can be divided into two sequences respectively corresponding to

  4. Sedimentary profile from oxbow lake as an archive for past productivity and vegetation changes: a case study from Ganges basin, West Bengal, India

    Science.gov (United States)

    Rakshit, Subhadeep; Ghosh, Sambit; Sanyal, Prasanta; Ambili, Anoop

    2015-04-01

    Isotope (δ13CSOM) and biomarker (lipid n-alkane) investigations has been carried out on three sedimentary profiles (ca. 1.8 m depth) collected from Mohanpur, West Bengal, India with the aim of reconstructing paleovegetational and paleoproductivity changes. Satellite images reveal that the investigated sediments has been deposited in an oxbow lake setting of the river Ganges. The correlation of the three sedimentary profiles has been achieved using lithological and isotopic (δ13CSOM) marker layers. The total organic carbon (TOC) content of the profile ranges from 0.9% to 0.1%. The isotopic analysis (δ13CSOM) shows values mostly fluctuating between -19.2o to -22o with a rapid excursions (~5) showing enriched δ13CSOMvalue (-14.2) observed at ca. 1.5 m depth. The biomarker studies of the profile reveals dominant preferences in short carbon chain (C14, C16, C18, C20) with a little preferences for higher chain (C29, C31, C33). Interestingly, n-alkanes at 1.5 m depth shows very high concentration in short chain n-alkanes. Since the lower chain n-alkane represents aquatic vegetation/productivity and higher chain indicates the terrestrial contribution, the data from the investigated sedimentary profile shows contribution mostly from aquatic vegetation with a little contribution from terrestrial plants. This inference has been further corroborated by δ13CSOMvalues (-19.2o to -22) of the sedimentary profile typical of mixed aquatic and terrestrial vegetation. Additionally, the enriched δ13CSOMvalue (-14.2) coupled with very high concentration of short chain n-alkanes at 1.5 m depth reveals intense lake eutrophication. The development of rigorous chronology and high resolution data set of additional analytical parameters (e.g., C/N, δ15N) will provide crucial paleoclimate data set from this unexplored setting of Indian summer monsoon domain.

  5. Unravelling the structural control of mississippi valley-type deposits and prospects in carbonate sequences of the Western Canada Sedimentary Basin

    Science.gov (United States)

    Pana, D.

    2006-01-01

    Re-examination of selected MVT outcrops and cores in the Interior Plains and Rocky Moun-tains of Alberta, corroborated with previous paragenetic, isotopic and structural data, suggests Laramide structural channelling of dolomitizing and mineralizing fluids into strained carbonate rocks. At Pine Point, extensional faults underlying the trends of MVT ore bodies and brittle faults overprinting the Great Slave Lake Shear Zone define apinnate fault geometry and appear to be kinematically linked. Chemical and isotopic characteristics of MVT parental fluids are consistent with seawater and brine convection within fault-confined verticalaquifers, strong water-basement rock interaction, metalleaching from the basement, and focused release of hydrothermal fluids within linear zones of strained carbonate caprocks. Zones of recurrent strain in the basement and a cap of carbonate strata constitute the critical criteria for MVTexploration target selection in the WCSB.

  6. CSPG - SEPM joint convention : Program with abstracts - Sedimentary events and hydrocarbon systems

    International Nuclear Information System (INIS)

    This joint conference of the Canadian Society of Petroleum Geologists (CSPG) and the Society for Sedimentary Geology (SEPM) was held in Calgary, to encourage collaboration between the petroleum resource industry and academia. Well over 150 papers were presented in various special sessions. The principal topics of discussion included examination, investigation and assessment of the geology, geophysics, geochemistry and the resource potential of sedimentary basins in Canada and around the world. In the course of the presentations the depositional, tectonic and diagenetic histories of various formations, augmented with interpretations of the origin and evolution of the basins were reviewed. The new interpretations were made possible by the new concepts and models of sedimentary geoscience that were born in the creative cauldron of collaboration that exists between industry, government institutions and the universities. The widespread use of modern sequence stratigraphy was used as an example of how scientific and engineering synergy evolved over time to shed new light on the nature of the stratigraphic record. Environmental issues regarding the petroleum industry also received much attention. This volume contains the complete conference program listing, a list of the sponsors and exhibitors, and provides brief abstracts of all papers presented at the conference

  7. New insights into the structure and stratigraphy of the Swedish sector of the Baltic Sea sedimentary Basin from vintage 2D marine seismic data

    Science.gov (United States)

    Sopher, Daniel; Juhlin, Christopher; Erlström, Mikael

    2014-05-01

    A large dataset originally acquired by the Swedish Oil Prospecting CO. (OPAB) between 1970 and 1990 including 2D marine seismic data, well log data, core data and seismic interpretations has recently been made available by the Swedish Geological Survey (SGU). In this study this dataset has been used to produce a set of regional geoseismic sections across the Swedish sector of the Baltic Sea. Regional depth structure maps detailing the deep structure of the basin produced from previous interpretations are also presented. The Baltic Sea Basin is an intra-cratonic basin located in northern Europe. The Swedish sector of the basin is characterised primarily by two structural elements, the Hanö Bay Basin and the Baltic Syneclise. The largest of these, the Baltic Syneclise, is a large synclinal depression formed during the Caledonian Orogeny. The Hanö Bay Basin was formed during the Mesozoic due to subsidence along the Christiansø Fault Zone. The Swedish sector of the Baltic Sea Basin is primarily characterised by a sequence of shallow marine Cambrian sediments overlain by a relatively thin succession of Ordovician marine limestone and marls; these are in turn overlain by a thick layer of marl, siltstone and claystone deposited during the Silurian. Mesozoic sediments are found in the Hanö Bay and outer Hanö Bay area. These were deposited in areas of local subsidence, associated with transtensional tectonics prevalent within and adjacent to the Tornquist Zone, during the Late Carboniferous/Early Permian. Block faulting occurring throughout the Mesozoic also affected sedimentation patterns in the area. In this study a sparse grid of marine seismic reflection profiles have been reprocessed across the Swedish sector of the Baltic Sea Basin. These have been interpreted based on the available well data and synthetic seismograms. Several regional seismic profiles were constructed which detail the major structural elements and basin stratigraphy across the Swedish sector. A

  8. Estimating Low-Flow Frequency Statistics and Hydrologic Analysis of Selected Streamflow-Gaging Stations, Nooksack River Basin, Northwestern Washington and Canada

    Science.gov (United States)

    Curran, Christopher A.; Olsen, Theresa D.

    2009-01-01

    Low-flow frequency statistics were computed at 17 continuous-record streamflow-gaging stations and 8 miscellaneous measurement sites in and near the Nooksack River basin in northwestern Washington and Canada, including the 1, 3, 7, 15, 30, and 60 consecutive-day low flows with recurrence intervals of 2 and 10 years. Using these low-flow statistics, 12 regional regression equations were developed for estimating the same low-flow statistics at ungaged sites in the Nooksack River basin using a weighted-least-squares method. Adjusted R2 (coefficient of determination) values for the equations ranged from 0.79 to 0.93 and the root-mean-squared error (RMSE) expressed as a percentage ranged from 77 to 560 percent. Streamflow records from six gaging stations located in mountain-stream or lowland-stream subbasins of the Nooksack River basin were analyzed to determine if any of the gaging stations could be removed from the network without significant loss of information. Using methods of hydrograph comparison, daily-value correlation, variable space, and flow-duration ratios, and other factors relating to individual subbasins, the six gaging stations were prioritized from most to least important as follows: Skookum Creek (12209490), Anderson Creek (12210900), Warm Creek (12207750), Fishtrap Creek (12212050), Racehorse Creek (12206900), and Clearwater Creek (12207850). The optimum streamflow-gaging station network would contain all gaging stations except Clearwater Creek, and the minimum network would include Skookum Creek and Anderson Creek.

  9. Comparison of Factorial Kriging Analysis Method and Upward Continuation Filter to Recognize Subsurface Structures – A Case Study: Gravity Data from a Hydrocarbon Field in the Southeast Sedimentary Basins of the East Vietnam Sea

    Directory of Open Access Journals (Sweden)

    Azad Mohammad-Reza

    2016-04-01

    Full Text Available To interpret geophysical anomaly maps, it is necessary to filter out regional and sometimes noise components. Each measured value in a gravity survey consists of different components. Upward continuation (UC is one of the most widely used filters. The shortcoming of this filter is not to consider the spatial structure of the data, and also the fact that the trial and error approach and expert’s judgment are needed to adjust it. This study aims to compare the factorial kriging analysis (FKA and UC filters for separation of local and regional anomalies in the gravity data of a hydrocarbon field in the southeast sedimentary basins of the East Vietnam Sea. As shown in this paper, FKA method permits to filter out all of the identified structures, while the UC filter does not possess this capability. Therefore, beside general and classic filtering methods, the FKA method can be used as a strong method in filtering spatial structures and anomaly component.

  10. Comparison of Factorial Kriging Analysis Method and Upward Continuation Filter to Recognize Subsurface Structures - A Case Study: Gravity Data from a Hydrocarbon Field in the Southeast Sedimentary Basins of the East Vietnam Sea

    Science.gov (United States)

    Azad, Mohammad-Reza; Koneshloo, Mohammad; Kamakar Rouhani, Abolghasem; Aghajani, Hamid

    2016-04-01

    To interpret geophysical anomaly maps, it is necessary to filter out regional and sometimes noise components. Each measured value in a gravity survey consists of different components. Upward continuation (UC) is one of the most widely used filters. The shortcoming of this filter is not to consider the spatial structure of the data, and also the fact that the trial and error approach and expert's judgment are needed to adjust it. This study aims to compare the factorial kriging analysis (FKA) and UC filters for separation of local and regional anomalies in the gravity data of a hydrocarbon field in the southeast sedimentary basins of the East Vietnam Sea. As shown in this paper, FKA method permits to filter out all of the identified structures, while the UC filter does not possess this capability. Therefore, beside general and classic filtering methods, the FKA method can be used as a strong method in filtering spatial structures and anomaly component.

  11. From Flysch to Molasse-Sedimentary and Tectonic Evolution of Late Caledonian-Early Hercynian Foreland Basin in North Qilian Mountains

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Late Caledonian to Early Hercynian North Qilian orogenic belt in northwestern China is an elongate tectonic unit situated between the North China plate in the north and the Qaidam plate in the south. North Qilian started in the latest Proterozoic to Cambrian as a rift basin on the southern margin of North China, and evolved later to an archipelagic ocean and active continental margin during the Ordovician and a foreland basin from Silurian to the Early and Middle Devonian. The Early Silurian flysch and submarine alluvial fan, the Middle to Late Silurian shallow marine to tidal flat deposits and the Early and Middle Devonian terrestrial molasse are developed along the corridor Nanshan. The shallowing-upward succession from subabyssal flysch, shallow marine, tidal flat to terrestrial molasse and its gradually narrowed regional distribution demonstrate that the foreland basin experienced the transition from flysch stage to molasse stage during the Silurian and Devonian time.

  12. Dietary habits of polar bears in Foxe Basin, Canada: possible evidence of a trophic regime shift mediated by a new top predator.

    Science.gov (United States)

    Galicia, Melissa P; Thiemann, Gregory W; Dyck, Markus G; Ferguson, Steven H; Higdon, Jeff W

    2016-08-01

    Polar bear (Ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. In the Foxe Basin region of Nunavut, Canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. We used fatty acid analysis to examine polar bear feeding habits in Foxe Basin and thus potentially identify ecological factors contributing to population stability. Adipose tissue samples were collected from 103 polar bears harvested during 2010-2012. Polar bear diet composition varied spatially within the region with ringed seal (Pusa hispida) comprising the primary prey in northern and southern Foxe Basin, whereas polar bears in Hudson Strait consumed equal proportions of ringed seal and harp seal (Pagophilus groenlandicus). Walrus (Odobenus rosmarus) consumption was highest in northern Foxe Basin, a trend driven by the ability of adult male bears to capture large-bodied prey. Importantly, bowhead whale (Balaena mysticetus) contributed to polar bear diets in all areas and all age and sex classes. Bowhead carcasses resulting from killer whale (Orcinus orca) predation and subsistence harvest potentially provide an important supplementary food source for polar bears during the ice-free period. Our results suggest that the increasing abundance of killer whales and bowhead whales in the region could be indirectly contributing to improved polar bear foraging success despite declining sea ice habitat. However, this indirect interaction between top predators may be temporary if continued sea ice declines eventually severely limit on-ice feeding opportunities for polar bears. PMID:27547372

  13. Western Canada SAGD drilling and completions performance

    Energy Technology Data Exchange (ETDEWEB)

    Turchin, S.; Tucker, R. [Ziff Energy Group (Canada)

    2011-07-01

    In the heavy oil industry, steam assisted gravity drainage (SAGD) is a thermal recovery method used to enhance oil recovery. In 2009, Ziff Energy carried out a study on SAGD drilling and completions performance in Western Canada. This paper presents the methodology used to assess drilling performances and the results obtained. This study was conducted on 159 SAGD well pairs and 1,833 delineation wells in the Western Canadian Sedimentary Basin from late 2004 to fall 2008. The drilling performance assessment was calculated from several aspects including well quality, drilling and completions cost performance and drilling time analysis. This study provided a detailed analysis of drilling and completions costs of SAGD which can help companies to improve their performance.

  14. The high-resolution stratigraphic architecture and evolution of the Burdigalian carbonate-silici-clastic sedimentary systems on the Mut Basin, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Bassant, Ph.

    1999-06-01

    The subject of this doctorate study are the Lower Miocene (Burdigalian) carbonate systems in the Mut basin, in south central Turkey. This area is chosen because it presents extraordinary large (seismic) scale 3D outcrops showing depositional geometries. In addition, these carbonates are considered as good outcrop analogues for time equivalent carbonate buildups in the Far East, that are oil and gas bearing. The carbonates were deposited in a complex relict topography, following a tectonically active phase in the Oligocene. During the Burdigalian transgression shallow platform carbonates were deposited in a variety of settings, locally accompanied by some silici-clastic input. Observations on the strata geometries and the facies were combined into a high resolution sequence stratigraphic framework controlled by bio-stratigraphy. With the help of relative sea level curves constructed for the three studied sites, a basin-wide correlation scheme is proposed. This chronostratigraphic framework permits the recognition of condensation and omission surfaces in the basinal and platform settings, to identify basin-wide variations in sedimentation pattern, and to evaluate the relative influence of tectonism, eustatism and the environment. The exceptional quality of the outcrops with its variety of environments, and its location at the Tethys margin, make this a good candidate for a reference model for Burdigalian reef and platform architectures. Examples of a quantitative approach of the geometries of potential carbonate reservoir bodies are given in the annex. The data-files are incorporated in the carbonate reservoir body database CARABAS. (author)

  15. Magnetostratigraphy and radio-isotope dating of upper Miocene-lower Pliocene sedimentary successions of the Black Sea Basin (Taman Peninsula, Russia)

    NARCIS (Netherlands)

    Vasiliev, I.; Iosifidi, A.G.; Khramov, A.N.; Krijgsman, W.; Kuiper, K.; Langereis, C.G.; Popov, V.V.; Stoica, M.; Tomsha, V.A.; Yudin, S.V.

    2011-01-01

    We present a new chronology for the upper Miocene to Pliocene deposits of the Black Sea basin based on highresolution magnetostratigraphic data coupled with 40Ar/39Ar dating from the 475 m long Zheleznyi Rog section on the Taman Peninsula (Russia). This section comprises the stratigraphic interval o

  16. Quantitative characterisation of sedimentary grains

    Science.gov (United States)

    Tunwal, Mohit; Mulchrone, Kieran F.; Meere, Patrick A.

    2016-04-01

    Analysis of sedimentary texture helps in determining the formation, transportation and deposition processes of sedimentary rocks. Grain size analysis is traditionally quantitative, whereas grain shape analysis is largely qualitative. A semi-automated approach to quantitatively analyse shape and size of sand sized sedimentary grains is presented. Grain boundaries are manually traced from thin section microphotographs in the case of lithified samples and are automatically identified in the case of loose sediments. Shape and size paramters can then be estimated using a software package written on the Mathematica platform. While automated methodology already exists for loose sediment analysis, the available techniques for the case of lithified samples are limited to cases of high definition thin section microphotographs showing clear contrast between framework grains and matrix. Along with the size of grain, shape parameters such as roundness, angularity, circularity, irregularity and fractal dimension are measured. A new grain shape parameter developed using Fourier descriptors has also been developed. To test this new approach theoretical examples were analysed and produce high quality results supporting the accuracy of the algorithm. Furthermore sandstone samples from known aeolian and fluvial environments from the Dingle Basin, County Kerry, Ireland were collected and analysed. Modern loose sediments from glacial till from County Cork, Ireland and aeolian sediments from Rajasthan, India have also been collected and analysed. A graphical summary of the data is presented and allows for quantitative distinction between samples extracted from different sedimentary environments.

  17. Coupled Heat and Fluid Flow Modeling of the Earth's Largest Zinc Ore Deposit at Red Dog, Alaska: Implications for Structurally-Focused, Free Convection in Submarine Sedimentary Basins

    Science.gov (United States)

    Garven, G.; Dumoulin, J. A.; Bradley, D. A.; Young, L. E.; Kelley, K. D.; Leach, D. L.

    2002-12-01

    Crustal heat flow can provide a strong mechanism for driving groundwater flow, particularly in submarine basins where other mechanisms for driving pore fluid flow such as topography, compaction and crustal deformation are too weak or too slow to have a significant effect on disturbing conductive heat flow. Fault zones appear to play a crucial role in focusing fluid migration in basins, as inferred in ancient rocks by many examples of hydrothermal deposits of sediment-hosted ores worldwide. Many rift-hosted deposits of lead, zinc, and barite ore appear to have formed at or near the seafloor by focused venting of hot basinal fluids and modified seawater, although the geophysical nature of these systems is not so well known. For example, the upper Kuna Formation, a finely laminated, black, organic-rich siliceous mudstone and shale in the Western Brooks Range of northwest Alaska, is host to the largest resources of zinc yet discovered in the Earth's crust, containing ore reserves in excess of 175 Mt averaging about 16% Zn and 5% Pb. Although situated today in a highly-deformed series of structural allocthonous plates thrusted during the Jurassic to Cretaceous Brookian Orogeny, the stratiform ores are thought to have formed much earlier in the anoxic, mud-rich Carboniferous-age Kuna Basin when adjacent carbonate platforms were drowned by rifting and tectonic subsidence. Fluid inclusion studies of ore-stage sphalerite and gangue minerals indicate sub-seafloor mineralization temperatures less than 200oC and most likely between 120 to 150 oC, during a period of sediment diagenesis and extensional faulting. We have constructed fully-coupled numerical models of heat and fluid flow to test hydrologic theories for free convection, submarine venting and subsequent ore formation, as constrained by paleoheat flow and petrologic observations. A finite element grid was designed and adapted for a cross section of the Kuna Basin, geologically restored to latest Mississippian time

  18. Distribution characteristics of interlayer oxidation zone and its relationship with sedimentary facies and uranium mineralization in QJD uranium deposit, Songliao basin, NE China

    International Nuclear Information System (INIS)

    QJD uranium deposit is a sandstone-type uranium deposit with the special shape of the interlayer oxidation zone. After studying the palaeoclimate condition and sedimentation of host sandstones, contrasting drilling cross sections, this paper suggests that primary colors of host sandstones are mostly in gray, red and yellow colors of sandstones are the result of oxidation alteration. According to the positions of drill holes with red and yellow alteration sandstones, the plane distribution of oxidation roll fronts of the Upper and Lower Member of Yaojia Formation are delineated. By contrasting the plane distribution of oxidation fronts and sedimentary facies, it can be found that oxidation fronts are obviously controlled by interchannel fine-grained sediments. The movement of uranium-bearing oxidizing groundwater can be obstructed by interchannel sediments and pelitic interbeds of host sandstones. As a result, redox interface will be developed and uranium can be concentrated in neighbouring sandstones. (authors)

  19. Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012

    Science.gov (United States)

    Curran, Janet H.; Barth, Nancy A.; Veilleux, Andrea G.; Ourso, Robert T.

    2016-03-16

    Estimates of the magnitude and frequency of floods are needed across Alaska for engineering design of transportation and water-conveyance structures, flood-insurance studies, flood-plain management, and other water-resource purposes. This report updates methods for estimating flood magnitude and frequency in Alaska and conterminous basins in Canada. Annual peak-flow data through water year 2012 were compiled from 387 streamgages on unregulated streams with at least 10 years of record. Flood-frequency estimates were computed for each streamgage using the Expected Moments Algorithm to fit a Pearson Type III distribution to the logarithms of annual peak flows. A multiple Grubbs-Beck test was used to identify potentially influential low floods in the time series of peak flows for censoring in the flood frequency analysis.For two new regional skew areas, flood-frequency estimates using station skew were computed for stations with at least 25 years of record for use in a Bayesian least-squares regression analysis to determine a regional skew value. The consideration of basin characteristics as explanatory variables for regional skew resulted in improvements in precision too small to warrant the additional model complexity, and a constant model was adopted. Regional Skew Area 1 in eastern-central Alaska had a regional skew of 0.54 and an average variance of prediction of 0.45, corresponding to an effective record length of 22 years. Regional Skew Area 2, encompassing coastal areas bordering the Gulf of Alaska, had a regional skew of 0.18 and an average variance of prediction of 0.12, corresponding to an effective record length of 59 years. Station flood-frequency estimates for study sites in regional skew areas were then recomputed using a weighted skew incorporating the station skew and regional skew. In a new regional skew exclusion area outside the regional skew areas, the density of long-record streamgages was too sparse for regional analysis and station skew was used

  20. Developmental geology of coalbed methane from shallow to deep in Rocky Mountain basins and in Cook Inlet-Matanuska Basin, Alaska, USA and Canada

    Science.gov (United States)

    Johnson, R.C.; Flores, R.M.

    1998-01-01

    The Rocky Mountain basins of western North America contain vast deposits of coal of Cretaceous through early Tertiary age. Coalbed methane is produced in Rocky Mountain basins at depths ranging from 45 m (150 ft) to 1981 m (6500 ft) from coal of lignite to low-volatile bituminous rank. Although some production has been established in almost all Rocky Mountain basins, commercial production occurs in only a few. despite more than two decades of exploration for coalbed methane in the Rocky Mountain region, it is still difficult to predict production characteristics of coalbed methane wells prior to drilling. Commonly cited problems include low permeabilities, high water production, and coals that are significantly undersaturated with respect to methane. Sources of coalbed gases can be early biogenic, formed during the early stages of coalification, thermogenic, formed during the main stages of coalification, or late stage biogenic, formed as a result of the reintroduction of methane-gnerating bacteria by groundwater after uplift and erosion. Examples of all three types of coalbed gases, and combinations of more than one type, can be found in the Rocky Mountain region. Coals in the Rocky Mountain region achieved their present ranks largely as a result of burial beneath sediments that accumulated during the Laramide orogeny (Late Cretaceous through the end of the eocene) or shortly after. Thermal events since the end of the orogeny have also locally elevated coal ranks. Coal beds in the upper part of high-volatile A bituminous rank or greater commonly occur within much more extensive basin-centered gas deposits which cover large areas of the deeper parts of most Rocky Mountain basins. Within these basin-centered deposits all lithologies, including coals, sandstones, and shales, are gas saturated, and very little water is produced. The interbedded coals and carbonaceous shales are probably the source of much of this gas. Basin-centered gas deposits become overpressured

  1. Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012

    Science.gov (United States)

    Curran, Janet H.; Barth, Nancy A.; Veilleux, Andrea G.; Ourso, Robert T.

    2016-03-16

    Estimates of the magnitude and frequency of floods are needed across Alaska for engineering design of transportation and water-conveyance structures, flood-insurance studies, flood-plain management, and other water-resource purposes. This report updates methods for estimating flood magnitude and frequency in Alaska and conterminous basins in Canada. Annual peak-flow data through water year 2012 were compiled from 387 streamgages on unregulated streams with at least 10 years of record. Flood-frequency estimates were computed for each streamgage using the Expected Moments Algorithm to fit a Pearson Type III distribution to the logarithms of annual peak flows. A multiple Grubbs-Beck test was used to identify potentially influential low floods in the time series of peak flows for censoring in the flood frequency analysis.For two new regional skew areas, flood-frequency estimates using station skew were computed for stations with at least 25 years of record for use in a Bayesian least-squares regression analysis to determine a regional skew value. The consideration of basin characteristics as explanatory variables for regional skew resulted in improvements in precision too small to warrant the additional model complexity, and a constant model was adopted. Regional Skew Area 1 in eastern-central Alaska had a regional skew of 0.54 and an average variance of prediction of 0.45, corresponding to an effective record length of 22 years. Regional Skew Area 2, encompassing coastal areas bordering the Gulf of Alaska, had a regional skew of 0.18 and an average variance of prediction of 0.12, corresponding to an effective record length of 59 years. Station flood-frequency estimates for study sites in regional skew areas were then recomputed using a weighted skew incorporating the station skew and regional skew. In a new regional skew exclusion area outside the regional skew areas, the density of long-record streamgages was too sparse for regional analysis and station skew was used

  2. Sedimentary Basins of the Republic of Yemen : Their Structural Evolution and Geological Characteristics Evolution structurelle et caractéristiques géologiques des bassins sédimentaires de la république du Yemen

    Directory of Open Access Journals (Sweden)

    Beydoun Z. R.

    2006-11-01

    Full Text Available The distribution and evolution of the sedimentary basins of Yemen was, until recently, poorly understood as this was based entirely on surface geology and correlations of the older stratigraphic units which were exposed only in the deeply dissected bordering uplifts of the Gulf of Aden and Red Sea or the high plateau of the north west. Elsewhere cover by the tabular Tertiary sedimentary blanket and the Tertiary Volcanic Group lavas masked the major underlying pre-Cenozoic structural elements and sedimentary successions. Earlier attempts at the delineation of the country's structural framework were, thus, sketchy and/or only partially correct. The discovery of commercial oil and gas in several interior Mesozoic rift basins of Yemen in the late 1980s and in the early 1990s after unification of the former two Yemens, spured many oil companies to enter the exploration race and carry out detailed seismic surveys and intensive exploration drilling in many areas. This resulted in a rapid rise in overall new subsurface geological data acquisition and an increasingly clearer perception of the distribution, orientation and inception times of the main basins. No overall synthesis of results was, however, undertaken since each individual company was primarily concerned with its own concession area and its immediate surroundings. Recent studies involving the review, correlation and synthesis of the mass of new subsurface stratigraphic data in connection with standardisation of lithostratigraphic nomenclature in use in Yemen and its further formalisation in accordance with internationally accepted rules, have, perforce, required the establishment of an overall structural framework within which inter and intra-basinal stratigraphic correlation could be carried out. It is this new framework of depositional basins and interbasinal uplifts that is discussed here. The main Mesozoic basins are related to late Jurassic extension and rifting, principally involving

  3. A modern analog of past climatic impacts on sedimentary processes and landscape evolution in an intermontane basin: The Del Medio fan, NW Argentina

    Science.gov (United States)

    Savi, Sara; Schildgen, Taylor F.; Tofelde, Stefanie; Wittmann, Hella; Strecker, Manfred

    2014-05-01

    The combined effects of tectonic and climatic forcing govern the evolution of landscapes, setting the scale of topographic relief and the pace of landscape changes over time. Tectonic uplift or changes in precipitation regimes can fundamentally modify erosional processes and sediment flux from hillslopes, change river profiles, and ultimately impact depositional systems downstream. The complexity of the response, however, often means that we cannot predict a priori how a given landscape will react to future changes in climate, or how it responded in the past to multiple episodes of climate change. The Del Medio catchment is located in the southern part of the Humahuaca Basin, an intermontane valley within the Eastern Cordillera in transition to the Puna Plateau. This area coincides with a climatic and vegetation divide between a sub-humid environment downstream and the semi-arid upper Humahuaca Basin. An extensive fan sourced in the Del Medio catchment covers ca. 18.6 km2 of the basin outlet. The fan stratigraphy and surface morphology suggest that the fan dynamics are dominated by debris-flow processes. The surface comprises abandoned channels, levees and lobes, while exposed sections in channel cuts reveal unsorted, matrix-dominated deposits, with individual boulders reaching a diameter of 5 m. To investigate rates and timing of the Del Medio fan evolution, we analyzed cosmogenic 10Be concentrations on the surfaces of large boulders from the fan surface, river sands in active channels, a depth profile, and bedrock exposed atop the drainage basin margins. Our preliminary CRN results illustrate the rapid rate at which the active fan surface is subject to change, with each of the 11 analyzed boulder samples providing ages of river sands record very high denudation rates that range from several mm/yr to tens of mm/yr, despite bedrock denudation rates from the basin margins of only 0.04 mm/yr. These contrasting denudation rates likely result from frequent landsliding

  4. Heavy silicon isotopic composition of silicic acid and biogenic silica in Arctic waters over the Beaufort shelf and the Canada Basin

    Science.gov (United States)

    Varela, D. E.; Brzezinski, M. A.; Beucher, C. P.; Jones, J. L.; Giesbrecht, K. E.; Lansard, B.; Mucci, A.

