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Sample records for basins sedimentary

  1. Western Canada Sedimentary Basin competitiveness

    International Nuclear Information System (INIS)

    Recent dramatic expansion of the natural gas industry in the Western Canada Sedimentary Basin provided ample proof of the potential of this area for further development of natural gas supply. However, the inherent competitive advantages provided by the Western Canada Sedimentary Basin were said to have been offset by low netback prices resulting in poor producer economics when competitiveness is measured by availability of opportunities to find and develop gas supply at costs low enough to ensure attractive returns. Technology was identified as one of the key elements in improving basin competitiveness, but the greatest potential lies in reduced transportation costs and increased access to North American market centres. 8 figs

  2. Geodynamic evolution of sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Roure, F.; Ellouz, N.; Shein, V.S.; Skvortsov, I.I. [eds.

    1996-12-01

    This volume constitutes the proceedings of a conference held in Moscow in 1992, and organized by the Institut Francais du Petrole (IFP), the IGIRGI and VNIGNI Russian institutes under the auspices of the Russian Ministries of Fuels and Energy, Ecology and Nature. Geological features of the CIS countries, especially Russia, have driven their geologists` interest to specific questions as the petroleum potential of Proterozoic series, the resources located at a depth of 5000 m and more, or the impact of recent deformations on petroleum exploration and production. From the 27 papers of this conference, only 16 were selected which deal with oil and natural gas fields or coal deposits and geologic traps in the extensional and compressional basins of the CIS republics or in their western counterparts, or with physical and numerical structural models and other modeling techniques used for petroleum potential appraisal in sedimentary basins. The other papers deal with thematic aspects of basin formation in general or in specific areas with no reference to hydrocarbon genesis. (J.S.).

  3. 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...

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Sedimentary characteristics of cretaceous in northwestern Ordos basin

    International Nuclear Information System (INIS)

    Based on the integration of previous research achievements and combined with results of field geological investigation, and analysis and determination of samples, as well as the indoor comprehensive study, the paleoclimate characteristics, indications of sedimentary facies, the direction of paleocurrent and the provenance, as well as sedimentary facies and depositional systems of Zhidan Group, Lower Cretaceous in northwestern Ordos basin are systematically analyzed in the framework of the basin evolution. Authors come to a conclusion that sediments of Zhidan Group are mainly of lacustrine and fluvial facies. On the above basis types and features of sand bodies developed in Zhidan Group, Lower Cretaceous are summarized and the potential of uranium ore-formation in different types of sand bodies is discussed.Finally, deltasand bodies of Huachi-Huanhe Formation are thought to be favorable for the formation of sandstone type uranihm deposits. (authors)

  12. Modelling depositional shifts between sedimentary basins: Sediment pathways in Paratethys basins during the Messinian Salinity Crisis

    OpenAIRE

    J. Bartol; L. Matenco; D. Garcia-Castellanos; K. Leever

    2012-01-01

    The evolution of sedimentary basins separated by uplifted topographic barriers is characterised by gradual regressive deposition until one of the basins is filled and its sedimentation bypasses to the adjacent basin, defining a depositional shift. One of the critical parameters controlling these depositional shifts is sea level variation, its drop potentially triggering a depositional shift by cancelling the available accommodation space. Conversely, a sea level rise can create new accommodat...

  13. Regional heat flow patterns in the Western Canadian Sedimentary Basin

    Science.gov (United States)

    Majorowicz, J. A.; Jessop, A. M.

    1981-04-01

    The regional geothermal pattern of the Western Canadian Sedimentary Basin has been studied using available temperature data from wells. Average heat conductivity for various geological formations has been estimated on the basis of net rock studies by Canadian Stratigraphie Services. These data and observations of temperature made in "shut-in holes" in some of the oil pools have been used in heat flow estimations by the Bullard method. The geothermal gradient and heat flow within the basin are exceptionally high in comparison with the other world wide Precambrian platform areas. Especially high geothermal gradient areas are found in the northwestern part of the Prairies Basin in Alberta and British Columbia and most of southeastern and southwestern Saskatchewan. Areas of low gradient are found mainly in the Disturbed Belt of the Foothills, southern and southeastern Alberta, and the Peace River area in British Columbia. Neither the analysis of regional heat conductivity distribution nor the heat generation distribution of the basement rock of the Prairies Basin evaluated on the basis of U, Th and K data after Burwash (1979), explain the observed heat flow patterns of the Prairies Basin. Comparison of heat flow patterns with some of the hydrogeological phenomena suggests the significant influence of fluid flow in the basin formations on geothermal features. Low geothermal gradient areas coincide with water recharge areas and high hydraulic head distribution regions. The phenomenon of upward water movement in the deep strata and downward flow through much of the Cenozoic and Mesozoic strata seems to control the regional heat flow distribution in the basin. The analyses of coal metamorphism in the upper and middle Mesozoic formations of the Foothills Belt and in the central Prairies Basin suggest that the pre-Laramide paleogeothermal heat flow distribution was different from the present one. It is very probable that the Foothills Belt area was characterized by a higher

  14. Basin analysis and modeling of the burial, thermal and maturation histories in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Makhous, M.; Galushkin, Y.

    2004-11-01

    This book is devoted to the field of basin analysis, and in particular to the one- and two-dimensional modeling of the burial, thermal and maturation histories of sedimentary basins, in the context of evaluating their hydrocarbon potential. A new modeling system is elaborated in this work and applied to continental basins. Particular attention is paid to specific features of basin evolution, including the compaction of sediments deposited at a variable rate, erosion of the sedimentary strata and basement, intrusive and hydrothermal activity, thermal activation and reactivation of the basement, lateral heat exchange of multiple-aged blocks of the oceanic and continental lithospheres, the jumping of spreading axes, etc. Alternative methods are applied for the control of tectonic subsidence, isostasy and rheology, lithosphere stretching and thinning. In order to evaluate their respective contributions to the thermal history of basins, a variety of situations are modeled, including spreading jumping, the evaluation of erosion heat, its impact on thermal history and links to pre- and post-sedimentation history, intrusion activity, and the formation and degradation of cryolitic zones (permafrost) in high-latitude basins of the Northern and Southern Hemispheres. A joint analysis of heat flow transfer in the sedimentary cover and the underlying lithosphere and asthenosphere is applied to better reconstruct their thermal and maturation histories. To further enhance the model's validity, an additional powerful control tool is applied, based on the coincidence of two calculations of tectonic curve subsidence of the basement surface, obtained by two independent approaches: back-stripping and temperature-dependant density distribution in the crust. This approach is also used to refine the simulation sequence for tectonic and thermal events in the history of sedimentary basins. Contents: 1. The Geodynamic Setting and Some Geomechanical Aspects of the Initiation and

  15. Sedimentary basin analysis using airborne gravity data: a case study from the Bohai Bay Basin, China

    Science.gov (United States)

    Li, Wenyong; Liu, Yanxu; Zhou, Jianxin; Zhou, Xihua; Li, Bing

    2015-12-01

    In this paper, we discuss the application of an airborne gravity survey to sedimentary basin analysis. Using high-precision airborne gravity data constrained by drilling and seismic data from the Bohai Bay Basin in eastern China, we interpreted faults, structural elements, sedimentary thickness, structural styles and local structures (belts) in the central area of the Basin by the wavelet transform method. Subsequently, these data were subtracted from the Bouguer gravity to calculate the residual gravity anomalies. On this basis, the faults were interpreted mainly by linear zones of high gravity gradients and contour distortion, while the sedimentary thicknesses were computed by the Euler deconvolution. The structural styles were identified by the combination of gravity anomalies and the local structures interpreted by the first vertical derivative of the residual gravity. The results showed evidence for seven faults, one sag and ten new local structure belts.

  16. Realistic modelling of observed seismic motion in complex sedimentary basins

    International Nuclear Information System (INIS)

    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 total energy of ground motion, determined from our numerical simulation in Rome, is in very good agreement with the distribution of damage observed during the Fucino earthquake. For epicentral distances in the range 50km-100km, 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 permit the estimate of the maximum and average spectral amplification for specific sites, i.e. are a very powerful tool for accurate micro-zonation. (author). 38 refs, 19 figs, 1 tab

  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. Radon distribution in groundwater of the Po sedimentary basin (Italy)

    International Nuclear Information System (INIS)

    222Rn in groundwaters from some areas of the Po sedimentary basin characterized by different hydrological conditions has been determined by alpha-ray activity. Aquifers of three different lithological domains have been considered: (a) an Apennine one, mainly sedimentary (Emilia); (b) an Alpine one, predominantly igneous acid-subacid (Lombardy); and (c) another Alpine one, mainly calcareous (Verona plain). In the first two areas, recent continental waters, waters with a long residence in the aquifers (paleowaters) and sodium chloride waters formed by squeezing of underlying marine sediments have been investigated. In the Verona area, thermal waters coming from deep fissured carbonate formations were analyzed. Rn content is significantly different in the various areas (averages: Lombardy plain, 392; Emilia upper plain, 291; Emilia lower plain, 142; sodium chloride waters, 160; paleowaters, 168 pCi/l). For the Verona thermal waters, the Rn values correlate with temperature and geothermal indicators (SiO2, etc). Hydrodynamic parameters within the aquifers seem to control the Rn distribution in groundwaters circulating in unconsolidated sediments. Factors governing the generation of 222Rn in the rock grains as well as parameters and processes contributing to its transport into the circulating fluids are discussed. Besides known parameters the effect of water molecules, bonded to solid-fluid interfaces on the Rn concentation in the fluids is considered. The release of Rn from these molecules into the circulating fluids is discussed in relation to fluid movement and temperature. (Auth.)

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. Lithofacies-paleo-geography and uranium sedimentary facies in Hailar basin

    International Nuclear Information System (INIS)

    Cretaceous-Tertiary sedimentary paleo-structure and lithofacies-paleo-geography in Hailar Basin are described. Taking Chenqi coal field as an example, the sedimentary facies pattern of coal-bearing series characterized by alternating sedimentation of fluviatile and lacustrine-swampy facies is reconstructed. It is pointed out that this sedimentary facies not only controls the sedimentation and distribution of syngenetic uranium mineralization, but also is a favourable place that converges uranium-bearing solution and reduces and precipitates uranium for the second time in epigenetic mineralization

  5. Tectono-sedimentary evolution of Erlian basin since late mesozoic and sandstone-hosted uranium metallogenesis

    International Nuclear Information System (INIS)

    Various mineral resources in a basin are associated with its tectono-sedimentary evolution. Based on the analysis of the tectono-sedimentary evolution of Erlian basin, three evolutional stages of Erlian basin are classified, they are: the continental extensional down-faulting stage, the transitional stage from down-faulting to down-warping in Early Cretaceous, and slightly compressional differentiated uplifting-subsidence since Late Cretaceous. According to the mechanism of sandstone-hosted uranium metallogenesis it is suggested that the grey clastic rock series deposited at the stage of down-faulting down-warping transition must be the important target for uranium prospecting, and the differentiated uplifting-subsidence offers necessary conditions for sandstone-hosted uranium ore-formation. Then, types of uranium mineralization that could occur in Erlian basin are discussed, and uranium metallogenic model has been preliminarily summarized. (authors)

  6. 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.

  7. Postseismic deformation and body forces shaping the Apennines and adjacent sedimentary basins in Umbria-Marche

    Directory of Open Access Journals (Sweden)

    A. Aoudia

    2008-06-01

    Full Text Available The geodynamic complexity of the Apennines and adjacent sedimentary basins in Umbria-Marche (North-Central Italy makes the dynamics of the present day deformation and its relationships with the seismicity less well understood. In this paper, we argue that, further to buoyancy forces, postseismic deformation of earthquakes taking place on the Apennines contributes to the regional deformation. We investigate the interaction between the normal faulting system responsible of the 1997 Umbria-Marche earthquake sequence (Colfiorito fault and the low angle normal faulting system bordering the sedimentary basins, namely the Altotiberina fault. We set-up a 2D finite element model of the lithosphere-asthenosphere accounting for lateral heterogeneities and investigate how this heterogeneous structure is capable of localizing strain under the Umbria-Marche sedimentary basins, providing a way for the Colfiorito fault to influence the evolution of the Altotiberina fault. We show how the two different length and time scale processes, namely postseismic deformation and buoyancy, are complementary in shaping the Apennines and adjacent sedimentary basins. The high resolution deformation patterns modeled in this study can hardly be reproduced by a model accounting only for external forces such as a rotating or subducting or retreating Adria.

  8. Thermal history of sedimentary basins of the Czech Republic and its relation to tectonic processes

    Czech Academy of Sciences Publication Activity Database

    Šafanda, Jan; Suchý, V.; Sýkorová, Ivana; Stejskal, M.; Filip, Jiří; Machovič, V.; Borecká, Lenka; Dobeš, P.

    11 (128) (2003), s. 45-54. ISSN 1212-1576 R&D Projects: GA AV ČR IAA3012703; GA AV ČR IBS3046004 Institutional research plan: CEZ:AV0Z3013912; CEZ:AV0Z3012916 Keywords : thermal history * tectonics * sedimentary basins Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  9. Diagenesis of sedimentary phosphorite deposits in Djebel Onk basin, Algeria

    DEFF Research Database (Denmark)

    Redjehimi, Hacène; Friis, Henrik; Boutaleb, Abdelhak

    have been formed by diagenetic processes. Based upon on the environment of deposition for the phosphate grains, the detailed Petrographic analysis using back scattered electron (BSE) imaging, and taking into account the paleogeography of Djebel Onk basin. The following main diagenetic processes...

  10. 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.

  11. 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.

  12. 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

  13. Fluvial geomorphic elements in modern sedimentary basins and their potential preservation in the rock record: A review

    Science.gov (United States)

    Weissmann, G. S.; Hartley, A. J.; Scuderi, L. A.; Nichols, G. J.; Owen, A.; Wright, S.; Felicia, A. L.; Holland, F.; Anaya, F. M. L.

    2015-12-01

    Since tectonic subsidence in sedimentary basins provides the potential for long-term facies preservation into the sedimentary record, analysis of geomorphic elements in modern continental sedimentary basins is required to understand facies relationships in sedimentary rocks. We use a database of over 700 modern sedimentary basins to characterize the fluvial geomorphology of sedimentary basins. Geomorphic elements were delineated in 10 representative sedimentary basins, focusing primarily on fluvial environments. Elements identified include distributive fluvial systems (DFS), tributive fluvial systems that occur between large DFS or in an axial position in the basin, lacustrine/playa, and eolian environments. The DFS elements include large DFS (> 30 km in length), small DFS (discharge through climatic variability or tectonic processes. We demonstrate that rivers on DFS commonly decrease in width down-DFS caused by infiltration, bifurcation, and evaporation. In proximal areas, channel sands are amalgamated through repeated avulsion, reoccupation of previous channel belts, and limited accumulation space. When rivers flood on the medial to distal portions of a DFS, the floodwaters spread across a large area on the DFS surface and typically do not re-enter the main channel. In these distal areas, rivers on DFS commonly avulse, leaving a discrete sand body and providing high preservation potential for floodplain deposits. Additional work is needed to evaluate the geomorphic character of modern sedimentary basins in order to construct improved facies models for the continental sedimentary rock record. Specifically, models for avulsion, bifurcation, infiltration, and geomorphic form on DFS are required to better define and subsequently predict facies geometries. Studies of fluvial systems in sedimentary basins are also important for evaluating flood patterns and groundwater distributions for populations in these regions.

  14. 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.

  15. 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.

  16. 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

  17. Palynostratigraphy of the Erkovtsy field of brown coal (the Zeya-Bureya sedimentary basin)

    Energy Technology Data Exchange (ETDEWEB)

    Kezina, T.V.; Litvinenko, N.D. [Amur State University, Blagoveshchensk (Russian Federation)

    2007-08-15

    The Erkovtsy brown coal field in the northwestern Zeya-Bureya sedimentary basin (129-130{sup o}E, 46-47{sup o}N) is structurally confined to southern 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 (data of 1998 by M.A. Akhmetiev and S.P. Manchester). 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, Mukhino, Buzuli, and Sazanka formations.

  18. 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.

  19. 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.

  20. Comparison of metallogenic conditions for sandstone-type uranium deposit between Erlian basin of China and sedimentary basins of Mongolia

    International Nuclear Information System (INIS)

    Based on the study of metallogenic background and basic metallogenic characteristics,this paper summarizes the main ore-controlling factors of sandstone-type uranium deposits in Erlian basin of China and basins in southeastern Mongolia with the theory of sandstone-type uranium metallogeny,and systematically analyses similarities and differences between the two areas. The general similarities of tectonic attribute, basin type and scale, uranium source, and tectonic evolution in both areas are proposed in this paper, and also their obvious differences in uranium-hosting strata, late tectonic activity and regional uranium mineralization occurrences, especially in tectonic activity and ore-controlling sedimentary system are proposed. The authors believe that the two areas have approximate uranium-productive potentialities, and propose the importence of prospecting 'Sumin-river model' sandstone-type uranium deposit in Erlian basin in the future. (authors)

  1. 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

  2. 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.

  3. 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.

  4. Peculiarities of the Earth's crust sedimentary layer structure in the Falkland Basin

    Science.gov (United States)

    Schreider, A. A.; Mazo, E. L.; Bulychev, A. A.; Kulikova, M. P.; Gilod, D. A.; Schreider, Al. A.; Boiko, A. N.

    2010-12-01

    An electronic databank including the results of seismic investigations and schemes of the sediment thickness's distribution patterns was built up for two seismostratigraphic complexes in the Falkland Basin. The interface's border was dated, and the sedimentation rates were estimated for each complex. An integrated map of the cumulative thickness of the deposits and sedimentation rates was developed. The lowest limits of the parameters of the sedimentation process were characterized for the sedimentary layers affected by compaction and erosion.

  5. 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...

  6. 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.

  7. 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.

  8. Geochemical element mobility during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin (Saskatchewan, Canada)

    International Nuclear Information System (INIS)

    In order to understand the mechanisms of migration and deposition of ore elements, it is essential to determine the timing, source, and destination of the geochemical element mass transfers and/or transportation on a scale encompassing the great sedimentary basins. The purpose of this study is to trace and to date the element migrations that occurred during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin, which hosts the world's largest and richest uranium deposits. As this geological environment was proved to be efficient to preserve high grade ore deposits for over more than one billion years, it provides an opportunity to study some natural analogues of deep geological nuclear waste storage. Five research topics were studied: 3D modelling of the distribution of normative minerals and trace elements on a basin-wide scale; U-Pb and Rb-Sr systematics; average chemical age estimation; thermodynamic modelling of the major mineralogical assemblages; U-Pb geochronology of uranium oxides. Some elements have remained immobile (Zr) since their initial sedimentary deposition, or were transferred from one phase to another (Al, Th). Other elements have been transported during fluid flow events that occurred: (1) on a basin wide scale during diagenesis (REE, Y, Sr, Fe), (2) at the unconformity and in the vicinity of the fault zones that represent preferential fluid flow pathways between the basement and the sandstone cover (U, Ni, As, B, Mg, K, Fe, Sr, REE), (3) during the late fault reactivation events associated with the basin uplift (U, Pb, Ni, S, Sr, REE). The successive tectonic events related to the geodynamical context that lead to the formation of these high-grade U concentrations (1460 Ma, 1335 Ma and 1275 Ma in the McArthur River deposit), did not however systematically occur in the whole basin (1275 Ma only at Shea Creek). The exceptionally high grade and tonnages of some deposits seem to be related to a larger number of U

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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)

  14. 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.