    2016-06-01

    The silicon isotopic composition of silicic acid (δ30Si(OH)4) and biogenic silica (δ30Si-bSiO2) were measured for the first time in marine Arctic waters from the Mackenzie River delta to the deep Canada Basin in the late summer of 2009. In the upper 100 m of the water column, δ30Si(OH)4 signals (+1.82‰ to +3.08‰) were negatively correlated with the relative contribution of Mackenzie River water. The biogenic Si isotope fractionation factor estimated using an open system model, 30ɛ = -0.97 ± 0.17‰, agrees well with laboratory and global-ocean estimates. Nevertheless, the δ30Si dynamics of this region may be better represented by closed system isotope models that yield lower values of 30ɛ, between -0.33‰ and -0.41‰, depending on how the contribution of sea-ice diatoms is incorporated. In the upper 400 m, δ30Si-bSiO2 values were among the heaviest ever measured in marine suspended bSiO2 (+2.03‰ to +3.51‰). A positive correlation between δ30Si-bSiO2 and sea-ice cover implies that heavy signals can result from isotopically heavy sea-ice diatoms introduced to pelagic assemblages. Below the surface bSiO2 production zone, the δ30Si(OH)4 distribution followed that of major water masses. Vertical δ30Si(OH)4 profiles showed a minimum (average of +1.84 ± 0.10‰) in the upper halocline (125-200 m) composed of modified Pacific water and heavier average values (+2.04 ± 0.11‰) in Atlantic water (300-500 m deep). In the Canada Basin Deep Water (below 2000 m), δ30Si(OH)4 averaged +1.88 ± 0.12‰, which represents the most positive value ever measured anywhere in the deep ocean. Since most Si(OH)4 enters the Arctic from shallow depths in the Atlantic Ocean, heavy deep Arctic δ30Si(OH)4 signals likely reflect the influx of relatively heavy intermediate Atlantic waters. A box model simulation of the global marine δ30Si(OH)4 distribution successfully reproduced the observed patterns, with the δ30Si(OH)4 of the simulated deep Arctic Ocean being the

  5. Biostratigraphy of Cretaceous-Paleogene marine succession, foraminiferal changes across the K/T boundary, sequence stratigraphy and response to sedimentary cyclicity in the Haymana Basin (Central Anatolia, Turkey)

    Science.gov (United States)

    Amirov, Elnur

    2016-04-01

    The aim of this study is to establish the planktonic foraminiferal biozonation, to construct the sequence stratigraphical framework and to determine the foraminiferal response to sedimentary cyclicity in the sedimentary sequence spanning Upper Cretaceous-Paleocene in the Haymana basin (Central Anatolia, Turkey). In order to achieve this study, the stratigraphic section was measured from sedimentary sequence of the Haymana, Beyobası and Yeşilyurt formations. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternating of siliciclastic and carbonate units. On the account of the detailed taxonomic study of planktonic foraminifers, the biostratigraphic framework was established for the Maastrichtian-Paleocene interval. The biozonation includes 7 zones; Pseudoguembelina hariaensis, Pα, P1, P2, P3, P4 and P5 zones. The Cretaceous-Paleogene (K/P) boundary was delineated between the samples HEA-105 and 106. In order to construct the sequence-stratigraphical framework, the A, B, C and D-type meter-scale cycles were identified. Based on the stacking patterns of them, six depositional sequences, six third and two second order cycles were determined. Third order cycles coincide with the Global Sea Level Change Curve. On the account of the conducted petrographic analysis sandstone, mudstone, marl, limestone and muddy-limestone lithofacies were recorded in the studied samples. In order to demonstrate the response of foraminifers to cyclicity, quantitative analysis has been carried out by counting the individuals of planktonic, benthonic foraminifers and ostracods. The best response to sedimentary cyclicity was revealed from planktonic foraminifers. The average abundance of planktonic foraminifers increases in the transgressive systems tract and decreases in the highstand systems tract. Foraminifera are the most abundant marine protozoa in the benthic, epipelagic and pelagic realm. Because of the complexity and diversity of habitats

  6. Sedimentary Micro-facies and Macro Heterogeneity of Reservoir Beds in the Third Member of the Qingshankou Formation, Qian'an Area,Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An analysis of drill cores and well logs shows that the main micro-facies of the third member sand bodies of the Qingshankou Formation in Qian'an are subaqueous distributary channel facies,sheet sand facies and subaqueous fan facies (olistostrome). Maps showing the distribution of these micro-facies together with inter-channel bay and prodelta mocro-facies are presented for different time-slices (lower, middle and upper parts of the Qingshankou Formation). These maps reveal the instability and change of sediment transport in the Baokang sedimentary system during the depositional period. Sediment transport was from the west in the early stage, from the south in the middle stage and from the northwest in the late stage. Values of thickness, porosity and permeability of the sand bodies in the third member of the Qingshankou Formation show that they have low to medium porosity and low permeability, and are characterized by serious reservoir heterogeneity. The joints between micro-facies and subaqueous fan micro-facies are characterized by the highest heterogeneity,the sheet sand and distal sand bar subfacies come next, and the heterogeneity of the subaqueous distributary channel sand bodies is relatively weak.

  7. High resolution continuous sedimentary records of Upper Cretaceous obtained from the continental drilling (SK-1) borehole in Songliao Basin:Sifangtai and Mingshui Formations

    Institute of Scientific and Technical Information of China (English)

    Guodong Wang; Rihui Cheng; Pujun Wang; Youfeng Gao; Chengshan Wang; Yanguang Ren; Qinghua Huang

    2015-01-01

    The Sifangtai and Mingshui formations were continuously cored in the SK-1n borehole (China Cretaceous Continental Scientific DrillingeSongKe1-the north borehole). The core is 767.96 m long, and the recovery is 94.7%. The ages of the formations range from middle Campanian to Danian. The sequence and process of lithology-lithofacies and cyclic stratigraphy were described in detail. Eight litho-types compose the Sifangtai Formation, and 15 litho-types compose the Mingshui Formation. Deposition was predominantly in meandering river and lacustrine environments, including 10 microfacies in the Sifangtai Formation and 15 microfacies in the Mingshui Formation. The complete sequence is composed of 535 m-scale cycles (sixth-order cycle), 152 fifth-order cycles, 42 fourth-order cycles and five third-order cycles. The centimeter-scale description of the section revealed some previously unknown horizons such as a special type of mudstone, marl, volcanic ash and favorable sand reservoirs in the formations. The new-found evidence is very important for the interpretation of the evolution of the basin, conditions such as lake oxic events, the K/Pg boundary, tectonism in the late sag basin stage, and the reservoir-cap rock as-semblages in the shallow stratigraphy.

  8. Sedimentary paleoenvironment and fossil plants of the El freno formation (early jurassic in Las leñas valley, Neuquén basin

    Directory of Open Access Journals (Sweden)

    Silvia Lanés

    2013-12-01

    Full Text Available Non-marine Early Jurassic successions in Las Leñas valley and their paleofloristic fossil content have been known since late nineteenth century, though they are scarce in the bibliography. It led us to study the sedimentology and paleobotanical content of El Freno Formation outcrops in the surroundings of the Portezuelo and Peuquenes creeks, report the first finding of fossil plants there and interpret their taphonomic features and enclosing sedimentary environment. The studied section is a lensoidal, fining- and thinning-upwards, conglomerate and sandy succession, with carbonaceous plant impressions and silicified trunks. It records the evolution of a gravel braided fluvial system (with longitudinal and transverse bars, abandoned channels and strong topographic irregularities into a sand braided fluvial system (with transverse bars, overbank deposits and no evidence of lateral migration. Both flowed mainly towards the NNW and show a continuously increasing accommodation probably driven by a relative base level rise and regional sag or erosional lowering of the topography. Collected fossil plants include Dictyophylum (Dictyophylum sp., Goeppertella sp. and undetermined Equisetopsida. Goeppertella sp. is recorded for the first time in this unit. Equisetopsida would have thrived in semi-permanent water bodies on abandoned channels and Dipteridaceae, in well-drained zones of the channel belt above the permanent channel level. Conversely, the trees would have lived in higher and well-drained areas with well-developed soils, probably outside the channel belt. Based largely on lithostratigraphical considerations, the age of the studied deposits was limited to the Hettangian?-Middle Sinemurian without identifying hiatus inside the fluvial succession or between it and the overlain marine beds.

  9. Sedimentary Evolution of Mesozoic Era in Kuche Depression, Tarim Basin%塔里木盆地库车坳陷中生代沉积演化

    Institute of Scientific and Technical Information of China (English)

    李维锋; 高振中

    2000-01-01

    塔里木盆地库车坳陷中生代为一前陆坳陷,其内沉积了一套厚度巨大的冲积-湖泊碎屑沉积体,可识别出5种相类型、15种亚相及38种微相。坳陷呈北陡南缓的箕状,沉积体北厚南薄,沉降中心与沉积中心发生明显的错位。中生代,坳陷内湖泊经历了深陷-充填-变浅加宽的过程;三叠纪为深陷期,沉积区范围小;早、中侏罗世为充填期;晚侏罗世至白垩纪湖泊变浅加宽。气候变化总体趋势为:干旱-潮湿-干旱;早、中三叠世为干旱气候;晚三叠世至中侏罗世气候潮湿,煤系地层广泛发育;晚侏罗世至白垩纪气候转为干燥,沉积物皆呈红色。%Kuche Depression, situated in the northern part of Tarim Basin,was a foreland depression and there was a set of extremely thick, alluvial-lake classic deposits in it in Mesozoic Era. Five facies(meandering river facies, fandeltas facies, braided-river deltas facies, meandering-river deltas facies and lacutrine facies), fifteen subfacies and thirty-eight microfacies are recognised. Kuche Depression was a ”dustpan” shape depression with steep slope in the north side and gentle slope in the south side. Deposits are thicker in the north side than in the south and the depocenter did not coordinate with the center of subsidence. The lake in Kuche Depression went through a period from deep subsidence lacustrine (Triassic Period, fan-deltas and braided-river deltas sediments are dominant) to filling lacustrine (early and middle Jurassic, braided-river deltas is dominant) to broad and shallow lacustrine (late Jurassic and Cretaceous Period, coastal lake and shallow lake sediments are dominant). From Triassic Period to middle Jurassic, Kuche Depression was an isolated basin and area was small, not joining with Tarim Basin because there was a provenance in its south side. Beginning from late Jurassic, the southern provenance vanished and Kuche Depression joined

  10. The origin and evolution of sulfur in an Archean volcano-sedimentary basin, Deer Lake area, Minnesota. M.S. Thesis

    Science.gov (United States)

    Nicol, D. L.

    1980-01-01

    Rocks of the Deer Lake area, northcentral Minnesota, consist of Archean (age greater than 2.6 billion years) metasediments and metavolcanics intruded by mafic layered sills. Geologic and sulfur isotopic data suggest that sulfides in the sediments are bacteriogenic, having formed in response to the activity of sulfate reducing bacteria during diagenesis. Deposition of the sediments appears to have occurred in a deep marine basin with restricted circulation of sea water. The bulk of the sulfur in the igneous rocks is of deep seated origin, but basal contacts of the sills show evidence of assimilation of biogenic sulfur from the intruded sediments. This assimilation of biogenic sulfur is the primary geochemical control of local Cu-Ni sulfide mineralization.

  11. Primary uranium sources for sedimentary-hosted uranium deposits in NE China: insight from basement igneous rocks of the Erlian Basin

    Science.gov (United States)

    Bonnetti, Christophe; Cuney, Michel; Bourlange, Sylvain; Deloule, Etienne; Poujol, Marc; Liu, Xiaodong; Peng, Yunbiao; Yang, Jianxing

    2016-05-01

    Carboniferous-Permian, Triassic and Jurassic igneous basement rocks around the Erlian Basin in northeast China have been investigated through detailed mineralogical, whole-rock geochemistry, geochronological data and Sm-Nd isotope studies. Carboniferous-Permian biotite granites and volcanic rocks belong to a calc-alkaline association and were emplaced during the Late Carboniferous-Early Permian (313 ± 1-286 ± 2 Ma). These rocks are characterised by positive ɛNd(t) (3.3-5.3) and fairly young T DM model ages (485-726 Ma), suggesting a dominant derivation from partial melting of earlier emplaced juvenile source rocks. Triassic biotite granites belong to a high-K calc-alkaline association and were emplaced during the Middle Triassic (243 ± 3-233 ± 2 Ma). Their negative ɛNd(t) (-2 to -0.1) and higher T DM model ages (703-893 Ma) suggest a contribution from Precambrian crust during the magma generation processes, leading to a strong enrichment in K and incompatible elements such as Th and U. Highly fractionated magmas crystallised in U-rich biotite (up to 21 ppm U) and two-mica granites. In biotite granite, the major U-bearing minerals are uranothorite and allanite. They are strongly metamict and the major part of their uranium (90 %) has been released from the mineral structure and was available for leaching. Mass balance calculations show that the Triassic biotite granites may have, at least, liberated ˜14,000 t U/km3 and thus correspond to a major primary uranium source for the U deposits hosted in the Erlian Basin.

  12. Mooring-based long-term observation of oceanographic condition in the Chukchi Ses and Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Kikuchi, Takashi; Itoh, Motoyo; Nishino, Shigeto; Watanabe, Eiji

    2015-04-01

    Changes of the Arctic Ocean environment are well known as one of the most remarkable evidences of global warming, attracting social and public attentions as well as scientists'. However, to illustrate on-going changes and predict future condition of the Arctic marine environment, we still do not have enough knowledge of Arctic sea ice and marine environment. In particular, lack of observation data in winter, e.g., under sea ice, still remains a key issue for precise understanding of seasonal cycle on oceanographic condition in the Arctic Ocean. Mooring-based observation is one of the most useful methods to collect year-long data in the Arctic Ocean. We have been conducting long-term monitoring using mooring system in the Pacific sector of the Arctic Ocean. Volume, heat, and freshwater fluxes through Barrow Canyon where is a major conduit of Pacific-origin water-masses into the Canada Basin have been observed since 2000. We show from an analysis of the mooring results that volume flux through Barrow Canyon was about 60 % of Bering Strait volume flux. Averaged heat flux ranges from 0.9 to 3.07 TW, which could melt 88,000 to 300,000 km2 of 1m thick ice in the Canada Basin, which likely contributed to sea ice retreat in the Pacific sector of the Arctic Ocean. In winter, we found inter-annual variability in salinity related to coastal polynya activity in the Chukchi Sea. In collaboration with Distributed Biological Observatory (DBO) project, which is one of the tasks of Sustaining Arctic Observing Network (SAON), we also initiated year-long mooring observation in the Hope Valley of the southern Chukchi Sea since 2012. Interestingly, winter oceanographic conditions in the Hope Valley are greatly different between in 2012-2013 and in 2013-2014. We speculate that differences of sea ice freeze-up and coastal polynya activity in the southern Chukchi Sea cause significant difference of winter oceanographic condition. It suggests that recent sea ice reduction in the Pacific

  13. Neoproterozoic-Paleozoic Sedimentary Basins Evolution of Xing-Meng Orogenic Belt%兴蒙造山系新元古代-古生代沉积盆地演化

    Institute of Scientific and Technical Information of China (English)

    杨文麟; 骆满生; 王成刚; 徐增连

    2014-01-01

    Based on comprehensive analysis of the type,sedimentary formation,biostratigraphy and chronostratigraphy for 24 main sedimentary basins,we study the evolution of sedimentary basins of Xing-Meng orogenic belt in the Neoproterozoic-Paleo-zoic,dividing it into six phases as follows.(1)The epicontinental accretion in the Neoproterozoic to Early Cambrian character-ized by the assembly of Ergun and Xingan blocks,as Huanyu-Xinlin ophiolite accreted to margin of southern Ergun blocks;(2)The stable epicontinental sediment in the Terreneuvian-Serises 2,with the feature of a relatively stable clastic-calciclastic sediment around the blocks while Jiamusi massif affected by Late Pan-African metamorphic event;(3)The formation of archi-pelagic arc-basin systems in the Early and Middle Ordovician,marked by the distribution of arc-basin in the margin of Duobaoshan and the different levels oceanic crust subduction effect among other land masses;(4)The development of archipe-lagic arc-basin systems in the Late Ordovician to Pridoli,as the erosion of the uplifted land masses;(5)The subduction of ar-chipelagic arc-basin systems in the Early Devonian to Early Carboniferous,characterized by the collage of Ergun-Xingan and Songnen blocks and the transformation of western margin of Jiamusi massif from passive to active in the late Early Carbonifer-ous;(6)The oceanic-continental transition in the Late Carboniferous-Lopingian,characterized by the assembly of Jiamusi mas-sif,Songnen massif,and Khanka massif.Massifs of Northeast China completely collaged to a whole.%在系统分析兴蒙造山系新元古代-古生代24个沉积盆地类型、沉积建造、生物地层与年代地层等特征的基础上,划分了6个沉积大地构造演化阶段并对其进行讨论:(1)新元古代-寒武纪早期陆缘增生阶段:额尔古纳地块向南增生并与兴安地块拼贴,形成环宇-新林蛇绿岩拼合带;(2)寒武纪纽芬兰世-第二世陆缘稳定沉积阶段:各地块边

  14. Evidence of shallow gas in the Queen Charlotte Basin from waveform tomography of seismic reflection data

    Energy Technology Data Exchange (ETDEWEB)

    Takam Takougang, Eric M.; Calvert, Andrew J. [Simon Fraser University (Canada)], email: eta9@sfu.ca

    2011-07-01

    The Geological Survey of Canada (GSC) collected eight seismic reflection lines in 1988 across the Queen Charlotte sedimentary basin of western Canada, which is the largest tertiary basin on the west coast. This work furthers the study of the upper part of the basin by using quantitative imaging of its structure through application of 2-D waveform tomography to the limited offset seismic reflection data. With the help of waveform tomography, seismic reflection data has allowed the identification of pockmark structures and pipe-like gas chimney in the recovered velocity and attenuation models. Overall, there is an excellent match between field data and predicted data. and a good match between the sonic log and a 1-D velocity function derived from the 2-D velocity model. This shows that specific preconditioning of the data and a good inversion strategy make it possible to use waveform tomography of relatively short offset reflection data for the imaging of shallow geological features.

  15. Multi-method provenance model for early Paleozoic sedimentary basins of southern Peru and northern Bolivia (13°-18°S)

    Science.gov (United States)

    Reimann Zumsprekel, Cornelia R.; Bahlburg, Heinrich; Carlotto, Victor; Boekhout, Flora; Berndt, Jasper; Lopez, Shirley

    2015-12-01

    In early Paleozoic time the Peru-Bolivia Trough at the South American Gondwana margin accommodated large volumes of siliciclastic detritus of hitherto largely unknown provenance. A multi-method provenance study of framework components, heavy minerals and whole rock geochemistry of Ordovician to Devonian formations of southern Peru and northern Bolivia reveals the predominant contribution from upper crustal sources. Main heavy minerals include zircon, tourmaline, rutile, apatite, garnet, epidote, monazite, and titanite and are strongly biased diagenetically towards the stable phases. Electron microprobe single grain analysis of tourmaline and rutile indicate that detrital tourmalines were derived mainly from metasedimentary, and subordinately, from granitic sources. Cr/Nb ratios in rutiles point to a metamafic derivation for 20-40% of grains, the remainder originating in felsic lithologies. Zr in rutile thermometry indicates a provenance from relatively high-grade metamorphic rocks transformed at temperatures between 500 °C and 900 °C, with clusters at c. 600 °C, 700 °C and 800 °C. U-Pb geochronological analysis of rutiles was largely unsuccessful due to high concentrations of common Pb. Three ages could be obtained and fall between 525 and 545 Ma, probably linking this detritus to the hidden Neoproterozoic orogen in what are now Cordillera Oriental and Sierras Subandinas. The most notable feature of the whole rock geochemical data is a high Cr content in the majority of samples, which otherwise have a composition similar to weathered upper continental crust. The elevated Cr contents indicates that ophiolitic rocks were either exposed to erosion abundantly in the source areas or had previously supplied significant volumes of detritus to intermittent sediment storage systems now eroded into the studied sedimentary rocks. Potential source candidates include the Ordovician metamorphic Tapo Ultramafic Complex in the Cordillera Oriental of central Peru, and the

  16. Physical volcanology, geochemistry and basin evolution of the Ediacaran volcano-sedimentary succession in the Bas Draâ inlier (Ouarzazate Supergroup, Western Anti-Atlas, Morocco)

    Science.gov (United States)

    Karaoui, Brahim; Breitkreuz, Christoph; Mahmoudi, Abdelkader; Youbi, Nasrrddine

    2014-11-01

    New geologic mapping, lithofacies and granulometric analysis, and geochemistry from the volcano-sedimentary successions of the central part of the Bas Draâ inlier, Western Anti-Atlas, constrain the Ediacaran Ouarzazate Supergroup evolution during the post-collisional stage of the Pan-African orogeny. Volcanosedimentary facies analysis is the key aspect of the present contribution. We distinguished sixteen terrestrial volcanosedimentary lithofacies in the Bas Draâ succession (BDS), which reaches a total thickness of 2000 m. BDS evolution can be grouped into four units (Aouinet Aït Oussa I to IV, AO I-AO IV). The earliest volcanic activity produced rhyolitic ignimbrite sheets (AO I), which had been considered as lava flows by previous workers, and which were presumably related to caldera system(s). During AO II, a complex of high-silica andesitic and rhyolitic lavas formed, punctuated by the explosive eruption of a high-temperature silica-rich magma leading to the formation of parataxitic ignimbrite. AO III consists of basalt and andesite lava fields and small explosive, in parts phreatomagmatic volcanic vents. It is dissected by fluvial systems depositing external non-volcanic and local volcanic debris. BDS evolution terminated with the formation of a large SiO2-rich lava dome complex (AO IV), accompanied by small basalt effusive event. Volcanosedimentary facies analysis infers that the BDS evolved in a continental extensional setting developing in a low topography under humid paleoclimatic conditions. Alteration textures are dominated by a piemontite-calcite-albite-quartz (+ iron oxides) assemblage. Chemical analysis of BDS volcanic and subvolcanic rocks belongs to high-k calc-alkaline and alkali-calcic to alkaline magmatic trend typical for a post-collision setting. Trace elements spidergrams show a pattern typical for subduction-related suites of orogenic belts. REE patterns show moderate enrichment in LREE relative to flat HREE, with strong negative Eu

  17. Pedo-sedimentary record of human-environment interaction in ditches and waterlogged depressions on tableland (roman and early medieval period) : micromorphological cases studies from Marne-la-Vallée area (Paris Basin, France)

    Science.gov (United States)

    Cammas, C.; Blanchard, J.; Broutin, P.; Berga, A.

    2012-04-01

    On lœss derived soils located on the Stampien plateau from the Paris Basin (France), archaeological anthroposols and ancient cultivated soils are only preserved in very few places. Recent archaeological excavations showed the presence of a pattern of roman ditches and waterlogged depressions (« mares ») under the actual cultivated horizon (Ap). This presence strongly suggests extensive past agricultural practices and water management. An original system of ditches was found Near Marne-la-Vallée (France). It is composed of two parts, one being large ditches characterized by flat bottom and sometimes water layered deposits, called « fossés collecteurs » by the archaeologists, and the orher being smaller ditches with colluvial deposits. Our objectives was to use archaeological and micromorphological studies in order to study i) the agricultural function of these ditches and depressions, ii) their evolution with time. Observations conducted on the infilling of a « fossé collecteur » at Bussy-Saint-Georges suggest that it was not part of a drainage system, but that it was a linear water controlled system, with a ramp in one part, and a basin or a tank in another, and that it was used for others anthropic activities. In the same area, a large waterlogged depression was studied, and micromorphological analysis helped to elucidate its pedo-sedimentary formation processes. At the bottom, massive silty clayey matrix retained water. Thin layers composed of silt and clay (indicating low energy flows and decantation), sometimes impregnated and hardened by iron, alternated with silty deposit (indicating higher ernergy water layered deposits). The thin, non porous and iron impregnated crusts helped to raise the depression level, as well as, most likely the water table during roman period, maintaining waterlogging conditions. At the beginning of the early medival period, a slightly peaty event was discriminated. Higher in the profile, in more redoxic conditions

  18. Comparison of isotopic time-series partitioning analysis with an evaporative enrichment model in lake- and wetland-dominated river basins, Mackenzie basin, Canada

    International Nuclear Information System (INIS)

    The use of the water isotope tracers oxygen-18 and deuterium to partition the streamflow components into snowmelt, surface water and groundwater can provide fundamental information about the factors that influence water balance and runoff generation in cold regions. Defining the isotopic composition of surface water (lakes and wetlands) is a challenge with the partitioning strategy, since the surface water contribution to streamflow, which is influenced seasonally by inputs of snowpack in spring and evaporative enrichment in summer, is a mixture from different water sources. Furthermore, the isotopic composition of streams in cold climates, particularly in subarctic wetlands, is often skewed because of noncontributing water balance compartments that undergo evaporative enrichment. That is, streams tend to reflect lower isotopic enrichment, especially in wetland-dominated basins

  19. Towards new Integrated Uses of Potential Fields: Estimating the Heat Generation Potential of the Basement Underlying the Barents Sea Sedimentary Basins, North Norway, and its Importance for Hydrocarbon Maturation.

    Science.gov (United States)

    Skilbrei, J.; Barrere, C.; Ebbing, J.; Gernigon, L.; Olesen, O.; Pascal, C.; Wienecke, S.

    2006-12-01

    We estimate the composition of main basement complexes underlying the Barents Sea continental shelf off North Norway, in order to provide input to thermal modelling; radiogenic heat production varies as a function of lithology and constitutes about half of the total heat flow in a typical sedimentary basin. Basement characterization in the coastal areas of Norway will provide ground truth for estimated basement types in the Barents Sea region. Where possible, we also try to project major tectonic units and basement terranes from North Norway and Svalbard into the Barents Sea. The aim is to characterise the basement composition in the offshore areas, to estimate the mean content of radiogenic elements, as well as heat flow estimations. This has been done on land by a series of techniques including heat flow measurements, geochemical analysis and geophysical techniques. In addition thermal measurements have been made in boreholes. Thermal conductivity measurments have been carried out on samples. We use a series of geophysical techniques: Potential field modelling, depth-to-source techniques, isostatic modelling, thermal modelling and interpretation of reflection seismic data, OBS data and velocity data. Integration of the different data sets is a key to the understanding of the deep geology of the area. Moho depths, basement depths, major fault zones and extensional detachments zones, have been interpreted. Preliminary results will be presented from a 5-year research project sponsored by the Norwegian Research Council and Statoil.

  20. Identifying the origin of differences between 3D numerical simulations of ground motion in sedimentary basins: lessons from stringent canonical test models in the E2VP framework

    Science.gov (United States)

    Chaljub, Emmanuel; Maufroy, Emeline; Moczo, Peter; Kristek, Jozef; Priolo, Enrico; Klin, Peter; De Martin, Florent; Zhang, Zenghuo; Hollender, Fabrice; Bard, Pierre-Yves

    2013-04-01

    Numerical simulation is playing a role of increasing importance in the field of seismic hazard by providing quantitative estimates of earthquake ground motion, its variability, and its sensitivity to geometrical and mechanical properties of the medium. Continuous efforts to develop accurate and computationally efficient numerical methods, combined with increasing computational power have made it technically feasible to calculate seismograms in 3D realistic configurations and for frequencies of interest in seismic design applications. Now, in order to foster the use of numerical simulations in practical prediction of earthquake ground motion, it is important to evaluate the accuracy of current numerical methods when applied to realistic 3D sites. This process of verification is a necessary prerequisite to confrontation of numerical predictions and observations. Through the ongoing Euroseistest Verification and Validation Project (E2VP), which focuses on the Mygdonian basin (northern Greece), we investigated the capability of numerical methods to predict earthquake ground motion for frequencies up to 4 Hz. Numerical predictions obtained by several teams using a wide variety of methods were compared using quantitative goodness-of-fit criteria. In order to better understand the cause of misfits between different simulations, initially performed for the realistic geometry of the Mygdonian basin, we defined five stringent canonical configurations. The canonical models allow for identifying sources of misfits and quantify their importance. Detailed quantitative comparison of simulations in relation to dominant features of the models shows that even relatively simple heterogeneous models must be treated with maximum care in order to achieve sufficient level of accuracy. One important conclusion is that the numerical representation of models with strong variations (e.g. discontinuities) may considerably vary from one method to the other, and may become a dominant source of

  1. Exhumation history of the Northern Andes from the Cenozoic syn-tectonic sedimentary fill of the Middle Magdalena Valley Basin, Colombia

    Science.gov (United States)

    Moreno, C. J.; Caballero, V. M.; Horton, B. K.; Mora, A.

    2009-12-01

    The Central Cordillera and the Eastern Cordillera of the northern Andes form the western and eastern flanks of the Colombian Middle Magdalena Valley Basin, respectively. Previous estimates of the timing of onset of exhumation of the two cordilleras vary, and although some recent studies have been in agreement, more work is needed to develop a clear picture. The spatial and chronological distribution of deformation has direct implications for the shortening history of the greater South American Andean margin, as well as for improving predictions of the rapid, lateral facies changes associated with the varying nearby sediment sources. Field-based analyses of the basin fill using paleocurrent measurements of trough-cross-beds, clast imbrication and flute casts, not only provide new insights into the tectonic history, but directly complement recent detrital zircon U-Pb work completed in the MMVB. Between the lower and upper Paleocene strata, the paleocurrent direction shifts from northward to eastward, indicating that uplift of the Central Cordillera was underway by the mid-Paleocene and consistent with the shift from a cratonic to Central Cordilleran sediment source observed in the detrital zircon record. This paleocurrent shift occurs coevally with a shift from delta to fluvial facies. An eastward paleoflow in upper Eocene through lowest Oligocene strata indicate a continuing influence of the Central Cordillera. Paleocurrent directions in the lower Oligocene deposits are highly variable, and, beginning in the middle Oligocene strata, show a switch to a dominantly westward orientation that continues through the Neogene. As the orientation changes, deposits show an increase in energy from muddy, meandering river deposits, to coarser, braided channel facies. We attribute this switch, from eastward to westward paleocurrent orientations, to the onset of exhumation of the Eastern Cordillera. The results of a current, detailed sandstone petrographic study combined with

  2. A telephone survey of eel fishermen regarding external lesions and mortalities of American eels (Anguilla rostrata) from Lake Ontario and the St. Lawrence River basin, Canada.

    Science.gov (United States)

    Dutil, L; Bélanger, D; Couillard, C M

    1997-07-01

    Signs of decreasing landings and recruitment have been observed during the last decade in American eels (Anguilla rostrata) from the St. Lawrence River basin, Canada. A study was undertaken to examine whether important manifestational diseases among commercial catches could be associated with these declines. During this survey, 56 fishermen from Lakes Ontario, Saint-François and Saint-Pierre, the Richelieu River, the Québec City area and the St. Lawrence Estuary were interviewed. Most fishermen from every area reported decreasing catches since the 1980s. Eel mortalities were reported from 1990 to 1992 in Lake Saint-François, Lake Saint-Pierre and the Québec City area, but in apparently lower magnitude than in the past decades. The lesions observed on dead eels in Lake Saint-François indicated that the cause of the mortalities might be associated with the upstream hydroelectric dam. Eels with 'scratches all over the body' were only observed in the St. Lawrence Estuary. Fishermen from almost every area reported that they had observed eels with 'crooked tail', 'humpback' and 'cut tail' in low frequency in 1992. The questionnaire data were validated by comparing some of the results of the questionnaire survey and a processing plant survey in 1992. The use of questionnaires for assessing fish diseases in commercial species is discussed. The results of this survey do not indicate that the health of the American eels from the St. Lawrence River basin is severely impaired. However, the magnitude of diseases and mortalities was probably underestimated. PMID:9234424

  3. Occurrence of ignimbrite volcanics in the northern Espirito Santo Basin, Brazil: an advance in the model of tectonic-sedimentary evolution of the basin; Ocorrencia de rochas vulcanicas ignimbriticas na porcao norte da Bacia do Espirito Santo: evolucao do modelo tectono-sedimentar

    Energy Technology Data Exchange (ETDEWEB)

    Novais, Luis Carlos Chaves [PETROBRAS, ES (Brazil). Unidade de Negocio de Exploracao e Producao do Espirito Santo. Gerencia de Reservatorios], e-mail: novais@petrobras.com.br; Zelenka, Tibor [University of Miskolc (Hungary). Dept. of Geology], e-mail: zelenka.tibor@freemail.hu; Szatmari, Peter [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas Leopoldo A. Miguez de Mello. Gerencia de Geologia Estrutural e Geotectonica], e-mail: szatmari@petrobras.com.br; Motoki, Akihisa [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Dept. de Mineralogia e Petrologia Ignea], e-mail: motoki@uerj.br; Aires, Jose Ribeiro [PETROBRAS, Rio de Janeiro, RJ (Brazil). Abastecimento-Petroquimica e Fertilizantes. Gerencia Setorial de Seguranca, Meio Ambiente e Saude], e-mail: aires@petrobras.com.br; Tagliari, Claudio VInicius [PETROBRAS, ES (Brazil). Unidade de Negocio de Exploracao e Producao do Espirito Santo. Gerencia de Avaliacao de Blocos e Interpretacao Geologica e Geofisica], e-mail: tagliari@petrobras.com.br

    2007-11-15

    The intention of this work is to provide information on ignimbrite volcanoclastics, outcropping in the northern onshore part of the Espirito Santo Basin, and to examine their role in the tectonic-sedimentary evolution of the basin. We identified ignimbrites, pyroclastics of rhyolitic to dacitic composition, along the NNW-SSE to NW-SE trending transcurrent fault system named here Sao Mateus Alignment or Sao Mateus Arch. We followed the mostly horizontally layered ignimbrites, at least 50 m thick, for about 10 km along and close to the margins of the Sao Mateus River. These ignimbrite bodies had been mapped before as fluvio-lacustrine sandstones of the Tertiary Rio Doce/Barreiras Formation, without recognizing their partially volcanoclastic character. Microscopic examination suggests idiomorphic and fragmented {proportional_to}-quartz phenocrysts, contained in a hydrothermally altered matrix of clay minerals and zeolites. The fragmented form of the phenocrysts points to explosive volcanic activity; grain size tends to increase westward, probably indicating the principal place of volcanic centers. The outcropping sequence of ignimbritic rocks provides a major advance in the understanding of the basin's Cenozoic tectonic-structural history contributing to a revision of its stratigraphy. (author)

  4. Post-sedimentary Transformation of Lateral Moraines-the Tributary Tongue Basins of the Kvíárj(o)kull(Iceland)

    Institute of Scientific and Technical Information of China (English)

    Lasafam Iturrizaga

    2008-01-01

    The Kvíárj(o)kull.a southern outlet glacier of the Vatnaj(o)kull,is confined in the mountain foreland by lateral moraines measuring a height of up to 150 m.Each of the lateral moraines shows consjderable breaches with deviations of the main moraine ridges.The paper discusses the possible origins of these modifications of the lateral moraines as result of:1)ice overlappings during glacier advances and subsequent breaches of the lateraltongue triggered by the preglacial relief conditions and the prehistorical moraine landscape leading to affiux conditions,3)drainage of ice-marginal glacier lakes and 4.volcanic activities,such as lava flows and volcanic-induced j(o)kulhlaups. A historic-genetic model of the formation of the lateral moraines is presented considering the breaches in the lateral moraines as result from glacier bifurcations and therefore as former tributary tongue basins.Such breaches in the lateral moraines are also common landscape features at glaciers outside of Iceland and are from wider importance for the paleoreconstruction of former glacier stages.The knowledge of their development is essential for an adequate relative age classification of individual moraine ridges.In regard to the origin of the debris the resedimentation of prehistoric till deposits by younger glacier advances plays a role in the formation of the lateral moraines apart from englacial and supraglacial sediment transfer processes.

  5. 2D SEDFLUX 1.0C:. an advanced process-response numerical model for the fill of marine sedimentary basins

    Science.gov (United States)

    Syvitski, James P. M.; Hutton, Eric W. H.

    2001-07-01

    Numerical simulators of the dynamics of strata formation of continental margins fuse information from the atmosphere, ocean and regional geology. Such models can provide information for areas and times for which actual measurements are not available, or for when purely statistical estimates are not adequate by themselves. SEDFLUX is such a basin-fill model, written in ANSI-standard C, able to simulate the delivery of sediment and their accumulation over time scales of tens of thousands of years. SEDFLUX includes the effects of sea-level fluctuations, river floods, ocean storms, and other relevant environmental factors (climate trends, random catastrophic events), at a time step (daily to yearly) that is sensitive to short-term variations of the seafloor. SEDFLUX combines individual process-response models into one fully interactive model, delivering a multi-sized sediment load onto and across a continental margin, including sediment redistribution by (1) river mouth dynamics, (2) buoyant surface plumes, (3) hyperpycnal flows, (4) ocean storms, (5) slope instabilities, (6) turbidity currents, and (7) debris flows. The model allows for the deposit to compact, to undergo tectonic processes (faults, uplift) and isostatic subsidence from the sediment load. The modeled architecture has a typical vertical resolution of 1-25 cm, and a typical horizontal resolution of between 1 and 100 m.

  6. Palynological and sedimentary analysis of the Igarapé Ipiranga and Querru 1 outcrops of the Itapecuru Formation (Lower Cretaceous, Parnaíba Basin), Brazil

    Science.gov (United States)

    Ferreira, Neila N.; Ferreira, Elizabete P.; Ramos, Renato R. C.; Carvalho, Ismar S.

    2016-03-01

    The siliciclastic sediments of the Itapecuru Formation occur in a large area of the Parnaíba Basin and its deposits crop out along the Itapecuru River, in Maranhão State, northern Brazil. The palynological analysis of the Igarapé Ipiranga and Querru 1 outcrops strata yields a rich and diversified data. The presence of index-palynofloras in assemblages allows the identification of the Complicatisaccus cearensis Zone, of Late Aptian-Early Albian age. Terrestrial palynomorphs are abundant in the assemblages, being represented by bryophytes and pteridophytes, especially perisporate trilete spores (Crybelosporites and Perotrilites), and gymnosperms and angiosperms (Afropollis and Elaterosporites). The composition of palynological assemblages suggests the presence of moist soils for both outcrops. Acritarchs were recovered in the Querru 1 outcrop, which suggest a marine setting supporting a tidal flat environment indicated by facies associations. Furthermore, reworked Paleozoic palynomorphs were observed in the Querru 1 outcrop. The microflora from Igarapé Ipiranga outcrop suggests terrestrial environment corroborating with floodplain environment indicated by facies association.

  7. Identifiation of Phymatolithon lamii (Me. Lemoine Y.M. Chamberlain 1991 following bleaching in the upper intertidal zone of the Minas Basin, Nova Scotia, Canada

    Directory of Open Access Journals (Sweden)

    Brady Keith Quinn

    2016-03-01

    Full Text Available Objective: To identify an unusual encrusting calcareous organism found growing on upper intertidal rocks along the coast of the Minas Basin, Nova Scotia, Canada, which was thought to potentially represent a new, perhaps invasive species to the area. Methods: Observations were made of the organism growing in situ and of intact and dissected specimens under microscopes in the laboratory. Taxonomic keys were used to determine probable identity of the organism as a tunicate, sponge, bryozoan, marine lichen, or coralline red alga. These keys were then further used to identify samples to species. Results: The organism was determined to be Phymatolithon lamii (Me. Lemoine Y.M. Chamberlain 1991, an encrusting coralline red alga native to the study region. This species normally occurs in the subtidal zone, so its occurrence in the high intertidal zone was unusual and resulted in the alga becoming bleached and taking on an unusual appearance. Conclusions: The sample did not represent a new or invasive species to the study area. However, occurrence of this species on the high intertidal zone was novel and may have resulted from unusual climatic and/or oceanographic conditions in the study area in 2015 that allowed this alga to settle and grow in the intertidal zone for a time before death and bleaching occurred. Events such as this resulting from climate change may negatively impact recruitment to populations of coastal marine species and should be investigated further.

  8. Identiifcation ofPhymatolithon lamii (Me. Lemoine) Y.M. Chamberlain 1991 following bleaching in the upper intertidal zone of the Minas Basin, Nova Scotia, Canada

    Institute of Scientific and Technical Information of China (English)

    Brady Keith Quinn

    2016-01-01

    Objective:To identify an unusual encrusting calcareous organism found growing on upper intertidal rocks along the coast of the Minas Basin, Nova Scotia, Canada, which was thought to potentially represent a new, perhaps invasive species to the area. Methods: Observations were made of the organism growingin situ and of intact and dissected specimens under microscopes in the laboratory. Taxonomic keys were used to determine probable identity of the organism as a tunicate, sponge, bryozoan, marine lichen, or coralline red alga. These keys were then further used to identify samples to species. Results:The organism was determined to bePhymatolithon lamii (Me. Lemoine) Y.M. Chamberlain 1991, an encrusting coralline red alga native to the study region. This species normally occurs in the subtidal zone, so its occurrence in the high intertidal zone was unusual and resulted in the alga becoming bleached and taking on an unusual appearance. Conclusions: The sample did not represent a new or invasive species to the study area. However, occurrence of this species on the high intertidal zone was novel and may have resulted from unusual climatic and/or oceanographic conditions in the study area in 2015 that allowed this alga to settle and grow in the intertidal zone for a time before death and bleaching occurred. Events such as this resulting from climate change may negatively impact recruitment to populations of coastal marine species and should be investigated further.

  9. Air mass distribution and the heterogeneity of the climate change signal in the Hudson Bay/Foxe Basin region, Canada

    Science.gov (United States)

    Leung, Andrew; Gough, William

    2016-08-01

    The linkage between changes in air mass distribution and temperature trends from 1971 to 2010 is explored in the Hudson Bay/Foxe Basin region. Statistically significant temperature increases were found of varying spatial and temporal magnitude. Concurrent statistically significant changes in air mass frequency at the same locations were also detected, particularly in the declining frequency of dry polar (DP) air. These two sets of changes were found to be linked, and we thus conclude that the heterogeneity of the climatic warming signal in the region is at least partially the result of a fundamental shift in the concurrent air mass frequency in addition to global and regional changes in radiative forcing due to increases in long-lived greenhouse gases.

  10. Microfractures due to overpressures caused by thermal cracking in well-sealed Devonian reservoirs, deep Alberta basin, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Marquez, X.M. [Dept. de Exploracion, Maraven, S.A., Caracas (Venezuela); Mountjoy, E.W. [McGill Univ., Montreal (Canada)

    1996-08-01

    Microfractures (< 1 mm in width) filled with reservoir bitumen crosscut all diagenetic phases in the upper 200 m of the partially to completely dolomitized Upper Devonian (Leduc Formation) Strachan buildup and other buildups in the deep Alberta basin. They display three patterns: (1) subhorizontal, extending from intraskeletal pores and perpendicular to sub-vertical fractures, (2) random in the matrix, and (3) radial around vugs and fossil molds. Subhorizontal microfracturing is most common and radial is the least common. Overpressuring caused by thermal cracking of crude oil to gas during burial can produce most of the characteristics exhibited by these microfractures: their association with all pore types, bitumen fillings and relatively late diagenetic timing. Microfractures are restricted to isolated buildups below depths of about 3800 m in the Alberta Basin. Thermal cracking of crude oil to gas during burial is also indicated by finely and coarsely deformed lamellar textures of the reservoir bitumen that fill the microfractures in the Strachan buildup. Also, the stress field was modified by tectonic compression during the Late Cretaceous and Early Tertiary Laramide orogeny. Pressures generated during thermal cracking of oil together with tectonic compression probably created the microfractures in the isolated and effectively sealed reservoirs. The increased horizontal stresses resulted in subhorizontal microfractures, whereas rare radial and random microfractures formed under conditions of more uniform stress. The lack of microfractures in adjacent gas-bearing and updip buildups along the Rimbey-Meadowbrook reef trend is likely due to the connection of these buildups to a regional conduit system in the underlying Cooking Lake platform, preventing them from developing sufficient overpressures.

  11. 华南西部新元古代中期沉积盆地性质及其动力学分析——来自桂北丹洲群的沉积学制约%An Analysis on Property and Dynamics of the Middle Neoproterozoic Sedimentary Basin in the Western of South China: Constraint from the Sedimentary Data of Danzhou Group in Northern Guangxi

    Institute of Scientific and Technical Information of China (English)

    杨菲; 汪正江; 王剑; 杜秋定; 邓奇; 伍浩; 周小琳

    2012-01-01

    在桂北,新元古代丹洲群出露在九万大山至越城岭一带,为一套角度不整合在中—新元古界四堡群变质岩系之上,整合于南华冰期沉积之下的浅变质/未变质沉积岩夹火山岩组合.本文通过对罗城黄金丹洲群剖面的沉积相及沉积序列研究表明:白竹组至合桐组为冲洪积相(移地滨岸相)、三角洲相、浅海陆棚相、碳酸盐缓坡(台地)、深水陆棚相(或欠补偿盆地相)等沉积组合,拱洞组为深水浊积岩、浅海陆棚相沉积组合,晚期为滨浅海相或三角洲相组合.综合剖面沉积相、沉积层序以及其中多幕式的火山—岩浆活动等沉积记录分析,作者认为与新元古代新生沉积盆地开启相伴的双模式的、同期的、一系列大火成岩省的形成,沉积盆地早期的海侵上超和饥饿沉积,晚期差异沉降和快速充填,以及与盆地演化阶段相伴的幕式火山岩浆活动等一系列事实与弧陆碰撞模式是相矛盾的,丹洲群及其相当层位地层应为裂谷盆地充填序列,其盆地演化的阶段性可能是地幔柱幕式活动的沉积响应.%The mid-Neoproterozoic Danzhou Group outcropped across the Jiuwandashan Mountains and the Yuecheng Mountains in Northern Guangxi. The Danzhou Group, which consisted of low metamorphic or normal sedimentation inter-bedded with igneous rocks, overlay the Metamorphite series of the Sibao Group with unconformity; and underlay the Nanhua glacial deposition with conformity. Writers characterized the sedimentary facies and depositional sequences of the Danzhou Group at the Huangjin section, Luocheng County, northern Guangxi, From the bottom to the top, the Baizhu Formation and Hetong Formation were composed of five kinds of facies, alluvial—fluvial facies (immigrating beach facies) , delta facies, shallow shelf facies, carbonate ramp (or platform) , deep shelf facies (or starved basin facies) ,respectively. The Gongdong Formation contained deep water

  12. Late production of hydrocarbon gases in sedimentary basins: kinetic and isotopic study; Genese tardive des gaz hydrocarbures dans les bassins sedimentaires: etude cinetique et isotopique

    Energy Technology Data Exchange (ETDEWEB)

    Lorant, F.

    1999-06-23

    The thermal decomposition of sedimentary organic matter, or kerogen, within the metagenesis zone (T > 170 deg. C) leads to the formation of large amounts of late gas, mainly composed by methane. The work reported in this dissertation aims at understanding and quantifying the mechanisms of late methane generation and isotopic fractionation. With this purpose, natural samples of Type II and Type III mature kerogens (Ro > 1.3%, H/C < 0.65), were artificially heated in both open (T = 350 to 900 deg. C at 25 deg. C/min) and closed (T = 375 to 550 deg. C with t = 1 to 216 h) systems. For each experiment, mass and atomic (C, H, O) balances were obtained by recovering, fractionating and quantifying the entire pyrolysis effluents. Moreover, the isotopic compositions ({sup 13}C/{sup 12}C ratios) of methane and insoluble residue produced in closed system were measured. These experimental simulations have shown that the amounts of methane generated in an open-pyrolysis system (9 to 40 mg/gC) are systematically inferior to that observed in a closed-pyrolysis system (44 to 68 mg/gC), even after correction of the possible C{sub 2}-C{sub 5} and C{sub 6+} hydrocarbons secondary cracking. This shift, which is larger for Type II kerogens compared to coals and Type II-S kerogens, seems to be correlated with the pyrite content of the samples. Based on the closed-pyrolysis system data, a kinetic scheme, suitable for both Type II and Type III kerogens, was established. It includes three consecutive reactions, whose apparent kinetic parameters do not allow accounting for the corresponding rate constants observed in open system: E{sub 1} = 64.7 kcal/mol and A{sub 1} = 2.58 x 10{sup 15} s{sup -1}, E{sub 2} = 52.8 kcal/mol and A{sub 2} = 5.50 x 10{sup 10} s{sup -1}, E{sub 3} = 55-58 kcal/mol and A{sub 3} = 7.52 x 10{sup 9} s{sup -1}. By extrapolation to geological setting, it was thus predicted that kerogens might generate about 15 mg/gC of late methane between 170 and 200 deg. C. In order

  13. Late production of hydrocarbon gases in sedimentary basins: kinetic and isotopic study; Genese tardive des gaz hydrocarbures dans les bassins sedimentaires: etude cinetique et isotopique

    Energy Technology Data Exchange (ETDEWEB)

    Lorant, F.

    1999-06-23

    The thermal decomposition of sedimentary organic matter, or kerogen, within the metagenesis zone (T > 170 deg. C) leads to the formation of large amounts of late gas, mainly composed by methane. The work reported in this dissertation aims at understanding and quantifying the mechanisms of late methane generation and isotopic fractionation. With this purpose, natural samples of Type II and Type III mature kerogens (Ro > 1.3%, H/C < 0.65), were artificially heated in both open (T = 350 to 900 deg. C at 25 deg. C/min) and closed (T = 375 to 550 deg. C with t = 1 to 216 h) systems. For each experiment, mass and atomic (C, H, O) balances were obtained by recovering, fractionating and quantifying the entire pyrolysis effluents. Moreover, the isotopic compositions ({sup 13}C/{sup 12}C ratios) of methane and insoluble residue produced in closed system were measured. These experimental simulations have shown that the amounts of methane generated in an open-pyrolysis system (9 to 40 mg/gC) are systematically inferior to that observed in a closed-pyrolysis system (44 to 68 mg/gC), even after correction of the possible C{sub 2}-C{sub 5} and C{sub 6+} hydrocarbons secondary cracking. This shift, which is larger for Type II kerogens compared to coals and Type II-S kerogens, seems to be correlated with the pyrite content of the samples. Based on the closed-pyrolysis system data, a kinetic scheme, suitable for both Type II and Type III kerogens, was established. It includes three consecutive reactions, whose apparent kinetic parameters do not allow accounting for the corresponding rate constants observed in open system: E{sub 1} = 64.7 kcal/mol and A{sub 1} = 2.58 x 10{sup 15} s{sup -1}, E{sub 2} = 52.8 kcal/mol and A{sub 2} = 5.50 x 10{sup 10} s{sup -1}, E{sub 3} = 55-58 kcal/mol and A{sub 3} = 7.52 x 10{sup 9} s{sup -1}. By extrapolation to geological setting, it was thus predicted that kerogens might generate about 15 mg/gC of late methane between 170 and 200 deg. C. In order

  14. Interactions of polychlorinated biphenyls and organochlorine pesticides with sedimentary organic matter of retrogressive thaw slump-affected lakes in the tundra uplands adjacent to the Mackenzie Delta, NT, Canada

    Science.gov (United States)

    Eickmeyer, David C.; Kimpe, Linda E.; Kokelj, Steve V.; Pisaric, Michael F. J.; Smol, John P.; Sanei, Hamed; Thienpont, Joshua R.; Blais, Jules M.

    2016-02-01

    Using a comparative spatial analysis of sediment cores from eight lakes in tundra uplands adjacent to the Mackenzie Delta, NT, we examined how the presence of retrogressive thaw slumps on lake shores affected persistent organic pollutant (POPs, including polychlorinated biphenyls and organochlorine pesticides) accumulation in lake sediments. Sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes that were unaffected by thaw slumps. Mean focus-corrected inorganic sedimentation rates were positively related to TOC-normalized contaminant concentrations, explaining 58-94% of the variation in POP concentrations in sediment, suggesting that reduced organic carbon in slump-affected lake water results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Inferred chlorophyll a, S2, and S3 carbon fluxes to sediment were not significantly correlated to POP fluxes. Higher POP concentrations observed in sediment of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic organic contaminants onto a smaller pool of available organic carbon when compared to neighboring lakes unaffected by thaw slump development.