  15. Sedimentary and tectonic environments for uranium mineralization on the Parana Basin, Brazil

    International Nuclear Information System (INIS)

    The Parana Basin is an isolated intracratonic basin in Southeastern South America and is characterized by Paleozoic and Mesozoic clastic sediments and by the location of one of the world's largest lava flows. Uranium mineralization occurs mainly in lower Devonian epineritic feldsphatic sandstones and in fluvio-deltaic channels developed in middle Permian mudstones and sandstones. Stratigraphic and sedimentologic conditions plus tectonic barriers in association with underground water controlled the mineralization. Two uranium deposits with 4250 and 6800 tonnes U of RAR plus EAR were found containing primary (pitchblende and coffinite) and secondary (autunite, sabugalite, uranocircite) minerals. A paleochannel model for the Permo-carboniferous mineralization is quite well established whereas many questions are still open for the confirmation of a model for the Devonian occurrences. Host rock sedimentary environment, ore-forming conditions and source rocks are discussed. (author)

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Seismic ground motion amplification in a 3D sedimentary basin: the effect of the vertical velocity gradient

    International Nuclear Information System (INIS)

    Ground motion amplification in sedimentary basins has been observed in some moderate or large earthquakes, such as the 1994 Northridge and 1999 Chi-Chi event. Many numerical studies with simplified 2D models have shown significant effects of the vertical velocity gradient of sediment on basin amplification. However, we need to consider a more realistic 3D model and solve wave equations with 3D numerical methods in order to improve our understanding of basin amplification. In this study, we extend a 2D pseudospectral and finite difference hybrid method to a 3D case and investigate the effects of the vertical velocity gradient for a 3D basin model. Numerical simulations were performed for four basin models with increasing vertical velocity gradients on a PC cluster using 64 processors for 67 108 864 discretized grids. The results show that the vertical velocity gradient enhances basin amplification through strong secondary surface waves and basin trapped waves. The 3D geometry of the basin causes a wave-front focusing effect that contributes significantly to a localized strong amplification with the maximum peak ground velocity in the basin. The results of this study suggest that it is important to consider the detailed properties of sedimentary basins in seismic ground motion studies. (paper)

  2. 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.

  3. 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

  4. A comprehensive approach to the 3D geological modelling of sedimentary basins: example of Latvia, the central part of the Baltic Basin

    Directory of Open Access Journals (Sweden)

    Konrāds Popovs

    2015-05-01

    Full Text Available This paper presents a semi-automatic approach adapted to the modelling of the geological structure of sedimentary basins. The modelling approach is based on developing the algorithm of the main geological processes so that the geometrical relationship is automatically defined between model elements. The algorithm is based on the assumption that sedimentary basins are formed as a result of the repeated sequence of sedimentation, faulting and erosion. This approach allows of successful modelling of the geological structure of the sedimentary basins with limited data coverage: stratigraphic intervals from well logs describing the thicknesses of sedimentary strata and a limited amount of structural data. Sedimentary layers are handled by modelling assuming non-eroded thickness distribution and using geometrical adjustment from the known fault displacements. As a result geometrical relationships of the model layers are deduced automatically in the presence of unconformities. An application of this methodology, a 3D geological model of Latvia, the central part of the Baltic Basin, is presented. The results show that this model is geologically reasonable for achieving the structural and stratigraphic concepts.

  5. 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.

  6. 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...

  7. 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...

  8. Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

    DEFF Research Database (Denmark)

    Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas;

    2008-01-01

    The conditions and timing of carbonate cementation in Cambrian sandstones of the Baltic sedimentary basin were determined by oxygen and carbon stable isotope and chemical data in combination with optical and cathodoluminescence petrographic studies. Studied samples represent a range in present...... burial depth from 340 to 2150 m. The carbonate cement is dominantly ferroan dolomite that occurs as dispersed patches of poikilotopic crystals. Temperatures of dolomite precipitation, based on delta O-18 values, range from 27 degrees C in the shallow buried to 95 degrees C in the deep buried sandstones....... The burial history modelling points to development of most of the dolomite cement during rapid Silurian-Devonian subsidence and Carboniferous-early Permian uplift. A wide range of precipitation temperatures indicate that temperature was not a major factor in triggering the carbonate cementation. Dolomite...

  9. 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.

  10. 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

  11. 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

    2016-05-01

    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 ˜3,000-m-thick Jurassic sedimentary sequence in the Qiangtang Basin on the central Tibetan Plateau, which is called the Yanshiping Group, recorded these geological events. However, the chronology of the sequence is surprisingly poorly constrained. Here, we perform a detailed palaeomagnetic analysis on the ˜1,060-m-thick middle and upper portions of the Yanshiping Group (the Xiali and Suowa Formations) in the Yanshiping section of the eastern Qiangtang Basin. Three bivalve zones at stratigraphic intervals of ˜40-140 m, 640-800 m 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.

  12. Short-term natural gas deliverability from the Western Canada Sedimentary Basin 2000-2002

    International Nuclear Information System (INIS)

    Factors which affect natural gas supply in the short term are discussed and a forecast for deliverability to the year 2002 is provided as part of the ongoing effort by the National Energy Board to provide analyses of the major energy commodities on either an individual or integrated commodity basis. The objective of these energy market assessment reports is to advance the understanding of the short-term supply situation by reviewing recent trends in the production characteristics of the Western Canada Sedimentary Basin and to update previous reports on short-term deliverability. This report focuses on a review of producing characteristics of natural gas wells from 1990 to 1999. These producing characteristics are then combined with forecasts of drilling activity in order to generate a forecast of natural gas deliverability from 2000 to 2002. Two key trends were identified during the review process. First, recently drilled wells were found to produce at lower rates than wells drilled more than five years ago; second, production from these wells were shown to decline more quickly than production from older wells. Based on these observations, it was concluded that future wells will be generally less productive than wells which were drilled a few years ago, therefore, more wells will have to be drilled to offset production declines from existing gas wells if deliverability is to be maintained or increased. The National Energy Board expects 8,100 wells to be drilled in 2000, followed by 8,700 natural gas wells in 2001 and 8,900 in 2002. A shift in drilling activity to more prolific areas located in the western and northern parts of the Western Canada Sedimentary Basin is also expected. Based on these estimates of expected drilling activity, total deliverability is projected to increase from 465 million cubic feet per day in 1999 to 495 million cubic feet in 2002. Specialized statistics and forecast data are provided in the appendices. 3 tabs., 11 figs., 6 appendices

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. Stratigraphical analysis of the neoproterozoic sedimentary sequences of the Sao Francisco Basin

    International Nuclear Information System (INIS)

    A stratigraphic analysis was performed under the principles of Sequence Stratigraphy on the neoproterozoic sedimentary sequences of the Sao Francisco Basin (Central Brazil). Three periods of deposition separated by unconformities were recognized in the Sao Francisco Megasequence: (1) Sequences 1 and 2, a cryogenian glaciogenic sequence, followed by a distal scarp carbonate ramp, developed during stable conditions, (2) Sequence 3, a Upper Cryogenian stack homoclinal ramps with mixed carbonate-siliciclastic sedimentation, deposited under a progressive influence of compressional stresses of the Brasiliano Cycle, (3) Sequence 4, a Lower Ediacaran shallow platform dominated by siliciclastic sedimentation of molassic nature, the erosion product of the nearby uplifted thrust sheets. Each of the carbonate-bearing sequences presents a distinct δ13C isotopic signature. The superposition to the global curve for carbon isotopic variation allowed the recognition of a major depositional hiatus between the Paranoa and Sao Francisco Megasequences, and suggested that the glacial diamictite deposition (Jequitai Formation) took place most probably around 800 Ma. This constrains the Sao Francisco Megasequence deposition to the interval between 800 and 600 Ma (the known ages of the Brasiliano Orogeny defines the upper limit). A minor depositional hiatus (700.680 Ma) was also identified separating sequences 2 and 3. Isotopic analyses suggest that from then on, more restricted environmental conditions were established in the basin, probably associated with a first order global event, which prevailed throughout deposition of the Sequence 3. (author)

  20. 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)

  1. 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.

  2. 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. PMID:26767550

  3. Geology of the Mesozoic-Tertiary sedimentary basins in southwestern Somalia

    Science.gov (United States)

    Kassim M, Ali; Carmignani, L.; Conti, P.; Fantozzi, P. L.

    2002-02-01

    Two main sedimentary basins can be recognized in southern Somalia, the NE-SW trending Mesozoic-Tertiary Somali coastal basin, and the NNE-SSW Mesozoic Luuq-Mandera basin. The two basins are separated by the Bur region where the Proterozoic-Early Paleozoic Metamorphic basement of southern Somalia outcrops. The investigated area covers part of the Metamorphic basement of southern Somalia and of the Luuq-Mandera basin, although this basement is not described in details in this paper. In the Bur region the basement outcrops discontinuously near inselbergs and monadnocks, which stand out of a blanket of recent sediments. Because of this patchy distribution and the limited areal extent of the outcrops, the structure of the metamorphic basement is difficult to reconstruct. A NW-SE trend of structures prevails and two metamorphic complexes (the Olontole and Diinsor complexes) can be recognized. The Luuq-Mandera basin is a wide NNE-SSW synclinorium, delimited to the SE by the basement high of the Bur region, and to the west by the crystalline basement high of NE Kenya (Northern Frontier district). The extreme thickness of Triassic sediments in the axial part of the basin, and the thinner and younger succession on both sides of the basin suggest that the Luuq-Mandera basin was a subsiding elongated area that was invaded by the sea in the early Mesozoic, during the dismembering of Gondwana. The Jurassic-Cretaceous succession that followed comprises two main cycles of transgression and regression; the carbonate sediments that lie at the bottom pass up section into shales, evaporites and sandstone deposits. Since late Cretaceous, continental contition prevaled, with a long phase of peneplanation, and then a general uplift, which brought about the creation of lake depressions and the capture of the Dawa river, with formation of the present Jubba valley. The main tectonic events in the study area, and throughout SW Somalia, are represented by strike-slip movements along vertical

  4. 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.

  5. Earthquake ground motion prediction for real sedimentary basins: which numerical schemes are applicable?

    Science.gov (United States)

    Moczo, P.; Kristek, J.; Galis, M.; Pazak, P.

    2009-12-01

    Numerical prediction of earthquake ground motion in sedimentary basins and valleys often has to account for P-wave to S-wave speed ratios (Vp/Vs) as large as 5 and even larger, mainly in sediments below groundwater level. The ratio can attain values larger than 10 in unconsolidated sediments (e.g. in Ciudad de México). In a process of developing 3D optimally-accurate finite-difference schemes we encountered a serious problem with accuracy in media with large Vp/Vs ratio. This led us to investigate the very fundamental reasons for the inaccuracy. In order to identify the very basic inherent aspects of the numerical schemes responsible for their behavior with varying Vp/Vs ratio, we restricted to the most basic 2nd-order 2D numerical schemes on a uniform grid in a homogeneous medium. Although basic in the specified sense, the schemes comprise the decisive features for accuracy of wide class of numerical schemes. We investigated 6 numerical schemes: finite-difference_displacement_conventional grid (FD_D_CG) finite-element_Lobatto integration (FE_L) finite-element_Gauss integration (FE_G) finite-difference_displacement-stress_partly-staggered grid (FD_DS_PSG) finite-difference_displacement-stress_staggered grid (FD_DS_SG) finite-difference_velocity-stress_staggered grid (FD_VS_SG) We defined and calculated local errors of the schemes in amplitude and polarization. Because different schemes use different time steps, they need different numbers of time levels to calculate solution for a desired time window. Therefore, we normalized errors for a unit time. The normalization allowed for a direct comparison of errors of different schemes. Extensive numerical calculations for wide ranges of values of the Vp/Vs ratio, spatial sampling ratio, stability ratio, and entire range of directions of propagation with respect to the spatial grid led to interesting and surprising findings. Accuracy of FD_D_CG, FE_L and FE_G strongly depends on Vp/Vs ratio. The schemes are not

  6. Amplification and Attenuation in the Los Angeles and Kanto Sedimentary Basins using the Ambient Seismic Field

    Science.gov (United States)

    Denolle, M.; Prieto, G.; Lawrence, J. F.; Beroza, G. C.; Hirata, N.; Nakagawa, S.; Miyake, H.; Kasahara, K.; Sakai, S.; Aketagawa, T.; Kimura, H.

    2010-12-01

    Ground motion prediction is traditionally estimated in seismic hazard analysis using parametric scaling relations, which are often referred to as "attenuation relations." Increasingly, seismologists are turning to simulation-based hazard analysis. There are at least two reasons for this. First, it allows seismologists to overcome the scarcity of data from large events in the data. Second, it exploits our growing knowledge of the geological complexity of the Earth's crust and our ability to model wave propagation through it. The accuracy of these simulations is critical to their use for risk reduction, but is limited by our incomplete knowledge of the elastic and anelastic structure of the subsurface. The situation is particularly acute for sedimentary basins that underlie densely populated urban centers such as Los Angeles and Tokyo, both because the exposure is so high, and because it is difficult to obtain new images of Earth structure in urban settings. In this study, we show how ambient seismic field analysis can improve this situation. We take the advantage of the dense seismic networks in those areas and use 9 months of continuous records for about 180 stations from the Southern Californian Seismic Networks for Los Angeles and 6 months of a combination of 190 MeSO-net stations and 110 Hi-net instruments in Tokyo area. We estimate the basin amplification of these comparable urban centers with ambient field transfer function, or impulse response. The ambient seismic field also provides constraints on the attenuation signal in surface waves, and hence on the anelastic structure of the Earth. We exploit this by using the real part of the complex coherence to estimate the attenuation coefficient of Rayleigh waves, and from it variations in the anelastic structure. We acknowledge the support by the Special Project for Earthquake Disaster Mitigation in Tokyo Metropolitan Area from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

  7. 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%, Pb isotopes ( 207Pb/204Pb 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 of small to mid-sized vein, replacement, and skarn intrusion-related metal deposits

  8. 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.

  9. 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.

  10. Stratigraphic sequence and sedimentary characteristics of Lower Silurian Longmaxi Formation in Sichuan Basin and its peripheral areas

    Directory of Open Access Journals (Sweden)

    Yuman Wang

    2015-03-01

    Full Text Available A high-precision sedimentary environment study of the Lower Silurian Longmaxi Formation is an important subject for shale gas exploration and development in Sichuan Basin and its surrounding areas. On the basis of outcrops and drilling data, its isochronous stratigraphic framework was built according to a particular graptolite zone and an important marker bed, and lithofacies, paleontology, calcareous content, well logging, geochemistry and other geologic information were combined to describe the sedimentary microfacies of Longmaxi Formation and its stratigraphic sequence, sedimentary evolution process and high quality shale distribution features as follows: ① with regional diachronism of the top and the bottom, the Longmaxi Formation is divided into two third-order sequences (SQ1 and SQ2, of which SQ1 is mainly an abyssal sedimentary assemblage deposited in the marine transgression period, and SQ2 is a bathyal to shallow sea sedimentary assemblage deposited in the marine regression period; ② there are eight microfacies such as deep calcareous shelf and deep argillaceous shelf in this formation and the organic-rich shale was mainly deposited in the deep water area of SQ1; and ③ from SQ1 to SQ2, the depocenter moved from the depression area in southern-eastern to northern Sichuan Basin, but the central Sichuan uplift remained an underwater one. It is concluded from this study that: ① shale gas production layers were mainly deposited in SQ1, the southern-eastern depression area was the depocenter in SQ1 and a shale gas enrichment area; and ② black shale in northern Sichuan was deposited in late SQ2, with limited distribution and relatively insufficient exploration potential, but the potential of shale gas exploration in western Hubei area is between southern-eastern and northern Sichuan Basin.

  11. 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.

  12. 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

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

    Science.gov (United States)

    Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

    2015-01-01

    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" character. PMID

  14. 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

  15. Seasonal and spatial contrasts of sedimentary organic carbon in floodplain lakes of the central Amazon basin.

    Science.gov (United States)

    Sobrinho, Rodrigo; Kim, Jung-Hyun; Abril, Gwenaël; Zell, Claudia; Moreira-Turcq, Patricia; Mortillaro, Jean-Michel; Meziane, Tarik; Damsté, Jaap; Bernardes, Marcelo

    2014-05-01

    Three-quarters of the area of flooded land in the world are temporary wetlands (Downing, 2009), which play a significant role in the global carbon cycle(Einsele et al., 2001; Cole et al., 2007; Battin et al., 2009; Abril et al., 2013). Previous studies of the Amazonian floodplain lakes (várzeas), one important compartment of wetlands, showed that the sedimentation of organic carbon (OC) in the floodplain lakes is strongly linked to the periodical floods and to the biogeography from upstream to downstream(Victoria et al., 1992; Martinelli et al., 2003). However, the main sources of sedimentary OC remain uncertain. Hence, the study of the sources of OC buried in floodplain lake sediments can enhance our understanding of the carbon balance of the Amazon ecosystems. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverage. 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 C:N ratio and stable isotopic composition of organic carbon (δ13COC). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus (Hedges and Ertel, 1982) and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the soil OC from land to the aquatic settings (Hopmans et al., 2004). Our data showed that during the RW and FW seasons, the concentration of lignin and brGDGTs were higher in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of a mixture of C3 plant detritus and soil OC. However, a downstream increase in C4 plant-derived OC contribution was observed along the gradient of increasingly open waters, i

  16. 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.

  17. 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

  18. 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

  19. 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)

  20. 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).

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

    International Nuclear Information System (INIS)

    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)

  2. 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)

  3. 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

  4. 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/

  5. 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

  6. 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

  7. 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).

  8. 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).

  9. 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.

  10. 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

  11. A modern analog for carbonate source-to-sink sedimentary systems: the Glorieuses archipelago and adjacent basin (SW Indian Ocean)

    Science.gov (United States)

    Jorry, S.; Jouet, G.; Prat, S.; Courgeon, S.; Le Roy, P.; Camoin, G.; Caline, B.

    2014-12-01

    This study presents the geomorphological and sedimentological analysis of a modern carbonate source-to-sink system located north of Madagascar (SW Indian Ocean). The sedimentary system is composed of an isolated carbonate platform sited on top of a seamount rising steeply from the seabed located at 3000 m water depth. The slope of the seamount is incised by canyons, and meandering channels occur above lobbed sedimentary bodies at the foot of the slope. The dataset consists of dredges, sediment piston cores, swath bathymetry and seismic (sparker and 2D high-resolution) lines collected from inner platform (less than 5 m deep) to the adjacent deep sedimentary basin. Particle size analysis and composition of carbonate grains are used to characterize the distribution and heterogeneity of sands accumulated on the archipelago. Main results show that composition of carbonate sediments is dominated by segments of Halimeda, large benthic foraminifera, coral debris, molluscs, echinoderms, bryozoans and sponges. According to the shape and the position of sandwaves and intertidal sandbars developed in the back-barrier reef, the present organization of these well-sorted fine-sand accumulations appears to be strongly influenced by flood tidal currents. Seismic lines acquired from semi-enclosed to open lagoon demonstrate that most of the sediment is exported and accumulated along the leeward margin of the platform, which is connected to a canyon network incising the outer slope. Following the concept of highstand shedding of carbonate platforms (Schlager et al., 1994), excess sediment is exported by plumes and gravity flows to the adjacent deep sea where it feeds a carbonate deep-sea fan. Combined observations from platform to basin allow to explain how the Glorieuses carbonate source to sink system has evolved under the influence of climate and of relative sea-level changes since the last interglacial.

  12. 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.

  13. Influence of stress on the permeability of coal and sedimentary rocks of the Upper Silesian Basin

    Czech Academy of Sciences Publication Activity Database

    Konečný, Pavel; Kožušníková, Alena

    2011-01-01

    Roč. 48, č. 2 (2011), s. 347-352. ISSN 1365-1609 Institutional research plan: CEZ:AV0Z30860518 Keywords : permeability * triaxial test * coal and sedimentary rocks Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 1.272, year: 2011 http://www.sciencedirect.com/science/article/pii/S1365160910002194

  14. 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.

  15. 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.

  16. Modelling of wave propagation and attenuation in the Osaka sedimentary basin, western Japan, during the 2013 Awaji Island earthquake

    Science.gov (United States)

    Asano, Kimiyuki; Sekiguchi, Haruko; Iwata, Tomotaka; Yoshimi, Masayuki; Hayashida, Takumi; Saomoto, Hidetaka; Horikawa, Haruo

    2016-03-01

    On 2013 April 13, an inland earthquake of Mw 5.8 occurred in Awaji Island, which forms the western boundary of the Osaka sedimentary basin in western Japan. The strong ground motion data were collected from more than 100 stations within the basin and it was found that in the Osaka Plain, the pseudo velocity response spectra at a period of around 6.5 s were significantly larger than at other stations of similar epicentral distance outside the basin. The ground motion lasted longer than 3 min in the Osaka Plain where its bedrock depth spatially varies from approximately 1 to 2 km. We modelled long-period (higher than 2 s) ground motions excited by this earthquake, using the finite difference method assuming a point source, to validate the present velocity structure model and to obtain better constraint of the attenuation factor of the sedimentary part of the basin. The effect of attenuation in the simulation was included in the form of Q(f) = Q0(f/f0), where Q0 at a reference frequency f0 was given by a function of the S-wave velocity, Q0 = αVS. We searched for appropriate Q0 values by changing α for a fixed value of f0 = 0.2 Hz. It was found that values of α from 0.2 to 0.5 fitted the observations reasonably well, but that the value of α = 0.3 performed best. Good agreement between the observed and simulated velocity waveforms was obtained for most stations within the Osaka Basin in terms of both amplitude and ground motion duration. However, underestimation of the pseudo velocity response spectra in the period range of 5-7 s was recognized in the central part of the Osaka Plain, which was caused by the inadequate modelling of later phases or wave packets in this period range observed approximately 2 min after the direct S-wave arrival. We analysed this observed later phase and concluded that it was a Love wave originating from the direction of the east coast of Awaji Island.