  15. Tracing of natural radionuclides mobility in deep sedimentary environment using radioactive (234U/238U) disequilibria: application to the Mesozoic formations of the Eastern part of the Paris Basin

    International Nuclear Information System (INIS)

    This thesis forms part of the geological investigations undertaken by the French agency for nuclear waste management, ANDRA, around the Meuse/Haute-Marne Underground Research Laboratory (URL) located in the Eastern part of the Paris Basin in order to evaluate the feasibility of high-level radioactive waste repository in deep argilite formations. The aim of the study is to examine the radionuclide migration in the deep Callovo-Oxfordian target argilite layer and its surrounding low- permeability Bathonian and Oxfordian limestone formations in order to assess the long term confining capacities of the sedimentary series. This study is based on measurement of radioactive disequilibria within U-series by Multiple- Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The high precision and accuracy achieved allowed to demonstrate the 234U/238U radioactive equilibrium in the Callovo-Oxfordian argilites. This result shows the uranium immobility in the target formation and provides a strong evidence for the current chemical stability and closure of the system for uranium and most probably for the other actinides. This is a fundamental result with respect to the problematic of disposal of high level radioactive waste in deep geological formation since it provides a in situ indication of the confining capacities of the clayey target formation in the current settings. Conversely, (234U/238U) disequilibria are systematically observed within zones, located in the surrounding carbonate formations, that are characterized by pressure dissolution structures (stylolites or dissolution seams). These disequilibria provide evidence for a discrete uranium relocation during the last two million years in the vicinity of stylolitic structures. This is a surprising result since it is generally supposed that these deep, low permeability, compact formations behave as closed system at the time scale of the U-series. (author)

  16. Provenance Direction and Sedimentary Characteristics of the Carboniferous in Bayanhot Basin%巴彦浩特盆地石炭系物源及沉积相研究

    Institute of Scientific and Technical Information of China (English)

    陈蓉; 侯明才; 王峰; 王涛; 王艳琴

    2013-01-01

    Provenance of the Carboniferous in the Bayanhot Basin has been studied by means of thin section analysis cathodoluminescence of quartz etc.. The results show that the dominant sediment source during the deposition of the Car-boniferous in Bayanhot Basin came from the Alxa ancient land in the northern, the Longxi ancient land in the southeast, the Longshou mountain in the western, and the Luozi mountain in the Eastern. The mother rock is mainly metamorphic rocks of Archean and Proterozoic, sedimentary rocks of Former Carboniferous and magmatic rocks of Caledonian. Paleo-provenance have favorable spatial combination with depositional system. By outcrop observation and the study of phase signs, the early Carboniferous of the study area developed barrier coast and the diamictic continental shelf,which is af-fected by the Alxa ancient land,and in the late,the study area developed barrier coast,no-barrier coast,fan delta, meander-ing river delta and the diamictic continental shelf,which is affected by the combined effect of multi-material source.%  通过岩石薄片分析和石英阴极发光特征,对巴彦浩特盆地石炭系进行物源分析。结果表明,该盆地石炭系存在北部阿拉善古陆、东南部陇西古陆、西部龙首山隆起及东部骡子山隆起4个物源方向,母岩分别为太古界及元古界变质岩、前石炭系沉积岩及加里东期岩浆岩。古物源与沉积体系具良好空间配置关系,通过野外剖面观察,结合物源和相标志,认为研究区石炭系早期主要受阿拉善古陆影响,发育障壁海岸和混积陆棚相,中晚期受多物源共同影响,发育障壁海岸、无障壁海岸、扇三角洲、曲流河三角洲和混积陆棚相。

  17. Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California: Chapter CC of Evolution of sedimentary basins/onshore oil and gas investigations - Santa Maria province

    Science.gov (United States)

    Willingham, C. Richard; Rietman, Jan D.; Heck, Ronald G.; Lettis, William R.

    2013-01-01

    The Hosgri Fault Zone trends subparallel to the south-central California coast for 110 km from north of Point Estero to south of Purisima Point and forms the eastern margin of the present offshore Santa Maria Basin. Knowledge of the attributes of the Hosgri Fault Zone is important for petroleum development, seismic engineering, and environmental planning in the region. Because it lies offshore along its entire reach, our characterizations of the Hosgri Fault Zone and adjacent structures are primarily based on the analysis of over 10,000 km of common-depth-point marine seismic reflection data collected from a 5,000-km2 area of the central and eastern parts of the offshore Santa Maria Basin. We describe and illustrate the along-strike and downdip geometry of the Hosgri Fault Zone over its entire length and provide examples of interpreted seismic reflection records and a map of the structural trends of the fault zone and adjacent structures in the eastern offshore Santa Maria Basin. The seismic data are integrated with offshore well and seafloor geologic data to describe the age and seismic appearance of offshore geologic units and marker horizons. We develop a basin-wide seismic velocity model for depth conversions and map three major unconformities along the eastern offshore Santa Maria Basin. Accompanying plates include maps that are also presented as figures in the report. Appendix A provides microfossil data from selected wells and appendix B includes uninterpreted copies of the annotated seismic record sections illustrated in the chapter. Features of the Hosgri Fault Zone documented in this investigation are suggestive of both lateral and reverse slip. Characteristics indicative of lateral slip include (1) the linear to curvilinear character of the mapped trace of the fault zone, (2) changes in structural trend along and across the fault zone that diminish in magnitude toward the ends of the fault zone, (3) localized compressional and extensional structures

  18. Ancient sedimentary environments and their subsurface diagnosis, third edition

    Energy Technology Data Exchange (ETDEWEB)

    Selley, R.C.

    1985-01-01

    All the worlds coal, most of its petroleum, and many ore deposits occur within sedimentary rocks (sandstones, limestones and shales). The distribution of these minerals is closely related to the sedimentary environment of the host rock. For example, an oil field trapped in an old beach sand will be elongated parallel to the basin margin, while a bed of coal within an abandoned river channel will trend into the basin. This book shows how to diagnose the depositional environments of sedimentary rocks and indicates how this knowledge may be applied to the search for petroleum, coal and sedimentary ore deposits. The first edition of this book appeared in 1970. It was primarily concerned with the interpretation of sedimentary environments from outcrop, from an aesthetic stance, with no thought of vulgar commercial application. The second edition (1977) reflected the author's experience in the oil industry and included sections on the use of geophysical well logs in subsurface facies analysis. In recent years the field that is loosely termed seismic stratigraphy developed, where sedimentary concepts are applied to the interpretation of seismic data. Today seismic surveys may delineate channels, deltas, reefs, submarine fans, and other deposits. The thrid edition contains sections on the seismic characteristics of the various sedimentary facies, and the sections on metalliferous sedimentary deposits and recent environments have been expanded.

  19. Development of large-area land cover and forest change indicators using multi-sensor Landsat imagery: Application to the Humber River Basin, Canada

    Science.gov (United States)

    van Lier, O. R.; Luther, J. E.; Leckie, D. G.; Bowers, W. W.

    2011-10-01

    Monitoring ecological indicators is important for assessing impacts of human activities on ecosystems. A means of identifying and applying appropriate indicators is a prerequisite for: environmental assessment; better assessment and understanding of ecosystem health; elucidation of biogeochemical trends; and more accurate predictions of future responses to global change, particularly those due to anthropogenic disturbance. The challenge is to derive meaningful indicators of change that capture the complexities of ecosystems yet can be monitored consistently over large areas and across time. In this study, methods for monitoring indicators of land cover (LC) and forest change were developed using multi-sensor Landsat imagery. Mapping and updating procedures were applied to the Humber River Basin (HRB) in Newfoundland and Labrador, one of four test sites in Canada selected for testing the development of national-scale methods. Procedures involved unsupervised clustering and labeling of baseline imagery, followed by image-to-image spectral clustering to derive binary change masks within which new LC types were classified for non-baseline imagery. Updated maps were compatible with the baseline map and reflected change in LC for three time periods: 1976-1990, 1990-2001, and 2001-2007. From the LC products, several change indicators were quantified including: forest depletion, forest regeneration, forest change, net forest change, and annual rates of change. The procedures were validated using field plots to assess the accuracy of the 2007 LC product (74.2% for 10 LC classes) and change classes observed from 2001 to 2007 (87.8% for four change classes: depletion, regeneration, non-treed class no change, and treed class no change). Methods were considered to be highly efficient and operationally feasible over large areas spanning multiple Landsat scenes. Specific results for the test site provided trend information supporting land and resource management in the HRB region.

  20. The Changing Cold Regions Network: Improving the Understanding and Prediction of Changing Land, Water, and Climate in the Mackenzie and Saskatchewan River Basins, Canada

    Science.gov (United States)

    DeBeer, C. M.; Wheater, H. S.; Chun, K. P.; Shook, K.; Whitfield, P. H.

    2014-12-01

    Within the cold interior of western and northern Canada, rapid and widespread environmental changes are taking place, which are of serious concern for society and have a range of implications from local to regional and global scales. From a scientific standpoint there is an urgent need to understand the changes and develop improved diagnostic and predictive modelling tools to deal with the uncertainty faced in the future. The Changing Cold Regions Network (CCRN) is a research consortium of over 50 Canadian university and government scientists and international researchers aimed at addressing these issues within the geographic domain of the Mackenzie and Saskatchewan River Basins. CCRN's primary focus is to integrate existing and new experimental data with modelling and remote sensing products to understand, diagnose and predict changing land, water and climate, and their interactions and feedbacks. To support these activities, the network utilizes a suite of 14 world-class water, ecosystem, cryosphere and climate (WECC) observatories across this region that provide exceptional opportunities to observe change, investigate processes and their dynamics, and develop and test environmental models. This talk will briefly describe the CCRN thematic components and WECC observatories, and will then describe some of the observed environmental changes and their linkages across the northern and mountainous parts of the network study domain. In particular, this will include changes in permafrost, terrestrial vegetation, snowcover, glaciers, and river discharge in relation to observed climatic changes across the region. The observations draw on a wide range of literature sources and statistical analyses of federal and provincial regional monitoring network data, while more detailed observations at some of the WECC observatories help to show how these regional changes are manifested at local scales and vice versa. A coordinated special observation and analysis period across all

  1. Geothermal Energy Potential in Low Enthalpy Areas as a Future Energy Resource: Identifying Feasible Targets, Quebec, Canada, Study Case

    Directory of Open Access Journals (Sweden)

    Jacek Majorowicz

    2015-07-01

    Full Text Available Heat flow of the sedimentary succession of the Eastern Canada Sedimentary Basins varies from 40 mW/m2 close to the exposed shield in the north to high 60–70 mW/m2 in the southwest–northeast St. Lawrence corridor. As high fluid flow rates are required for a successful geothermal application, the most important targets are deep existing permeable aquifers rather than hard rock, which would need to be fracked. Unfortunately, the ten most populated Québec urban centers are in the areas where the Grenville (Canadian Shield is exposed or at shallow depths with sedimentary cover where temperatures are 30 °C or less. The city of Drummondville will be the exception, as the basement deepens sharply southwest, and higher temperatures reaching >120 °C are expected in the deep Cambrian sedimentary aquifers near a 4–5-km depth. Deep under the area where such sediments could be occurring under Appalachian nappes, temperatures significantly higher than 140 °C are predicted. In parts of the deep basin, temperatures as high as 80 °C–120 °C exist at depths of 3–4 km, mainly southeast of the major geological boundary: the Logan line. There is a large amount of heat resource at such depths to be considered in this area for district heating.

  2. Sedimentary cyclicity in early Pleistocene, evaporitic, playa-lake lacustrine deposits in the Guadix-Baza basin (Betic Cordillera, Spain); Ciclicidad sedimentaria en depositos lacustres evaporiticos tipo playa-lake del Pleistoceno inferior en la cuenca de Guadix-Baza (Cordillera Betica, Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Aguilar, J. M.; Guera-Menchan, A.; Serrano, F.; Palmqvist, P.

    2013-06-01

    The Guadix-Baza basin (Betic Cordillera, southern Spain) contains in its eastern sector an early Pleistocene (Gelasian and lowermost Calabrian) sedimentary unit that was deposited in a shallow lacustrine environment. Given that the chronological limits of this unit lie between 2.5 and 1.6 Ma BP, the thickness of its preserved sediments (400 m) and high sedimentation rate (44.4 cm/ka) are remarkable. Numerous sedimentary cycles marked by an alternation of marls and sands are commonly found in the marginal sectors and marls and gypsum in the central sector, which would owe their origins to permanent flooding and evaporation/ re-flooding phases due to global climatic changes. Spectral analyses carried out using Fourier transform have revealed the existence of temporary frequencies associated with sedimentary cycles of between 0.2 and 5.2 ka. The origin of these cycles may be associated with variations in solar radiation and oscillations in the Moons orbital position, which would induce global climatic changes resulting in the rise and fall of the water table of the lake. Autocorrelation analyses conducted separately on the marly and evaporitic levels support this conclusion, as they indicate the existence of significant direct correlations between about 4 to 12 sedimentary cycles, which would correspond to repetitions of the stratigraphic series over a time span of 1.3 to 4 ka. (Author)

  3. Sedimentary Characteristics and Evolution of the Upper Carboniferous Taiyuan Formation, Shenmu Gasfieid, Northeastern Ordos Basin%鄂尔多斯盆地神木气田太原组沉积特征与演化

    Institute of Scientific and Technical Information of China (English)

    兰朝利; 张君峰; 陶维祥; 张永忠; 杨明慧; 王金秀

    2011-01-01

    鄂尔多斯盆地东缘的神木气田太原组为特征性的碎屑岩与碳酸盐岩互层含煤岩系.近期天然气勘探证实其具有良好的开发潜力.为指导神木气田太原组开发和盆地太原组储层勘探,根据测井、录井、常规薄片、铸体薄片、物性和粒度资料,结合岩芯描述,研究了神木气田太原组地层组合、沉积特征、沉积环境演化、砂体宽度以及沉积相对储层控制作用.太原组地层发育了碎屑岩型、灰岩型和互层型3种组合.地层颜色、粒度、成分、结构、沉积构造、岩石相、测井相、含有物以及沉积序列特征反映其为潮控三角洲与低能碳酸盐台地沉积,主要发育三角洲平原分流河道、分流间洼地微相,三角洲前缘远砂坝、分流间湾微相,以及碳酸盐灰坪、灰泥坪微相.太原组下部(太二段)以三角洲平原沉积为主,分流河道砂体发育,但宽度较窄(7.1~131.9 m),上部太-段为三角洲前缘与碳酸盐潮坪沉积,反映其经历了一个沉积水体总体逐渐加深的海侵过程和/或碎屑供应逐渐减少的沉积过程,而太一段碎屑岩与灰岩的互层沉积则反映了太原组晚期沉积水体的振荡性加深→变浅和/或陆源碎屑供应的周期性缺乏.储层主要发育在太二段高能量的三角洲平原分流河道中、粗砂岩中.%The Upper Carboniferous Taiyuan Formation is a characteristic coal-bearing seam interbedded with terrigenous siliciclastic and carbonate rock in the Shenmu gasfield of northeastern Ordos basin, central China. Recent exploration shows its good potential for further gas development. To offer guidance for exploitation of Taiyuan Formation in this gas field as well as the Ordos basin, the strata assemblages,sedimentary characteristics, environment evolution, sandbody width and sedimentary facies control on reservoirs of Taiyuan Formation were investigated based on analysis of well-logging, mud-logging, routine thin

  4. Nonlinear Viscoelastic Compaction in Sedimentary Basins

    CERN Document Server

    Yang, Xin-She

    2010-01-01

    In the mathematical modelling of sediment compaction and porous media flow, the rheological behaviour of sediments is typically modelled in terms of a nonlinear relationship between effective pressure $p_e$ and porosity $\\phi$, that is $p_e=p_e(\\phi)$. The compaction law is essentially a poroelastic one. However, viscous compaction due to pressure solution becomes important at larger depths and causes this relationship to become more akin to a viscous rheology. A generalised viscoelastic compaction model of Maxwell type is formulated, and different styles of nonlinear behaviour are asymptotically analysed and compared in this paper.

  5. Towards Simulating Streamflow in Ungauged Basins Utilizing isoWATFLOOD: Time-Series Distribution of Oxygen-18 and Deuterium across Canada

    Science.gov (United States)

    Delavau, C. J.; Stadnyk, T.; Birks, S. J.; YI, Y.; Gibson, J. J.

    2011-12-01

    With growing awareness of the impact of climate change on environmental processes, hydrological modelling is a critical tool for the sustainable management and development of water resources. However, problems such as model validation and quantification of uncertainty arise in calibrating hydrological models over the large, often remote basins for which these predictions are required. Therefore, new tools are being sought that are capable of providing reliable, large-scale predictions of current and future water availability. The isoWATFLOOD model has the ability to simulate both quantity and isotopic composition of streamflow and runoff generation processes. Water mass and isotopes simulated in tandem can further constrain model simulations to measured isotopic signals in streamflow, facilitating calibration and constraining parameterization. isoWATFLOOD simulations of isotopes in streamflow first require isotopic forcing from climate, which is provided from the distribution of stable water isotopes in precipitation (δ18O and δ2H) observations. This study will highlight the development of seasonal time-series prediction models for precipitation δ18O and δ2H for the Canadian domain. It has been well documented that the isotopic composition of precipitation is dependent on climate, geographic location, topography, and moisture sources, among other factors. Based on this understanding, climate parameters obtained from the NCEP-NARR (National Centre for Environmental Prediction North American Regional Reanalysis) data set are stepwise regressed with CNIP (Canadian Network for Isotopes in Precipitation) isotopic observations to create monthly time-series multivariate prediction models for the distribution of precipitation δ18O and δ2H across Canada. By modelling both oxygen-18 and deuterium, d-excess and delta-delta space act as diagnostic tools to quantify model performance, alongside statistical methods. Stepwise regression results show significant correlation

  6. Structure and Evolution Characteristics of the Global Sedimentary Basins:Evidence from the N-S Long Profiles%全球沉积盆地结构与构造演化背景--洲际经向超长构造剖面对比

    Institute of Scientific and Technical Information of China (English)

    李江海; 杨静懿; 程雅琳; 李维波; 周肖贝

    2013-01-01

    沉积盆地地层及其结构可记录盆地构造演化过程,而盆地演化则记录了不同历史时期的构造背景。为系统认识盆地构造演化及其演化背景,本文在全球构造理论指导下,收集全球上百个重要沉积盆地资料,编制了洲际超经向长剖面2条:(1)印度-西伯利亚-北美-南美经向超长剖面;(2)非洲东海岸-地中海-欧洲-北冰洋沿岸-西伯利亚-澳大利亚超长剖面。它们成为探讨沉积盆地结构特征、构造演化对比的重要基础,由此获得的主要认识包括:超长剖面是全球沉积盆地分类的基础,不同类型的沉积盆地有序并列。盆地构造演化和发育受控于板块构造边界作用以及基底沉降作用。不同的盆地类型在时间演化和空间分布具有密切成因联系。从板块边缘出发一般为大洋盆地、海沟、弧前盆地、弧后前陆盆地、前陆盆地、克拉通盆地、裂谷盆地、被动陆缘盆地。位于欧亚板块的各个盆地均受到阿尔卑斯造山运动(喜马拉雅运动)影响,亚洲大陆盆地群发育及其后期改造受古亚洲、特提斯和西太平洋构造域控制。受板块边界作用影响,相同板块上的不同盆地群之间具有密切的构造-沉积联系和构造事件响应。全球油气最富集的巨型盆地主要出现于板块内部、远离挤压板块边界的环境下。%Basin formation and its structure record basin tectonic evolution, which reflects the different periods of tectonic settings. As the development of the exploration in oil and gas, lots of seismic sections have been accumulated. This provides a large number of basic data for comparison of the characteristics of basins. Materials from hundreds of important sedimentary basins were collected to study the basin tectonic evolution and evolutionary background systematically based on the global structure theory. Two large scale profiles (thousands of km length) were

  7. A Method for Determining Sedimentary Micro-Facies Belts Automatically

    Institute of Scientific and Technical Information of China (English)

    Linfu Xue; Qitai Mei; Quan Sun

    2003-01-01

    It is important to understand the distribution of sedimentary facies, especially the distribution of sand body that is the key for oil production and exploration. The secondary oil recovery requires analyzing a great deal of data accumulated within decades of oil field development. At many cases sedimentary micro-facies maps need to be reconstructed and redrawn frequently, which is time-consuming and heavy. This paper presents an integrated approach for determining the distribution of sedimentary micro-facies, tracing the micro-facies boundary, and drawing the map of sedimentary micro-facies belts automatically by computer technique. The approach is based on the division and correlation of strata of multiple wells as well as analysis of sedimentary facies. The approach includes transform, gridding, interpolation, superposing, searching boundary and drawing the map of sedimentary facies belts, and employs the spatial interpolation method and "worm" interpolation method to determine the distribution of sedimentary micro-facies including sand ribbon and/or sand blanket. The computer software developed on the basis of the above principle provides a tool for quick visualization and understanding the distribution of sedimentary micro-facies and reservoir. Satisfied results have been achieveed by applying the technique to the Putaohua Oil Field in Songliao Basin, China.

  8. Sedimentary pyrite formation: An update

    Science.gov (United States)

    Berner, Robert A.

    1984-04-01

    Sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time. The amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter, dissolved sulfate, and reactive detrital iron minerals. Organic matter appears to be the major control on pyrite formation in normal (non-euxinic) terrigenous marine sediments where dissolved sulfate and iron minerals are abundant. By contrast, pyrite formation in non-marine, freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic-rich fresh water shales from marine shales. Under marine euxinic conditions sufficient H 2S is produced that the dominant control on pyrite formation is the availability of reactive iron minerals. Calculations, based on a sulfur isotope model, indicate that over Phanerozoic time the worldwide average organic carbon-to-pyrite sulfur ratio of sedimentary rocks has varied considerably. High C/S ratios during Permo-Carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time. Low C/S ratios, compared to today, during the early Paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean. The latter could have been due to lower oceanic oxygen levels and/or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time.

  9. 中国沉积盆地深部CO2地质封存联合咸水开采容量评估%Assessment of CO2 Storage Capacity and Saline Water Development in Sedimentary Basins of China

    Institute of Scientific and Technical Information of China (English)

    李琦; 魏亚妮; 刘桂臻

    2013-01-01

    CO2 geological storage and deep saline water recovery (CO2 Enhanced Water Recovery,CO2-EWR) system,as a new CCUS (CO2 capture,utilization,and storage) technology,is a win-win choice for enhancement of China's energy security and promotion of western development.A large number of sedimentary basins are distributed in the mainland and continental shelf of China,which have a large volume of saline aquifers for storage of CO2.The reliable and reasonable assessment of CO2 storage capacity and water recovery is an important prerequisite for storage site selection.In this paper,the universal pyramid method is adopted to assess the CO2 storage capacity for 25 major sedimentary basins.Three typical sedimentary basins are chosen to develop example models to determine the potential water recovery quantity using the volume ratio between basins and the example models based on the deposition and inflow characteristics.The results show that the total storage capacity of CO2 in the deep saline aquifers of 25 major sedimentary basins is about 1191.95×108 t,which is equal to 14.13 times of the total CO2 emission of China in 2010.The potential water recovery is about 40.90×108 t,which is enough for 10 coal chemical enterprises with 20 years of operation.The sedimentary basin has a large distribution in the western region of China and the water resources recovery quantity is abundant which can alleviate the water resources shortage problem during the production process and utilization of energy.%CO2地质封存联合深部咸水开采(CO2驱水技术,CO2-EWR)的新型CCUS(CO2捕集、利用和封存)技术是一种促进西部发展、加强我国能源安全的双赢选择.我国陆地及大陆架分布有大量的沉积盆地,可用于CO2封存的咸水层体积巨大,而可靠合理地评估CO2封存容量及其驱水量是封存场址选择的重要前提.现采用国际上较为通用的金字塔评价方法评估了我国25个主要沉积盆地的CO2封

  10. New Understanding of Sedimentary Facies of Baijiantan Formation in Baikouquan Area,Junggar Basin%准噶尔盆地百口泉地区白碱滩组沉积相新认识

    Institute of Scientific and Technical Information of China (English)

    尚建林; 金振奎; 王林生; 时晓章; 杜卫星; 王智忠; 刘林

    2011-01-01

    关于准噶尔盆地百口泉地区上三叠统白碱滩组的砂、砾岩,前人普遍认为是三角洲前缘沉积,主要依据是与砂砾岩互层的泥岩为还原色,认为还原色代表水下还原环境沉积。但大量的岩心观察以及测井、录井和地震资料分析表明,白碱滩组的砂、砾岩储集层主要为辫状河沉积,仅少数为三角洲前缘沉积。大部分与砂、砾岩互层的泥岩虽为暗色,但含有大量植物根、杆、茎、叶等化石,甚至夹煤层,白碱滩组自下而上是一个逐渐变浅的沉积旋回,其下段为湖泊沉积,中段为三角洲沉积,上段为辫状河沉积。研究区辫状河沉积的砂体呈条带状,粒度较粗,泥质含量较低,储集物性较好,形成重要的含油层;而三角洲前缘砂体呈席状,粒度较细,泥质含量较高,储集层物性较差,目前尚未发现油层。%Previous studies regarded the glutenite of Baijiantan formation of the Upper Triassic in Baikouquan area in Junggar basin as deposits of the delta front,and the main basis was that the mudstone interbedded with glutenite was in reduction color which represents underwater reduction environment deposits.But the analyses of a large amount of core observation,well logs,logging data and seismic information indicate that the glutenite reservoir of Baijiantan formation is dominated by braided fluvial deposits,a few belong to delta front deposits.The colors of most mudstones interbeddedd with the glutenite are dark,because they contain a lot of fossils of many plant roots,rods,stems,leaves,and even have coal seam interbed.Also,the Baijiantan formation is a sedimentary cycle gradually becoming shallow from the top to the bottom,the lower part is lake deposit,the middle is delta deposit and the upper is braided fluvial one.The sands of braided fluvial deposits in the studied area are characterized by strip,coarse granularityand,low shale content and good reservoir quality,in which the main oil

  11. 苏北盆地金湖凹陷碳酸盐岩沉积特征及演化模式%Sedimentary characteristics and evolutionary patterns of carbonates in Jinhu depression, Subei Basin

    Institute of Scientific and Technical Information of China (English)

    邵先杰; 王彩凤; 黄伟; 钟思瑛; 刘金华; 廖光明; 陈军

    2013-01-01

    of boron to gallium averages 3.6,indicating a brackish environment.The combination of sedimentary characteristics with analyses of organism assemblages and special minerals indicated a feature of a brackish lagoon environment as well,suggesting transgression or channels connecting with ocean during the deposition of the E1f22 interval in the J inhu depression.At that time,a suite of carbonates with 10~20 m in thickness was deposited widely in the west slope,indicating clear waters,relatively tranquil tectonic activities,slow lake-basin subsidence and deposition rate,and moderate compensation.Based on grain types and depositional characteristics,this suite of carbonates can be classified into four different sedimentary microfacies,i.e.mixed facies of terrigenous clastics and carbonates,oolite beach facies,bioclastic beach facies and cryptite facies.Vertically and horizontally each facies appears alternately.Dissolved pores are well-developed in bioclastic limestones which contain plenty of hydrocarbons.These carbonate reservoirs have been developed as a block of production succession in the Jinhu depression and certain deliverability has been obtained.

  12. Examples of transient sounding from groundwater exploration in sedimentary aquifers

    Science.gov (United States)

    Fitterman, D.V.

    1987-01-01

    Examples of the use of transient electromagnetic soundings for three groundwater exploration problems in sedimentary aquifers are given. The examples include: 1) estimating depths to water table and bedrock in an alluvium-filled basin, 2) mapping a confined freshwater aquifer in bedrock sediments, and 3) locating a freshwater/saltwater interface in a glacial-outwash aquifer. -from Author

  13. Potentiality if Rb-Sr method for dating the argillous sedimentary rocks

    International Nuclear Information System (INIS)

    The potentiality of application Rb-Sr method in argillous sediments, using samples from paleozoic and mesozoic formation in brazilian sedimentaries basin was tested. Physical, chemistry and isotopic analysis of thirty eight samples were made in the laboratories of geochronology Research Center from the University of Sao Paulo. Four isochronic diagrams for the argillous sedimentary rocks were also proposed. (author)

  14. 四川盆地中—上寒武统层序地层划分与沉积模式%Division and Sedimentary Model of Middle-Upper Cambrian Sequence Strata in Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    袁立; 姚君波; 李国蓉; 彭博; 麻宇杰

    2013-01-01

    According to the observation of the field outcrop profiles at Fandian,Yankong and Sanhuichang,and the sequence boundary characters and succession analysis of two connecting well sections cross Sichuan Basin,the Cambrian strata can be divided into 12 third-order sequences,named as SQ1 to SQ12 from lower to upper,which include SQ1 to SQ6 in lower Cambrian Series and SQ7 to SQ12 in middle to upper Cambrian Series.Several shallowing-upward cycles develop in the middle-upper Cambrian strata,which include lagoons to platform inner shoals,lagoons to tidal flats,and platform inner shoals to tidal flats.The middle-upper Cambrian sediments are the tidal flat-platform inner shoals-lagoon facies from west to east and the thickness of sediments show a varying pattern that is thick in the east and thin in the west,which is complementary to Lower Cambrian sediments.The total thickness of HST is thicker than that of TST in middle-upper Cambrian strata (SQ7-SQ12) so that it is generally characterized of fast transgression and slow regression.Semi-closed shallow-water carbonate platform gradually formed in the east and shoreline developed in the west in the SQ7 during middle Cambrian epoch.The middle Cambrian sedimentary model was inherited in SQ8 to SQ12 during upper Cambrian but more platform inner shoals developed in the west due to the weakening influence of the terrestrial detritus input and shallowing water.The platform inner shoals generally develop in the middle to top parts of HST invertical and in the center and eastern parts of Sichuan Basin in plan.%据对四川盆地范店、岩孔以及三汇场等3个野外寒武系剖面的观察,特别是根据岩孔单井剖面和女基井—宫深1井等连井剖面的层序界面特征和序列分析,将四川盆地寒武系自下而上划分为SQ1、SQ2、……、SQ12共12个三级层序,其中下寒武统6个(SQ1-SQ6),中—上寒武统6个(SQ7-SQ12).中—上寒武统发育多个潟湖→台内滩、潟湖→潮坪、台内

  15. Canterbury Basin Sea Level

    OpenAIRE

    Fulthorpe, C. S.; Institute for Geophysics John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin J.J. Pickle Research Campus, Building 196 (ROC) 10100 Burnet Road (R2200) Austin TX 78758-4445 USA; Hoyanagi, K.; Department of Geology Faculty of Science Shinshu University 3-1-1 Asahi, Matsumoto 390-8621 Japan; Blum, P.; United States Implementing Organization Integrated Ocean Drilling Program Texas A&M University 1000 Discovery Drive College Station TX 77845 USA; Guèrin, G.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Slagle, A. L.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Blair, S. A.; Department of Geological Sciences Florida State University 006 Carraway Building Tallahassee FL 32306 USA; Browne, G. H.; Hydrocarbon Section GNS Science PO Box 30368 Lower Hutt New Zealand; Carter, R. M.; Marine Geophysical Laboratory James Cook University of North Queensland Townsville QLD 4811 Australia; Ciobanu, M.; Laboratoire de Microbiologie des Environnements Extrêmes CNRS UMR-6197 Institut Universitaire Européen de la Mer Technopole Brest-Iroise Plouzane 29280 France; Claypool, G. E.; Organic Geochemist 8910 West 2nd Avenue Lakewood CO 80226 USA; Crundwell, M. P.; New Zealand Observer/Paleontologist (foraminifers) Paleontology and Environmental Change Section GNS Science PO Box 30368 Lower Hutt New Zealand; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ding, X.; School of Marine Sciences China University of Geosciences (Beijing) 29 XueYuan Road, Haidian District Beijing P.R. China; George, S. C.; Department of Earth and Planetary Sciences Macquarie University Sydney NSW 2109 Australia; Hepp, D. A.; MARUM – Center for Marine Environmental Sciences and Department of Geosciences University of Bremen Leobener Strasse MARUM Building, Room 2230 28359 Bremen Germany

    2010-01-01

    Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence stratigraphy of the late Miocene to recent, when global sea level change was dominated by glacioeustasy. Drilling in the Canterbury Basin,...

  16. A study of provenance and sedimentary facies of accretionary wedge basin: Taking a block in Myanmar as an example%增生楔盆地物源及沉积相分析——以缅甸某区块为例

    Institute of Scientific and Technical Information of China (English)

    蔡文杰; 朱光辉; 姜烨; 杨松岭; 李爱山

    2012-01-01

    As an important part of the trench - arc - basin system at active continental margin, the accretionary wedge basin has complex geologic setting and intensive tectonic deformation. Formations in accretionary wedge underwent multiple folding and overthrusting due to multiphase tectonic nappe. Therefore, it is very difficult to study the sedimentary facies. On the basis of comprehensive research on regional tectonic evolution history and heavy mineral analysis, two main source di- rections are identified in a certain exploration block of Myanmar. And sedimentary facies is studied on a basis of outcrop investigation, grain size analysis and single well facies interpretation. It is considered that except the north provenance came from Bengal gulf,the east provenance of one side of the Ruokai mountain after late Oligocene epoch is also an important sedimentary source. So two source directions commonly controlled the sedimentary facies distribution of the area.%作为主动大陆边缘“沟一弧一盆”体系中的重要组成部分,增生楔盆地地质背景复杂,构造变形强烈,多期构造推覆造成地层重复叠置,开展沉积相分析难度非常大。本文以缅甸某区块为例,从区域构造沉积演化分析出发,通过重矿物分析确定该区物源,同时利用以露头沉积相为基础,结合粒度分析和测井相分析,对该区的沉积相进行了深入细致的分析。分析认为,该区除了来自孟加拉湾的北向物源,晚渐新后若开山一侧的东部物源也是重要的沉积来源,两套物源共同控制了该区的沉积相展布。

  17. 太平洋夏季水对加拿大海盆海冰的影响%The impact of Pacific summer water on sea ice of the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    宋雪珑; 周生启

    2014-01-01

    近年来,北极海冰发生了大面积减少,减少的原因仍存在着争议。基于2003-2011年的水文和遥感卫星数据,对北冰洋加拿大海盆的太平洋水和海冰进行研究。通过对比2006年和2007年太平洋水位温与海冰密集度的空间分布,发现太平洋水暖异常于2007年1-3月进入加拿大海盆的中部,并可能导致了2007年夏季海冰大面积的融化。2003-2011年,在加拿大海盆的中部,太平洋水位温与海冰密集度存在着时间上的负相关。选取2007年8月,发现两者在空间上也存在着负相关。这很可能说明太平洋水暖异常在流动的过程中,向上输送了热量,在一定程度上,融化了海冰,从而触发海冰-反照率正反馈,导致海冰的减少。因此,通过白令海峡进入北冰洋的太平洋夏季水,对北极海冰面积的减少有着重要影响。%In recent years,the area of sea ice have been substantially reduced in the Arctic Ocean.The reason behind this is still in debate.Based on the data of hydrology and remote sensing satellite from 2003 to 2011,the relation-ship of Pacific Water and sea ice in the Canada Basin were studied.Spatial distributions of potential temperature of Pacific Water and sea ice concentration in 2006 were compared with those in 2007.It was found that the warm Pa-cific Water anomalies entered the central Canada Basin in January to March 2007,which probably led to the melting of sea ice in the summer of 2007.Between 2003 and 2011,it was found that the potential temperature of Pacific Water and sea ice concentration were negatively correlated in the central Canada Basin.In August 2007,the spatial correlation was also found to be negative in the central Canada Basin.It might indicate that the inflow of warm Pa-cific Water anomalies transferred the heat upwardly.To a certain extent,the heat melted the sea ice and triggered the ice-albedo feedback,which resulted in the decline of sea ice area

  18. From cold to hot: post Hirnantian sedimentary basins in Bolivia- a source rock for hydrocarbon deposits in the Andes? – A case study of the Cancañiri formation

    OpenAIRE

    Mehus, Trine

    2013-01-01

    This thesis introduces to sedimentary rocks sampled in Bolivia, in the Eastern Cordillera. Samples were taken from two different outcrops of the Late Ordovician to Early Silurian Cancañiri Formation, and the comparison of these two localities will be drawn in the results. These rocks have been studied using petrography, geochemistry analysis, TOC, heavy minerals using SEM and CL detector analysis, to reveal the shape, composition and interesting features of the rocks. The Cancañiri Formation ...

  19. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology

    International Nuclear Information System (INIS)

    We describe here the most important milestones and contributions to Sedimentary Petrology compared to other geological disciplines. We define the main aim of our study and the scientific and economic interests involved in Sedimentary Petrology. The body of the paper focuses upon the historical development of this discipline from Henry Sorby's initial work until the present day. The major milestones in its history include: 1) initial descriptive works; 2) experimental studies; 3) the establishment of the different classifications of sedimentary rocks; 4) studies into facies and sedimentary environments; 5) advances in the study of diagenetic processes and their role in hydrocarbon prospection; and 6) the development of Sedimentary Geochemistry. Relationships and coincidences with Sedimentology are discussed. We go on to look at the advances that have taken place over the last 30 years, in which the study of sedimentary rocks is necessarily included in the wider field of Sedimentary Geology as a logical result of the proposal of global models of a changing Earth in which Sedimentary Geology plays a significant part. Finally we mention the notable contributions of Spanish sedimentary petrologists to this whole field of science. (Author) 120 refs.

  20. Sedimentary environment indicators: Benzothiazole and its derivatives

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Benzothiazoles distributional characteristics of crude oils and non-hydrocarbon fractions of source rocks in Mangya depression of the Qaidam Basin, Lunnan oil field in the Tarim Basin, Kelamayi oil field in the Junggar Basin and the Tulufan Basin oil field were analyzed. It was found that the distributions of benzothiazole are remarkable diversity in different sedimentary environmental oils. The swamp crude oils contain high quantity of benzothiazole and relatively high quantity of alkylthio-benzothiazole and 2(3H)-benzothiazolone. But the quantity of the 2,2′-dithiobis- ben-zothiazole is relatively low. The abundance of benzothiazole and 2,2′-dithiobis-benzothiazole are relatively high in semi-brackish water lacustrine crude oils, but the quantity of alkylthio-benzothiazole and 2(3H)-benzothiazolone are rela-tively low. The benzothiazoles belong to weak acid and mild base compound, and their stabilization conditions relate to their environmental medium. The nitrogenous bases are in favor of alkalescence environment, while weak acid nitroge-nous compounds are the main stable products under the weak acid environment. Benzothiazoles have great signifi-cance in identifying the oil- and gas-formed environment and the geochemistry study of non-hydrocarbon fraction in the future.

  1. Uranium isotopes (U-234/U-238) in rivers of the Yukon Basin (Alaska and Canada) as an aid in identifying water sources, with implications for monitoring hydrologic change in arctic regions

    Science.gov (United States)

    Kraemer, Thomas F.; Brabets, Timothy P.

    2012-01-01

    The ability to detect hydrologic variation in large arctic river systems is of major importance in understanding and predicting effects of climate change in high-latitude environments. Monitoring uranium isotopes (234U and 238U) in river water of the Yukon River Basin of Alaska and northwestern Canada (2001–2005) has enhanced the ability to identify water sources to rivers, as well as detect flow changes that have occurred over the 5-year study. Uranium isotopic data for the Yukon River and major tributaries (the Porcupine and Tanana rivers) identify several sources that contribute to river flow, including: deep groundwater, seasonally frozen river-valley alluvium groundwater, and high-elevation glacial melt water. The main-stem Yukon River exhibits patterns of uranium isotopic variation at several locations that reflect input from ice melt and shallow groundwater in the spring, as well as a multi-year pattern of increased variability in timing and relative amount of water supplied from higher elevations within the basin. Results of this study demonstrate both the utility of uranium isotopes in revealing sources of water in large river systems and of incorporating uranium isotope analysis in long-term monitoring of arctic river systems that attempt to assess the effects of climate change.

  2. Sedimentary condensation and authigenesis

    Science.gov (United States)

    Föllmi, Karl

    2016-04-01

    Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin ( 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and paleoenvironmental change themselves.

  3. Seismic stratigraphy and sedimentary architecture of the Chalk Group in south-west Denmark

    DEFF Research Database (Denmark)

    Larsen, Connie; Ineson, Jon; Boldreel, Lars Ole

    2014-01-01

    The article focuses on a study undertaken by the Chalk Group on the western onshore region of the Danish Basin in Eastern Denmark related on the seismic stratigraphy and sedimentary architecture of the region. The study is undertaken through subdividing the northern North German Basin and the south...

  4. Uranium in Canada

    International Nuclear Information System (INIS)

    In 1988 Canada's five uranium producers reported output of concentrate containing a record 12,470 metric tons of uranium (tU), or about one third of total Western world production. Shipments exceeded 13,200 tU, valued at $Cdn 1.1 billion. Most of Canada's uranium output is available for export for peaceful purposes, as domestic requirements represent about 15 percent of production. The six uranium marketers signed new sales contracts for over 11,000 tU, mostly destined for the United States. Annual exports peaked in 1987 at 12,790 tU, falling back to 10,430 tU in 1988. Forward domestic and export contract commitments were more than 70,000 tU and 60,000 tU, respectively, as of early 1989. The uranium industry in Canada was restructured and consolidated by merger and acquisition, including the formation of Cameco. Three uranium projects were also advanced. The Athabasca Basin is the primary target for the discovery of high-grade low-cost uranium deposits. Discovery of new reserves in 1987 and 1988 did not fully replace the record output over the two-year period. The estimate of overall resources as of January 1989 was down by 4 percent from January 1987 to a total (measured, indicated and inferred) of 544,000 tU. Exploration expenditures reached $Cdn 37 million in 1987 and $59 million in 1988, due largely to the test mining programs at the Cigar Lake and Midwest projects in Saskatchewan. Spot market prices fell to all-time lows from 1987 to mid-1989, and there is little sign of relief. Canadian uranium production capability could fall below 12,000 tU before the late 1990s; however, should market conditions warrant output could be increased beyond 15,000 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are now or are expected to be in service by the late 1990s. There is significant potential for discovering additional uranium resources. Canada's uranium production is equivalent, in

  5. Quantification of heat and fluid flow through time by 3D modeling : an example from the Jeanne d'Arc basin, offshore eastern Canada

    OpenAIRE

    Baur, Friedemann Ulrich Maximilian

    2010-01-01

    Demand for energy is growing rapidly, causing worldwide concerns on security of supply. Petroleum systems modeling in 4 dimensions (cube + time) predicts generation, migration, and quality/quantity of accumulated hydrocarbons in reservoirs, incorporating temperature and pressure through the entire evolution of the basin. A petroleum systems model thus provides the only means to combine all physical aspects (source, trap, seal, and reservoir) and timing (charge) to reduce exploration risk and ...

  6. 山西地堑湖盆湖退-湖侵的地貌沉积响应及其构造指示意义%MORPHO-SEDIMENTARY RESPONSES TO THE REGRESSION-TRANSGRESSION OF THE PALEOLAKES ASSOCIATED WITH THE TECTONICS IN THE SHANXI GRABEN BASINS

    Institute of Scientific and Technical Information of China (English)

    胡小猛; 卢海龙; 吴冰; 吴洁利

    2011-01-01

    针对区域第四纪环境的特点,本文首先提炼和归纳了山西地堑湖盆湖退-湖侵的地貌沉积响应一般表现;然后,依据一些保留比较清晰的区域地貌沉积遗存,对区域第四纪,特别是第四纪中晚期的湖退-湖侵历史进行了分析和追溯.分析结果显示,自S8古土壤或L8黄土层发育或堆积以来,区域湖盆曾在对应于古土壤S8,S5,S2和S1发育时期发生过4次快速的湖退;而在相邻两次湖退期间发生的是缓慢湖侵.结合区域构造运动的特点,本文最后对区域湖退-湖侵过程与区域构造运动的关系进行了分析,指出盆地中湖泊的快速湖退→缓慢湖侵→再次快速湖退…,这样的变化过程是与区域上地幔强烈上隆→减弱或渐趋稳定→再次强烈上隆…构造循环相对应的.%The Shanxi Graben Basins include the Linfen Basin,Taiyuan Basin,Xinding Basin and Datong Basin,in which lake sediments were developed and aeolian loess had also continuously deposited during the Quaternary. The regressions and transgressions of the paleolakes in these basins displayed various morpho-sedimentary phenomena. This paper first analyzes and lists the different responses of the morpho-sedimentary features to the paleolake regressions and transgressions, such as lake terraces, lake erosion shores, alluvial terraces in the surrounding mountainous areas, the vertical alternations of loess and lacustrine sediments, the horizontal expansion or contraction of loess and lacustrine sediment, and the changes in depositional rhythm. Second, based on the field data about the landform and lacustrine sediment in the basins, the paper analyzes the history and processes of the paleolake regressions and transgressions during the middle-late Quaternary. There exist four times when loess-paleosol sediment rapidly capped the lacustrine sediment and three times when the lacustrine sediment gradually covered the loess-paleosol sediment since the paleosol S8 or

  7. Late Permian-Early Triassic Sedimentary Evolution in Sichuan Basin and Its Significance on Gas Accumulation%四川盆地晚二叠世-早三叠世沉积演化及其对天然气富集的意义

    Institute of Scientific and Technical Information of China (English)

    冯冲; 邹华耀; 郭彤楼

    2015-01-01

    四川盆地上二叠统—下三叠统碳酸盐岩地层中富集天然气,天然气藏的分布受优质烃源岩和礁滩相储层的控制。为了揭示四川盆地沉积演化背景下天然气的富集规律及预测成藏有利区,对晚二叠世—早三叠世扬子古板块地质构造背景进行分析,讨论地质构造背景控制下四川盆地晚二叠世—早三叠世沉积演化特征;根据不同时期构造和沉积演化特征确定优质烃源岩和储层的发育机理和分布范围;结合天然气成藏模式的认识,确定天然气成藏有利区。结果表明:四川盆地晚二叠世—早三叠世海湾及其后陆棚的发育演化控制了该区龙潭组主力烃源岩与长兴组—飞仙关组礁滩相储层的发育分布,形成了下生上储的有利配置关系;川东北地区长兴组—飞仙关组台地边缘礁滩相储层邻近龙潭组海湾相优质烃源岩的区域为天然气成藏最有利区。总之,四川盆地晚二叠世—早三叠世沉积演化特征控制了海相优质烃源岩和储层的发育分布,决定了天然气的富集与分布。%Upper Permian-Low Triassic carbonate formations in Sichuan Basin enrich gas,and the distribution of gas accumulation is controlled by high quality source rocks and reef-shoal facies reservoir.In order to reveal the gas enrichment rule and forecast the favorable areas under the sedimentary evolution settings in Sichuan Basin, the geological structure settings of Late Permian-Early Triassic Yangtze palaeoslab were analyzed, and the characteristics of Late Permian-Early Triassic sedimentary evolution under the geological structure settings were discussed;the development mechanism and distribution of high quality source rocks and reservoirs were explained according to the characteristics of tectonic evolution in different periods;combined with the gas accumulation model,the favorable areas of gas accumulation were divided.The results show that the

  8. Sedimentary environment analysis of Yaojia formation--the ore-hosting stratum of Qianjiadian uranium deposit

    International Nuclear Information System (INIS)

    Qianjiadian uranium deposit is the first uranium deposit discovered in Songliao basin. In this paper, the sedimentary environment of Yaojia formation, the ore-hosting stratum of Qianjiadian uranium deposit and its relationship with uranium mineralization are studied from several aspects such as lithological combination, sedimentary structures, logging curves, thickness ratio of sandstone layer to mudstone layer, sedimentary petrology and petrological geochemistry. The sedimentary features are characterized by the average value 5.0 between thickness ratio of sandstone layer to mudstone layer of Yaojia formation, and typical tabular cross bedding and trough cross bedding. The lithology of Yaojia formation is mostly composed of intermediate to fine-grained sandstone and mudstone with less conglomerate, and the debris grains have moderate sorting and roundness. These indicate that the source area is far, and that the sediments underwent long-distance transportation before deposition. The large scale and stable extension sand body of the Yaojia formation demonstrated the sedimentary features ora large sedimentary basins. Therefore, the sedimentary environment of Yaojia formation in the study area should be far-sourced sandy braided stream in the united great Songliao basin. The uranium mineralization of Qianjiadian deposit is mainly controlled by the sand bodies of channel-bar and point-bar subfacies, and the scale of the mineralization is closely related to that of the sand bodies. (authors)

  9. Stratigraphic Correlation of Middle Triassic Sequences among Different Paleogeographic Sedimentary Facies in South China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Affected by the Indosinian movement, the sediments in the main part of South China, Yangtzeplatform, started to transform from marine to continental during the Middle Triassic. In the meantime, a noticeable paleogeographic and sedimentary facies differentiation occurred in the marginal regions of the platforms and produced completely different lithologic and paleontologicsequences in various paleogeographic gradients and sedimentary facies areas, which brought about the difficulties for the stratigraphic correlation based on the traditional stratigraphies. This paper proposes to use some characteristic environmental events as the markers of the stratigraphic corre lation across various paleogeographic sedimentary facies, considering that some distinctive regionalenvironmental events should have affected at the same time on the entire basin or the connectedsedimentary regions and produced some closely related sedimentary records in the stratigraphic sequences though the affected intensity and recorded pattern might be different among the regions.The change of violent relative sea level (generally water depth) and the alteration of tectonic activity summarized from the dynamic mechanism of sedimentation are the best markers of environmental events for stratigraphic correlation. Based on the analysis and recognition of some significantenvironmental events at the typical stratigraphic sequences from various paleogeographic sedimentary facies and combined with the consideration of the variations in expressed form and strength fthe events among different paleogeographic gradients and sedimentary facies, the stratigraphic sequences from different sedimentary facies can be easily correlated directly. Furthermore, the evolutionary history of the whole sedimentary basin can be clearly established.

  10. Sedimentary and tectonic evolution of ancient Lake Ohrid (Macedonia / Albania)

    OpenAIRE

    Lindhorst, Katja; Krastel, Sebastian; Wagner, Bernd

    2010-01-01

    Lake Ohrid (Macedonia / Albania) is probably the oldest lake in Europe (2-5 Ma), and is considered an important sedimentary archive to study the evolution of a graben system over several million years. Multichannel seismic profiles were acquired in 2007 and 2008 showing that the lake can be divided into two main parts, the slope areas and a large, deep central basin. The basin is bordered by the major eastern and western graben fault, additional faults were identifi ed in the northern part...

  11. Identification of thick sedimentary plains north of Hellas

    Science.gov (United States)

    Salese, Francesco; Mangold, Nicolas; Ansan, Veronique; Carter, John; Ody, Anouck; Poulet, François; Ori, Gian Gabriele

    2016-04-01

    Understanding the origin and timing of intercrater plains is crucial to understand the Martian history in relation with endogenic and/or exogenic cycles. Intercrater plains north of Hellas basin on Mars are thought to have hosted different sedimentary environments during the Late Noachian/Early Hesperian, and they offer a well-preserved insight into the regional geological history of Mars. Our new geologic mapping of the intercrater plains north of Hellas Basin is based on the rich data set from MRO and Mars Express and provides new insights into the region's geological history. These findings appear to constrain the interpretation of the nature and age of intercrater plains in this region, although we acknowledge that for example the source of the sedimentary deposits must be subject to further analysis. The northern part of Hellas basin displays topographically flat area, which was characterized during the Late Noachian by sedimentary deposition and later, in the Late Hesperian, by fissural volcanism. The map and crater retention ages enable us to interpret the geologic history of the region. The stratigraphically lower unit is represented by crustal outcrops. Across most of the region, the sedimentary unit covers the basement and is eroded into mesas, erosional windows and perched by fresh craters. Intercrater plains' sedimentary deposits north of Hellas display horizontal light-toned layered rich in Fe/Mg-phyllosilicates and local crossbedding stratification. The Noachian sedimentary deposits of the intercrater plains north of Hellas are locally covered by Hesperian lava flows, showing that intercrater plains are sedimentary and volcanic in origin. We found different erosional (regional and local) surfaces, at HiRISE scale inside sediments due to local erosional windows and at CTX scale we found two important regional erosional surfaces. The oldest between crustal outcrops and sediments, which is likely Middle Noachian in age and the youngest between sediments

  12. Instability in eight sub-basins of the Chilliwack River Valley, British Columbia, Canada: A comparison of natural and logging-related landslides

    Science.gov (United States)

    Wolter, Andrea; Ward, Brent; Millard, Tom

    2010-08-01

    Logging causes increased landslide frequency in British Columbia. In this study, the slope, type, initiation location, aspect, rate, bedrock geology, and size of mass movements located in eight logged tributary valleys of the Chilliwack River Valley are investigated. A landslide inventory was created by digitizing landslides identified on aerial photographs dating from 1941 to 2002. This database was analysed using qualitative observations and simple statistical tests, and a comparison between natural and logging-related landslides was made. Slope tests displayed a significant difference between natural and logging-related events, indicating that, on average, logging-related landslides require lower slope gradients to initiate than natural events. Although aspect, initiation location, and landslide type did not show a significant relationship between natural and logging-related landslides, they do suggest subtle differences. Landslide rate was calculated and compared for natural and logging-related landslides. It was significantly higher for logging-related events, attaining a maximum of 31 times the natural rate in 1978 and an overall average increase of nine times the natural rate. Logging-related landslides were on average smaller than natural landslides but this nevertheless resulted in a 3.1 times increase in area affected by logging-related landslides compared to natural landslides. Geology may influence landslide frequency as well; it appears to be higher over the less resistive sedimentary rocks of the Cultus Formation and Chilliwack Group and lower in granodioritic areas. Finally, roads affected slope stability more than clearcuts in the early decades of the study, but this effect decreased over time, suggesting a correlation with improved road construction.

  13. Origin and paleoenvironment of Pleistocene-Holocene Travertine deposit from the Mbéré sedimentary sub-basin along the Central Cameroon shear zone: Insights from petrology and palynology and evidence for neotectonics

    Science.gov (United States)

    Tchouatcha, Milan Stafford; Njoya, André; Ganno, Sylvestre; Toyama, Réné; Ngouem, Paul Aubin; Njiké Ngaha, Pierre Ricard

    2016-06-01

    The Mbéré sub-basin belongs to the Mbéré-Djerem intra-continental basin of Central North Cameroon. In this sub-basin, a travertine outcrop has been discovered and investigated palynologically and petrologically in this study. The sporopollinic content of the studied travertine is mainly composed of fungal spores (Rhyzophagites sp., Monoporisporites sp …) associated with rare fresh water algae spores such as Chomotriletes minor and angiosperm pollens (compositae, graminae, …). This sporopollinic association is indicative of hot and semi-arid to arid paleoclimate and reveals a Pleistocene-Holocene depositional age. The whole rock major element geochemistry shows relative enrichment of CaO (49.48%) and CO2 (38.49%). The origin of CO2 is probably from magmatic and/or metamorphic fluids. Compared to other travertines, SiO2 and Al2O3 contents are significant with average concentrations of 5.68% and 2.58% respectively. The mineralogical composition revealed by a microscopic study of bulk rocks is dominated by calcite (90-92%) associated to quartz (2-4%) and feldspar (2-3%), meanwhile the heavy mineral concentrate is formed by various mineral types such as zircon (most abundant), garnet, tourmaline, epidote, biotite, peridot and aegirine augite suggesting that the underground water has crossed both volcanic, plutonic and metamorphic rocks. With the mineral composition made of both chemical and detrital derived elements, the Mbéré travertine corresponds to chemico-lithoclastic/detrital limestone. In the Mbéré trough, numerous thermo-mineral springs are located along major fractures and faults. This result suggests that the Mbéré travertine deposit is related to the rising of deep water with the help of a fracturing system, similar to those of Irdi (Morocco), Italy and Turkey where there is much volcanism.

  14. Using 137Cs as a tool for the assessment and the management of erosion/sedimentation risks in view of the restoration of the Rainbow Smelt (Osmerus mordax) fish population in the Boyer River basin (Quebec, Canada)

    International Nuclear Information System (INIS)

    The Boyer River (Quebec, Canada) drains a 217 km2 watershed that is under cultivation at 60%. The last 2 km of the river bed has always been used as a spawning ground by Rainbow Smelts (Osmerus mordax). This fish population, which plays an important ecological role in the St. Lawrence River estuary, has dramatically declined over the last decades. Siltation and excessive algal growth in the spawning area were identified as the most probable causes of the fish population decline; suggesting that soil erosion, nutrient and sediment transport are major factors underlying the environmental problem. In this context, 137Cs provides an effective tool for investigating the magnitude and spatial distribution of long-term soil redistribution taking place in the watershed. Sampling of cultivated fields, riverbanks, bottom sediments and forested sites were thus undertaken to help understand the erosive behaviour of the watershed. Results obtained so far suggest in-field erosion rates of up to 13 t ha-1 yr-1 with net outputs reaching 11 t ha-1 yr-1. These results agree well with estimates obtained from the USLE. The 137Cs data indicate that fields located in the upstream half of the basin produce smaller sediment loadings than those in the downstream portion, despite higher soil erodibilities and more frequent use for annual crops. They also suggest that more than 75% of the sediment deposited in the spawning area originates from cultivated fields, and less than 25% from streambanks. (author)

  15. Relating petroleum system and play development to basin evolution: West African South Atlantic basins

    NARCIS (Netherlands)

    Beglinger, S.E.; Doust, H.; Cloetingh, S.A.P.L.