  17. 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.

  18. Deformation within the Pisco Basin sedimentary record (southern Peru): Stratabound orthogonal vein sets and their impact on fault development

    Science.gov (United States)

    Rustichelli, Andrea; Di Celma, Claudio; Tondi, Emanuele; Bianucci, Giovanni

    2016-01-01

    This outcrop-based study reports diffuse joints and veins, normal to strike-slip fault zones and minor folds that developed, from Miocene to Quaternary, within the clastic to siliceous sedimentary record of the forearc Pisco Basin of southern Peru. Patterns, orientations, dimensional parameters and other outcrop-scale characteristics of the various deformation features are illustrated and their genetic mechanisms and timing of development are inferred. These new structural data and interpretations allow a better constraint of the structural style and evolution of the Pisco Basin, and can represent useful guidelines for characterizing the outcrop-scale deformation affecting similar forearc basins along the Peruvian coast. Major results of this study are that the development of the documented deformation features, their patterns, dimensional parameters and kinematics seem influenced by local perturbations of the paleostress field by mechanic processes partly independent of plate tectonics forces. These processes include strain localization on both pre-existing and progressively forming new structural discontinuities, and cyclic switches of the horizontal, principal stress axes σ2 and σ3. In particular, we discuss how different normal fault patterns, from sub-parallel to multidirectional/polygonal, could form in a same deformation phase in response of the local σ2/σ3 magnitude ratio, as an evolution of stratabound, mutually orthogonal vein sets.

  19. 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 (Basin may be more 34S-enriched than pyrite due to equilibration with relatively 34S-enriched OS. The difference between OS and pyrite δ34S values would then reflect the balance between microbial sulfide formation and the abundance of exchangeable OS. Both OS and pyrite δ34S records thus have the potential to provide valuable information about biogeochemical cycles and redox structure in sedimentary paleoenvironments.

  20. 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.

  1. 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.

  2. A hybrid method for the estimation of ground motion in sedimentary basins: Quantitative modelling for Mexico City

    International Nuclear Information System (INIS)

    To estimate the ground motion in two-dimensional, laterally heterogeneous, anelastic media, a hybrid technique has been developed which combines modal summation and the finite difference method. In the calculation of the local wavefield due to a seismic event, both for small and large epicentral distances, it is possible to take into account the sources, path and local soil effects. As practical application we have simulated the ground motion in Mexico City caused by the Michoacan earthquake of September 19, 1985. By studying the one-dimensional response of the two sedimentary layers present in Mexico City, it is possible to explain the difference in amplitudes observed between records for receivers inside and outside the lake-bed zone. These simple models show that the sedimentary cover produces the concentration of high-frequency waves (0.2-0.5 Hz) on the horizontal components of motion. The large amplitude coda of ground motion observed inside the lake-bed zone, and the spectral ratios between signals observed inside and outside the lake-bed zone, can only be explained by two-dimensional models of the sedimentary basin. In such models, the ground motion is mainly controlled by the response of the uppermost clay layer. The synthetic signals explain the major characteristics (relative amplitudes, spectral ratios, and frequency content) of the observed ground motion. The large amplitude coda of the ground motion observed in the lake-bed zone can be explained as resonance effects and the excitation of local surface waves in the laterally heterogeneous clay layer. Also, for the 1985 Michoacan event, the energy contributions of the three subevents are important to explain the observed durations. (author). 39 refs, 15 figs, 1 tab

  3. 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.

  4. 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.

  5. 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.

  6. Mapping geological storage prospectivity of CO2 for the world's sedimentary basins and regional source to sink matching

    International Nuclear Information System (INIS)

    Most hydrocarbon producing sedimentary basins as well as many non-petroliferous sedimentary basins will be potential sites for carbon dioxide (CO2) storage. The degree to which geological storage of CO2 will be implemented in the future will depend on the geographical and technical relationships between emission sites and storage locations, and the economic drivers that affect the implementation for each source to sink match. Despite many attempts to estimate the world's total storage potential for CO2 in terms of capacity, there are inherent uncertainties associated with delivering such an output. As such, maps have yet to be published on the global distribution of the most likely areas for CO2 storage. However, it is possible to make a preliminary estimate of where the world's CO2 storage potential might be located by comparing detailed assessments that have been done for a few locations with geological data on hydrocarbon potential. The acquired information can provide insight as to which regions will be likely to provide the most technically and economically viable CO2 storage sites by overlaying this geological data with the locations of the world's current large stationary energy CO2 emissions point sources. This paper reviewed datasets from the Australian and United States Geological Surveys in terms of matching CO2 sources with suitable geological provinces. Some regions have significant prospectivity with good source to sink matches, while others may require longer transport distances between sources and sinks, at higher costs. The latter may need to plan for the future and reduce costs by locating new emission sites closer to storage sites, or by potentially considering hub or industrial ecosystem approaches. It was suggested that access to the development of centralized storage locations for a region could become a critical component to any future involving large scale implementation of geological storage of CO2 technology. 8 refs., 6 figs

  7. 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.

  8. 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.

  9. 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)

  10. 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

  11. 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

  12. 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

  13. Pollen analysis of coal-bearing Miocene sedimentary rocks from the Seyitomer basin (Kutahya), western Anatolia

    Energy Technology Data Exchange (ETDEWEB)

    Yavuz-Isik, N. [Ondokuz Mayis University, Kurupelit (Turkey). Dept. of Civil Engineering

    2007-09-15

    The late Early-Middle Miocene sequences of the Seyitomer Basin (western Anatolia) were palynologically investigated. Fifty-five taxa belonging to seven gymnospermous and 48 angiospermous pollen genera were identified in the 19 productive samples. Two pollen zones were recognised based on the changing abundance of individual tree taxa. Zone 1 is characterized by predominance of Pinus and Cedrus. Zone 2 is characterized by predominance of deciduous Quercus and evergreen Quercus and a marked reduction in representation of Taxodiaceae. The differences in the pollen spectra between Zone 1 and Zone 2 may reflect the global Middle Miocene cooling. These results are largely comparable to pollen data derived from the neighbouring areas. The vegetation of the Seyitomer Basin was dominated by trees. This palynological analysis reveals the existence of a swamp-forest developed in a subtropical to warm-temperate humid climate.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  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. Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

    DEFF Research Database (Denmark)

    Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas; Musteikyte, D.

    2008-01-01

    burial depth from 340 to 2150 m. The carbonate cement is dominantly ferroan dolomite that occurs as dispersed patches of poikilotopic crystals. Temperatures of dolomite precipitation, based on delta O-18 values, range from 27 degrees C in the shallow buried to 95 degrees C in the deep buried sandstones....... The burial history modelling points to development of most of the dolomite cement during rapid Silurian-Devonian subsidence and Carboniferous-early Permian uplift. A wide range of precipitation temperatures indicate that temperature was not a major factor in triggering the carbonate cementation....... Dolomite precipitation is related to early stages of organic matter maturation and thus to the oil generation history in the basin. delta C-13 values vary from +0.03% to -6.2%( PDB), suggesting limited addition of carbon from an organic source, with the major part derived from marine bicarbonate. The...

  20. The Late Devensian (<22,000 BP) Irish Sea Basin: The sedimentary record of a collapsed ice sheet margin

    Science.gov (United States)

    Eyles, Nicholas; Marshall McCabe, A.

    The Late Devensian (Shropshire Lowlands) and initiated the collapse of the ice sheet. Thick wedges of ice-contact glaciomarine sediments were deposited during ice retreat as morainal bank complexes by successive tidewater ice margins stabilized at pinning points around the Irish Sea coast. Where morainal banks occur on the seaward side of drumlin swarms there is a clear sequential relationship between rapid ice loss from calving ice margins, the development of fast flowing ice streams, drumlinization and the pumping of subglacial sediment to tidewater. Raised delta complexes are locally associated with marine limits along the high relief coastal margins of Wales, east central Ireland, and the Lake District. Associated valley infill complexes record downslope resedimentation of heterogenous sediments into the marine environment during ice retreat. Co-eval offshore deposits are represented by well-stratified glaciomarine complexes that infill a subglacially-scoured topography that shows networks of tunnel valleys. Glaciomarine mud drapes occur well to the south of the maximum limit of grounded ice in the basin (e.g. North Devon, Scilly Islands, Southern Ireland). The age of these distal sediments, previously mapped as pre-Devensian tills, is constrained by amino acid ratios. Basin rebound following deglaciation was rapid, with over 100 m recovery in 3 ka, and was followed by a low marine still stand. Peat, accumulating in offshore areas now as much as 55 m below sea level has been drowned by the postglacial eustatic rise in sea level. The glacio-sedimentary model identified in this paper, involving rapid ice retreat and related sedimentation triggered by rising relative sea level, suggests that isotatic downwarping is an important mechanism for deglaciating continental shelves.

  1. 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)

  2. 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.

  3. 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.

  4. Spatial variations in magnetic properties in three reservoirs of the Western Canada Sedimentary Basin : insights into hydrocarbon generation and migration

    Energy Technology Data Exchange (ETDEWEB)

    Cioppa, M.T.; Symons, D.T.A. [Windsor Univ., Dept. of Earth Sciences, Windsor, ON (Canada); Gillen, K.P. [Vox Terrae International, Calgary, AB (Canada)

    1999-11-01

    Some of the possible applications of paleomagnetism and rock magnetism in the petroleum industry were discussed. It has been shown that paleomagnetic and rock magnetic data can be used to track and map fluid migration. A study was conducted in 1997 in which limestones, dolostones and anhydrites of the Mississippian Upper Debolt Formation in the Dunvegan, Cindy and Belloy fields in the Western Canada Sedimentary Basin were sampled for rock magnetic, paleomagnetic, petrological and geochemical analysis. It was determined that, contrary to expectations, there was a significant spatial variation in the paleomagnetic and rock magnetic data. Analysis of about 300 specimens indicated the presence of three components: (1) a low temperature or low coercivity `A` component, removed at temperatures of less than 250 degrees C and coercivities of less than 20 mT, (2) the `B` component removed at temperatures between 250 and 350 degrees C and AF fields between 20 and 80 mT, and (3) the `C` component, a high temperature or high coercivity component removed at temperatures above 350 degrees C and fields above 20 mT. The spatial variation in paleomagnetic and rock magnetic properties has important implications for fluid migration, fluid migration pathways, and possible hydrocarbon sources. 3 refs.

  5. Two equations of state assembled for basic analysis of multiphase CO 2 flow and in deep sedimentary basin conditions

    Science.gov (United States)

    McPherson, Brian J. O. L.; Han, Weon Shik; Cole, Barret S.

    2008-05-01

    The purpose of the study presented in this manuscript is to describe and make available two equation-of-state (EOS) algorithms assembled for multiphase flow and transport of carbon dioxide (CO2). The algorithms presented here calculate solubility, compressibility factor, density, viscosity, fugacity, and enthalpy of CO2 in gaseous and supercritical phases, and mixtures or solutions of CO2 in water, as functions of pressure and temperature. Several features distinguish the two algorithms, but the primary distinction concerns treatment of supercritical/gas-phase CO2: one EOS we assembled is based on Redlich and Kwong's original algorithm developed in 1949, and the other is based on an algorithm developed by Span and Wagner in 1996. Both were modified for application to sedimentary basin studies of multiphase CO2 flow processes, including carbon sequestration applications. We present a brief comparison of these two EOS algorithms. Source codes for both algorithms are provided, including "stand-alone" Matlab © scripts for the interactive calculation of fluid properties at specified P-T conditions and FORTRAN subroutines for inclusion in existing FORTRAN multiphase fluid simulation packages. These routines are intended for fundamental analyses of CO2 sequestration and the like; more advanced studies, such as brine processes and reactive transport, require more advanced EOS algorithms.

  6. Veins and related past fluid flow through the Mesozoic sedimentary cover in the Swiss Molasse Basin

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The study is based on core samples from the recently drilled, 719 m deep borehole at Oftringen (near Olten), located in the northwestern Molasse basin, 1.5 km from the frontal thrust of the Folded Jura. Veins of calcite (± celestite, pyrite) occur in the whole Malm sequence (up to 8 veins/m), including the more clay-rich Effingen Member (marl and argillaceous limestone). Such an intensity of veining in the Effingen Member has never been found to date in other deep boreholes located in the Molasse basin. Most of the veins are related to tectonic activity, but clay-filled karst structures are recognized in the overlying Geissberg Member limestone, and a few structures probably related to diagenetic processes are documented in the Effingen Member. Fluid inclusions show average salinities between 3.3 and 4.4 wt% eq. NaCl in vein celestite and 2.7 wt% eq. NaCl in vein calcite. Average homogenization temperatures in calcite fluctuate between 56 and 68 deg. C, with a broad increase with depth and no correlation with salinity. Malm whole-rock carbonates have δ18O values fluctuating within a narrow range, probably determined by equilibrium with seawater. Their 87Sr/86Sr ratios follow a well-defined depth profile with minimum values in the middle part of the Effingen Member, fitting with Oxfordian seawater. No correlation is observed between 87Sr/86Sr and clay content, and values higher than contemporary seawater might be related to the incorporation of radiogenic detrital carbonate. The δ18O values of vein calcite are systematically lower than the corresponding whole rock carbonate, consistent with precipitation from seawater at 50-70 deg. C (homogenization temperatures of fluid inclusions). The δ34S and δ18O values of vein celestite follow a bacterial reduction trend pointing to Miocene seawater sulfate. Two vein pyrites gave negative δ34S values consistent with bacterial sulfate reduction. Calcite and celestite of

  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. 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

  11. 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.

  12. 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

  13. 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

  14. 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

  15. Detecting Light Hydrocarbon Microseepages and related Intra-sedimentary Structures at the São Francisco Basin, Brazil, using Airborne Geophysical Data

    Science.gov (United States)

    Curto, J. B.; Pires, A. C.; Silva, A.; Crosta, A. P.

    2011-12-01

    The use of indirect techniques for the detection of light hydrocarbons occurrences on the surface, named as microseepages, has been used to augment hydrocarbon exploration. Surveys developed for this type of application are normally targeted at mapping the effects that microseepages cause on the environment. In Brazil, most available airborne geophysical surveys were not appropriately designed for this type of application and, thus far they have been mostly used to define the main basin structural features. Existing microseepages are known in Remanso do Fogo area (Minas Gerais State, Brazil), located in São Francisco Basin, where the Quaternary sedimentary cover made the identification of new occurrences and associated controlling structures quite difficult. This study investigates the spatial distribution of hydrocarbon related structures in shallower to intra-sedimentary depths in the Remanso do Fogo area, using airborne magnetic and gamma-ray spectrometry data. These data were managed by the ANP (Brazilian Petroleum National Agency) and conducted by Lasa Engineering & Surveys in 2006. In the study area, data were acquired along north-south flight lines spaced 500 m apart and along orthogonal tie lines flown 4 Km apart at a terrain clearance of 100 m. The geophysical data were processed using techniques developed to suppress the influence of regional geological signatures. For the magnetic data, this study focuses on the enhancement of intra-sedimentary structures and possible near surface accumulations of diagenetic magnetic minerals, provided by hydrocarbon related chemical reactions. The amplitude of the analytic signal, calculated with second order derivatives, combined with the total horizontal gradient of the subtraction between the 1200 and 400 meter upward continuations, illuminated the NW and EW magnetic lineaments, which are partially related to the microseepages and the drainage of the area. The distinction of near-surface and deeper signatures also

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

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    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...... 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...

  17. 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 D.

    2016-01-01

    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.

  18. 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.

  19. Constraints on the history and topography of the Northeastern Sierra Nevada from a Neogene sedimentary basin in the Reno-Verdi area, Western Nevada

    Science.gov (United States)

    Trexler, James; Cashman, Patricia; Cosca, Michael

    2012-01-01

    Neogene (Miocene–Pliocene) sedimentary rocks of the northeastern Sierra Nevada were deposited in small basins that formed in response to volcanic and tectonic activity along the eastern margin of the Sierra. These strata record an early phase (ca. 11–10 Ma) of extension and rapid sedimentation of boulder conglomerates and debrites deposited on alluvial fans, followed by fluvio-lacustrine sedimentation and nearby volcanic arc activity but tectonic quiescence, until ~ 2.6 Ma. The fossil record in these rocks documents a warmer, wetter climate featuring large mammals and lacking the Sierran orographic rain shadow that dominates climate today on the eastern edge of the Sierra. This record of a general lack of paleo-relief across the eastern margin of the Sierra Nevada is consistent with evidence presented elsewhere that there was not a significant topographic barrier between the Pacific Ocean and the interior of the continent east of the Sierra before ~ 2.6 Ma. However, these sediments do not record an integrated drainage system either to the east into the Great Basin like the modern Truckee River, or to the west across the Sierra like the ancestral Feather and Yuba rivers. The Neogene Reno-Verdi basin was one of several, scattered endorheic (i.e., internally drained) basins occupying this part of the Cascade intra-arc and back-arc area.

  20. A regional view of urban sedimentary basins in Northern California based on oil industry compressional-wave velocity and density logs

    Science.gov (United States)

    Brocher, T.M.

    2005-01-01

    Compressional-wave (sonic) and density logs from 119 oil test wells provide knowledge of the physical properties and impedance contrasts within urban sedimentary basins in northern California, which is needed to better understand basin amplification. These wire-line logs provide estimates of sonic velocities and densities for primarily Upper Cretaceous to Pliocene clastic rocks between 0.1 - and 5.6-km depth to an average depth of 1.8 km. Regional differences in the sonic velocities and densities in these basins largely 1reflect variations in the lithology, depth of burial, porosity, and grain size of the strata, but not necessarily formation age. For example, Miocene basin filling strata west of the Calaveras Fault exhibit higher sonic velocities and densities than older but finer-grained and/or higher-porosity rocks of the Upper Cretaceous Great Valley Sequence. As another example, hard Eocene sandstones west of the San Andreas Fault have much higher impedances than Eocene strata, mainly higher-porosity sandstones and shales, located to the east of this fault, and approach those expected for Franciscan Complex basement rocks. Basement penetrations define large impedence contrasts at the sediment/basement contact along the margins of several basins, where Quaternary, Pliocene, and even Miocene deposits directly overlie Franciscan or Salinian basement rocks at depths as much as 1.7 km. In contrast, in the deepest, geographic centers of the basins, such logs exhibit only a modest impedance contrast at the sediment/basement contact at depths exceeding 2 km. Prominent (up to 1 km/sec) and thick (up to several hundred meters) velocity and density reversals in the logs refute the common assumption that velocities and densities increase monotonically with depth.

  1. 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

  2. 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

  3. 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

  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

    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

  5. 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

  6. 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 ...

  7. On the Applicability of Joint Inversion of Gravity and Resistivity Data to the Study of a Tectonic Sedimentary Basin in Northern Portugal

    Science.gov (United States)

    Represas, Patricia; Monteiro Santos, F. A.; Ribeiro, Joana A.; Andrade Afonso, A.; Ribeiro, José; Moreira, Mário; Mendes-Victor, L. A.

    2015-10-01

    The Chaves basin is a pull-apart tectonic depression implanted on granites, schists, and graywackes, and filled with a sedimentary sequence of variable thickness. It is a rather complex structure, as it includes an intricate network of faults and hydrogeological systems. The topography of the basement of the Chaves basin still remains unclear, as no drill hole has ever intersected the bottom of the sediments, and resistivity surveys suffer from severe equivalence issues resulting from the geological setting. In this work, a joint inversion approach of 1D resistivity and gravity data designed for layered environments is used to combine the consistent spatial distribution of the gravity data with the depth sensitivity of the resistivity data. A comparison between the results from the inversion of each data set individually and the results from the joint inversion show that although the joint inversion has more difficulty adjusting to the observed data, it provides more realistic and geologically meaningful models than the ones calculated by the inversion of each data set individually. This work provides a contribution for a better understanding of the Chaves basin, while using the opportunity to study further both the advantages and difficulties comprising the application of the method of joint inversion of gravity and resistivity data.