    2012-01-01

    Sedimentary basins can be classified according to their structural genesis and evolutionary history and the latter can be linked to petroleumsystem and playdevelopment. We propose an approach in which we use the established concepts in a new way: breaking basins down into their natural basin cycle d

  16. EXTENSION OF SEQUENCE STRATIGRAPHIC MODEL AND SEQUENCE STRATIGRAPHC ANALYSIS IN LIMNIC DEPOSITIONAL BASIN

    Institute of Scientific and Technical Information of China (English)

    李增学; 魏久传; 王民镇; 李守春; 李青山; 金秀昆; 兰恒星

    1996-01-01

    The architectural patterns of sedimentary succession are diverse in different depositionalbasins. The sedimentary architecture and geological condition of such basins asepicontinental sea, intraplate limnic basins, etc., differ clearly from those of continentalmargin basin. Extension, complement and perfection of sequence stratigraphic models are needed in the studies ofvarious depositional basins based on the classical sequence model. This paper, for this reason,expounds the thought, principles of sequence division, methodology and technology of the studyof sequence stratigraphy in epicontinental and limnic basins.

  17. Contribution of seismic processing to put up the scaffolding for the 3-dimensional study of deep sedimentary basins: the fundaments of trans-national 3D modelling in the project GeoMol

    Science.gov (United States)

    Capar, Laure

    2013-04-01

    Within the framework of the transnational project GeoMol geophysical and geological information on the entire Molasse Basin and on the Po Basin are gathered to build consistent cross-border 3D geological models based on borehole evidence and seismic data. Benefiting from important progress in seismic processing, these new models will provide some answers to various questions regarding the usage of subsurface resources, as there are geothermal energy, CO2 and gas storage, oil and gas production, and support decisions-making to national and local administrations as well as to industries. More than 28 000 km of 2D seismic lines are compiled reprocessed and harmonized. This work faces various problems like the vertical drop of more than 700 meters between West and East of the Molasse Basin and to al lesser extent in the Po Plain, the heterogeneities of the substratum, the large disparities between the period and parameters of seismic acquisition, and depending of their availability, the use of two types of seismic data, raw and processed seismic data. The main challenge is to harmonize all lines at the same reference level, amplitude and step of signal processing from France to Austria, spanning more than 1000 km, to avoid misfits at crossing points between seismic lines and artifacts at the country borders, facilitating the interpretation of the various geological layers in the Molasse Basin and Po Basin. A generalized stratigraphic column for the two basins is set up, representing all geological layers relevant to subsurface usage. This stratigraphy constitutes the harmonized framework for seismic reprocessing. In general, processed seismic data is available on paper at stack stage and the mandatory information to take these seismic lines to the final stage of processing, the migration step, are datum plane and replacement velocity. However several datum planes and replacement velocities were used during previous processing projects. Our processing sequence is to

  18. Syn- to post-Taconian basin formation in the Southern Québec Appalachians, Canada: constraints from detrital zircon U-Pb geochronology

    Science.gov (United States)

    Perrot, Morgann; Tremblay, Alain; David, Jean

    2015-04-01

    . These preliminary results suggest a time gap as high as 30 m.y. between the St-Victor Formation and underlying rocks of the lower Magog Group and the Ascot Complex. Combined with current mapping in southern Quebec, this implies the probable occurrence of a major unconformity at the base of the St-Victor, and suggests that a large part of the Magog Group sedimentary sequence has been the result of post-Taconian sedimentation rather than that of a typical forearc sequence as commonly reported in literature.

  19. Orphan Basin crustal structure from a dense wide-angle seismic profile - layered modeling

    Science.gov (United States)

    Lau, K. W. Helen; Watremez, Louise; Louden, Keith E.; Nedimović, Mladen R.; Karner, Garry D.

    2014-05-01

    The Orphan Basin is a large, deep water basin to the east of Newfoundland and northwest of Flemish Cap, Canada. It contains a considerably wide series of rift basins that provides an excellent opportunity to study continental crustal deformations under varying degrees of extension. We present a 500-km-long P-wave velocity model across the complete rift system of the Orphan Basin, from Flemish Cap to the Bonavista Platform, using high-resolution refraction and wide-angle reflection data from 89 ocean-bottom seismometers (OBS). This layered model builds on a first-arrival traveltime tomography model (Watremez et al., this session) and is formed using additional constraints from a coincident multichannel seismic reflection profile, gravity data and borehole data from three wells. The layered model helps detail deep sediment and crustal variations across this wide region of extended continental crust. The sedimentary section contains post-rift Tertiary (vp~1.7-3.5 km/s) and syn-rift Cretaceous and Jurassic (vp~4-5.4 km/s) layers within both the eastern and the western sub-basins, separated by three basement highs, suggesting that the two sub-basins may have opened during a single, extended rifting event. The crust is composed of three layers with vp of 5.4-6.1, 6.1-6.5 and 6.3-7.1 km/s of highly variable combined thicknesses, from 32 km beneath Flemish Cap and the Bonavista Platform to Orphan Basin, Porcupine Bank and the East Orphan Basin, and the Central Orphan High and Porcupine Bank. Unlike the Rockall and Porcupine Basins, no evidence for partial serpentinization of the upper mantle is observed beneath the E. Orphan trough. However, hyperextension (crustal thickness Orphan trough, which might have allowed the basement to have been covered by syn-rift sediment that inhibited the flow of water down the faults.

  20. A discussions on the Cryogenian-Cambrian tectonic-sedimentary event and tectonic setting of northern Tarim Basin%塔里木盆地北缘南华纪—寒武纪构造背景及构造-沉积事件探讨

    Institute of Scientific and Technical Information of China (English)

    周肖贝; 李江海; 傅臣建; 李文山; 王洪浩

    2012-01-01

    Based on field geological investigation in northwestern and northeastern Tarim Basin, in combination with paleomagnetic mapping and previous researches, this paper has discussed the evolution process of the basin in Cryogenian-Cambrian period according to sedimentary-tectonic event and other evidence. Across the Tarim Basin, surface outcrops of Cryogenian to Cambrian sedimentary succession are completely exposed in the vicinity of Aksu area (northwest Tarim), Kuruktag (northeast Tarim) and southwest Tarim, thus providing a unique, well preserved and accessible means with which researchers can study the early development of northern Tarim Basin. The major lithologic types of Cryogenian-Cambrian strata in northeast Tarim include tillite, clastic rocks (rich in organic matter) and carbonate intercalated with volcanic rocks; in northwest Tarim, calstic rocks and carbonate are the common rock types, intercalated with small amounts of tillite and volcanic rocks. The north margin of Tarim block, which was a part of Rodinia supercontinent and neighbored the northwestern margin of Australia, was deeply rifted in Cryogenian-Ediacaran period and developed into two rifts in the northwestern and northeastern margin, forming a thick layer of rift-passive margin deposits, but the layer in the northwestern rift was not so completely developed as the layer in the northeastern margin. The earliest rift-passive margin sediments which can be observed are Cryogenian-Middle Ordovician strata, and the period can be divided into Cryogenian faulted period (supercontinent rifting stage) and Ediacaran-Middle Ordovician subsidence period (plate drifting stage).%以塔里木盆地西北缘和东北缘南区南华系—寒武系野外地质调查为基础,结合古地磁成图及前人研究资料,针对构造-沉积事件等探讨盆地北缘南华纪—寒武纪成盆演化过程.研究区保存了完整的南华纪—寒武纪地层,其中塔东北缘以冰碛岩、碎屑岩(富含有机

  1. TransCanada PipeLines Limited 1996 annual report : profitable today, prepared for tomorrow

    International Nuclear Information System (INIS)

    Operations and financial activities of TransCanada PipeLines Limited (TPL) during 1996 were reviewed and made available for the benefit of shareholders. TransCanada PipeLines Limited is a Canadian company with assets in excess of $12 billion. Its pipeline system transports natural gas and crude oil from the Western Canada Sedimentary Basin to North America's major energy markets. By all accounts the company had a successful year in 1996, having delivered a record 2.4 Bcf of gas, up 3.7 per cent from 1995, through the Canadian Mainline, TransCanada's largest asset. Among other notable achievements was the decision to join the Portland Natural Gas Transmission System as a 20 per cent partner in a project to construct a natural gas pipeline between Quebec and Haverhill, Massachusetts. Another accomplishment was the completion of the acquisition of all remaining shares of Alberta Natural Gas company, thereby extending the company's energy transmission, gas processing and specialty chemical operations. Other achievements were the purchase of Enron Louisiana Energy Company, the acquisition of assets that position TPL as one of the largest natural gas liquids processors in North America and the completion and commissioning of two new independent power generation plants in Ontario. Shareholder's return on investment was 34 per cent, more than double the target of between 12 to 15 per cent. Net income to common shares amounted to $1.85 per share, up from $1.75 in 1995. The strong performance was attributed to continued growth in all four segments of TPL's business, i. e. energy transmission, energy marketing, energy processing and international. tabs., figs

  2. Modeling of stability of gas hydrates under permafrost in an environment of surface climatic change – terrestrial case, Beaufort-Mackenzie basin, Canada

    Directory of Open Access Journals (Sweden)

    J. Majorowicz

    2011-09-01

    Full Text Available Modeling of the onset of permafrost formation and succeeding gas hydrate formation in the changing surface temperature environment has been done for the Beaufort-Mackenzie Basin (BMB. Numerical 1-D modeling is constrained by deep heat flow from deep well bottom hole temperatures, deep conductivity, present permafrost thickness and thickness of Type I gas hydrates. Latent heat effects were applied to the model for the entire ice bearing permafrost and Type I hydrate intervals. Modeling for a set of surface temperature forcing during the glacial-interglacial history including the last 14 Myr was performed. Two scenarios of gas formation were considered; case 1: formation of gas hydrate from gas entrapped under deep geological seals and case 2: formation of gas hydrate from gas in a free pore space simultaneously with permafrost formation. In case 1, gas hydrates could have formed at a depth of about 0.9 km only some 1 Myr ago. In case 2, the first gas hydrate formed in the depth range of 290–300 m shortly after 6 Myr ago when the GST dropped from −4.5 °C to −5.5. °C. The gas hydrate layer started to expand both downward and upward subsequently. These models show that the gas hydrate zone, while thinning persists under the thick body of BMB permafrost through the current interglacial warming periods.

  3. Using pseudo-entropy of seismic reflection data to predict sedimentary facies

    Institute of Scientific and Technical Information of China (English)

    LIANG; Guanghe; (梁光河); CAI; Xinping; (蔡新平); ZHANG; Baolin; (张宝林); XU; Xingwang; (徐兴旺)

    2003-01-01

    A recent research shows that the internal structures developed during a sedimentary process vary regularly with the direction of deposition. The complexity of the internal structures can be described by using pseudo-entropy from seismic reflection data. By analyzing spatial variation in the pseudo-entropy of seismic data, the sedimentary facies types can be estimated and the pro- spective zones of sandstone can be predicted. This new method for sedimentary facies analysis has shown particular promise in the Erlian basin in North China.

  4. Natural CO{sub 2} migrations in the South-Eastern Basin of France: implications for the CO{sub 2} storage in sedimentary formations; Contribution a la connaissance des migrations de CO{sub 2} naturel dans le Bassin du Sud-Est de la France: enseignements pour le stockage geologique du CO{sub 2} dans les reservoirs sedimentaires

    Energy Technology Data Exchange (ETDEWEB)

    Rubert, Y.

    2009-03-15

    Study of natural CO{sub 2} analogues brings key informations on the factors governing the long term stability/instability of future anthropogenic CO{sub 2} storages. The main objective of this work, through the study of cores from V.Mo.2 well crosscutting the Montmiral natural reservoir (Valence Basin, France), is to trace the deep CO{sub 2} migrations in fractures. Petrographic, geochemical and micro-thermometric studies of the V.Mo.2 cores were thus performed in order: 1) to describe the reservoir filling conditions and 2) to detect possible CO{sub 2}-leakage through the sediments overlying the reservoir. Fluid inclusions from the Paleozoic crystalline basement record the progressive unmixing of a hot homogeneous aquo-carbonic fluid. The Montmiral reservoir was therefore probably fed by a CO{sub 2}-enriched gas component at the Late Cretaceous-Paleogene. The study of the sedimentary column in V.Mo.2 well, demonstrates that the CO{sub 2} did not migrate towards the surface through the thick marly unit (Domerian-Middle Oxfordian). These marls have acted as an impermeable barrier that prevented the upward migration of fluids. Two main stages of fluid circulation have been recognized: 1) an ante- Callovian one related to the Tethysian extension 2) a tertiary stage during which the upper units underwent a karstification, with CO{sub 2} leakage related but which remained confined into the deeper parts of the Valence Basin. Since the Paleogene, the Montmiral reservoir has apparently remained stable, despite the Pyrenean and alpine orogeneses. This is mainly due to the efficient seal formed by the thick marly levels and also to the local structuration in faulted blocks which apparently acted as efficient lateral barriers. (author)

  5. Preliminary Rock Physics Characterization of Mississippian Carbonate Reservoir in Canada

    Science.gov (United States)

    Lee, M.; Keehm, Y.; Kim, H.

    2011-12-01

    The Mississippian formations in the Western Canada Sedimentary Basin are known to have large hydrocarbon resources. The Lodgepole formation is the most important reservoir for oil production in Daly and Virden fields. In this study, we performed preliminary reservoir characterization using rock physics modeling. We first delineated the Lodgepole formation by geological information, well-logs and core analysis data. Then, we conducted rock physics analyses such as GR-AI, DEM modeling, porosity-Vp, density-Vp, and porosity-permeability. We identified the Lodgepole formation has different porosity types, volume of shale, and the degree of fractures in difference intervals. In the upper part of the formation, we found that vuggy pores are well developed. Inter-particular porosity and fractures become significant as the depth increases. We found that the lower part can be divided into two groups by acoustic impedance. The prospective reservoir interval, one of the two groups, has higher fracture density, which can be identified by lower acoustic impedance. This result also implies that we could also use AVO analyses to delineate good reservoir intervals. In conclusion, rock physics modeling can be effectively applied to characterize the Lodgepole formation quantitatively with well-log and core analysis data. Acknowledgement: This work was supported by the Energy Resources R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 2009201030001A).

  6. 江汉盆地江陵凹陷南缘古新统沙市组四段含盐岩系沉积特征及其沉积环境意义%Sedimentary characteristics and its environmental significance of salt-bearing strata of the Member 4 of Paleocene Shashi Formation in southern margin of Jiangling Depression, Jianghan Basin

    Institute of Scientific and Technical Information of China (English)

    王春连; 刘成林; 胡海兵; 毛劲松; 沈立建; 赵海彤

    2012-01-01

    Based on drilling core and experimental analyses, the authors studied the sedimentary characteristics of salt-bearing strata of the Member 4 of Paleocene Shashi Formation in southern margin of Jiangling Depression of Jianghan Basin. The sedimentation of salt lake is characterized by multi-period, continuous and periodically alternating of fresh and salt water. Therefore, it has become the important research focus to study palaeoclimate and palaeoenvironment. The salt-bearing strata of the Member 4 of Shashi Formation in southern margin of Jiangling Depression is composed of non-sandstone, mainly peperite of evaporate mineral, carbonate mineral, terrigenous clay and fine detrital mineral. The layer thickness can be a few millimeter to a few dozen centimeters. The accumulated bed thickness is up to a few dozen centimeters to a few meters. Through comparison analysis of Fe, Mn, Al, Ca, Mg, Co, Ni, V, Cu content and Sr/Ba, Mg/Ca, V/(V+Ni), Ni/Co, Cu/Zn ratio, the sedimentary characteristics and sedimentary environment of salt-bearing strata are studied systematically. It shows that the lake environment in the Yanjian Member of Shashi Formation is perennial relative deep delamination salt lake, which can be classified as brackish-water lake, semi-salt-water lake, salt-water lake and brine lake. The lake depth becomes shallow from downward to upward. Primary glauberite, typically warm facies saline minerals, is widely developed in this formation. The Fe2O3/FeO ratio represents drought climate. This feature reveals that the Paleocene Shashi Formation in southern margin of Jiangling Depression of Jianghan Basin is characterized by a drought and warm palaeoclimate.%通过钻井岩心观察及室内测试分析等方法,对江汉盆地江陵凹陷南缘古新统沙市组四段含盐岩系的沉积特征进行了研究.该时期研究区盐湖的特点是:成盐多期次、沉积连续、淡化—成化周期性交替,因而成为恢复古气候和古环境的重要研究对

  7. The evolution of the exploratory effort in Brazil in relation to its distribution in sedimentary basins and changes in the institutional structure: 1922 to 2008; A evolucao do esforco exploratorio no Brasil em relacao a sua distribuicao nas bacias sedimentares e as mudancas na estrutura institucional: 1922 a 2008

    Energy Technology Data Exchange (ETDEWEB)

    Accioly, Felipe; Draghi, Julia [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil)

    2012-07-01

    This study is based on the available data on the georeferred database of the Brazilian oil and gas government regulatory agency (ANP - Agencia Nacional do Petroleo Gas e Biocombustiveis) regarding the position, year of drilling and results of the oil and gas wells drilled in Brazil. The position of the wells were plotted on their sedimentary basins and grouped into five periods (1922-1953, 1954-1961, 1962 - 1970, 1971-1997, after 1997). For each period some of the most significant changes in the technical or institutional background were compiled and reported. Those maps allowed an interesting discussion on the criteria and methodology used to establish the prospect locations at each period and presented a possible explanation for the very low productivity of drilling in Brazil up to the 80's as much as the changes in the conceptual basis that lead to the successful performance of the 90's and the first decade of the 21st century (author)

  8. 渤海湾盆地歧口凹陷古近系沙一段物源—沉积体系重建%Reconstruction of Provenance-Sedimentary System of the First Member of the Paleogene Shahejie Formation in the Qikou Sag,Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    吕琳; 焦养泉; 吴立群; 鲁超; 荣辉; 汪小妹

    2012-01-01

    采用布格重力异常手段宏观地区分物源区和沉积区,根据重矿物特征分析物源区位置及影响范围,依据地震反射特征识别物源运移方向,通过砂分散体系精细分析和表征物源—沉积体系特征,并利用岩石地球化学资料进一步佐证物源—沉积体系分析。综合研究表明,渤海湾盆地歧口凹陷沙一段时期存在五个物源区,分别为葛沽物源、小站物源、增福台物源、钱圈物源和北大港潜山物源。葛沽物源为板桥次凹提供沉积物,且沉积物主体呈两支向歧口主凹进一步推进;小站物源、增福台物源和钱圈物源影响范围较小,均呈两支进入板桥次凹;北大港潜山物源为歧北次凹提供沉积物,向马棚口和高尘头地区推进时物源频繁分叉。综合岩芯、录井、测井和古生物等沉积成因标志,认为板桥次凹发育扇三角洲沉积体系,歧口主凹和歧北次凹发育深湖浊流体系。%Accoding to the characteristics of the Bouguer gravity anomalies,the source and deposition areas were macroscopically distinguished in this paper.Based on the characteristics of heavy mineral,the location and extent of the source areas were described.In addition,the direction of the sources were determined on the basis of seismic reflection characteristics.Furthermore,the characteristics of provenance-sedimentary system were finely pictured by the distribution of sandbody,and could be further verified through geochemical characteristics.Different ways exerted respective superiority,and various means revised each other,the provenance-sedimentary system of the first member of the Paleogene Shahejie Formation in the Qikou sag of the Bohai bay basin was reconstructed by these ways.The results suggested that,there were five sources in the first member of Shahejie Formation in the Qikou sag,that were Gegu source,Xiaozhan source,Zengfutai source,Qianquan source and Beidagang buried hill source.The Gegu source was

  9. Open system sulphate reduction in a diagenetic environment - Isotopic analysis of barite (δ34S and δ18O) and pyrite (δ34S) from the Tom and Jason Late Devonian Zn-Pb-Ba deposits, Selwyn Basin, Canada

    Science.gov (United States)

    Magnall, J. M.; Gleeson, S. A.; Stern, R. A.; Newton, R. J.; Poulton, S. W.; Paradis, S.

    2016-05-01

    Highly positive δ34S values in sulphide minerals are a common feature of shale hosted massive sulphide deposits (SHMS). Often this is attributed to near quantitative consumption of seawater sulphate, and for Paleozoic strata of the Selwyn Basin (Canada), this is thought to occur during bacterial sulphate reduction (BSR) in a restricted, euxinic water column. In this study, we focus on drill-core samples of sulphide and barite mineralisation from two Late Devonian SHMS deposits (Tom and Jason, Macmillan Pass, Selwyn Basin), to evaluate this euxinic basin model. The paragenetic relationship between barite, pyrite and hydrothermal base metal sulphides has been determined using transmitted and reflected light microscopy, and backscatter electron imaging. This petrographic framework provides the context for in-situ isotopic microanalysis (secondary ion mass spectrometry; SIMS) of barite and pyrite. These data are supplemented by analyses of δ34S values for bulk rock pyrite (n = 37) from drill-core samples of un-mineralised (barren), siliceous mudstone, to provide a means by which to evaluate the mass balance of sulphur in the host rock. Three generations of barite have been identified, all of which pre-date hydrothermal input. Isotopically, the three generations of barite have overlapping distributions of δ34S and δ18O values (+22.5‰ to +33.0‰ and +16.4‰ to +18.3‰, respectively) and are consistent with an origin from modified Late Devonian seawater. Radiolarian tests, enriched in barium, are abundant within the siliceous mudstones, providing evidence that primary barium enrichment was associated with biologic activity. We therefore propose that barite formed following remobilisation of productivity-derived barium within the sediment, and precipitated within diagenetic pore fluids close to the sediment water interface. Two generations of pyrite are texturally associated with barite: framboidal pyrite (py-I), which has negative δ34S values (-23‰ to -28

  10. Modèle de compaction élastoplastique et viscoplastique pour simulateur de bassins sédimentaires Elastoplastic and Viscoplastic Compaction Model for the Simulation of Sedimentary Basins

    Directory of Open Access Journals (Sweden)

    Schneider F.

    2006-11-01

    stress reached by the sediment during its burial. The elastoplastic parameters (Ee, Ea, Eb, phi index (a, phi index (b, phi index (r of function Beta can be easily calibrated from experimental data or from well logs data (Hamilton, 1959; Schneider et al, 1993. The viscoplastic parameters (µ index b, phi to the power of (min of function alpha can be calibrated from well logs data as shown in this study. They can also be extrapolated, for a given lithology, from experimental data (Gratier and Guiguet, 1986. A sensitivity analysis has been carried out with different values of extrapolated viscous coefficients. The viscous deformation is important (50% of the total strain for basins older than 1 Ma when the viscous coefficient is lower than a critical value of 10 MPa. Ma This critical value is equal to 100 MPa. M for basin older than 10 Ma and is equal to 1000 MPa. Ma for basin older than 100 Ma. With field data from Scholle (1977, it is possible to estimate the elastoplastic and viscoplastic parameters which define a chalk rheology. Assuming that chalk which had no suffer diagenesis, has been compacted along an elastoplastic path, it is possible to calibrate easily the elastoplasic parameters. Such a calibration can be also performed with laboratory measurements as suggested by Hamilton (1959. When chalk has suffered diagenesis, we assume that the present-day porosity versus effective-stress relationships, extracted from well logs, result both from elastoplastic deformation and viscoplastic deformation. With this assumption, chalk viscosity is evaluated around 2. 5 GPa. Ma. According to the sensitivity analysis, chalk pressure solution (viscoplastic deformation is noteworthy (10% of the total strain for basin older than 20 Ma. In conclusion, this model allow to take into account, in a realistic way, pressure solution phenomena which participate to sediments compaction. The major hypotheses are : (1 the transport of species in solution can be neglected in regard to the size

  11. Sedimentary features, reservoir characteristics and seismic signature of an Aptian incised valley and its lateral equivalent, in the north Ben Nevis field of the Jeanne d`Arc Basin

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, P.J.; Hodder, J.; Harding, S.; Zanussi, L. [Husky Oil, Calgary, AB (Canada); Plint, G. [Western Ontario Univ., London, ON (Canada)

    1998-09-01

    In 1988 three cores from an oil well in the Avalon Formation reservoir zone of the north Ben Nevis field were studied. The field is located within the Jeanne d`Arc Basin on the Grand Banks of Newfoundland. The cores indicated a shallowing-upward clastic sequence of prograding marine shoreface sandstones which end in back barrier lagoon deposits. Recent studies and current ongoing surveys using seismic logs and reservoir characterizations confirmed the original interpretation. An attempt was made to correlate two wells, the M-61 and the P-93. Correlations between the two wells indicate a gross similarity in depositional facies, but core and log analysis indicate major differences, particularly in the upper third of the Avalon Formation where the oil and gas is trapped. Two shallowing-upward shoreface successions are preserved in both wells, but local depositional variations are evident. M-61 showed much better reservoir characteristics than the same unit in P-93. New 3-D seismic data is expected to provide a better resolution of the geology. 1 fig.