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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)

  14. Synthesis of Late Cretaceous-Quaternary tectonic, sedimentary and magmatic processes and basin formation related to episodic subduction-collision in the easternmost Mediterranean region

    Science.gov (United States)

    Robertson, Alastair; Kinnaird, Timothy; McCay, Gillian; Palamakumbura, Romesh; Taslı, Kemal

    2015-04-01

    Mesozoic oceanic crust of the easternmost Mediterranean has experienced northwards subduction during Late Cretaceous-Cenozoic, either continuously or discontinuously based on kinematic evidence. Much of the existing information on sedimentation within the easternmost Mediterranean oceanic basin comes from the non-emplaced continental margins of the Levant and North Africa. In addition, sedimentary basins related to plate convergence are recorded along the northern margin of the Southern Neotethyan ocean, mainly in the Kyrenia Range of northern Cyprus and its extension into the Misis Mountains of southern Turkey, coupled with the adjacent submerged areas. In a setting of only incipient continental collision such as the easternmost Mediterranean the sedimentary basins would be expected to remain entirely submarine. In contrast, the Kyrenia Range has been strongly uplifted and subaerially exposed during Late Pliocene-Quaternary time. This allows the recognition of a number of discrete phases of sedimentary basin formation: 1. Late Cretaceous (Campanian-Maastrichtian): silicic volcanism to create a subaqueous volcaniclastic apron; 2. Maastrichtian-Paleocene: pelagic carbonate deposition interspersed with proximal gravity flows and within-plate type alkaline volcanics; 3. Early Eocene: large-scale sedimentary melange (olistostrome) emplacement; 4. Late Eocene-Late Miocene: terrigenous gravity-flow deposition in a deep-water fault dissected 'fore arc' setting. Initial, Late Eocene non-marine coarse clastic alluvial fan deposition was succeeded by Oligocene-Miocene deep-marine siliciclastic gravity flow deposits, fining and shallowing upwards during the Late Miocene; 5. Messinian: localised precipitation of evaporites in small fault-controlled basins; 6. Pliocene: shallow-marine siliciclastic-carbonate deposition in a shelf-depth, overall regressive setting; 7. Latest Pliocene to mid-Pleistocene: gravitational accumulation of coarse talus along a strongly uplifting

  15. Joint-inversion of Seismic and Gravity Survey Data in Sedimentary Basins for 3-D Underground Structures in Strong Motion Simulation

    Science.gov (United States)

    Koketsu, K.; Afnimar, A.

    2001-12-01

    Modeling of underground structures is one of important tasks for strong motion predition. Seismic surveys such as refraction and reflection explorations can give precise estimates of seismic velocities, but they are too expensive to cover the whole area of a sedimentary basin with a fine spacing of survey points. On the other hand, gravity surveys can be carried out densely and homogeneously with reasonable cost, but they cannot measure seismic velocities directly. In order to compromise this inconsistency, we combine data from the seismic and gravity surveys, and jointly invert them assuming a relation between densities and seismic velocities. An interface separating sediments and basement rocks is parameterized by the Lagrange interpolation with knot points distributed for representing a steep part related to a fault zone. The linear and absolute constraints are imposed to avoid oscillatory artifacts in the solution and to minimize the non-uniqueness of the solution. The joint inversion also overcome the ray coverage problem of a refraction survey in a complex underground structure. The validity of the formulation is verified using synthetic data for a valley-like basin with pseudo-random noises. The proposed method is successfully applied to the actual data obtained in and around the Osaka basin, Japan. The result shows a good agreement with the geological setting in this region. The instability due to the lack of data beneath the Osaka bay is improved by the introduction of the absolute constraints. We then apply the method to the Kanto basin around Tokyo assuming two layers in the sediments. This layering increases the number of variables introducing some instabilities into the inversion, and so measurements at boreholes and reflection survey lines are used as fixed points in the model.

  16. 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)

  17. 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.

  18. 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.

  19. 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.

  20. Stratigraphic architecture and forcing processes of the late Neogene Miradouro da Lua sedimentary prism, Cuanza Basin, Angola

    Science.gov (United States)

    Cauxeiro, C.; Durand, J.; Lopez, M.

    2014-07-01

    The Miradouro da Lua cliffs, which are 60 km south of Luanda, record the building and uplift of the late Neogene Palaeo-Cuanza delta. The detailed study of the sedimentary architecture and stacking pattern permitted separation of the pile into five depositional units bounded by erosional surfaces and characterised by separate facies associations (genetic sequences = units in this paper). At the base of the series, aeolian deposits (Unit 1) mark the development of a possible coastal desert during the late Miocene aridification. The major Pliocene sea-level rise (Transgressive Systems Tract) led to the drowning of the continental platform into a discrete shoreface-foreshore sequence (Unit 2), followed by an expanded deltaic sequence (Unit 3) that represents the main outcrop of the area. The sedimentary fabric of this prograding wedge during the Highstand Systems Tract reveals laterally stacked pluri-hectometic mouth bars built by the abrupt switching of a bird-foot delta during the Pliocene highstand. The clinoforms are deeply incised by submarine gullies filled both by periodic river-driven turbidite and tidal currents (Unit 4) during the coeval growing of the delta. The topset of the prograding wedge and associated gullies infill is truncated by an overall erosional unconformity that marks the widespread development of an extensive braid-delta system (Unit 5) during the lower Pleistocene sea-level drop (Lowstand Systems Tract). The last 6 m of the Braid-delta unit is overprinted by a ferallitic profile, forming the surface of the plateau and indicating long-term subaerial exposure and weathering processes consistent with the maximum warming of the middle to late Pleistocene interglacial periods. The successive abrupt shifts of the depositional systems through the sedimentary pile indicate a high-amplitude sea level amplified by major coastal uplifts and the reorganisation of the fluvial network. In this context, the palaeo-Cuanza prograding wedge signals the

  1. Field investigation with regard to the impermeability of clay formations. Helium-4 soil gas surveys in sedimentary basins as a tentative study of secondary permeability in clayey sequences

    International Nuclear Information System (INIS)

    This report deals with a tentative study for the detection of the secondary permeability in clayey formations conducted in several sedimentary basins in Central Italy, by means of geochemical methods. The main purposes are: to try a geochemical method, based on the distribution of deep origin gases in soil gas (4He and 222Rn), to detect buried fault systems and to study the permeability of clay as a potential migration pathway for nuclides of radioactive waste deposits; to verify the effectiveness of this method for the selection of suitable sites for radwaste disposal. This research programme consists in a collaboration between ENEA and the University of Rome within the communitarian programme for the disposal of high level and long-live radwaste. Investigations concerned sedimentary basins filled by sand-clay formations 1000-2000 meters thick and characterized by different tectonic: Era and Chiani-Paglia Valleys (Tuscany and North Latium), structural trenches due to extensive tectonics along the tyrrhenian edge, and Vasto region, a basin in the 'Adriatic foretrench', characterized by compressive tectonics. The investigated areas are near or directly correspond to geothermal fields or to hydrocarbon reservoirs supplying gases which may migrate upward along fractures. Almost 4000 soil gas samples were collected in the three surveyed areas; the sampling density was of about 1.5 points / km2, normally used in the regional scale surveys. The obtained results show that the observed helium anomalies are distributed or elongated according to the main tectonic features of the substratum (fault systems, fractures, deep structures); the magnitude of anomalies seems to correlate with the nature of the deep gas reservoir (i.e. oil in Vasto), geothermal reservoir in the Paglia valley. These observations seem to confirm that the presence of deep origin gases in soils is controlled by tectonics. Clay thickness does not significantly control the uprising of deep gases: in fact a

  2. 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

  3. 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。

  4. Revisiting the uplift history of the Qilian Shan in the northeast margin of the Tibetan Plateau: Evidence for sedimentary archive from the Jiuxi basin

    Science.gov (United States)

    Wang, W.; Zhang, P.; Liu, C.

    2012-12-01

    interpreted as heralding dramatically strengthening of the East Asian monsoon system. Consisting with the appearance of coarse detritus with provenance from the Qilian Shan at 10-11 Ma, we interpreted the late Miocene (~10 Ma) increase in sedimentary rate as the response of the initial uplift of the north Qilian Shan. This result is consistent with the rapid cooling and exhumation of the Qilian Shan at the late Miocene time (Zheng et al., 2006). The sedimentary characterizes of the Cenozoic deposits hold in the Jiuxi basin seems to suggest that the outmost region of the northeastern margin of the Tibetan Plateau had only been subject to influence associated with the climate change before ~17 Ma. Since 10 Ma, the northeastern perimeter of the Tibetan Plateau probably has under taken nearly the first time contractional deformation related to India-Eurasia continent collision.

  5. 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

  6. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil

    International Nuclear Information System (INIS)

    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 -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 μW m-3, 0,23 to 5,55 μW m-3 and 0,60 to 2,24 μW m-3, respectively. In this case, the heat production rates vary from 0,10 to 1,44 μW m-3. The basic granulites have the smaller rates, from 0,06 to 0,36 μW 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 μW m-3 for metatonalites, 0,71 +- 0,57 μW m-3 for metamonzonites and 1,20 +- 0,51 μW m-3 for sienites. (author)

  7. Probabilistic Seismic Hazard Maps of Seattle, Washington, Including 3D Sedimentary Basin Effects and Rupture Directivity: Implications of 3D Random Velocity Variations (Invited)

    Science.gov (United States)

    Frankel, A. D.; Stephenson, W. J.; Carver, D.; Odum, J.; Williams, R. A.; Rhea, S.

    2010-12-01

    We have produced probabilistic seismic hazard maps of Seattle for 1 Hz spectral acceleration, using over five hundred 3D finite-difference simulations of earthquakes on the Seattle fault, Southern Whidbey Island fault, and Cascadia subduction zone, as well as for random deep and shallow earthquakes at various locations. The 3D velocity model was validated by modeling the observed waveforms for the 2001 M6.8 Nisqually earthquake and several smaller events in the region. At these longer periods (≥ 1 sec) that are especially important to the response of buildings of ten stories or higher, seismic waves are strongly influenced by sedimentary basins and rupture directivity. We are investigating how random spatial variations in the 3D velocity model affect the simulated ground motions for M6.7 earthquakes on the Seattle fault. A fractal random variation of shear-wave velocity with a Von Karman correlation function produces spatial variations of peak ground velocity with multiple scale lengths. We find that a 3D velocity model with a 10% standard deviation in shear-wave velocity in the top 1.5 km and 5% standard deviation from 1.5-10 km depth produces variations in peak ground velocities of as much as a factor of two, relative to the case with no random variations. The model with random variations generally reduces the peak ground velocity of the forward rupture directivity pulse for sites near the fault where basin-edge focusing of S-waves occurs. It also tends to reduce the peak velocity of localized areas where basin surface waves are focused. However, the medium with random variations also causes small-scale amplification of ground motions over distances of a few kilometers. We are also evaluating alternative methods of characterizing the aleatory uncertainty in the probabilistic hazard calculations.

  8. THE JURASSIC SEDIMENTARY EVOLUTION OF A CARBONATE PLATFORM INTO A DEEP-WATER BASIN, MT. MANGART (SLOVENIAN-ITALIAN BORDER

    Directory of Open Access Journals (Sweden)

    ANDREJ SMUC

    2005-03-01

    Full Text Available A complete Jurassic succession, recording the evolution from platform margin to a deep-water basin, is exposed at Mt. Mangart in the Julian Alps. The succession is a part of the Julian Nappe, where the Southern Alps overlap with the Dinarides. In the Jurassic, the area comprised part of the south Tethyan passive continental margin. The section was studied sedimentologically in detail and dated with radiolarians. It is divided into five lithostratigraphic units: Unit 1: Lower Jurassic shallow-water peloidal and oncoidal limestones; Unit 2: Pliensbachian distal shelf limestones rich in juvenile ammonites and sponge spicules topped by an Fe-Mn hardground; Unit 3: lower to possibly middle Toarcian sequence of black shales with interbedded siliceous limestone; Unit 4: upper Bajocian/Bathonian to lower Tithonian cherts, cherty limestones, and carbonate gravity-flow deposits; Unit 5: upper Tithonian red nodular cherty limestones with abundant calpionellids and aptychi. A stratigraphic gap, comprising the late Toarcian to early Bajocian, separates Unit 4 from Unit 3. In general, the succession correlates well with known Tethyan transgressive/regressive facies cycles. In addition, two periods of accelerated subsidence were recognized, the first, in the Pliensbachian, drowned the platform, the second, prior to the late Bajocian, created accommodation space for resedimented carbonate deposits from the adjacent Friuli Carbonate Platform. The present day position of the succession is between the Belluno Basin to the west and the Slovenian Basin to the south. The hitherto described successions of these two basins were located more distally from the Friuli Carbonate Platform than the Mt. Mangart succession. 

  9. 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

  10. Geochemistry of Precambrian sedimentary rocks used to solve stratigraphical problems: An example from the Neoproterozoic Volta basin, Ghana

    DEFF Research Database (Denmark)

    Kalsbeek, F.; Frei, Robert

    2010-01-01

    siltstones and mudstones, intercalated with the sandstones from the different units, were used in an attempt to solve some of these problems. Siltstones and mudstones from the Bombouaka Group can be unequivocally distinguished from similar rocks from the Oti and Obosum Groups by higher K2O and Rb, larger Eu...... anamalies, higher 87Sr/86Sr, and more negative var epsilonNd values. Geochemical distinction between samples from the Oti and Obosum Groups is ambiguous because published geological maps differ with respect to the relative extents of the Oti and Obosum Groups. Rb–Sr isotope data, combined with high degrees...... from the Oti and Obosum Groups is used to solve one of the outstanding controversies regarding the stratigraphy of the Volta basin....

  11. Ejected Sedimentary Rocks of Mud Volcanoes as Indicators of Depositional Environments and of Hydrocarbon Generation within the South Caspian Basin, Azerbaijan

    Science.gov (United States)

    Berner, U.; Scheeder, G.; Kus, J.; Köthe, A.; Movsumova, U.

    2009-04-01

    Mud volcanoes are prominent geological features of the South Caspian Basin of Azerbaijan, one of the oldest oil producing regions worldwide. The basin is characterized by extreme sedimentation rates, which lead to the accumulation of large volumes of Mesozoic and Cenozoic sediments. These mostly unconsolidated strata reach thicknesses of up to 20 km and overlay a continental basement in the onshore part. Tectonic forces control the occurrences of mud volcanoes in regions with over-pressured subsurface sediments as mud volcanoes are closely linked to fault systems. The mud volcanoes of Azerbaijan are a surface expression of vertical hydrocarbon migration and offer the chance to investigate the subsurface by means of ejected rocks transported to the surface. These rocks of Mesozoic and Cenozoic sedimentary sequences are potential indicators of the regional hydrocarbon generation. The mud of nineteen volcano cones contained numerous ejected rock fragments, which we use to identify environmental and depositional parameters of the sediments of the Caspian Basin. We also intended to estimate the depth range from which the mud was transported to the surface using organic geochemical parameters. Mircopalaeontological investigations (calcareous nannoplankton) have been performed on selected samples. These analyses suggest that the investigated sediments are of Late Cretaceous to Palaeogene ages and relate to the stratigraphic interval during which the main hydrocarbon source rocks of Azerbaijan have been deposited. Organic geochemical, organic petrographical and mircopalaeontological investigations have been performed on selected samples of nineteen mud volcanoes. Analyses total organic carbon and total sulphur were performed on an elemental analyzer. These analyses suggest that the sediments can be classified as anoxic marine deposits whereas only few are sediments of a lacustrine environment. Bulk source rock information were obtained from RockEval pyrolysis. Resulting

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

    Science.gov (United States)

    Farid, Asam; Khalid, Perveiz; Jadoon, Khan Zaib; Jouini, Mohammed Soufiane

    2014-10-01

    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. PMID:25004850

  13. 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.

  14. 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.

  15. 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)

  16. 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

    2016-01-01

    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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Methane leakage during the evolution of petroleum systems in the Western Canada Sedimentary Basin and the Central Graben area of the North Sea

    Science.gov (United States)

    Berbesi, L. A.; di Primio, R.; Anka, Z.; Horsfield, B.

    2012-04-01

    Around 500 to 600 Tg (1 Tg = 1012 g) of methane enter the atmosphere every year, mainly as product of microbial processes and combustion of fossil fuels and burning biomass. The importance of another source, the geologic emissions of methane, is up to now only loosely constrained. In this study, we addressed the potential methane emissions during the geological evolution of the Western Canada sedimentary basin (WCSB), which holds the largest oil sand accumulations in the world, and the Central Graben area of the North Sea. In the case of the WCSB, thermogenic gas generation and leakage at the sediment surface were addressed through 3D petroleum systems modeling. In this basin, the accumulated oil experienced intense biodegradation that resulted in large masses of biogenic methane. We quantified this latter mass though a two-step mass balance approach. Firstly, we estimated the rate of petroleum degradation and the magnitude of petroleum loss. After this, we calculated the mass of biogenic methane generated using a model that assumes hexadecane (C16H34) as representative of the saturated compounds (Zengler et al., 1999). Our 3D model suggests that 90000-150000 Tg of dry gas (mostly methane) could have leaked during the interval from 80 Ma to 60 Ma. Therefore, uniform leakage rates would have been in the order of 10-3-10-2 Tg yr-1. Biogenic methane generation could have taken place at rates of 10-4 to 10-2 Tg yr-1. However, the effective mass of thermogenic and biogenic methane reaching the atmosphere might have been up to 90% lower than calculated here due to methanotrophic consumption in soils (Etiope and Klusman, 2002). We addressed the thermogenic gas generation and leakage in the Central Graben through two different methods. The first is based on a previous 3D petroleum system modeling of the region (Neumann, 2006). The second consisted of calculating the mass of generated petroleum based on source rock extension and properties (Schmoker, 1994), and then

  2. 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

  3. 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

  4. 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

  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. Hydrogen isotopic compositions of individual alkanes as a new approach to petroleum correlation: case studies from the Western Canada Sedimentary Basin

    Energy Technology Data Exchange (ETDEWEB)

    Maowen Li; Obermajer, M.; Chunqing Jiang; Snowdon, L.R.; Fowler, M.G. [Geological Survey of Canada, Calgary (Canada); Yongsong Huang [Brown University, Providence, RI (United States). Department of Geological Science

    2001-07-01

    Isotopic compositions of carbon-bound hydrogen in individual n-alkanes and acyclic isoprenoid alkanes, from a number of crude oil samples, were measured using gas chromatography-thermal conversion-isotope ratio mass spectrometry. The precision of this technique is better than 3 per cent for most alkanes, compared to the large range of {delta}D variation among the samples (up to 160 per cent). The oils were selected from major genetic oil families in the Western Canada Sedimentary Basin, with source rocks ranging in age from Ordovician (and possibly Cambrian) to Cretaceous. The hydrogen isotopic composition of alkanes in crude oils is controlled by three factors: isotopic compositions of biosynthetic precursors, source water {delta}D values, and postdepositional processes. The inherited difference in the lipid's biosynthetic origins and/or pathways is reflected by a small hydrogen isotopic variability within n-alkanes, but much larger differences in the {delta}D values between n-alkanes and pristane/phytane. The shift toward lighter hydrogen isotopic compositions from Paleozoic to Upper Cretaceous oils in the WCSB reflects a special depositional setting and/or a minor contribution of terrestrial organic matter. The strong influence of source water {delta}D values is demonstrated by the distinctively lower {delta}D values of lacustrine oils than marine oils, and also by the high values for oils with source rocks deposited in evaporative environments. Thermal maturation may alter the {delta}D values of the alkanes in the oil to some extent, but secondary oil migration does not appear to have had any significant impact. The fact that oils derived from source rocks that could be of Cambrian age still retain a strong signature of the hydrogen isotopic compositions of source organic matter, and source water, indicates that {delta}D values are very useful for oil-source correlation and for paleoenvironmental reconstructions. (author)

  7. 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

  8. 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)

  9. Potential use of petroleum inclusions in the study of hydrocarbon degradation in oil sands and heavy oils in the Western Canada Sedimentary Basin : examples from western Saskatchewan

    Energy Technology Data Exchange (ETDEWEB)

    Chi, G.; Tong, A. [Regina Univ., SK (Canada). Dept. of Geology; Lai, J. [Regina Univ., SK (Canada). Dept. of Geology]|[Central South Univ. Changsha, Hunan (China). School of Geoscience and Environmental Engineering; Pedersen, P. [Apache Canada Ltd., Calgary, AB (Canada)

    2006-07-01

    This paper presented the results of a microthermometric inclusion study of the Celtic Pool in western Saskatchewan's Lloydminster Deposit. Petroleum inclusions are useful for investigating hydrocarbon biodegradation processes that influenced the diagenesis of oil sands and heavy oils in the Western Canada Sedimentary Basin (WCSB). The significant biodegradation which has occurred in the Lower Cretaceous Mannville Group in the WCSB is closely associated with the burial temperatures of the reservoir rocks. These inclusions record petroleum characteristics in the different stages of reservoir evolution and can potentially give information about the conditions associated with biodegradation. The heavy oil reservoir contains two types of oil inclusions, namely a brown, non-fluorescent one; and, a light-coloured, fluorescent type. The latter occurs as secondary inclusions in detrital quartz and may record the petroleum in the reservoir before significant biodegradation. According to microthermometric studies, this type of oil inclusion suggests a wide range of homogenization temperatures mainly attributed to heterogenous oil trapping. Possible trapping temperatures may be 76 to 98 degrees C. However, homogeneous trapping was also recorded, with valid homogenization temperatures ranging from 29 to 113 degrees C. These range of temperature may reflect the change of petroleum temperature during the evolution of the reservoir, with the higher temperatures representing a hot oil charge event responsible for lower degree of biodegradation compared to that in the Athabasca and Cold Lake deposits. The study identified several problems associated with heterogeneous trapping and validation of homogenization temperatures. It was suggested that these problems may be solved by finding trails of petroleum inclusions with consistent homogenization temperatures. 21 refs., 2 tabs., 3 figs.

  10. A Hypothetical Scenario for Full-Scale Deployment of Geological Carbon Sequestration: Investigating the Interaction Between Multiple CO2 Storage Sites in a Sedimentary Basin

    Science.gov (United States)

    Birkholzer, J.; Zhou, Q.; Jordan, P.; Tsang, C.; Leetaru, H.; Mehnert, E.; Frailey, S.; Finley, R.

    2008-12-01

    Most ongoing projects of geological carbon sequestration (GCS) are relatively small in size, with annual injection rates from a few thousand to less than a million tonnes. These projects help build the GCS technology with respect to modeling, monitoring, risk assessment, and mitigation, and have been successful so far in terms of CO2 containment and caprock geomechanical integrity. In the future, GCS will be implemented at full-scale, multiple industrial-size CO2 storage sites in large sedimentary basins to make full use of the potential storage capacity. Simultaneous injection into multiple not-too-distant storage sites will lead to interference between the individual regions of pressure build-up and possible interference between the individual CO2 plumes. The Illinois Basin is used to model the future impact of multiple injection sites in the thick, extensive Mount Simon Formation. The basin-scale model domain of 241,000 km2 covers a core injection area of 24,000 km2, a larger near-field area where significant pressure buildup is expected, and an even larger far-field area for investigating environmental impacts on groundwater resources. The model assumes that there are twenty sequestration sites (spaced 30 km apart) within the core injection area. Three injection scenarios are considered, featuring annual injection rates of 5, 10, and 15 million tonnes of CO2 at each site, respectively. These scenarios correspond to 33%, 67% and 100% of the current single-point large CO2 sources in the relevant states (Illinois, Indiana and Kentucky). The model adequately captures the characteristics of the Mount Simon Formation in the core injection area, which include (1) an overall thickness of 300 to 680 m, (2) an upper unit of sandstone and shale tidally influenced and deposited, (3) a thick middle unit of clean sandstone of relatively high permeability, and (4) a lower arkosic unit of higher permeability (one Darcy) with an average thickness of 90 m. At each site, CO2 is

  11. 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

  12. 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)

  13. 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

  14. Late quaternary uplift and subsidence of the west coast of Tanna, south Vanuatu, southwest Pacific: U-Th ages of raised coral reefs in the Median Sedimentary Basin

    International Nuclear Information System (INIS)

    Twelve Late Quaternary TIMS U-Th ages are reported here from 10 coral samples collected in situ from five transgressive coral/algal raised reefs (height: max. 113m, min. 8m) and two raised lagoonal deposits (height: max. 18 m, min. 8 m) along and near the west coast of Tanna, which lies in the Median Sedimentary Basin of South Vanuatu, southwest Pacific. These reefs and raised lagoonal deposits represent several age groups: (i) 215ka (marine oxygen-isotope stage 7) penultimate interglacial (highest elevation and oldest); (ii) one lagoonal deposit of ca 127 ka (marine oxygen-isotope stage 5e); (iii) three last interglacial reefs with ages 102, 89 and 81 ka (representing marine oxygen-isotope stages 5c, 5b and 5a, respectively, of the latter part of the last interglacial); (iv) a lagoonal deposit with a 92 ka age (5b); and (v) a Holocene reef (age >5.7-5.0 ka) (lowest elevation and youngest). A ca 4.9 ka regressive reef (at elevation of 1.5 m above sea-level) is consistent with an island-wide 6.5m uplift (probably largely coseismic), and a probable further island-wide uplift-occurred in the late Holocene. The U-series ages taken together with the heights of transgressive reefs show that uplift since 215 ka was, on average, at -0.52 mm/y, although since 5 ka the uplift rate was, on average, ∼1.6 mm/y (the assumption being that a 1.5 m above sea-level reef has a coseismic origin) Elevation of transgressive reefs 5a, 5b and 5c and their ages indicates an island-wide subsidence during the period ?124-89 ka (i.e. Late Quaternary uplift/subsidence was jerky). Late Quaternary uplift/subsidence on the northwest coast of Tanna is considered to be due to irregular thickness of crust being subducted beneath Tanna. Copyright (2003) Geological Society of Australia

  15. 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

  16. 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

  17. Eocene to Pleistocene lithostratigraphy, chronostratigraphy and tectono-sedimentary evolution of the Calama Basin, northern Chile Litoestratigrafía, cronoestratigrafía durante el Eoceno al Pleistoceno y evolución tectono-sedimentaria de la Cuenca de Calama, norte de Chile

    OpenAIRE

    Geoffrey May; Adrian J Hartley; Guillermo Chong; Fin Stuart; Peter Turner; Stephanie J Kape

    2005-01-01

    New 40Ar/39Ar radiometric, sedimentological and structural data from post-Paleocene sedimentary strata in the Calama Basin, northern Chile suggest that the established lithostratigraphy of the basin-fill requires revision. A new lithostratigraphic scheme for the Eocene-Pleistocene stratigraphy of the Calama Basin is proposed here. The key features of this scheme are that the existing Calama Formation is retained although the age of the formation is redefined as (?Lower) Eocene to (?)Lower Mio...

  18. 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

  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. A contribution to regional stratigraphic correlations of the Afro-Brazilian depression - The Dom João Stage (Brotas Group and equivalent units - Late Jurassic) in Northeastern Brazilian sedimentary basins

    Science.gov (United States)

    Kuchle, Juliano; Scherer, Claiton Marlon dos Santos; Born, Christian Correa; Alvarenga, Renata dos Santos; Adegas, Felipe

    2011-04-01

    the Dom João Stage, in which distinctive sedimentary environments were developed, reflecting depositional system arrangements, paleoflow directions were diverse, and continuous or compartmented basins were developed.

  2. 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

  3. Evaluation criteria for uranium potential of sedimentary basins based on analysis of host sand body and structurally reworking pattern host sand body has been subject to

    International Nuclear Information System (INIS)

    On the basis of the introduction and the analysis of regional evaluation criteria for sandstone-type uranium deposits summarized by uranium geologists of USA and former Soviet Union, and by introducing new scientific progress in the field of sedimentology of clastic rocks, and basin geodynamics, main evaluation criteria composed of host sand body criterion and the criterion of structurally reworking pattern the host sand body has been subject to, are proposed, and the evaluation model based on analyzing the regional tectonic history and the evolution of prototype basin is set up. Finally, taking the Chaoshui basin as an example, the possibility for hosting epigenetic uranium mineralization in each horizon of the basin cover is discussed, then the main prospecting target horizon is discriminated, and potential ore-formation areas are proposed. (authors)

  4. RRS "Charles Darwin" Cruise CD166, 29 Oct - 22 Nov 2004. Sedimentary processes and deposits in the Agadir Basin and Gulf of Cadiz

    OpenAIRE

    Wynn, R.B.; Cronin, B.T.

    2005-01-01

    The primary aim of CD166 was to undertake intensive coring in the Agadir Basin on the Northwest African margin, with the intention of characterising deep-water gravity flow processes and deposits at a basin-wide scale. In addition, it was hoped that sampling of volcaniclastic turbidites derived from Canary Islands landslides would provide insights into landslide processes and aid assessment of potential tsunami hazards. In addition, the first two days of the cruise were assigned to piston cor...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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)

  10. 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

  11. 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)

  12. Polygon/Cracked Sedimentary Rock

    Science.gov (United States)

    2004-01-01

    4 December 2004 Exposures of sedimentary rock are quite common on the surface of Mars. Less common, but found in many craters in the regions north and northwest of the giant basin, Hellas, are sedimentary rocks with distinct polygonal cracks in them. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example from the floor of an unnamed crater near 21.0oS, 311.9oW. Such cracks might have formed by desiccation as an ancient lake dried up, or they might be related to ground ice freeze/thaw cycles or some other stresses placed on the original sediment or the rock after it became lithified. The 300 meter scale bar is about 328 yards long. The scene is illuminated by sunlight from the upper left.

  13. Palaeontology, sedimentary environments and climatic indices of the Kloubouky horizon (Líně formation, Upper Pennsylvanian, Kladno-Rakovník basin, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Z.; Martínek, K.; Zajíc, Jaroslav; Drábková, J.; Mikuláš, Radek; Valentová, D.

    Kraków : Akademia górniczo-hutnicza im. S. Staszica, 2009, s. 69-78. ISBN 978-83-919850-5-9. [Sympozjum geologia formacji weglonosnych Polski /32./. Kraków (PL), 22.04.2009-23.04.2009] R&D Projects: GA AV ČR IAA300130703 Institutional research plan: CEZ:AV0Z30130516 Keywords : Upper Pennsylvanian * palaeontology * Kladno-Rakovník Basin (Czech Republic) Subject RIV: DB - Geology ; Mineralogy

  14. 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

  15. Deciphering sedimentary recycling via multiproxy in situ analyses

    OpenAIRE

    Lancaster, Penelope J.; Tyrrell, Shane; Daly, J. Stephen; Storey, Craig D.

    2013-01-01

    Sedimentary rocks and modern sediments sample large volumes of the Earth’s crust, and pre-serve units that vary greatly in age and composition. Determining the provenance of component minerals is complicated by the ability of some minerals to be recycled through multiple sedimentary cycles, so minerals from completely unrelated sources may end up in the same sedimentary basin. To untangle these multi-stage signals, two or more chemical signatures measured in minerals with different stability ...

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  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. 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)

  15. 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。

  16. 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)

  17. 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

  18. 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.

  19. 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.

  20. Climatic changes in Stephanian C (uppermost Pennsylvanian): sedimentary facies, paleosols, environments and biota of the Ploužnice lacustrine system, Krkonoše Piedmont Basin, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Martínek, K.; Šimůnek, Z.; Drábková, J.; Zajíc, Jaroslav; Stárková, M.; Opluštil, S.; Rosenau, N.; Lojka, R.

    Freiberg: Technische Universität Bergakademie Freiberg, Institut für Geologie, 2014 - (Elicki, O.; Schneider, J.; Spindler, F.). s. 34-35 [Field Meeting on Carboniferous and Permian Nonmarine – Marine Correlation. 21.07.2014-27.07.2014, Freiberg] Institutional support: RVO:67985831 Keywords : Stephanian C * Pennsylvanian * sedimentary facies * paleosols * environments * biota Subject RIV: DB - Geology ; Mineralogy

  1. 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

  2. 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)

  3. 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

  4. 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,...

  5. 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 ...

  6. 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.

  7. 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.

  8. 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...

  9. Eocene to Pleistocene lithostratigraphy, chronostratigraphy and tectono-sedimentary evolution of the Calama Basin, northern Chile Litoestratigrafía, cronoestratigrafía durante el Eoceno al Pleistoceno y evolución tectono-sedimentaria de la Cuenca de Calama, norte de Chile

    Directory of Open Access Journals (Sweden)

    Geoffrey May

    2005-01-01

    Full Text Available New 40Ar/39Ar radiometric, sedimentological and structural data from post-Paleocene sedimentary strata in the Calama Basin, northern Chile suggest that the established lithostratigraphy of the basin-fill requires revision. A new lithostratigraphic scheme for the Eocene-Pleistocene stratigraphy of the Calama Basin is proposed here. The key features of this scheme are that the existing Calama Formation is retained although the age of the formation is redefined as (?Lower Eocene to (?Lower Miocene. The El Loa Formation is elevated to group status and redefined as Lower Miocene to Upper Pliocene in age. The El Loa Group includes four newly defined formations: the Jalquinche, Opache, Lasana and Chiquinaputo formations. The existing definition of the uppermost unit within the Calama Basin, the Upper Pliocene to Pleistocene Chiu-Chiu Formation, is retained. The tectono-sedimentary evolution of the Calama Basin-fill reveals three distinct unconformity-bounded phases of sedimentation: Eocene-Oligocene, early Miocene to late mid-Miocene and late Miocene to late Pliocene. Sedimentation commenced in the Eocene with deposition of alluvial braidplain deposits (Calama Formation. This style of sedimentation occurred across northern Chile throughout the Oligocene following the Incaic Orogeny. From 22 Ma to 10 Ma ephemeral fluvial sediments were developed along the Calama Basin flanks (Lasana Formation, playa sandflat and mudflat deposits (Jalquinche Formation in the basin centre. Equivalently-aged sediments in both the Salar de Atacama and Pampa del Tamarugal basins also indicate deposition in endorheic basins. Late Miocene sedimentation occurred diachronously across the north Chilean forearc. The Pampa del Tamarugal and Calama Basin areas were linked around 6 Ma following tectonic activity. Regional palustrine carbonate sedimentation occurred in the Calama Basin centre (Opache Formation with fluvial sedimentation along the eastern basin margin (Chiquinaputo

  10. 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)

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. Overview of the influence of syn-sedimentary tectonics and palaeo-fluvial systems on coal seam and sand body characteristics in the Westphalian C strata, Campine Basin, Belgium

    Science.gov (United States)

    Dreesen, Roland; Bossiroy, Dominique; Dusar, Michiel; Flores, R.M.; Verkaeren, Paul

    1995-01-01

    The Westphalian C strata found in the northeastern part of the former Belgian coal district (Campine Basin), which is part of an extensive northwest European paralic coal basin, are considered. The thickness and lateral continuity of the Westphalian C coal seams vary considerably stratigraphically and areally. Sedimentological facies analysis of borehole cores indicates that the deposition of Westphalian C coal-bearing strata was controlled by fluvial depositional systems whose architectures were ruled by local subsidence rates. The local subsidence rates may be related to major faults, which were intermittently reactivated during deposition. Lateral changes in coal seam groups are also reflected by marked variations of their seismic signatures. Westphalian C fluvial depositional systems include moderate to low sinuosity braided and anastomosed river systems. Stable tectonic conditions on upthrown, fault-bounded platforms favoured deposition by braided rivers and the associated development of relatively thick, laterally continuous coal seams in raised mires. In contrast, rapidly subsiding downthrown fault blocks favoured aggradation, probably by anastomosed rivers and the development of relatively thin, highly discontinuous coal seams in topogenous mires.

  16. 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

  17. 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

  18. 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.

  19. Linking basin evolution to plate tectonic processes in (northern) Africa

    OpenAIRE

    Gravråk, Mariann

    2011-01-01

    Several sedimentary basins in Africa are classified as intracratonic basins, but no conclusive formation mechanism has been identified for these basin types. Tectonic subsidence curves may help in unraveling formation mechanisms or identify tectonic forcing for these basins. This thesis presents and analyses basin subsidence curves for basins in the interior of Africa and near its passive margins. A backstripping program has been written to solve the backstripping equations needed to make the...

  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. 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)

  2. Stratigraphy of neoproterozoic sedimentary and volcano sedimentary successions of Uruguay

    International Nuclear Information System (INIS)

    Based on the new data the different characteristics of the Neoproterozoic (volcano) sedimentary succesions of Uruguay are described and discussed. Their stratigraphic tectonics and palaeoclimatic implications are analyzed.The results of the present investigations also allow to define the Maldonado Group which would beintegrated by the Playa Hermosa and Las Ventanas formations.

  3. The White Nile sedimentary system

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived

  4. 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)

  5. 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

  6. 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)

  7. Apport des expériences de mécaniques des roches à la géologie structurale des bassins sédimentaires Contribution of Rock-Mechanics Experiments to the Stuctural Geology of Sedimentary Basins

    Directory of Open Access Journals (Sweden)

    Poulet M.

    2006-11-01

    specify the area where rock-mechanics experiments con be applied to structural geology, this article begins by defining the ordres of magnitude of the different factors in nature that control stress/strain relations i, e. the stresses involaed, rate of strain, temperature and anisotropy of rock. A review is then made of laborofory test results of the uniaxial type (surface conditions and then of the triaxial type (deep conditions, with the nature of the stresses involved being specified in each case, i.e. tension, compression and/or shear. Rock behavior during compression tests enables them to be classified in three categories : so-called elastic rocks (compact sedimentary, metamorphic and crystalline rocks, so-called elasto-plastic rocks with some porosity (sandstone, iimestone, so called plastic rocks (salt, gypsum. With each type thus defined, laboratory experiments are performed ta analyze the influence of the following parameters : confining pressure which increases with depth and makes for considérable permanent...

  8. 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

  9. 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.

  10. Biostratigraphy and sedimentary evolution of continental Neogene in the Madrid area

    OpenAIRE

    Alberdi Alonso, María Teresa; Hoyos Gómez, Manuel; Junco, Fernando; López Martínez, Nieves; Morales, Jorge; Sesé, Carmen; Soria, Dolores

    1984-01-01

    ABSTRACT: This is a study of the Lower and Middle Miocene in the area of Madrid. Sedimentation in this zone of the Tajo Basin corresponds to endorheic deposits fed by alluvial fans from the Sistema Central which, after transition facies, flow into the centre of the basin. Three sedimentary units can be distinguished throughout the distribution of these deposits: Lower, Intermediate and Upper. The base of the Lower Unit has been dated only by mammals fossils from drillings. It has been attribu...

  11. 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

  12. 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)

  13. 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.

  14. Mineralogy of selected sedimentary interbeds at or near the Idaho National Engineering Laboratory, Idaho

    International Nuclear Information System (INIS)

    The US Geological Survey's (USGS) Project Office at the Idaho National Engineering Laboratory (INEL) analyzed 66 samples from sedimentary interbed cores during a 38-month period beginning in October 1990 to determine bulk and clay mineralogy. These cores had been collected from 19 sites in the Big Lost River Basin, 2 sites in the Birch Creek Basin, and 1 site in the Mud Lake Basin, and were archived at the USGS lithologic core library at the INEL. Mineralogy data indicate that core samples from the Big Lost River Basin have larger mean and median percentages of quartz, total feldspar, and total clay minerals, but smaller mean and median percentages of calcite than the core samples from the Birch Creek Basin. Core samples from the Mud Lake Basin have abundant quartz, total feldspar, calcite, and total clay minerals. Identification of the mineralogy of the Snake River Plain is needed to aid in the study of the hydrology and geochemistry of subsurface waste disposal

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth’s Sedimentary Cycle

    Science.gov (United States)

    Hadlari, Thomas; Swindles, Graeme T.; Galloway, Jennifer M.; Bell, Kimberley M.; Sulphur, Kyle C.; Heaman, Larry M.; Beranek, Luke P.; Fallas, Karen M.

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon. PMID:26658165

  20. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth's Sedimentary Cycle.