  12. Potassium, uranium and thorium contents in the basement rocks of the Camamu and Almada sedimentary basins; Teores de uranio, torio e potassio nas rochas do embasamento das bacias sedimentares de Camamu e Almada

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara S.; Argollo, Roberto M. de; Barbosa, Johildo S.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Pos-graduacao em Geofisica

    2004-07-01

    The basement of the of Camamu and Almada basins is inserted in the granulitic region of the southeast Bahia. It is characterized, in bigger proportion, by the rocks of the Cinturao Itabuna represented by metatonalites calcium - alkaline of low potassium and matamonzonites with high-potassium geochemistry shoshonitics trend, associate to the basic granulites. In lesser proportion, one has: the rocks of the Jequie block, characterized by charnockites, charnoenderbites and enderbites with calcium-alkaline chemical and high-K contents and associated with amphibolites with low K-contents; the granite of Teolandia and the granodiorite of Moenda, representatives of the Ipiau Domain; and the neoproterozoics syenites and mafic dikes. On this context, the acid rocks of intermediate compositions, as the charnockites, the metamonzonites, the granitic rocks of the Ipiau band and the sienites, are the main lithologic units that show relevant concentrations of the U, Th and K elements. Already the metatonalites are more abundant in this basement ad show intermediate values of K, varying of 0,5 to 2.5 %, while the basic granulitos and the amphibolites show low K-contents as low as 0,02%. The Th concentrations in the basic metatonalites and ten granulite are below 10 ppm, arriving to below the determination limit of 0.4 ppm; the same thing occurs with U concentrations in these rocks. (author)

  13. Chemostratigraphy of early Neoproterozoic sedimentary rocks of Yenisei ridge (Siberia, Russia)

    Science.gov (United States)

    Vishnevskaya, Irina; Pisareva, Natalia; Kanygina, Nadejda; Proshenkin, Artem

    2014-05-01

    One of the biggest Proterozoic sedimentary basins in Russia is around the Siberian platform. This study about little part of them - Neoproterozoic sedimentary rocks of Yenisei ridge (Southwestern margin of Siberian Platform). Thise geological structure is ancient and very difficult for reaserch. It is a collage of different blocks: volcanic arcks, ophiolite complexes and sedimentary rocks of various ages and degrees of metamorphism. Sedimentary complexes of Siberian platform are outcropping along Angara River and its tributary. Neoproterozoic ones are presented by terrigenous-carbonate rocks of Tungusik and Oslyan groups. Despite the long study history of the area is still controversial question of time of formation of these rocks. As determination of the age of Precambrian sedimentary rocks is very difficult, Sr isotopic chemostratigraphy appears to be the only approach to establish the age of carbonate sequences. All Rb-Sr author's data was investigated by the method of selective dissolution with the preliminary removal of epigenetic carbonate phases. The isotope dilution method with mixed 87Rb + 84Sr spike was used to determine Rb and Sr concentrations in both fractions on the MI 1201AT mass spectrometer. Sr isotope ratios were measured on the Finnigan MAT-262 (BAC CU, Irkutsk, Russia) and Triton Plus (IGG UB RAS, Ekaterinburg, Russia). The C-O isotopic composition in carbon samples was measured on the Finnigan MAT-253 equipment. The main criteria for integrity were correlations of impurity-elements (Mn, Fe, Sr) and stable isotopes (C, O) with each other. The less altered rocks of the Tungusik Group are characterized by 87Sr/86Sr ratio of 0.7055-0.7058, and wide variations in the δ13CPDB values from 0 to +5o [1]. The primary 87Sr/86Sr of Dashka Formation (Oslyan Group) is 0.7057 - 0.7060 and δ13CPDB value varies in interval 3.7-4.3o like in upper part of Tungusik Group. High positive values of δ13CPDB indicate that carbonates had accumulated in warm sea

  14. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil; Teores de potassio, uranio, torio e taxa de producao de calor radiogenico no embasamento adjacente as bacias sedimentares de Camamu e Almada, Bahia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara Santos; Barbosa, Johildo Salomao Figueiredo [Instituto de Geociencias, Universidade Federal da Bahia, Salvador, BA (Brazil); Argollo, Roberto Max de, E-mail: nss@cpgg.ufba.br, E-mail: johildo@cpgg.ufba.br, E-mail: robmax@ufba.br [Laboratorio de Fisica Nuclear Aplicada, Instituto de Fisica, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2005-10-15

    The bedrock adjacent to Camamu and Almada sedimentary basins is characterized mainly by rocks of granulite and amphibolite facies, with archaean and paleoproterozoic ages, which belong to orogen Itabuna-Salvador-Curaca. The units in major proportion in this context are the metatonalites associated with basic and metamonzonites belonging to Itabuna belt. In smaller area occur the Teolandia granite and the Moenda granodiorite associated with the Ipiau band amphibolites, the charnockites and charnoenderbites of Jequie bloc, the neoproterozoic sienites and the mafic dikes. The K, U and Th contents of the rocks vary from 0,02 to 6,33% for K, from < 0,2 to 9,10 ppm for U and from < 0,4 to 64,38 ppm for Th. These contents are higher in the charnockites, Moenda granodiorite, Teolandia granite and sienites, intermediate in the metatonalites and metamonzonites and lower in the basic granulites. The heat production rates are higher in the lithologies where K, U and Th are also higher, varying from 0,58 to 5,57 {mu}W m{sup -3}. The coverage areas of such lithologies are, however, small compared with that of the metatonalitic granulites, metamonzonitic granulites and sienites where the rates vary from 0,10 to 1,44 {mu}W m{sup -3}, 0,23 to 5,55 {mu}W m{sup -3} and 0,60 to 2,24 {mu}W m{sup -3}, respectively. In this case, the heat production rates vary from 0,10 to 1,44 {mu}W m{sup -3}. The basic granulites have the smaller rates, from 0,06 to 0,36 {mu}W m-3. The observation of the lithologies in the margins of the two basins suggest that, in the bedrock under the younger sediments, may predominate the metatonalites, followed by the metamonzonites, with some significant participation of sienites in the Almada basin. In those lithologies, the volumetric heat production rates, with one standard deviation range, are 0,41 +- 0,30 {mu}W m{sup -3} for metatonalites, 0,71 +- 0,57 {mu}W m{sup -3} for metamonzonites and 1,20 +- 0,51 {mu}W m{sup -3} for sienites. (author)

  15. Sedimentary remagnetizations involving pyrrhotite and greigite (Invited)

    Science.gov (United States)

    Roberts, A. P.

    2013-12-01

    Late diagenetic growth of the ferrimagnetic iron sulfide minerals, monoclinic pyrrhotite and greigite, will give rise to remagnetizations of their host sediments. Sedimentary pyrrhotite formation has been the subject of much confusion in the paleomagnetic literature. Its growth is kinetically limited. Authigenic monoclinic pyrrhotite has, therefore, not been reported in modern sediments. If monoclinic pyrrhotite is present in modern sediments, it is likely to have a detrital origin, as has been demonstrated in marginal basins adjacent to denuding regional metamorphic orogenic belts. If authigenic monoclinic pyrrhotite occurs in sediments, it will carry a magnetization that was acquired much later than deposition. Identification of authigenic pyrrhotite should, therefore, lead an investigator to suspect that the sediment has been at least partially remagnetized. Iron sulfides have high electron backscatter and are easily investigated using electron microscopy. Microtextural observations of sedimentary pyrrhotite can often provide direct confirmation that the pyrrhotite formed during later diagenetic reactions (e.g., after sediment compaction). Greigite can also give rise to remagnetizations, but, unlike pyrrhotite, it can grow quickly, even within an anoxic water column before deposition. Multiple generations of greigite can also form even during early diagenesis. These possibilities make it more difficult to use electron microscopic observations to detect remagnetization mechanisms, although microtextural relationships with other minerals can still provide strong direct evidence for remagnetization. For both pyrrhotite and greigite, remagnetizations are generally detected using conventional paleomagnetic observations. These include detection of magnetic polarities that contradict those carried by coexisting detrital magnetic minerals and failure of paleomagnetic field tests (mainly the fold and reversal tests). An overview of the features associated with

  16. Paleogene-Neogene Sedimentary Facies and Sequence Stratigraphic Characteristics in Qixinghe Coal-bearing Basin, Heilongjiang%黑龙江七星河含煤盆地古近纪-新近纪沉积相及层序地层特征

    Institute of Scientific and Technical Information of China (English)

    商晓旭; 邵龙义; 马立军; 野兆瑞; 曲延林

    2014-01-01

    The Qixinghe Basin in eastern Heilongjiang is a Cenozoic coal accumulation basin. Its coal-bearing strata belong to Paleo-gene Baoquanling Formation and Neogene Fujin Formation. The Baoquanling Formation is comprised of siltstone, sandstone of various grain sizes, mudstone, carbonaceous mudstone and lignite;developed littoral-shallow lacustrine facies, deep-semideep lacustrine fa-cies, delta plain facies belong to lake sedimentary system, lake delta sedimentary system. The Fujin Formation is comprised of mud-stone, siltstone, medium-grained sandstone, pebbly coarse-grained sandstone, coal, carbonaceous mudstone and diatomite;developed littoral-shallow lacustrine facies, fan delta plain facies, belong to lake sedimentary system and fan delta sedimentary system respective-ly. Sequence SI is corresponding to Baoquanling Formation;developed lowstand system tract, lacustrine transgressive system tract and highstand system tract. Coal seams were mainly developed during middle to late stages of highstand system tract;coal-forming environ-ment was mainly littoral-shallow lacustrine silting bog. Sequence SII is corresponding to Fujin Formation;mainly developed lacustrine transgressive system tract, highstand system tract, locally lowstand system tract. Also, coal seams were mainly developed during middle to late stages of highstand system tract;coal-forming environment was mainly fan delta silting bog and littoral-shallow lacustrine silt-ing bog. During sequences SI, SII middle to late stages of highstand system tract, basin basement settlement rate and sediment supply were in a relatively balanced state, mainly developed fan delta silting bog, in littoral-shallow lacustrine and littoral-shallow lacustrine silting bog environments have developed mineable coal seams.%黑龙江省东部七星河盆地是一新生代聚煤盆地,其含煤地层为古近系宝泉岭组、新近系富锦组。宝泉岭组由各级砂岩、泥岩、炭质泥岩以及褐煤组成,发育滨浅

  17. Designing the deep basin development entity : drawing and expanding the boundaries of DE number 2 for enhanced exploitation of Alberta's deep basin tight gas resource

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, B. [Petrel Robertson Consulting Ltd., Calgary, AB (Canada); Conrad, L.; Daniel, S. [EnCana Corp., Calgary, AB (Canada); Dahlin, A. [Shell Canada Ltd., Calgary, AB (Canada)

    2009-07-01

    This presentation examined the feasibility of expanding the boundaries of Deep Basin Development Entity (DE no.2) for enhanced exploitation of Alberta's deep basin tight gas resource. Specifically it presented a review of the development history of the basin and summarized the technical understanding of DE no.2. The presentation also emphasized the success of a collaborative process for regulatory change between the Canadian Association of Petroleum Producers and the Energy Resources Conservation Board. The DE no. 2 is located in the western flank of the western Canada Sedimentary Basin. It facilitates commingling of multiple stacked sands and reduces the regulatory requirements for drilling and completion programs. It was expanded in 2009 to include 464 townships. Gas resource mapping was discussed for several areas and an example was illustrated for the Cadomin Formation, with particular reference to the net porous sand isopach; average porosity; gas saturation; temperature; reservoir pressure; and resource density. The future of DE no. 2 has been identified as one of the priority areas for Alberta regulatory review as that it holds 400 TCF of resource potential. tabs., figs.

  18. Offshore CO2-EOR:Worldwide Progress and a Preliminary Analysis on Its Potential in Offshore Sedimentary Basins off China%离岸二氧化碳驱油的国际进展及我国近海潜力初步分析

    Institute of Scientific and Technical Information of China (English)

    周蒂; 李鹏春; 张翠梅

    2015-01-01

    二氧化碳驱油( CO2-EOR)是一项通过向油层注入二氧化碳而提高石油采收率的技术,它能同时实现CO2的利用和封存,因此是CCUS的重要技术。近年来,随着离岸CO2封存需求的日益增大, CO2-EOR的应用正迅速从陆上扩展到海上。介绍了CO2-EOR的概念和适用条件,综述了国际上离岸CO2-EOR项目和技术,特别是“下一代”CO2-EOR技术的最新进展。通过与国外实例的对比和对盆地石油地质条件的分析,初步探讨了我国近海含油气盆地的CO2-EOR的潜力,认为渤海湾盆地(海域)和珠江口盆地分别具有非混相和混相CO2-EOR的潜力,有可能获得数亿吨石油的增产和实现数亿吨CO2的地下永久封存,需要尽快地开展进一步的研究和评估。%CO2-Enhanced Oil Recovery ( CO2-EOR) is a technique of enhancing oil recovery by injecting CO2 into oil reservoirs.It also realizes both CO2 utilization and CO2 storage and thus is an important technique in the CCUS chain.In recent decade the applica-tion of CO2-EOR is extended rapidly from inland to offshore, as a respond to the increasing demand for offshore CO2 storage.This paper briefed the concept and application conditions of CO2-EOR, and introduced worldwide projects and technical developments on offshore CO2-EOR, including the“Next Generation” CO2-EOR technology.A first-order preliminary review on the potential of CO2-EOR in offshore sedimentary basins off China was given for the first time based on comparison and analysis of petroleum geology of the basins.The Bohai Bay Basin ( offshore) and the Pearl River Mouth Basin are regarded as having the potential of non-miscible and miscible CO2-EOR, respectively.The CO2-EOR application in these basins might be able to bring several hundred million tons of in-cremental oil production and to store several hundred million tons of CO2 underground permanently.Further studies and evaluations are needed urgently.

  19. Thermal Fluid Flow in Sedimentary Basins and Its Significance to Pool-form ing Dynamics%沉积盆地热流体活动及其成藏动力学意义

    Institute of Scientific and Technical Information of China (English)

    叶加仁; 杨香华

    2001-01-01

    Based on the analysis and some typical data of petroleum basins in China and world, it discusses some important expression forms and majo r research methods of thermal fluid flow, and emphasized its enhancement to orga nic-matter maturation and hydrocarbon generation in this paper. According to t he major controlling factor, passage of fluid migration, to thermal fluid flow, it divides thermal fluid flow into four types: (1)lithologic-type, (2)conformity -t ype, (3)fault-type and (4) compound-type. Finally, it also discusses the sign ifi cance of thermal fluid flow to pool-forming dynamics:(1)provides a new ex planation way to abnormal vitrinite reflectance, which can enlarge the fields of hydrocarbon exploration and development; (2)provides some important evidences to research of hydrocarbon migration, which support to choose exploration targ e ts; and (3)provides means to study diagnesis and porosity evolution of reservo ir rocks, which can be used to predict the development units of deep reservoir s.%在分析、总结国内外一些含油气盆地的典型资料的基础上,论述了热流体活动的若干重要表现形式及主要研究方法,强调了热流体活动对有机质热演化和油气生成的强化作用。根据控制热流体活动的主要因素之一--流体活动通道,将沉积盆地内的热流体活动类型划分为岩性型、不整合型、断裂型和复合型四大类。最后,探讨了热流体活动对成藏动力学研究的重要意义,认为其可为有机质演化异常提供新的成因解释途径,扩大油气勘探领域;为油气运移的研究提供线索,优化勘探目标选择;为成岩-孔隙演化的动态研究提供依据,预测深部储层发育层段。

  20. Deep controls on intraplate basin inversion

    DEFF Research Database (Denmark)

    Nielsen, S.B.; Stephenson, Randell Alexander; Schiffer, Christian

    2014-01-01

    Basin inversion is an intermediate-scale manifestation of continental intraplate deformation, which produces earthquake activity in the interior of continents. The sedimentary basins of central Europe, inverted in the Late Cretaceous– Paleocene, represent a classic example of this phenomenon. It ...

  1. Estudo florístico do componente herbáceo e relação com solos em áreas de caatinga do embasamento cristalino e bacia sedimentar, Petrolândia, PE, Brasil Herbaceous floristic study and relationship with soil of crystalline shield and sedimentary basin caatinga areas at Petrolândia, Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Kleber Andrade da Silva

    2009-03-01

    Full Text Available Realizou-se um levantamento florístico em áreas de caatinga do embasamento cristalino e de bacia sedimentar, em Petrolândia, Pernambuco, objetivando-se identificar diferenças na composição, hábito e forma de vida das herbáceas entre as duas áreas. Foram coletadas amostras de solo nas profundidades de 0 a 20 cm e de 20 a 40 cm. Foram estabelecidas 100 parcelas de 1×1 m em cada área e coletadas todas as espécies herbáceas. De modo geral, o solo da área do embasamento cristalino foi mais fértil, raso, com maior capacidade de reter água e maior porcentagem de argila. Os números de famílias, gêneros e espécies das áreas da bacia sedimentar e do embasamento cristalino foram 32, 62 e 78 e 31, 53 e 69, respectivamente. A similaridade florística entre as áreas foi alta (75%. A análise de agrupamento mostrou que os arranjos florísticos entre as parcelas amostradas são mais semelhantes dentro de cada área que entre áreas, sugerindo a existência de grupos distintos. Tipo de solo parece não ser um fator decisivo na similaridade florística, hábito e proporção de forma de vida das herbáceas da vegetação da caatinga quando as áreas são próximas, mas pode influenciar a ocorrência e a freqüência de algumas espécies.Floristic surveys were carried out in two close caatinga areas, one on the crystalline shield and the other on a sedimentary basin, both at Petrolândia, Pernambuco, Brazil, with the objective of identifying differences between the two areas in composition, habit and life form of the herbaceous flora. One hundred 1×1 m plots were established in each area and all the herbaceous species were identified. Soil samples were collected at 0-20 and 20-40 cm depths. In general, the soil in the crystalline shield area was shallower, had greater clay content, with higher water holding capacity, and was more fertile. The number of families, genera and species in the sedimentary basin and crystalline shield areas were 32

  2. 北部湾盆地涠西南凹陷WZ油田古近系流沙港组一段沉积相%Sedimentary facies of the Member 1 of Paleogene Liushagang Formation of WZ Oilfield in Weixinan Sag, Beibuwan Basin

    Institute of Scientific and Technical Information of China (English)

    杨玉卿; 崔维平; 蔡军; 许月明

    2012-01-01

    The Member 1 of Paleogene Liushagang Formation is the major oil-bearing formation of WZ Oilfield in Weixinan Sag of Beibuwan Basin. The actual drilling results demonstrated its complex origin types, obvious change of sandbody thickness and strong heterogeneity of the reservoir which resulted that not only forecast of sandbody distribution is very difficult, but also the development result is greatly restricted. Sedimentary facies of the Member 1 of Liushagang Formation of WZ Oilfield is finely studied based on cores observation and analysis, in combination with the data of well logging and masterlog, the results show that it is dominated by steep slope fan delta of fault-depressional lacustrine basin, which is mainly the fan delta front subfacies containing abundant gravity flow sediments. The fan delta front subfa-cies can be subdivided into subaqueous distributary channel, mouth bar, distant bar and interchannel mi-crofacies. The gravity flow sediments include gravity slump, debris flow, turbidity flow and fluidized flow, which are all generally small scale. The sedimentary microfacies maps of the key oil units of IV interval and II interval of the Member 1 of Liushagang Formation are made by ingoing interpretation of the sedimentary microfacies on a single-well section and fine multi-well correlation. According to the maps the whole sedimentary framework of the area is a stable fan dela front and the provenances are from north and northwest. The gravity flow deposits are common from fan delta front to prodelta areas because of steep slope. Moreover, the depositional model of deeper water of steep slope fan delta is established based on characteristics and distribution of microfacies. Analysis of physical property and oil potential of the different microfacies sandbody shows that the subaqueous distributary channel is the best, mouth bar is better, distant bar and distannurbidite are bad. A favorable development area and an adjustment well are proposed which

  3. Organic geochemistry of the Callovo-Oxfordian argillo-carbonated sedimentary series of the East of the Paris basin and of England. Variabilities and paleo-environmental implications; Geochimie organique des series argilo-carbonatees du Callovo-Oxfordien de l'Est du bassin de Paris et d'Angleterre: Variabilites et implications paleoenvironnementales

    Energy Technology Data Exchange (ETDEWEB)

    Hautevelle, Y

    2005-12-15

    The Callovo-Oxfordian clay-stones from the East of the Paris basin are studied by ANDRA in order to test the feasibility of a possible storage of radioactive waste. The molecular analysis of their organic matter indicates that they can be considered as homogenous from their organic content point of view because they are characterized by only one molecular facies. However, the transition to the surrounding limestones is underlined by a major evolution of the molecular facies indicating a change and an increase of the variability of the deposition and diagenesis conditions. The evolution of the distribution of the plant bio-markers indicates, at the end of the Lower Oxfordian, a paleo-floristic change characterized by the increase of the proportion of Pinaceae (a conifer family) or their forerunners on the London-Brabant massif. This paleo-floristic evolution reflects a paleo-climatic change characterized by the increase of aridity at the global scale. Other complementary results get on other sedimentary series of similar ages highlight the occurrence of a period of water anoxia during the Middle Callovian which certainly happened on the major part of the Western Europe. This event could be at the origin of the crisis of the carbonate production at the Dogger/Malm transition. On the other hand, an experimental technique based on artificial maturation of extant plants has been developed and will allow the acquisition of new palaeo-chemo-taxonomic data. These data will contribute to a better interpretation of plant bio-marker assemblages in terms of palaeo-floristic composition. (author)

  4. 含油气盆地矿产资源规划研究的思考--以M沉积盆地为例%Thoughts on the Research of Mineral Resource Planning of Petroliferous Basins-Taking M Sedimentary Basins as an Example

    Institute of Scientific and Technical Information of China (English)

    王步清; 董煜; 王尧

    2013-01-01

      含油气盆地的油气勘探开发进展较大,但固体矿产勘查评价相对较弱,有必要开展盆地矿产资源规划研究。以M盆地为例,探讨该盆地矿产资源规划研究的相关问题,尝试对盆地东北缘进行规划区块划分,并提出该区域勘探开发时序、矿业权设置模式和兼探兼采等建议。%Great progresses has made in oil and gas exploration and development in the petroliferous basin,but solid mineral exploration evaluation is relatively weak. Therefore, it is necessary to carry out the research on mineral resource planning of the basins. This paper focuses on the relevant problems concerning mineral resource planning in M Basin. It makes an attempt on block subdivision in northeastern edge of M Basin. Some suggestions on the sequence of exploration and exploitation, the mode for setting mining rights, and both exploration and exploitation of many kinds of mineral resources in this area are also made.

  5. Geodynamic evolution of the West Africa between 2.2 and 2 Ga: the Archaean style of the Birimian greenstone belts and the sedimentary basins in northeastern Ivory-Coast; Evolution de l`Afrique de l`Ouest entre 2,2 Ga et 2 Ga: le style archeen des ceintures vertes et des ensembles sedimentaires birimiens du nord-est de la Cote-d`Ivoire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, M.; Pouclet, A. [Orleans Univ., 45 (France); Delor, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Simeon, Y. [ANTEA, 45 - Orleans (France); Alric, G. [Etablissements Binou, 27 - Le Mesnil-Fuguet (France)

    1996-12-31

    The litho-structural features of Palaeo-proterozoic terrains of northeastern Ivory-Coast, greenstones belts and then sedimentary (basin Birimian), are similar to those of Archaean terrains. Their early deformation is only voluminal deformation due to granitoid intrusions, mainly between 2.2 and 2.16 Ga. The shortening deformation (main deformation) is expressed by right folds and transcurrent shear zones ca 2.1 Ga. Neither thrust deformation nor high pressure metamorphic assemblages are known. This pattern of flexible and hot crust, at least between 2.2 and 2.16 Ga, is pole apart to a collisional pattern, proposed for West African Craton by some authors. The Archaean/Palaeo-proterozoic boundary would not represent a drastic change of the geodynamic evolution of the crust. (authors). 60 refs., 5 figs., 6 photos.

  6. Sedimentary facies of dinosaur trackways and bonebeds in the Cretaceous Jiaolai Basin, eastern Shandong, China, and their paleogeographical implications%山东胶莱盆地白垩纪恐龙足迹与骨骼化石埋藏沉积相与古地理环境

    Institute of Scientific and Technical Information of China (English)

    柳永清; 旷红伟; 彭楠; 许欢; 刘燕学

    2011-01-01

    The core issue of taphonomy is to study the sedimentary facies of fossil-bearing rocks, reconstruct their depositional environments, and understand the paleogeographical background before and after the burying of fossils at different scales. One of current taphonomy interests focuses on the mass extinction or bonebeds of dinosaurs, including their paleogeography, paleoenvironment and preservation. Numerous Jurassic and Cretaceous dinosaur fossil sites have been discovered in China, making it number 1 in the world in terms of richness of dinosaur genera and species. The terrestrial Cretaceous Laiyang, Qingshan and Wangshi groups (130-65 Ma), in ascending order, are widely distributed in Jiaolai Basin of eastern Shandong Province, China. Litho-logically, the Early Cretaceous Laiyang Group consists of fluvial and lacustrine sediments and the Early Cretaceous Qingshan Group is mainly composed of medium or acid volcanic rocks and pyroclastic rocks interbeded with sedimentary rocks. The Late Cretaceous Wangshi Group is mainly deposits of alluvial fan, mud flow and braided-channel facies in the lower part; shallow lacustrine deposits and rhythmic fluvial sediments of mud-stone, siltstone, sandstone or soils (palesoil) in the middle part; and rhythmic depositions of silty-muddy conglomerate, sandstone and siltstone of mud flow, braided-channel and flooding plain facies, locally interbeded with basalt in the upper part. Sedimentary successions and facies associations of the Cretaceous Jiaolai Basin indicate an evolution of basin and sedimentary paleogeography, I. E. , from alluvial-lacustrine environment in humid and warm climate in the Early Cretaceous to an alluvial environment in hot and drought climate towards the Late Cretaceous. Biota of the Early Cretaceous in Jiaolai Basin is identical to the Jehol Biota in the northern areas of North China. In the Laiyang Group, a plentiful of dinosaur (theropod, sauropod and ornithopod) footprints were excellently preserved, as

  7. Terminal Fluvial Systems in a Semi-arid Endorheic Basin, Salar de Uyuni (Bolivia)

    NARCIS (Netherlands)

    Li, J.

    2014-01-01

    Many ancient sedimentary basins are interpreted as endorheic basins, internally drained basins with no direct hydrological connection to the marine environment. Some of these endorheic basins are economically important because of the abundance of hydrocarbon resources. To date, many studies have bee

  8. Complexity and Geodynamics of Ore-accumulating Basins in the Qinling Orogenic Belt, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Researches were made of different continental-margin and intraplate basin systems in the Qinling microplate in terms of hydrothermal deposition, geodynamics of basin formation, hydrothermal sedimentary rock facies, syntectonics in the basins, and the styles of ore accumulation in the basins.

  9. Geochemical characteristics of Paleogene sandstones in Nangqen basin and their implications for provenance and sedimentary environments%囊谦古近纪盆地砂岩地球化学特征及其对物源和沉积环境的指示作用

    Institute of Scientific and Technical Information of China (English)

    杜后发; 姜勇彪; 侯增谦; 严兆彬; 郭福生; 郭国林

    2011-01-01

    Geochemical characteristics of detrital sandstones provide an extremely important trace and indication for provenance, paleoclimate, depositional environment and properties of source rock. On the basis of field geological investigation, the authors studied the characteristics of trace and rare elements of the sandstones and probed into the features of depositional environment, paleoclimate and provenance by analyzing the change of the trace and rare element components of the sandstones. Sampling was conducted along the section of well-developed outcrops, and the weathered and altered samples were rejected under a microscope. The trace element content of sandstone samples collected from Gonjo Formation was determined by inductive coupling plasma mass spectrometry (ICP-MS). The sedimentary environment and properties of the source region of the sandstones in the Gonjo Formation were also investigated by means of ratios of Sr/Ba, Ce/Ce* , Th/Sc, Th/U and La/Th as well as graphic interpretation of depositional structure background and cross-analysis of such multiple parameters as La/Sc - Co/Th, Th - Hf - Co, Th/Sc - Sc and La/Yb -DREE. The results show that cerium was subjected to deficiency, and that the physicochemical properties of water bodies belonged to the oxide environment, becausethe ratio of Ce/Ce* is between 0.80 and 0.93, and the index of Ceanom is between -0.34 and -0.5. The values of deep source elements in trace elements are lower than the average value of earth crust claystone, which indicates that the sources of sediments were mainly derived from terrestrial material. Terrestrial elements and the average of earth crust clayrock are evenly matched, which reflect high deposition rate. The ratios of trace elements show obviously that the sedimentary environments were of fresh water quality, oxidizing environments and arid torrid climate during the period of the deposition of Gonjo Formation in the Paleogene basin, with the further deposition of the

  10. 利用等效孔隙度法恢复沉积盆地残余地层古厚度——以济阳坳陷惠民凹陷为例%Paleo-thickness recovery of residual strata in sedimentary basin by equivalent porosity methodcase of Huimin depression

    Institute of Scientific and Technical Information of China (English)

    郭颖; 倪金龙

    2012-01-01

    In order to raise the calculation accuracy of the paleothicknesses of residual strata in sedimentary basin, we improve traditional method and provide the method of equivalent porosity for Mesozoie and Cenozoic on the premise of porosity and depth following the exponential relationship in the compressive process of strata. Firstly, according to the principles of sedimentary compaction and the data of cores and well logging, we divide the strata of every well into different compaction units and establish the compaction parameter table of different lithological strata in the study area; then, considering compaction unit beds as the homogeneous mass which came into being from the uniform sedimentation of different lithological strata, and determine initial porosity, compacting factor and offset constant and porosity-depth relationship model in lithological proportion; finally, we retrieve and compute the paleo-thickness of residual strata in the light of the conversion law of solid thickness of strata, the variation of ancient water depth and the relative position of compaction unit. The application to the residual strata of the third member of Shahejie formation (Es3) in Huimin depression by this method, which regulate the impact of different lithology, tectonic activity, abnormal compaction and paleo-depth to a certain extent, shows significantly smaller results than traditional method and has higher accuracy and reliability.%为了进一步提高沉积盆地残余地层古厚度的计算精度,对传统方法进行了改进,以地层压实过程中孔隙度与深度遵循指数关系为前提,提出了适用于中、新生代残余地层古厚度恢复的等效孔隙度法.首先,根据沉积压实原理,以钻井岩心和测井数据为基础,划分各井地层压实单元,并通过测试确定适用于研究区不同岩性地层的压实参数;然后,将地层压实单元等效看作不同岩性地层匀速沉降的均质体,按岩性比例确定各地层压实

  11. Diagenesis of sedimentary phosphorite deposits in Djebel Onk basin, Algeria

    DEFF Research Database (Denmark)

    Redjehimi, Hacène; Friis, Henrik; Boutaleb, Abdelhak

    affecting the Upper Paleocene phosphorites of the Djebel Onk include: (1) accumulation of phosphate grains, (2) compaction, (3) dolomite cementation, (3) minor amount of other diagenetic mineral cements: opal-CT, K-feldspar overgrowth, clinoptinolite and pyrite, (4) dissolution of dolomite crystals...