    Science.gov (United States)

    Hadlari, Thomas; Swindles, Graeme T; Galloway, Jennifer M; Bell, Kimberley M; Sulphur, Kyle C; Heaman, Larry M; Beranek, Luke P; Fallas, Karen M

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon. PMID:26658165

  1. Composition and sources of sedimentary organic matter in the deep Eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    R. Pedrosa-Pàmies

    2015-07-01

    Full Text Available Surface sediments collected from deep slopes and basins (1018–4087 m depth of the oligotrophic Eastern Mediterranean Sea have been analysed for bulk elemental and isotopic composition of organic carbon, total nitrogen and selected lipid biomarkers, jointly with grain size distribution and other geochemical proxies. The distribution and sources of sedimentary organic matter (OM have been subsequently assessed and general environmental variables, such as water depth and currents, have been examined as causative factors of deep-sea sediment characteristics. Lithogenic and biogenic carbonates are the dominant sedimentary fractions, while both bulk and molecular organic tracers reflect a mixed contribution from autochthonous and allochthonous sources for the sedimentary OM, as indicated by relatively degraded marine OM, terrestrial plant waxes and anthropogenic OM including degraded petroleum by-products, respectively. Wide regional variations have been observed amongst the studied proxies, which reflect the multiple factors controlling sedimentation in the deep Eastern Mediterranean Sea. Our findings highlight the role of deep Eastern Mediterranean basins as depocentres of organic-rich fine-grained sediments (mean 5.4 ± 2.4 μm, with OM accumulation and burial due to aggregation mechanisms and hydrodynamic sorting. A multi-proxy approach is hired to investigate the biogeochemical composition of sediment samples, which sheds new light on the sources and transport mechanisms along with the impact of preservation vs. diagenetic processes on the composition of sedimentary OM in the deep basins of the oligotrophic Eastern Mediterranean Sea.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. Terminal Fluvial Systems in a Semi-arid Endorheic Basin, Salar de Uyuni (Bolivia)

    OpenAIRE

    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 been conducted on fluvial systems in endorheic basins; however, the fluvial architecture and facies distribution in ancient fluvial systems are not fully understood. Although they are an important key...

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. Sedimentary record of mid-Miocene seismotectonic activity in the Sinop Peninsula, north-central Turkey

    OpenAIRE

    Ayhan ILGAR

    2014-01-01

    The middle Miocene shallow-marine siliciclastic succession in the Sinop Peninsula, north-central Turkey, bears a well-preserved sedimentary record of syndepositional deformation associated with the buried escarpment of an oblique-slip dextral reverse fault and attributed to seismotectonic activity. The deposition occurred in a marginal trough at the edge of a tectonically inverted retroarc foreland basin of the Central Pontides. The synsedimentary deformation involved contemporaneous shorefac...

  14. 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...... major physical 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 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...

  15. 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...

  16. Relationships between basin architecture, basin closure, and occurrence of sulphide-bearing schists

    DEFF Research Database (Denmark)

    Kalliomäki, Henrik; Torvela, Taija; Moreau, Julien;

    2014-01-01

    We present field observations from the Palaeoproterozoic volcano-sedimentary Tampere palaeobasin, where the primary structures have been exceptionally well preserved. We use the observations to construct a new tectonic model for the southeastern margin of the Tampere basin during its inversion and...... subsequent closure. The observed volcano-sedimentary and structural features suggest a change in the local structural style from thick-skinned inversion to thin-skinned thrusting, in order to accommodate the crustal shortening during basin closure. Furthermore, it is suggested that there is a genetic...

  17. Cooperative Petroleum Contracts of the First Bidding Round are Perfectly Implemented in Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Pengpeng; Zhang Yirong

    1995-01-01

    @@ Tarim Basin is one of the largest sedimentary basins in the world covering an area of 560 000 square kilometers, with a fairly-good petroleum geological conditions and richaccumulated petroleum resources.Therefore, the southeast part of Tarim Basin was selected as the first bidding rotund area that are divided into five blocks. The coverage area is 72 730 square kilometers in total.

  18. Discussion on the characteristics of Meso-Cenozoic U-productive basins in northern China and their prospecting direction

    International Nuclear Information System (INIS)

    Based on the study of sedimentary evolution characteristics of main sedimentary basins and combined with characteristics of known uranium-productive basins in northern China, and the analysis on airborne geophysical survey data, the principles for selecting prospecting and target area have been set up. And the prospecting direction for uranium in Meso-Cenozoic basins of northern China has been proposed through a preliminary analysis. (authors)

  19. The geologic history of Margaritifer basin, Mars

    Science.gov (United States)

    Salvatore, M. R.; Kraft, M. D.; Edwards, C. S.; Christensen, P. R.

    2016-03-01

    In this study, we investigate the fluvial, sedimentary, and volcanic history of Margaritifer basin and the Uzboi-Ladon-Morava outflow channel system. This network of valleys and basins spans more than 8000 km in length, linking the fluvially dissected southern highlands and Argyre basin with the northern lowlands via Ares Vallis. Compositionally, thermophysically, and morphologically distinct geologic units are identified and are used to place critical relative stratigraphic constraints on the timing of geologic processes in Margaritifer basin. Our analyses show that fluvial activity was separated in time by significant episodes of geologic activity, including the widespread volcanic resurfacing of Margaritifer basin and the formation of chaos terrain. The most recent fluvial activity within Margaritifer basin appears to terminate at a region of chaos terrain, suggesting possible communication between surface and subsurface water reservoirs. We conclude with a discussion of the implications of these observations on our current knowledge of Martian hydrologic evolution in this important region.

  20. The 1997 Los Angeles Basin Passive Seismic Experiment – a dense, urban seismic array to investigate basin lithospheric structures

    OpenAIRE

    Kohler, Monica D.; Kerr, Bryan C.; Davis, Paul M.

    2000-01-01

    In 1997, 18 seismic stations were installed in the Los Angeles basin to record teleseismic, regional, and local earthquakes. The goals of the experiment were to quantify amplification of ground motion due to variations in sedimentary environments and subsurface structures, and to examine the tectonic extensional and compressional history of the Los Angeles basin and San Gabriel Mountains by tomograhic imaging. The linear array spanned the entire basin between Seal Beach to the south and Az...

  1. Composition and sources of sedimentary organic matter in the deep eastern Mediterranean Sea

    Science.gov (United States)

    Pedrosa-Pàmies, R.; Parinos, C.; Sanchez-Vidal, A.; Gogou, A.; Calafat, A.; Canals, M.; Bouloubassi, I.; Lampadariou, N.

    2015-12-01

    Surface sediments collected from deep slopes and basins (1018-4087 m depth) of the oligotrophic eastern Mediterranean Sea have been analysed for bulk elemental and isotopic composition of organic carbon, total nitrogen and selected lipid biomarkers, jointly with grain size distribution and other geochemical proxies. The distribution and sources of sedimentary organic matter (OM) have been subsequently assessed and general environmental variables, such as water column depth and physical circulation patterns, have been examined as causative factors of deep-sea sediment characteristics. Lithogenic and biogenic carbonates are the dominant sedimentary fractions, accounting for up to 85.4 and 66.5 % of the total weight respectively. The low OC and TN contents in the surface sediments of the study area, which ranged from 0.15 to 1.15 % and 0.06 to 0.11 % respectively, reflect the oligotrophic character of the eastern Mediterranean Sea. Both bulk and molecular organic tracers reflect a mixed contribution from autochthonous and allochthonous sources for the sedimentary OM, as indicated by relatively degraded marine OM, terrestrial plant waxes and anthropogenic OM (e.g. degraded petroleum by-products) respectively. Wide regional variations have been observed amongst the studied proxies, which reflect the multiple factors controlling sedimentation in the deep eastern Mediterranean Sea. Our findings highlight the role of deep eastern Mediterranean basins as depocentres of organic-rich fine-grained sediments (mean 5.4 ± 2.4 μm), with OM accumulation and burial being attributed to aggregation mechanisms and hydrodynamic sorting. A multi-proxy approach is applied aiming to investigate the biogeochemical composition of sediment samples, which sheds new light on the sources and transport mechanisms along with the impact of preservation vs. diagenetic processes on the composition of sedimentary OM in the deep basins of the oligotrophic eastern Mediterranean Sea.

  2. Provenance of zircon of the lowermost sedimentary cover, Estonia, East-European Craton

    Directory of Open Access Journals (Sweden)

    Konsa, M.

    1999-12-01

    Cambrian sequence, zircons resembling those of local basement sources are very rare or absent. Obviously, basal Vendian/Cambrian sedimentary rocks sealed off the basement as a source of zircon. Therefore a distant source, probably outside the Svecofennian Domain, could be supposed for the bulk clastic minerals and zircons of the upperpart of the Vendian and the lower part of the Cambrian. Probably, studies of isotopic ages of different typological varieties of zircons, both of obviously local and distant origin, could provide new information on respective source rock ages and areas, and on the general palaeogeographic pattern of the Vendian and Cambrian epicratonic sedimentary basins of the East-European Craton.

  3. Late Cenozoic sedimentary process and its response to the slip history of the central Altyn Tagh fault, NW China

    Institute of Scientific and Technical Information of China (English)

    陈正乐; 张岳桥; 陈宣华; 王小凤; A.S.Ramon; W.B.Zack

    2001-01-01

    The ENE-striking Altyn Tagh fault (ATF), extending along the northern edge of the Tibetan Plateau, is one of the major important strike-slip faults, and has been known as one of the key areas to debate the eastward extrusion and crustral shortening models of the Tibetan Plateau during and after India-Asia collision. This paper mainly presents new evidence of Late Cenozoic sedimentary process to reconstruct the slip history of the ATF during the Late Cenozoic. Field measurements and laboratory analyses of the sedimentary characteristics in the Late Cenozoic basins in the central Altyn Tagh fault suggest that Late Cenozoic sedimentary sequence should be divided into three units according to facies changes. The paleo-topography reconstruction shows that the sedimentation in these basins was tightly related with the fault, indicating that the ATF has experienced at least three stages of strike slipping in the Late Cenozoic. New geological data from the Late Cenozoic sedimentary basins and the formation of th

  4. Main Controlling Factors on Hydrocarbon Accumulation and Distribution in Marine Sedimentary Sequences in South China

    Institute of Scientific and Technical Information of China (English)

    Cai Liguo; Zhou Yan; Bai Zhenrui

    2008-01-01

    Multiple source rock assemblages were deposited in the sedimentary provinces in South China in geologic history,and some of them were destructed by and some survived against multiple tectonic movements.Therefore,multiple sources,mixed sources,and uneven distribution of sources occurred in the marine sedimentary basins in South China during the late stage of hydrocarbon pooling.Epidiagenesis of the marine carbonate reservoirs and its modification to reservoir poroperm characteristics determined the formation and the scale of natural gas pools.The exploration practices show that the large to medium gas fields mainly occur in areas with high-quality reservoirs.Detailed study of the paleo-oil accumulations and typical oil and gas reservoirs reveals that the basins experienced multiphase superimposition and modification,leading to the distribution of the Paleozoic paleo-oil accumulations and bitumen in the peripheral areas.The phenomenon that oil and gas production concentrates in the Sichuan basin indicates that the overall sealing conditions of a basin determine the oil/gas potentials and the scale of oil and gas production.This is a critical factor controlling the accumulation and distribution of gas in the marine sequences in South China.The early oil and gas pools in the Yangtze platform left billions of bitumen in the peripheral areas due to the destruction of seals.Since the Himalayan,"late-generation and late-accumulation" gas pools represented by the gas pools in the Sichuan (四川) basin were formed in the marine sedimentary sequences in South China as a result of the change of the sealing conditions.Current gas discoveries appear to be "paleo-generation and paleo-accumulation" gas pools but actually are "late-generation and late-accumulation" gas pools.These patterns of hydrocarbon pooling clearly depict themselves in western Sichuan basin and Weiyuan (威远)gas field.It is revealed that the gas pools in the Sichuan basin were mainly formed as a result of

  5. Jurassic sedimentary features and tectonic settings of southeastern China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Two types of the Jurassic basins are distinguished in SE China based on their geodynamic features: the Late Triassic-Early Jurassic post-orogenic basins and the Middle Jurassic intra-continental extensional basins. The Lower Jurassic sequence shows a change from coarseto fine-grained accumulation, suggesting a gradually deepening depositional environment from river to shore-lake and to deep-water lake. In contrast, the Middle Jurassic accumulation was changed from claystone to conglomerate along the coastal provinces in SE China, indicative of an initial crustal uplift. The Wuyi Mountains have been a paleogeograghic separating zone since the Middle Jurassic. The Late Jurassic strata are absent in most areas of SE China. A large-scale bimodal intra-continental rift-type volcanism occurred during the Middle Jurassic along a 40-60 km wide and 200 km long area in western Fujian and southern Jiangxi provinces, which is most likely the strongest volcanism in SE China since the Cambrian. The SHRIMP zircon U-Pb analyses on the rhyolite from the Dongkeng basin in the southern Jiangxi area yield a concord U-Pb age of 160±0.5 Ma, providing an upper age limit for the bimodal volcanic eruption. The analyses of the basin features indicate a change of the depositional environment during the interval from Middle Triassic to Late Triassic from a shallow-sea to an intra-continent in SE China in response to the strong collision between the Yangtze and North China Blocks. Sedimentary structures record a southward direction of Early Jurassic paleo-currents, reflecting that their source areas were to the north side. We propose that the Wuyi region was uplifted as early as Middle Jurassic, followed by a wide E-W-trending extended depression and bimodal volcanism in the western foot of the Wuyi Mountains. Presumably the uplift of the Wuyi domain changed the Middle Jurassic paleo geographic outline and formed the transformational tectonic regime from compression to extension as a tectonic

  6. Tracing of natural radionuclides mobility in deep sedimentary environment using radioactive ({sup 234}U/{sup 238}U) disequilibria: application to the Mesozoic formations of the Eastern part of the Paris Basin; Tracage de la mobilite des radionucleides naturels en milieu sedimentaire profond a l'aide des desequilibres radioactifs ({sup 234}U/{sup 238}U): application aux formations mesozoiques de l'est du Bassin de Paris

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, P

    2003-11-01

    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 {sup 234}U/{sup 238}U 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, ({sup 234}U/{sup 238}U) 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)

  7. Astrochronology for the Messinian Sorbas basin (SE Spain) and orbital (precessional) forcing for evaporite cyclicity

    OpenAIRE

    Krijgsman, W.; Fortuin, A. R.; F. J. Hilgen; F. J. Sierro

    2002-01-01

    The Sorbas basin of SE Spain contains one of the most complete sedimentary successions of the Mediterranean reflecting the increasing salinity during the Messinian salinity crisis. A detailed cyclostratigraphic study of these successions allows a correlation of the sedimentary cycle patterns to astronomical target curves. Here, we present an astrochronological framework for the Messinian of the central part of the Sorbas basin. This framework will form a solid basis for high-resolution correl...

  8. 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

  9. Spatial stochastic modeling of sedimentary formations to assess CO2 storage potential.

    Science.gov (United States)

    Popova, Olga H; Small, Mitchell J; McCoy, Sean T; Thomas, A C; Rose, Stephen; Karimi, Bobak; Carter, Kristin; Goodman, Angela

    2014-06-01

    Carbon capture and sequestration (CCS) is a technology that provides a near-term solution to reduce anthropogenic CO2 emissions to the atmosphere and reduce our impact on the climate system. Assessments of carbon sequestration resources that have been made for North America using existing methodologies likely underestimate uncertainty and variability in the reservoir parameters. This paper describes a geostatistical model developed to estimate the CO2 storage resource in sedimentary formations. The proposed stochastic model accounts for the spatial distribution of reservoir properties and is implemented in a case study of the Oriskany Formation of the Appalachian sedimentary basin. Results indicate that the CO2 storage resource for the Pennsylvania part of the Oriskany Formation has substantial spatial variation due to heterogeneity of formation properties and basin geology leading to significant uncertainty in the storage assessment. The Oriskany Formation sequestration resource estimate in Pennsylvania calculated with the effective efficiency factor, E=5%, ranges from 0.15 to 1.01 gigatonnes (Gt) with a mean value of 0.52 Gt of CO2 (E=5%). The methodology is generalizable to other sedimentary formations in which site-specific trend analyses and statistical models are developed to estimate the CO2 sequestration storage capacity and its uncertainty. More precise CO2 storage resource estimates will provide better recommendations for government and industry leaders and inform their decisions on which greenhouse gas mitigation measures are best fit for their regions. PMID:24824160

  10. Hydrocarbon habitat in rifted basins

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, P.A. [Basel Univ. (Switzerland)

    1996-12-01

    Tectonically active rifts, palaeo-rifts and passive margin basins contain major hydrocarbon provinces. Their hydrocarbon charge can rely exclusively on pre-rift, syn-rift sedimentary sequences or a combination thereof. Maturation of source-rocks can be achieved during the syn-and/or post-rift stage of basin evolution. During rifting, conductive and convective heat transfer accounts for elevated geothermal gradients; these play an important role in the maturation of pre- and syn-rift source-rocks; as geothermal gradients decrease asymptotically during the post-rift stage, maturation of late syn- and post-rift source-rocks depends on massif overburden thicknesses. In most rift structuration and trap-formation predate or are contemporaneous with peak oil and gas generation. Post-rift subsidence and stress-induced basin tilting or inversion can cause modification of trap configurations, causing loss of hydrocarbons. (author). 58 refs., 1 fig., 1 tab.

  11. Sedimentary Environments Offshore Norway - Palaeozoic to Recent

    Energy Technology Data Exchange (ETDEWEB)

    Martinsen, Ole J.; Dreyer, Tom [eds.

    1999-07-01

    The report includes the extended abstracts from the conference, 71 in number. The presentations discuss the sedimentary characteristics of the North Sea area and the the methods used in the research, a thorough knowledge of which is important for economic exploration of the oil and gas resources of the North Sea.

  12. Holocene Tectonic and Sedimentary Evolution of Coastal San Diego

    Science.gov (United States)

    Maloney, J. M.; Driscoll, N. W.; Brothers, D. S.; Babcock, J. M.; Kent, G.

    2010-12-01

    The shelf and nearshore region of San Diego, California, between La Jolla cove in the north and the U.S.- Mexico border in the south, is an important ecological and economic resource. It contains two of the largest kelp forests in southern California and lies offshore miles of popular beaches. Understanding the interplay between tectonic and sedimentary processes in this area is critical because it will allow us to assess how other forcing functions such as the rapid sea level rise (2 - 3 mm/yr) and predicted climate change associated with global warming are impacting the kelp and nearshore environments. The fault architecture and sedimentary deposits offshore San Diego have been mapped using high-resolution seismic CHIRP profiling. The mapped area lies within the inner California Continental Borderland (CCB), which is characterized by a system of basins and ridges and extensive strike-slip faulting. The CHIRP data clearly images several splays of the Coronado Bank Fault Zone (CBFZ), a major fault in the area, which show recent activity in the upper 30 m of sediment with the most recent deformation at ~4 m below seafloor. Several sediment packages as deep as 50 m below the seafloor are imaged and place important constraints on tectonic deformation and sediment dispersal in the region as well as the earthquake recurrence interval on the CBFZ. Exposed and buried wavecut terraces identified on numerous CHIRP profiles, which can be correlated to terraces mapped regionally, provide insight into tectonic uplift rates and sea-level fluctuations. Finally, the extensive kelp forests offshore Mount Soledad and Point Loma occur where hardgrounds are exposed at the seafloor as a consequence of tectonic uplift. High resolution mapping offshore San Diego is providing new insight into the complex interplay between tectonics, sedimentation, and biology in this ecologically diverse region.

  13. Stratigraphy and Tectonics of the East Ketungau Basin, West Kalimantan during Palaeogene

    OpenAIRE

    Suyono Suyono

    2014-01-01

    DOI: 10.17014/ijog.v8i4.170East Ketungau Basin is one of frontier basins in Indonesia. Some of these basins, especially those in eastern Indonesia, have been identified to possess potential of oil and gas. The existing publications of geological fieldworks and extensive exploration in the East Ketungau Basin are limited. The detailed sedimentological and biostratigraphical studies of the sedimentary succession will be used to reconstruct the tectonic and palaeogeographical history of the basi...

  14. Geochemistry of Fine-grained Sediments and Sedimentary Rocks

    Science.gov (United States)

    Sageman, B. B.; Lyons, T. W.