  12. Exploration Area and Potential of Natural Gas in Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    Yang Haibo; Chen Lei; Qian Yongxin; Li Chen

    2006-01-01

    @@ Junggar Basin, located in Northern Xinjiang between Altai and Tianshan Mountains, is the second largest basin in China with its sedimentary area being about 130,000square kilometers. A group of caprocks are developed over Carboniferous of the basin, including the Permian,Triassic, Jurassic, Cretaceous, Paleogene, and Neogene,among which the biggest sedimentary caprock is 15,000meters thick. The formation and accumulation of oil and gas in the basin can be characterized by multistage and multisource after undergoing multiperiod structural movements such as Late Hercynian, Indosinian,Yanshanian, and Himalaya, etc.

  13. 加拿大阿尔伯达盆地油砂开发状况和评价实践%Oil Sand Development Status and Evaluation Practice in Alberta Basin, Canada

    Institute of Scientific and Technical Information of China (English)

    赵鹏飞; 王勇; 李志明; 武静

    2013-01-01

    加拿大阿尔伯达盆地油砂资源丰富,Athabasca矿区是盆地中最大的油砂矿区,含油层段为白垩系Mannville组,矿区的目的层为潮汐环境下典型的曲流水道沉积.由于油藏曾发生生物降解作用,油矿地层沥青油黏度可达1×104~100×104 mPa·s.油砂开发主要采用露天开采和钻井开采方法,属钻井开采法的SAGD技术的机理是通过向油藏注入高温蒸汽,使固体沥青油变为可流动的原油,流入采油井筒中而被采出.连续油层厚度、隔夹层和气水层的分布以及水平井段的有效长度影响蒸汽腔的扩展和注汽效率.除考虑孔隙度、泥质含量、含油饱和度和电阻率外,SAGD开采方式下油砂的有效厚度识别标准还考虑连续油砂层、隔夹层和气水层的分布.油砂储量级别的确定,取决于储量的地质落实程度、资料获取情况和开发方案.%There is abundance of oil sand resources in Alberta Basin, Canada, where the Athabasca area is the largest one. The oil-bearing intervals in Athabasca area are located in Cretaceous Mannville Group, and the objective formation is typical meandering channel deposit in the tidal environment. As a result of occurrence of biodegradation, the reservoir oil viscosity is up to 1 X 104 ?100 X 104 mPa ?s. The main methods to develop the oil sands are open pit mining and drilling mining. SAGD technology belongs to drilling mining, whose mechanism is to inject high-temperature steam into the reservoir, so that the solid crude turns into flowing oil which flows into the wellbore to be produced. The expansion of steam chamber and the steam injection efficiency could be affected by the continuous reservoir thickness, interbed, gas/ water layer distribution and the net pay length in horizontal section. In addition to porosity, shale content, oil saturation and resistivity, the recognition standard of net pay thickness for SAGD technology should also consider the situation about continuous

  14. Noble gases in CH 4-rich gas fields, Alberta, Canada

    Science.gov (United States)

    Hiyagon, H.; Kennedy, B. M.

    1992-04-01

    The elemental and isotopic compositions of helium, neon, argon, and xenon in twenty-one CH 4-rich natural gas samples from Cretaceous and Devonian reservoirs in the Alberta, Canada, sedimentary basin were measured. In all but a few cases, radiogenic ( 4He, 40Ar, and 131-136Xe) and nucleogenic ( 21,22Ne) isotopes dominated. Based solely on the noble gas composition, two types of natural gas reservoirs are identified. One (Group B) is highly enriched in radiogenic-nucleogenic noble gases and varies little in composition: 3He /4He = 1.5 ± 0.5 × 10 -8, 40Ar /36Ar = 5000-6500 , 40∗Ar /4He = 0.10 , 136∗Xe /4He ~ 0.7 × 10 -9, and 21∗Ne /22∗Ne = 0.452 ± 0.041 (∗ denotes radiogenic or nucleogenic origin; all 4He is radiogenic). High nitrogen content with 4He /N 2 ~ 0.06 is also characteristic of Group B samples. The remaining samples (Group A) contain a radiogenic-nucleogenic component with a different composition and, relative to Group B samples, the extent of enrichment in this component is less and more variable: 3He /4He = 10-70 × 10 -8, 40Ar /36Ar Precambrian basement, consistent with a present-day mass flux into the overlying sedimentary basin. Inferred 40∗Ar /136∗Xe 4He ratios imply a basement source enriched in thorium relative to uranium and potassium (Th/U > 20). Combined, the overall lower total radiogenic-nucleogenic content of Group A reservoirs, the greater variability in composition, and the appearance of Group A noble gases in reservoirs higher in the sedimentary sequence relative to the underlying basement implies that the Group A radiogenic-nucleogenic noble gases are indigenous to the sediments. The most interesting aspect of the Group A noble gases are the very high 3He /4He ratios; ~ 10-70 times greater than expected if derived from average crust. The mantle, surface cosmogenic 3He production, cosmic dust, or production in a lithium-enriched environment as potential sources for the 3He excesses are evaluated. The present data set

  15. Red River Basin Mapping 2008-2010

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — This LiDAR data covers the Red River Basin with portions of ND, MN, SD and flows into Canada. The US Red River Basin boudnary covers 40,860 sqmi,with the additional...

  16. Plate tectonic setting and genetic types of gas (oil)-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    张一伟; 陈发景; 陆克政; 漆家福

    1997-01-01

    The plate tectonic setting and genetic types of the gas (oil)-bearing basins in China are studied. Based on the history of break-up and amalgamation of Pangea, the three tectonic evolutionary megastages can be divided and the sedimentary basins in China are classified as Palaeozoic and Meso-Cenozoic basins. The Palaeozoic gas(oil)-bearing basins are mainly located in intracratonic basins, on which different types of Meso-Cenozoic basins are superimposed, and located in cratonic marginal basins and aulacogens destroyed with a slight degree, (n contrast, the Mesozoic and Cenozoic gas (oil)-bearing basins mainly formed in extensional foreland and intracontmental shortening flexural basins.

  17. 鄂尔多斯盆地南部延7+8油层组滨浅湖滩坝体系沉积特征%Sedimentary characteristics of the shore-shallow lacustrine beach bar system of Yan 7+8 oil reservoirs in southern Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    王建民

    2013-01-01

    Retrograding sedimentary sequence and shore-shallow lacustrine beach bar system are developed in the Meso-zoic Jurassic Yan ’ an Formation in southern Ordos Basin ,and the latter has close paragenetic relationship with the mean-dering river delta around the lake basin of the Yan ’ an stage .Retrogradation and the destruction of the meandering delta provide clastic input for the development of the low-shallow lake beach bar system .During the depostion of Yan 7+8, An’ sai and Zhidan areas in the north of Shaaxi province were in shore-shallow lacustrine environment .Beach bar deposits were widely developed as the major part of sedimentation ,and can be divided into four microfacies types including beach sand,sand bar,sand sheet and mudstone .Generally,the beach bar sand bodies occur at the side of the river mouth and the flat open shore-shallow lake environment ,and are parallel with the lake shoreline .They are dominated by medium and fine sandstone,and have massive bedding ,wavy bedding,inclined wavy bedding and lenticular bedding ,etc.Beach sand is usually in sheet-like shape and is relatively thin.Bar sand,which is the most representative deposit of the beach bar system ,usually has banded shoreline-parallel distribution ,large thickness ,and lenticular shape on section ,reverse grading at the bottom and transgressive sequences in the middle and upper parts .A series of beach bar sandbodies superimposed with each other in different phases ,forming large-scale shoreline-parallel clustered reservoirs with high net-to-gross ratio . The mudstones of shore-shallow lake facies between the beach bars act as lateral barriers or overlying seals of the beach bar sandbodies .The sedimentary characteristics of the shore-shallow lacustrine beach bar system have significant influ-ences on reservoir development and oil/gas accumulation of the Yan ’ an Formation.%鄂南中生界侏罗系延安组发育退积型沉积层序及滨浅湖滩坝沉积体系;滨浅湖滩坝

  18. Geologic constraints on kinematic models and age of formation of the Amerasia Basin of the Arctic

    Science.gov (United States)

    Miller, E. L.

    2015-12-01

    A wealth of new geologic and geophysical data now exist for the Amerasia Basin, but the details of its age and the nature/kinematics of events that resulted in its formation remain elusive. Basement rock ages, detrital zircon signatures of sedimentary rocks, and sediment dispersal systems have been used to show how parts of the southern margin(s) of the Amerasia Basin (Arctic Alaska-Chukotka, AAC) match their rifted margin counterparts on the Eurasia and Canada side of the Amerasia Basin. Thus we know the approximate finite translations needed to restore the paleogeography of the Arctic, but not the kinematics involved. Important features of the Amerasia Basin that need to be explained in a model for its opening are the age and extent of the high Arctic LIP, the linearity of the strip of continental crust represented by the Lomonosov Ridge, its right angle intersection with the Canadian Arctic margin, and the directional fault patterns mapped bathymetrically and seismically across the Alpha-Lomonosov Ridge and surrounding seafloor. Across AAC, post-Early Cretaceous oroclinal bends provide insight into strike-slip components of deformation involved in opening of the Amerasia Basin: The Chukchi syntax offsets the Brooks Range in a right-lateral sense from Wrangel Island along the Herald Arch; right-lateral motion of Arctic Alaska with respect to the Chukchi Borderland during opening of the Canada Basin; right-lateral shear in Chukotka during 100 Ma magmatism; the tight bend in the northern Verkhoyansk, result of Cretaceous right-lateral shear. The land-based relationships imply a post-Early Cretaceous, younger than Barremian (~130 Ma) age for onset of magmatism and extension related to rifting and formation of the Amerasia Basin. At least two stages of extension are documented, with older E-W extension characterizing the longitude of the New Siberian Islands to Pevek, Russian Arctic, (ca.125 Ma to 100 Ma), with younger N-S extension superimposed on this system (ca

  19. Sedimentary environments of organic matter from Middle Permian source rocks in northern Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    MIAO Jianyu; KOU Hansheng; ZHOU Lifa; HAN Zhongyuan

    2006-01-01

    A systematic analysis of the inorganic and organic geochemistry of Middle Permian source rocks comprising carbonate rocks and mudstones was carried out, with samples collected from the outcrop and bore of the Junggar, Turpan and Ili basins in northern Xinjiang. This study confirmed that sedimentary parameters for an ancient water body, such as inorganic geochemistry and paleosalinity, have a close relation to the organic matter of source rocks. It is also disclosed that phytane predominance in the source rocks is mainly due to a reducing environment. Biomarkers, such as gammacerane and β-carotene, in the samples reflect a specific salinity in the sedimentary environments. Sedimentary zones with a strong reducing environment are more likely to produce deposits of primary organic matter, which will be buried and preserved contemporarily. Consequently, the source rocks are generally high in organic content and better in organic type than ordinary ones, and vice versa.

  20. Canada; Selected Issues

    OpenAIRE

    International Monetary Fund

    2000-01-01

    The issue of productivity growth in Canada has received considerable attention reflecting its marked slowdown since the early 1970s and concerns about its implications for Canadian competitiveness. To better understand productivity developments in Canada, it is useful to decompose total factor productivity (TFP) into investment-specific productivity change (ISP) and technologically neutral productivity change (TNP). The gap in manufacturing productivity growth between Canada and the United St...

  1. Petroleum geology of the Palo Duro Basin, Texas Panhandle

    International Nuclear Information System (INIS)

    The Palo Duro Basin, Permian Basin, Texas is an asymmetric, relatively shallow, intracratonic basin in the southern Texas Panhandle filled mostly by Mississippian, Pennsylvanian, and Permian sedimentary rocks. Although deeper and prolific prolific petroleum-producing basins adjoin it on the north (Anadarko Basin), south (Midland Basin), and east (Hardeman Basin), the Palo Duro Basin has produced remarkably small amounts of oil and gas to date. This is all the more noteworthy because the sedimentary sequence and rock types of the basin are similar to those of the adjacent basins. Analyses of the stratigraphic succession and structural configuration of the Palo Duro Basin suggest that adequate reservoir rocks, top-seals, and geologic structures are present. Most of the structures formed early enough to have trapped hydrocarbons if they were migrating in the rock column. Although additional work is under way to properly address the question of the petroleum source rocks, generation, and migration, the general absence of production in the basin may relate to an overall deficiency in hydrocarbon generation within the basin. Geologic information in this report will form part of the basis for further analysis and conclusions on hydrocarbon potential in the Palo Duro Basin

  2. Tectono-sedimentary processes at hyper-extended rifted margins: the Alpine and Pyrenean analogues

    Science.gov (United States)

    Masini, E.; Manatschal, G.; Mohn, G.; Tugend, J.

    2012-04-01

    The discovery of hyper-extended crust at deep-water rifted margins challenged the way of interpreting rifting and continental breakup. Indeed, syn-rift sedimentary basins, also referred to as either "supra-detachment basins" or "hyper-extended sag basins" are observed over thin hyper-extended crust that tapers oceanwards and is laterally replaced by exhumed subcontinental mantle. Studies performed off- and on-shore have shown that hyper-extended domains are formed by a complex interplay of exhumation faults leading to characteristic basin architectures. Despite of numerous interpretations of seismic sections across passive margins, the stratigraphic architecture of hyper-extended rift domains and their tectono-sedimentary evolution remain little understood. In this presentation, we present field-data from two well-preserved fossil hyper-extended domains exposed in the Alps and Pyrenees analogues that show some insights into the tectono-sedimentary evolution of hyper-extended rifted margins. Despite these two examples show a different sedimentary evolution, they exemplify how detachment systems can control accommodation space and sedimentary architecture. In both cases, the syn-rift sedimentary record can be studied in 3D allowing to evolutionary steps of supra-detachment basins to be identified. The study of these two field examples enables to identify key architectural elements of supra-detachment basins. These are detachment breakaway block and extensional allochthons, both controlling the first-order architecture of the basins. The former is the consequence of two successive low-angle detachment faults separated by a delaminated upper crustal block, whereas the latter results from the delamination of hanging-wall blocks and its emplacement over exhumed footwall. Exhumation along active detachment systems implies a very efficient creation of new real estate seafloor and results in a very specific stratigraphic record that includes from base to top: 1) a syn

  3. Structural Architecture and Evolution of Kumkuli Basin, North Tibet

    Institute of Scientific and Technical Information of China (English)

    He Bizhu; Xu Zhiqin; Jiao Cunli; Cui Junwen; Wang Shenglang; Wang Gonghuai; Li Zhaoyang; Qiu Zhuli

    2009-01-01

    Utilizing the new data of gravity, magnetic, and magnetotelluric survey, we analyzed the characteristics of the three geophysical attribute (gravity, magnetic, and resistivity) interfaces and the deep architecture and structure of Kumkuli basin. The research results can provide basic data for early basin structural study. From coupled basin and mountain system, analysis of the structure, and evolution of Knmknli basin, we found that there was zoning from north to south and from west to east. Kumkuli basin has three structural architecture layers including metamorphic crystallization basement, fold basement and sedimentary cover. Knmkuli basin can be divided into three structural units, two depressions, and one uplift. Structural evolution of the Kumkuli basin can be divided into five evolution stages, including Kumkuli microcontinent formed in Sinian-Ordovician, suture around Kumkuli basin formed in Eopaleozoic, retroarc foreland basin formed in Neopaleozoic, rejuvenated foreland hasin developed in Mesozoic, and strike slip and compression basin developed in Cenozoic.

  4. MESOZOIC-CENOZOIC INVERSION OFTHE TURPAN-HAMI BASIN, NORTHWEST CHINA

    Institute of Scientific and Technical Information of China (English)

    CaoDaiyong; QianGuangmo; ZhangPengfei; MeiMeitang; JinKuili; TangYuegang

    1996-01-01

    The Turpan-Hami basin, rich in coal and petroleum, is a superimposedbasin of three types basins in different tectonic environments. This coal, oil and gasbasin has undergone a complex tectonic-sedimentary evolution, in which two important stages were the negative inversion from a foredeep to a extensional basin duringEarly Mesozoic and the positive inversion to a thrust foreland basin in Late MesozoicEarly Cenozoic. The early normal faults residues are recognized with the addition oftectonic-sedimentary analysis to confirm the basin extension during Jurassic time andits tectonic inversion subsequently.

  5. Sedimentary characteristics and model of gravity flow in Triassic Yanchang Formation of Longdong Area in Ordos Basin%鄂尔多斯盆地陇东地区延长组重力流沉积特征及其模式

    Institute of Scientific and Technical Information of China (English)

    廖纪佳; 朱筱敏; 邓秀芹; 孙勃; 惠潇

    2013-01-01

    Sedimentary characteristics and depositionl model of Yanchang Formation of Longdong area in Ordos Basin were studied based on core, logging data and gravity flow theory. The gravity flow deposits of the area can be divided into turbidite, sandy debris flow sediment, muddy debris flow sediment and slump rock. The turbidite develops positive grading. The sandy debris flow sediment is characterized by freezing and massive deposition. The muddy debris flow sediment mainly contains muddy and a small number of sandy particles and clumps in its interior. The slump rock develops liquefied tectonic structure, such as convolute bedding. The differences of the development degree of gravity flow sediments are obvious. In terms of the number of drilling wells, the turbidite and sandy debris flow sediment are the major sedimentary types, and the muddy debris flow sediment is the less one. In terms of the single deposition thickness of gravity flow, the average thickness of sandy debris flow deposition is 0. 986 m. which is significantly higher than other types. The average deposition thickness of turbidite is the lowest, which is 0. 414 m. The gravity flow of the area is due to the slump of delta front sediments. The sandy debris flow sediment and turbidite are the main types of gravity flow deposits, followed by the slump rock and muddy debris flow sediment. The sandy debris flow sediment developed in deep-water area in front of the north-east delta front from meandering river. The turbidite mainly developed in deep-water area in front of the braided river delta front, whose provenance came from west, southwest and south. In terms of distribution area, the muddy debris-flow sediment and sandy debris flow sediment with mud gravel are very small in plane, and their distribution is not in a regular pattern.%利用岩心、测井资料和重力流沉积理论,系统研究了鄂尔多斯盆地陇东地区延长组重力流沉积特征及其沉积模式.该区重力流沉积物可

  6. Centimeter-scale sedimentary sequence description of Upper Cretaceous Nenjiang Formation (lower numbers 1&2) : Lithostratigraphy, facies and cyclostratigraphy, based on the scientific drilling (SK1) borehole in the Songliao Basin.%松辽盆地松科1井上白垩统嫩江组一、二段沉积序列厘米级精细刻画:岩性·岩相·旋回

    Institute of Scientific and Technical Information of China (English)

    高有峰; 王璞珺; 程日辉; 王国栋; 万晓樵; 吴河勇; 王树学; 梁万林

    2011-01-01

    中国白垩纪大陆科学钻探松科1井连续钻取嫩江组一、二段岩心长295.53m,岩心收获率为97.45%,是迄今获取的最连续完整的沉积记录。文章对此进行了厘米级沉积地质描述(分层厚度2~5cm)。嫩江组一、二段沉积时期与晚三冬早坎潘期对应。通过对松科1井嫩江组一、二段岩心的精细描述,揭示其岩性一岩相一旋回的沉积序列及其过程。嫩江组一、二段共识别出12种岩石类型,为半深湖一深湖亚相的白云岩沉积、泥灰岩沉积、灰质泥岩沉积、油页岩沉积、浊流沉积、深湖静水泥和火山灰沉积等7种沉积微相。在岩相序列上识别出5种共213个米级旋回(六级旋回)、54个五级旋回、12个四级旋回和2个三级旋回。连续的组段厘米级刻画为高精度沉积过程研究提供了可能,嫩江纽一、二段全井段取心对松辽盆地缺氧事件、烃源岩及湖海沟通事件的研究具有重要意义。该文的精细描述资料为今后相关的深入研究提供了迄今最精准的基本地质素材。%China Cretaceous Continental Scientific Drilling (CCSD) in the Songliao Basin, called SKI project, collected 295.53 m of the lower members 1&2 of Nenjiang Formation which correspond to the late Santonian to early Campanian. The borehole got a highly continuous core section with recovery of 97. 45%, that is the most complete and precise sedimentary records up to now in the basin. Thicknesses of the description can be as thin as 2 - 5 crn for the interbedding sequences. We described the sedimentary sequence, lithology, lithofacies and cyclic stratigraphy at the drilling spot in cm-scale. Twelve litho-types were recognized in the section. Sedimentary facies are pre- dominantly lacustrine that can be subdivided into seven microfacies including dolomite, marl, argillaceous limestone, oil shale, turbidite, deep lake mudstone and volcanic ash microfacies. The whole

  7. Characteristics and applications of isotopes in products from organic matter in sedimentary rocksby simulated thermal experiments

    Institute of Scientific and Technical Information of China (English)

    陈安定; 张文正; 徐永昌

    1995-01-01

    Isotopic compositions of carbon in the products obtained respectively from 25 sedimentary rocks at an early stage of maturation by the simulated thermogenetic hydrocarbons experiments have been determined. The fractional effect of methane carbon isotope during the thermal maturation of organic matter is observed. Based on the experimental data, the relative equations between δ13C and R0 were established and have been used for differentiation of origins of various kinds of natural gases in the Shan-Gan-Ning Basin.

  8. Direct stable isotope porewater equilibration and identification of groundwater processes in heterogeneous sedimentary rock.

    Science.gov (United States)

    David, Katarina; Timms, Wendy; Baker, Andy

    2015-12-15

    The off-axis integrated cavity output spectrometry (ICOS) method to analyse porewater isotopic composition has been successfully applied over the last decade in groundwater studies. This paper applies the off-axis ICOS method to analyse the porewater isotopic composition, attempts to use the isotopic shift in groundwater values along with simple geochemical mixing model to define the groundwater processes in the Sydney Basin, Australia. Complementary data included geophysical, hydrogeological, geochemical, and mineralogical investigations. Porewater from core samples were analysed for δ(18)O and δ(2)H from various sedimentary units in the Basin and compared to endpoint water members. Stable δ(18)O and δ(2)H values of porewaters in the Basin (-9.5 to 2.8‰ for δ(18)O and -41.9 to 7.9‰ for δ(2)H) covered a relatively narrow range in values. The variability in water isotopes reflects the variability of the input signal, which is the synoptic variability in isotopic composition of rainfall, and to a minor extent the subsequent evaporation. The porosity, bulk density and mineralogy data demonstrate the heterogeneity that adds the complexity to variations in the isotope profile with depth. The source of chloride in the sedimentary sequence was related to rock-water and cement/matrix-water interaction rather than to evaporation. The heterogeneous character of the sedimentary rock strata was supported by a change in pore pressures between units, density and variability in rock geochemical analyses obtained by using X-ray fluorescence (XRF) and X-ray power diffraction analyses. This research identified distinct hydrogeological zones in the Basin that were not previously defined by classic hydrogeological investigations. Isotopic signature of porewaters along the detailed vertical profile in combination with mineralogical, geochemical, geophysical and hydrogeological methods can provide useful information on groundwater movement in deep sedimentary environments. The

  9. Geophysical Estimation of Permeability in Sedimentary Media with Porosities from 0 to 50%

    OpenAIRE

    Díaz-Curiel Jesús; Biosca Bárbara; Miguel María Jesús

    2016-01-01

    The main objective of this study is to find a relationship between permeability and porosity, in the range 0 up to 50%, so that the permeability could be estimated only through geophysical parameters. This relationship should be consistent with the statistically expected values in sedimentary basins, and it should include the positive correlation between permeability and porosity in consolidated media and the negative correlation in unconsolidated ones. We have also developed another r...

  10. Petrography and sedimentology of Paleogene formations from Nathorstland, Spitsbergen: A diagenetic study of sedimentary facies associations

    OpenAIRE

    Vilberg, Anne Karin

    2011-01-01

    The studied Paleogene successions in the Central Basin Spitsbergen, comprises the Grumantbyen Formation, the Bjørnsonfjellet Member, Battfjellet Formation and the uppermost Aspelin toppen Formation. The objectives have been to describe the petrography and diagenesis relative to sedimentary facies associations. Another minor objective was to compare the reservoir quality of core and outcrop data. This have been done by description,facies interpretation and sampling from the Sysselmannsbreen co...

  11. Petrology and mineral chemistry of sedimentary rocks from the Western Solomon Sea

    Science.gov (United States)

    Crook, Keith A. W.

    1986-12-01

    Sedimentary rocks from the northern margin of the Trobriand Platform, the north wall of the New Britain Trench, and the floor of the Solomon Sea Basin are volcaniclastics, mudrocks, and neritic and bathyal limestones. Arc-volcanic debris from calc-alkaline or high-K magmatic sources is present at each locality. A minor metamorphic component occurs at one site on the Trobriand Platform which yielded Early Eocene to Middle Miocene material, and at the New Britain Trench site, which yielded Miocene or older and post-Miocene samples. Solomon Sea Basin samples are mudrocks which are apparently no older than Late Pliocene.

  12. Prediction of thermal conductivity of sedimentary rocks from well logs

    DEFF Research Database (Denmark)

    Fuchs, Sven; Förster, Andrea

    2014-01-01

    The calculation of heat-flow density in boreholes requires reliable values for the change of temperature and rock thermal conductivity with depth. As rock samples for laboratory measurements of thermal conductivity (TC) are usually rare geophysical well logs are used alternatively to determine TC...... equations is evaluated on subsurface data from four boreholes drilled into the Mesozoic sequence of the North German Basin, including more than 1700 laboratory-measured thermal-conductivity values. Results are compared with those from other approaches published in the past. The new approach predicts TC...... parameters (i.e. thermal conductivity, density, hydrogen index, sonic interval transit time, gamma-ray response, photoelectric factor) of artificial mineral assemblages consisting 15 rock-forming minerals that are used in different combinations to typify sedimentary rocks. The predictive capacity of the new...

  13. Volcanic and sedimentary-rock aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Volcanic and sedimentary-rock aquifers in the states of Montana, Wyoming, Idaho, Nevada, California, Oregon, and...

  14. Layer Formation in Sedimentary Fingering Convection

    CERN Document Server

    Reali, J F; Alsinan, A; Meiburg, E

    2016-01-01

    When particles settle through a stable temperature or salinity gradient they can drive an instability known as sedimentary fingering convection. This phenomenon is thought to occur beneath sediment-rich river plumes in lakes and oceans, in the context of marine snow where decaying organic materials serve as the suspended particles, or in the atmosphere in the presence of aerosols or volcanic ash. Laboratory experiments of Houk and Green (1973) and Green (1987) have shown sedimentary fingering convection to be simila