    2003-12-01

    The nature of detrital sedimentary (siliciclastic) rocks is determined by geological processes that occur in the four main Earth surface environments encountered over the sediment's history from source to final sink: (i) the site of sediment production (provenance), where interactions among bedrock geology, tectonic uplift, and climate control weathering and erosion processes; (ii) the transport path, where the medium of transport, gradient, and distance to the depositional basin may modify the texture and composition of weathered material; (iii) the site of deposition, where a suite of physical, chemical, and biological processes control the nature of sediment accumulation and early burial modification; and (iv) the conditions of later burial, where diagenetic processes may further alter the texture and composition of buried sediments. Many of these geological processes leave characteristic geochemical signatures, making detrital sedimentary rocks one of the most important archives of geochemical data available for reconstructions of ancient Earth surface environments. Although documentation of geochemical data has long been a part of the study of sedimentation (e.g., Twenhofel, 1926, 1950; Pettijohn, 1949; Trask, 1955), the development and application of geochemical methods specific to sedimentary geological problems blossomed in the period following the Second World War ( Degens, 1965; Garrels and Mackenzie, 1971) and culminated in recent years, as reflected by the publication of various texts on marine geochemistry (e.g., Chester, 1990, 2000), biogeochemistry (e.g., Schlesinger, 1991; Libes, 1992), and organic geochemistry (e.g., Tissot and Welte, 1984; Engel and Macko, 1993).Coincident with the growth of these subdisciplines a new focus has emerged in the geological sciences broadly represented under the title of "Earth System Science" (e.g., Kump et al., 1999). Geochemistry has played the central role in this revolution (e.g., Berner, 1980; Garrels and Lerman

  15. Relationships between basin architecture, basin closure, and occurrence of sulphide-bearing schists: an example from Tampere Schist Belt, Finland

    DEFF Research Database (Denmark)

    Kalliomäki, Henrik; Torvela, Taija; Moreau, Julien;

    The Tampere Schist Belt (TSB) in southern Finland is a c. 1.92-1.88 Ga volcano-sedimentary basin that underwent inversion and closure between c. 1.89-1.88 Ga. We present field observations from the Tampere palaeobasin, where the primary structures have been exceptionally well preserved. The TSB......, therefore, offers an excellent opportunity to examine the volcano-sedimentary evolution of an ancient marginal basin, and the mechanics of and strain distribution during its subsequent closure. The aim of this study is to investigate the structural development and the architecture of a part of the TSB in...... more detail, including the relationships between the volcano-sedimentary sequences, the tectonic structures, and the sulphide-bearing schist horizons. Important insights are gained into understanding the mechanisms of the basin closure and the localisation of the sulphide mineralisation within the...

  16. Contrasting sedimentary processes along a convergent margin: the Lesser Antilles arc system

    Science.gov (United States)

    Picard, Michel; Schneider, Jean-Luc; Boudon, Georges

    2006-12-01

    Sedimentation processes occurring in an active convergent setting are well illustrated in the Lesser Antilles island arc. The margin is related to westward subduction of the North and/or the South America plates beneath the Caribbean plate. From east to west, the arc can be subdivided into several tectono-sedimentary depositional domains: the accretionary prism, the fore-arc basin, the arc platform and inter-arc basin, and the Grenada back-arc basin. The Grenada back-arc basin, the fore-arc basin (Tobago Trough) and the accretionary prism on the east side of the volcanic arc constitute traps for particles derived from the arc platform and the South American continent. The arc is volcanically active, and provides large volumes of volcaniclastic sediments which accumulate mainly in the Grenada basin by volcaniclastic gravity flows (volcanic debris avalanches, debris flows, turbiditic flows) and minor amounts by fallout. By contrast, the eastern side of the margin is fed by ash fallout and minor volcaniclastic turbidites. In this area, the dominant component of the sediments is pelagic in origin, or derived from South America (siliciclastic turbidites). Insular shelves are the locations of carbonate sedimentation, such as large platforms which develop in the Limestone Caribbees in the northern part of the margin. Reworking of carbonate material by turbidity currents also delivers lesser amounts to eastern basins of the margin. This contrasting sedimentation on both sides of the arc platform along the margin is controlled by several interacting factors including basin morphology, volcanic productivity, wind and deep-sea current patterns, and sea-level changes. Basin morphology appears to be the most dominant factor. The western slopes of the arc platform are steeper than the eastern ones, thus favouring gravity flow processes.

  17. Petroleum geology of the northwest basin, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jae Hong [Yonsei University, Seoul (Korea, Republic of); Oh, Jae Ho [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of); Kim, Jong Young [Dong Won Co., Sabuk (Korea, Republic of)

    1997-06-30

    Petroleum geology of the Northwest Basin, Argentina has been studied in detail using seismic reflection profiles, drill holes and structure maps. The Northwest Basin comprises the following four successor basins that are different in characteristics and tectonic development: pre-Carboniferous, Carboniferous, Cretaceous, and Tertiary basins. Petroleum plays in the Northwest Basin can be divided into four types based on hydrocarbon-trap structures. These include thrust-folds, paleo-channels, volcanic mounds and roll-over anticlines related to normal faulting. The thrust-fold structure is a typical trap structure of pre-Carboniferous and Carboniferous basins, and consists of Cretaceous sedimentary rocks in southern exploration areas of the Northwest Basin. Paleo-channels provide a new possibility to the Carboniferous basin, and several of them occur in northern exploration areas of the Northwest Basin. Volcanic mounds and roll-over anticlines associated with the normal fault are related to the rifting event and play an important role in the Cretaceous basin. New prospects will be found if the above play types are well utilized. (author). 12 refs., 15 figs.

  18. Thermal Evolution of Crude Oils in Sedimentary Basins: Experimental Simulation in a Confined System and Kinetic Modeling Evolution thermique des huiles dans les bassins sédimentaires : simulation expérimentale par pyrolyse en milieu confiné et modélisation cinétique

    Directory of Open Access Journals (Sweden)

    Behar F.

    2006-11-01

    coefficients alphaij were optimized with reference to a dataset comprising the final compositions resulting from oil pyrolysis experiments. This optimization was carried out successively on each distillate and each residue, on both distillate and residue from the same oil, then on the two distillates and two residues altogether. The model accounts satisfactorily for the specific kinetics of cracking of both each oil and of the two oils together, suggesting that it is now possible to predict the thermal behavior of a given oil provided the proportions of the ten fractions selected for the model are known. The wide temperature range in which the model is valid, supports its extrapolation to the temperature range of sedimentary basins. Une meilleure connaissance des mécanismes du craquage thermique des huiles doit permettre de mieux comprendre leur évolution naturelle dans les bassins sédimentaires et donc d'améliorer les modèles actuels utilisés pour prédire la formation du gaz. Bien que les mécanismes de craquage soient bien connus pour des composés modèles ou des mélanges simples d'hydrocarbures, il n'existe pas à l'heure actuelle, à l'exception des modèles empiriques, de méthode pour rendre compte de la dégradation thermique des mélanges complexes, surtout, lorsque ces derniers sont enrichis en produits lourds. Au cours du craquage thermique, une huile produira à la fois des composés plus légers et des composés plus lourds que la charge initiale. En conséquence, les produits de pyrolyse seront un mélange complexe contenant des produits nouveaux et des composés non encore dégradés. Afin de pouvoir faire la distinction entre réactifs et produits, nous avons choisi de fractionner chaque huile en deux grandes fractions : la première (distillat 300- contenant des hydrocarbures légers de C6 à C16 et la seconde (résidu 300+ contenant des hydrocarbures et des produits polaires. Afin de simuler l'évolution thermique des huiles, nous avons réalisé une

  19. 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.

  20. Visualizing the sedimentary response through the orogenic cycle using multi-dimensional scaling

    Science.gov (United States)

    Spencer, C. J.; Kirkland, C.

    2015-12-01

    Changing patterns in detrital provenance through time have the ability to resolve salient features of an orogenic cycle. Such changes in the age spectrum of detrital minerals can be attributed to fluctuations in the geodynamic regime (e.g. opening of seaways, initiation of subduction and arc magmatism, and transition from subduction to collisional tectonics with arrival of exotic crustal material). These processes manifest themselves through a variety of sedimentary responses due to basin formation, transition from rift to drift sedimentation, or inversion and basement unroofing. This generally is charted by the presence of older detrital zircon populations during basement unroofing events and is followed by a successive younging in the detrital zircon age signature either through arrival of young island arc terranes or the progression of subduction magmatism along a continental margin. The sedimentary response to the aforementioned geodynamic environment can be visualized using a multi-dimensional scaling approach to detrital zircon age spectra. This statistical tool characterizes the "dissimilarity" of age spectra of the various sedimentary successions, but importantly also charts this measure through time. We present three case studies in which multi-dimensional scaling reveals additional useful information on the style of basin evolution within the orogenic cycle. The Albany-Fraser Orogeny in Western Australia and Grenville Orogeny (sensu stricto) in Laurentia demonstrate clear patterns in which detrital zircon age spectra become more dissimilar with time. In stark contrast, sedimentary successions from the Meso- to Neoproterozoic North Atlantic Region reveal no consistent pattern. Rather, the North Atlantic Region reflects a signature consistent with significant zircon age communication due to a distal position from an orogenic front, oblique translation of terranes, and complexity of the continental margin. This statistical approach provides a mechanism to

  1. Silurian to Devonian foreland basin in the south edge of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the theory of plate tectonics, combining with the isotopic dating of ophiolite, igneous and volcanics, geochemical test, rare earth element analyze and seismic interpretation, this paper studies the pre-Carboniferous tectonics and sedimentary formation of the south edge of the Tarim Basin and proves that there exists the Kunlun Ocean under tensional tectonics during the Sinian and Cambrian in the south edge of the Tarim Plate. After that, due to the collision orogenesis, there formed the peripheral foreland basin in the south edge of Tarim. The Upper Silurian and Devonian molasses sedimentary system superposed on the Sinian and Middle Silurian passive margin flysch sedimentary system and formed the bivariate structure of the foreland basin. And at the same time, based on the field geology and seismic interpretation, we have identified that the formation of the Silurian and Devonian have the character of half deposit which shows thick in the south area and thin in the north, and the pre-Carboniferous thrust compression tectonics remained in the foreland thrust belt, which further demonstrates that there existed the Silurian and Devonian peripheral foreland basin on the south edge of the Tarim Basin.

  2. Thermal conductivity of sedimentary rocks - selected methodological, mineralogical and textural studies

    Energy Technology Data Exchange (ETDEWEB)

    Midttoemme, Kirsti

    1997-12-31

    The thermal conductivity of sedimentary rocks is an important parameter in basin modelling as the main parameter controlling the temperature within a sedimentary basin. This thesis presents measured thermal conductivities, mainly on clay- and mudstone. The measured values are compared with values obtained by using thermal conductivity models. Some new thermal conductivity models are developed based on the measured values. The values obtained are less than most previously published values. In a study of unconsolidated sediments a constant deviation was found between thermal conductivities measured with a needle probe and a divided bas apparatus. Accepted thermal conductivity models based on the geometric mean model fail to predict the thermal conductivity of clay- and mudstone. Despite this, models based on the geometric mean model, where the effect of porosity is taken account of by the geometric mean equation, seem to be the best. Existing models underestimate the textural influence on the thermal conductivity of clay- and mudstone. The grain size was found to influence the thermal conductivity of artificial quartz samples. The clay mineral content seems to be a point of uncertainty in both measuring and modelling thermal conductivity. A good universal thermal conductivity model must include many mineralogical and textural factors. Since this is difficult, different models restricted to specific sediment types and textures are suggested to be the best solution to obtain realistic estimates applicable in basin modelling. 243 refs., 64 figs., 31 tabs.

  3. Pull-apart origin of the Satpura Gondwana basin, central India

    Indian Academy of Sciences (India)

    Chandan Chakraborty; Sanjoy Kumar Ghosh

    2005-06-01

    The Gondwana basins of peninsular India are traditionally considered as extensional-rift basins due to the overwhelming evidence of fault-controlled synsedimentary subsidence. These basins indeed originated under a bulk extensional tectonic regime, due to failure of the attenuated crust along pre-existing zones of weakness inherited from Precambrian structural fabrics. However, disposition of the basins and their structural architecture indicate that the kinematics of all the basins cannot be extensional. To maintain kinematic compatibility with other basins as well as the bulk lateral extension, some basins ought to be of strike-slip origin. The disposition, shape and structural architecture of the Satpura basin, central India suggest that the basin could be a pull-apart basin that developed above a releasing jog of a left-stepping strike-slip fault system defined by the Son-Narmada south fault and Tapti north fault in consequence to sinistral displacement along WSW-ENE. Development of a sedimentary basin under the above-mentioned kinematic condition was simulated in model experiments with sandpack. The shape, relative size, stratigraphic and structural architecture of the experimental basin tally with that of the Satpura basin. The experimental results also provide insights into the tectono-sedimentary evolution of the Satpura basin in particular and pull-apart basins in general.

  4. Extreme events in the sedimentary record of maar Lake Pavin: Implications for natural hazards assessment in the French Massif Central

    Science.gov (United States)

    Chassiot, Léo; Chapron, Emmanuel; Di Giovanni, Christian; Albéric, Patrick; Lajeunesse, Patrick; Lehours, Anne-Catherine; Meybeck, Michel

    2016-06-01

    A set of sedimentary cores, high resolution swath bathymetry and subbottom profiler data provides new insights on sedimentary processes in meromictic maar Lake Pavin, France. Three sedimentary environments (i.e., littoral, plateau and basin) have been identified in the lake from sediment composition using bulk organic geochemistry and the analysis of hydroacoustic images. Various forms of rapidly deposited layers (RDLs) have been identified and radiocarbon dated. An up to date stratigraphy of sedimentary events matching coeval RDLs across the lake is presented and illustrates a wide range of natural hazards linked to Lake Pavin during the last 2000 years. In AD 600, a sudden lake outburst triggered a slump deposit along with a 9 m lake-level drop that drove shifts in sedimentary organic matter composition. Outside the lake, outburst flood deposits have been described downstream and provide sedimentary evidence for this event. The lake-level drop also favored the generation of gravity reworking processes, as shown by (1) a regional earthquake-triggered large slope failure on the plateau connected to a mass-wasting deposit in the basin dated to AD 1300, and (2) a succession of turbidites in AD 1825 and AD 1860 contemporaneous to two historic earthquakes, suggesting that this lake is sensitive to earthquakes with a minimum epicentral intensity of V. Finally, past observations of lake water color changes in AD 1783 and AD 1936, similar to reports in other meromictic lakes, match iron-rich deposits identified in maar lake sediments and suggest that Lake Pavin could have undergone limnic eruptions.

  5. Three-dimensional sedimentary architecture of Quaternary deposits; a case study of environmental sedimentology (Bam, Iran)

    Science.gov (United States)

    Rezaei, K.; Guest, B.; Friedrich, A.; Fayazi, F.; Nakhaei, M.; Bakhtiari, H.; Nouri, L.

    2009-04-01

    Detailed 3-D analysis of the sedimentary structure and stratigraphy of these deposits allows for an accurate understand of sedimentary model of basin. This paper presents a case study in Bam (SE Iran) reconstructing the 3-D distribution of fluvial sediments based on a high resolution, process-orientated sedimentary facies classification and lithostratigraphy. We investigated the mean grain size with vertical and horizontal change of it, clay mineralogy, sediment texture, sedimentary structures, petrology and petrography and determination of paleo-environments and finally, we prepared two cross sections in S-N and W-E directions and a 3D block diagram for the situation of changes in subsurface sediments and compare them with the destruction rate map of earthquake in Bam city. Quaternary alluvial sediments are characterized by lithofacies deposited by braided river channels, debris flows and hyperconcentrated flows. The channel flow deposits constitute relatively well sorted, well imbricated and clast-supported gravels with coarse to medium sand matrix. Mostly poorly sorted, weakly imbricated to disorganized matrix supported pebble to boulder gravels with silty sand represent debris flow deposits. Hyperconcentrated flow deposits consist of clast-supported, poorly developed sorted polymodal gravel facies with poorly developed imbricated fabric, and generally occupy the lower parts of the terrace and fan sequences. The alternation from hyperconcentrated flow to channel flow deposits is predominant in the sequence, and is possibly the response to different climate modes. The high discharge and supply of sediments as well as the dispersal and deposition of these materials in the trunk stream is attributed to climatic perturbations during the Quaternary. These models allow quantifying the thickness and volume distribution of sandy gravel and clay deposits. We correlate these sedimentary units on the basis of lithofacies similarities, stratigraphic position. These

  6. Epigenetic alterations of sedimentary rocks at deposits

    International Nuclear Information System (INIS)

    Notions are explained, and technique for studying epigenetic alterations of sedimentary rocks at uranium deposits is described. Main types of epigenetic transformations and their mineralogic-geochemical characteristics are considered. Rock alterations, accompanying uranium mineralization, can be related to 2 types: oxidation and reduction. The main mineralogic-geochemical property of oxidation transformations is epigenetic limonitization. Stratal limonitization in primary grey-coloured terrigenic rocks and in epigenetically reduced (pyritized) rocks, as well as in rock, subjected to epigenetic gleying, are characterized. Reduction type of epigenetic transformations is subdivided into sulphidic and non-sulphidic (gley) subtypes. Sulphidic transformations in grey-coloured terrigenic rocks with organic substance of carbonic row, in rocks, containing organic substance of oil row, sulphide transformations of sedimentary rocks, as well as gley transformations, are considered

  7. Integrated Provenance Studies in Northwestern South America, Linking Tectonic and Sedimentary Processes

    Science.gov (United States)

    Montes, C.; Cardona, A.; Ramirez, V. O.; Bayona, G.; Ayala, C.; Valencia, V.

    2009-12-01

    Post-collisional late Eocene to Oligocene extensional basins (Plato-San Jorge basin in Colombia) and syn-collisional basins to the east contain the record of drainages and source areas as a former passive margin obliquely collided with the Caribbean deformation front. A 2 to 8 km thick, shallowing-upward and almost entirely fine-grained, upper Eocene and younger sedimentary sequence contains the record of post-collisional paleogeography behind the advancing deformation front. Sedimentation in the syn-collisional margin is fragmentary along the northern margins of Colombia and Venezuela in the Guajira province. An integrated provenance approach is being undertaken with detrital zircon geochronology, whole rock geochemistry, heavy mineral analysis and tectonic modeling. Source areas contain distinctive assemblages that should be diagnostic and include cratonic contributions with Grenville and older provinces, Andean contributions with Mesozoic-age signatures and Caribbean contributions with latest Cretaceous and Paleogene contributions. The complex Paleogene tectonic interactions along the northwestern South American margin include the simultaneous opening of basins (Plato-San Jorge basin in Colombia), micro-block rotation (Santa Marta massif), shortening and mountain building (Perija range) and oblique accretionary wedges along the margin (Sinu-San Jacinto deformed belts). Rivers draining the interior of South America to the north would have been deflected by this Paleogene configuration, and local drainages would have similarly developed in response to changing depocenters. Distinctive signatures should have developed in the sedimentary sequence as the sources dynamically changed from cratonic (Grenville and older cratonic) to Andean (Mesozoic continental crust and reworked) to Caribbean (volcanic arcs and collision zones).

  8. PREDICTED SEDIMENTARY SECTION OF SUBGLACIAL LAKE VOSTOK

    Directory of Open Access Journals (Sweden)

    G. I. Leychenkov

    2012-01-01

    Full Text Available In early February 2012, the drill hole at the Vostok Station encountered theLakeVostokwater. This step is important to study the lake composition including possible microbial life and to model subglacial environments however, the next ambitious target of the Vostok Drilling Project is sampling of bottom sediments, which contain the unique record of ice sheet evolution and environmental changes in centralAntarcticafor millions of years. In this connection, the forecast of sedimentary succession based on existing geophysical data, study of mineral inclusions in the accretion ice cores and tectonic models is important task. Interpretation of Airborne geophysical data suggests thatLakeVostokis the part of spacious rift system, which exists at least from Cretaceous. Reflection and refraction seismic experiments conducted in the southern part ofLakeVostokshow very thin (200–300 m stratified sedimentary cover overlying crystalline basement with velocity of 6.0–6.2 km/s. At present, deposition in southernLakeVostokis absent and similar conditions occurred likely at least last3 m.y. when ice sheet aboveLakeVostokchanged insignificantly. It can be also inferred that from the Late Miocene the rate of deposition inLakeVostokwas extremely low and so the most of sedimentary section is older being possibly of Oligocene to early to middle Miocene age when ice sheet oscillated and deposition was more vigorous. If so, the sampling of upper few meters of this condensed section is very informative in terms of history of Antarctic glaciation. Small thickness of sedimentary cover raises a question about existence of lake (rift depression during preglacial and early glacial times.

  9. Classification of Complex Reservoirs in Superimposed Basins of Western China

    Institute of Scientific and Technical Information of China (English)

    PANG Xiongqi; ZHOU Xinyuan; LIN Changsong; HUO Zhipeng; LUO Xiaorong; PANG Hong

    2010-01-01

    Many of the sedimentary basins in western China were formed through the superposition and compounding of at least two previously developed sedimentary basins and in general they can be termed as complex superimposed basins.The distinct differences between these basins and monotype basins are their discontinuous stratigraphic sedimentation,stratigraphic structure and stratigraphic stress-strain action over geological history.Based on the correlation of chronological age on structural sections,superimposed basins can be divided into five types in this study:(1)continuous sedimentation type superimposed basins,(2)middle and late stratigraphic superimposed basins,(3)early and late stratigraphic superimposed basins,(4)early and middle stratigraphic superimposed basins,and(5)long-term exposed superimposed basins.Multiple source-reservoir-caprock assemblages have developed in such basins.In addition,multi-stage hydrocarbon generation and expulsion,multiple sources,polycyclic hydrocarbon accumulation and multiple-type hydrocarbon reservoirs adjustment,reformation and destruction have occurred in these basins.The complex reservoirs that have been discovered widely in the superimposed basins to date have remarkably different geologic features from primary reservoirs,and the root causes of this are folding,denudation and the fracture effect caused by multiphase tectonic events in the superimposed basins as well as associated seepage,diffusion,spilling,oxidation,degradation and cracking.Based on their genesis characteristics,complex reservoirs are divided into five categories:(1)primary reservoirs,(2)trap adjustment type reservoirs,(3)component variant reservoirs,(4)phase conversion type reservoirs and(5)scale-reformed reservoirs.

  10. Contribution to the stratigraphy of the onshore Paraiba Basin, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Rossetti, Dilce F.; Valeriano, Marcio M., E-mail: rossetti@dsr.inpe.br [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Divisao de Sensoriamento Remoto; Goes, Ana M.; Brito-Neves, Benjamim B. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. de Geociencias; Bezerra, Francisco H.R.; Ochoa, Felipe L. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Centro de Ciencias Exatas e da Terra. Departamento de Geologia

    2012-06-15

    Several publications have contributed to improve the stratigraphy of the Paraiba Basin in northeastern Brazil. However, the characterization and distribution of sedimentary units in onshore areas of this basin are still incomplete, despite their significance for reconstructing the tectono- sedimentary evolution of the South American passive margin. This work provides new information to differentiate among lithologically similar strata, otherwise entirely unrelated in time. This approach included morphological, sedimentological and stratigraphic descriptions based on surface and sub-surface data integrated with remote sensing, optically stimulated luminescence dating, U+Th/He dating of weathered goethite, and heavy mineral analysis. Based on this study, it was possible to show that Cretaceous units are constrained to the eastern part of the onshore Paraiba Basin. Except for a few outcrops of carbonatic-rocks nearby the modern coastline, deposits of this age are not exposed to the surface in the study area. Instead, the sedimentary cover throughout the basin is constituted by mineralogically and chronologically distinctive deposits, inserted in the Barreiras Formation and mostly in the Post-Barreiras Sediments, of early/middle Miocene and Late Pleistocene-Holocene ages, respectively. The data presented in this work support tectonic deformation as a factor of great relevance to the distribution of the sedimentary units of the Paraiba Basin. (author)

  11. Rapid lithification masks the Venus sedimentary cycle

    Science.gov (United States)

    Ghail, R.

    2015-10-01

    Venera lander data are usually assumed to indicate basaltic lavas but a significant fraction of the rock material must be volatiles, such as sulphur, implying at least strongly weathered basalts. The lander images most closely resemble sedimentary material, with layered strata (which may be pyroclastic in origin)that are sometimes broken into cobbles and fine grained sediment. The Magellan SAR was relatively insensitive to loose fine-grained material under Venus surface conditions but the reprocessed data reveal a range of weathering processes, particularly at higher elevations, and mass wasting of steep slopes. Mean wind speeds are strongly altitude dependent and are able to erode and transport material throughout the highland regions. In some areas, this material is deposited on adjacent plains where, under the extreme Venus surface conditions, lithification is an apparently rapid process. Thus the largely featureless plains may not be igneous at all but sedimentary in origin. The settling out and lithification of sedimentary material is consistent with observed crater degradation, in which low-lying crater floors are infilled first.

  12. Adjoint-tomography Inversion of the Small-scale Surface Sedimentary Structures: Key Methodological Aspects

    Science.gov (United States)

    Kubina, Filip; Moczo, Peter; Kristek, Jozef; Michlik, Filip

    2016-04-01

    Adjoint tomography has proven an irreplaceable useful tool in exploring Earth's structure in the regional and global scales. It has not been widely applied for improving models of local surface sedimentary structures (LSSS) in numerical predictions of earthquake ground motion (EGM). Anomalous earthquake motions and corresponding damage in earthquakes are often due to site effects in local surface sedimentary basins. Because majority of world population is located atop surface sedimentary basins, it is important to predict EGM at these sites during future earthquakes. A major lesson learned from dedicated international tests focused on numerical prediction of EGM in LSSS is that it is hard to reach better agreement between data and synthetics without an improved structural model. If earthquake records are available for sites atop a LSSS it is natural to consider them for improving the structural model. Computationally efficient adjoint tomography might be a proper tool. A seismic wavefield in LSSS is relatively very complex due to diffractions, conversions, interference and often also resonant phenomena. In shallow basins, the first arrivals are not suitable for inversion due to almost vertical incidence and thus insufficient vertical resolution. Later wavefield consists mostly of local surface waves often without separated wave groups. Consequently, computed kernels are complicated and not suitable for inversion without pre-processing. The spatial complexity of a kernel can be dramatic in a typical situation with relatively low number of sources (local earthquakes) and surface receivers. This complexity can be simplified by directionally-dependent smoothing and spatially-dependent normalization that condition reasonable convergence. A multiscale approach seems necessary given the usual difference between the available and true models. Interestingly, only a successive inversion of μ and λ elastic moduli, and different scale sequences lead to good results.

  13. Tectonic and sedimentary evolution of a Cretaceous continental arc-backarc system in the Korean peninsula: New view

    Science.gov (United States)

    Chough, S. K.; Sohn, Y. K.

    2010-08-01

    This paper focuses on the tectonic and sedimentary evolution of the Cretaceous volcanic rocks and nonmarine successions in the southeastern part of the Korean peninsula, which constitute an ancient continental arc system. The arc system (Gyeongsang Arc System), comprising an arc platform (Gyeongsang Volcanic Arc) and a backarc basin (Gyeongsang Backarc Basin), was a southwestward extension of the Japanese Arc formed by oblique northward subduction of the proto-Pacific (Izanagi) plate under the Asian continent. The backarc basin was initiated in the southeastern part of the Korean peninsula in the Early Cretaceous as a narrow NS-trending trough. The basin was bounded by a major fault in the northern part of the basin from which sediments largely emanated. Sediments were deposited in streamflow-dominated alluvial fans adjacent to the fault-bounded basin margin in the north and low-gradient fluvial systems of braided channels that extended southward and southeastward for tens of kilometers. Sediments were also derived from the western highland margin, draining Precambrian to Jurassic basement rocks. The initially narrow trough progressively expanded toward the east, resulting in eastward migration of depocenters that eventually generated a broad fluvio-lacustrine plain fringing the volcanic arc platform. The arc platform played an important role for the derivation of volcanogenic materials and accreted sediments into the backarc basin via extensive fluvial network. Pyroclastic density currents and landslides, which originated from the arc platform, also entered the basin. In addition, extrusion of basaltic volcanic rocks was continual within the basin during basin expansion. The resultant succession of mixed sedimentary and volcanogenic rocks is generally indicative of a temporal increase in volcanic activity in the arc platform and in subsidence rate of the basin. In the Late Cretaceous, andesitic to rhyolitic volcanism became climactic in the arc platform, producing

  14. Seismic Characterization of the Jakarta Basin

    Science.gov (United States)

    Cipta, A.; Saygin, E.; Cummins, P. R.; Masturyono, M.; Rudyanto, A.; Irsyam, M.

    2015-12-01

    Jakarta, Indonesia, is home to more than 10 million people. Many of these people live in seismically non-resilient structures in an area that historical records suggest is prone to earthquake shaking. The city lies in a sedimentary basin composed of Quaternary alluvium that experiences rapid subsidence (26 cm/year) due to groundwater extraction. Forecasts of how much subsidence may occur in the future are dependent on the thickness of the basin. However, basin geometry and sediment thickness are poorly known. In term of seismic hazard, thick loose sediment can lead to high amplification of seismic waves, of the kind that led to widespread damage in Mexico city during the Michoacan Earthquake of 1985. In order to characterize basin structure, a temporary seismograph deployment was undertaken in Jakarta in Oct 2013- Jan 2014. A total of 96 seismic instrument were deployed throughout Jakarta were deployed throughout Jakarta at 3-5 km spacing. Ambient noise tomography was applied to obtain models of the subsurface velocity structure. Important key, low velocity anomalies at short period (<8s) correspond to the main sedimentary sub-basins thought to be present based on geological interpretations of shallow stratigraphy in the Jakarta Basin. The result shows that at a depth of 300 m, shear-wave velocity in the northern part (600 m/s) of the basin is lower than that in the southern part. The most prominent low velocity structure appears in the northwest of the basin, down to a depth of 800 m, with velocity as low as 1200 m/s. This very low velocity indicates the thickness of sediment and the variability of basin geometry. Waveform computation using SPECFEM2D shows that amplification due to basin geometry occurs at the basin edge and the thick sediment leads to amplification at the basin center. Computation also shows the longer shaking duration occurrs at the basin edge and center of the basin. The nest step will be validating the basin model using earthquake events

  15. The Nysa-Morava Zone: an active tectonic domain with Late Cenozoic sedimentary grabens in the Western Carpathians' foreland (NE Bohemian Massif)

    Czech Academy of Sciences Publication Activity Database

    Špaček, P.; Bábek, O.; Štěpančíková, Petra; Švancara, J.; Pazdírková, J.; Sedláček, J.

    2015-01-01

    Roč. 104, č. 4 (2015), s. 963-990. ISSN 1437-3254 R&D Projects: GA ČR GAP210/12/0573; GA MŠk LM2010008 Institutional support: RVO:67985891 Keywords : Bohemian Massif * Upper Morava Basin * tectonic evolution * seismicity * sedimentary grabens Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.093, year: 2014

  16. Large sedimentary aquifer system and sustainable management: investigations of hydrogeological and geochemical variations in Eocene sand aquifer, south western France.

    OpenAIRE

    Malcuit, Eline; Négrel, Philippe; Petelet Giraud, Emmanuelle; Durst, Pierre

    2010-01-01

    In the sedimentary Aquitaine Basin, the Eocene Sand Aquifer system, mostly confined, represents strategic resources for drinking water, irrigation, gas storage and geothermal resources. Therefore, its quantity and quality issues are essential for the sustainable management in this large region that extends over 116,000 km2 (i.e. one-fifth of the French territory). The Eocene Sand Aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands, early Eocene, middle Eoce...

  17. Global continental weathering trends across the Early Permian glacial to postglacial transition : correlating high- and low-paleolatitude sedimentary records

    OpenAIRE

    Yang, Jianghai; Cawood, Peter A.; Du, Yuansheng; Feng, Bin; Yan, Jiaxin

    2014-01-01

    Time-equivalent Early Permian sedimentary successions from high-latitude Gondwana basins and from equatorial accumulations in North China, covering the glacial to postglacial transition, display correlatable trends in continental weathering intensity based on chemical index of alteration (CIA) values. The successions display a pattern of CIA values that varies with latitude, similar to modern estuarine suspended sediments. Based on the modern-day CIA-temperature correlation, the glacial Early...

  18. Depositional Environment of Fine-Grained Sedimentary Rocks of the Sinamar Formation, Muara Bungo, Jambi

    OpenAIRE

    M. Heri Hermiyanto Zajuli; H. Panggabean

    2014-01-01

    DOI: 10.17014/ijog.v8i1.153The research area is situated in the northwestern side of South Sumatra Basin, which is a part of Muara Bungo Regency, Jambi Province. The Oligocene Sinamar Formation consists of shale, claystone, mudstone, sandstone, conglomeratic sandstone, and coal-seam intercalations. This research was focused on fine sedimentary rock of Sinamar Formation, such as shale, claystone, and mudstone. Primary data were collected from SNM boreholes which have depths varying from 75 m u...

  19. Integral study of the quantity and quality of the underground water in the Santa Lucia basin in Uruguay

    International Nuclear Information System (INIS)

    This work study different aspects about the underground water in the Santa Lucia sedimentary basin in Uruguay. It is situated between the San Jose and Santa Lucia river as well as the adyacent Rio de La Plata coast.

  20. Igneous-sedimentary petroleum systems; Sistemas petroliferos igneo-sedimentares

    Energy Technology Data Exchange (ETDEWEB)

    Eiras, Jaime Fernandes [Para Univ., Belem, PA (Brazil)]. E-mail: eiras@ufpa.br; Wanderley Filho, Joaquim Ribeiro [PETROBRAS S.A., Manaus, AM (Brazil). Unidade de Negocios-BSOL]. E-mail: jwand@petrobras.com.br

    2003-07-01

    Igneous-sedimentary petroleum systems are mixed systems in which one or more essential elements or processes are related to magmatic events. Many examples worldwide are presented to show the importance of igneous rocks in the exploratory activities, as well as in the petroleum occurrence. Volcanic ash layers are of great importance in stratigraphic correlation and elucidation of structures, particularly when they occur in thick nonfossiliferous strata. They are also good indicators of turbidite deposition where turbidity currents are related to earthquakes generated by magmatic events. Unconventional reservoirs can be created by volcanic eruptions or intrusions, crystallization, reworking, and fracturing. Unaltered igneous rocks can seal vertically and laterally conventional reservoirs due to its excellent cap capacity. Abnormal thermal effect of igneous rocks can compensate the lack of overburden in shallow basins. Structural or combined traps can be formed due to intrusions, such as folded, faulted, and unconformity traps. Porosity can be either primary or secondary, or both. Primary porosity mainly consists of cavities produced by gas volatilization during eruption and cooling. Secondary porosity refers to those pores that result from hydrothermal alteration, recrystallization, and dissolution by groundwater, and tectonic stress. It includes intercrystalline pores formed by crystallization of various secondary minerals, dissolution pores, and tectonic fractures. New technologies of petroleum development and production are encouraging to search for oil and gas within igneous rocks, and new discoveries are expected. (author)

  1. Antarctic Cenozoic climate history from sedimentary records: ANDRILL and beyond.

    Science.gov (United States)

    McKay, R M; Barrett, P J; Levy, R S; Naish, T R; Golledge, N R; Pyne, A

    2016-01-28

    Mounting evidence from models and geological data implies that the Antarctic Ice Sheet may behave in an unstable manner and retreat rapidly in response to a warming climate, which is a key factor motivating efforts to improve estimates of Antarctic ice volume contributions to future sea-level rise. Here, we review Antarctic cooling history since peak temperatures of the Middle Eocene Climatic Optimum (approx. 50 Ma) to provide a framework for future initiatives to recover sediment cores from subglacial lakes and sedimentary basins in Antarctica's continental interior. While the existing inventory of cores has yielded important insights into the biotic and climatic evolution of Antarctica, strata have numerous and often lengthy time breaks, providing a framework of 'snapshots' through time. Further cores, and more work on existing cores, are needed to reconcile Antarctic records with the more continuous 'far-field' records documenting the evolution of global ice volume and deep-sea temperature. To achieve this, we argue for an integrated portfolio of drilling and coring missions that encompasses existing methodologies using ship- and sea-ice-/ice-shelf-based drilling platforms as well as recently developed seafloor-based drilling and subglacial access systems. We conclude by reviewing key technological issues that will need to be overcome. PMID:26667911

  2. Late Cenozoic sedimentary and tectonic history of south Buton, Indonesia

    Science.gov (United States)

    Fortuin, A. R.; De Smet, M. E. M.; Hadiwasastra, S.; Van Marle, L. J.; Troelstra, S. R.; Tjokrosapoetro, S.

    A description and interpretation are given of the Upper Cenozoic sedimentary record of south Buton. Various sections and outcrops were studied and sampled for their microfossil content, to provide age and paleobathymetrical data. Together with information from the literature, these data from the base for a geohistory analysis to evaluate the vertical motions. Deposition started some 11 Ma ago, after the main deformation of the island, which was related to the collision of a microplate carrying Buton, with the southeast arm of Sulawesi. Coarse and fine terrigenous debris accumulated in a rapidly subsiding foreland basin; subsidence may have exceeded 100 cm/ka. When the rate of subsidence decreased a late Miocene-early Pliocene period of quiet pelagic sedimentation followed. From the late Pliocene onwards (around 3.5 Ma BP) an overall uplift took place, with rates between 30-120 cm/ka. This drastic change is explained by the collision of Buton with a submerged microcontinent that presently forms the Tukang Besi platform, situated southeast of Buton, which interaction resulted in wrench type tectonics and a clockwise rotation of over 60° for south Buton.

  3. Assessment of Deep Seated Geothermal Reservoirs in Selected European Sedimentary Environments

    Science.gov (United States)

    Ungemach, Pierre; Antics, Miklos

    2014-05-01

    Europe at large enjoys a variety of sedimentary environments. They most often host dependable geothermal reservoirs thus favouring the farming of hot fluids, within the low to medium enthalpy range, among which geothermal district heating (GDH) and combined heat and power (CHP) undertakings hold a dominant share. Three selected reservoir settings, addressing carbonate and clastic deposits, the Central part of the Paris Basin, the Southern Germany Molasse Basin in the Münich area and the Netherland Basin respectively will be presented and the exploratory, modeling and development strategies discussed accordingly. Whereas 2D (reprocessed) and 3D seismics have become a standard in matching the distinctive (reef facies, an echelon faulting, carbonate platform layering) features of a deep buried karst and a key to drilling success in the Molasse Basin, thus emphasizing a leading exploratory rationale, the Netherland and Paris Basin instead benefit from a mature data base inherited from extensive hydrocarbon exploration campaigns, with concerns focused on reservoir modeling and sustainable management issues. As a result the lessons learned from the foregoing have enabled to build up a nucleus of expertise in the whole chain from resource identification to reservoir assessment and market penetration. The seismic risk, indeed a sensitive though somewhat emotional issue, which is requiring special attention and due microseismic monitoring from the geothermal community will also be commented.

  4. The Punta del Este terrain and its volcano sedimentary cover, metamorphic and sedimentary: geology, geochemistry and geochronology

    International Nuclear Information System (INIS)

    Gariep belt it develops over the West Africa coastal region of Namibia underlying on Namaqua metamorphic complex.It characterized by supra crustal rocks affected for a very low to low metamorphism and in two tecto no-stratigraphic units identified by Base i et al 2005 showing that sediments of Formation Rocha in Uruguay and the Group Oranjemund Gariep in S E Africa have similar ages in the provenance of the zircons, suggesting that they were probably deposited in the same basin. This unit exhibits detrital zircons around 600my, sedimentation and metamorphism and deformación occur in a narrow time interval from 600-610 to 574 m (Granite de Castillo intrusion) .Cam pal et al, 2005 proposed to the Cerros Aguirre Formation similar in a range of age of different events. To the east separated from the Punta del Este Terrane –Pelotas. Aigua .Florianopolis batholith s by the shear zone Alferez Cordillera (Preciozzi et al. 1999, Basei et al. 2000) Another option develops this granitic belt is an integral part of Land Punta del Este Terrane(Preciozzi in this work), being deployed on a thin cratonic granite edge. The climax of the post-brasilian magmatism is 580my, strongly related to trans current movements (eg shear zones Major Gercino-Alferez- Cordillera and Sierra Ballena.In South America an old west domain is formed by the Piedra Alta Terrane which integrate the Río de la Pl ata Craton, a central domain intensely reworked by Neoproterozoic events known so far as Nico Perez . The primary coverage is integrated by two volcano-sedimentary basins (San Carlos Formation and Cerros de Aguirre Formation)In this study are considered the Geology,Geochemistry and Geochronology of the different units of Rocha Formation

  5. TECTONO-SEDIMENTARY EVOLUTION OF THE EOCENE TRANSGRESSIVE DEPOSITS IN THE ACIGÖL, BURDUR AND ISPARTA AREAS (SW TURKEY

    Directory of Open Access Journals (Sweden)

    EZHER TOKER

    2010-12-01

    Full Text Available The Eocene transgressive deposits of the Acıgöl, Burdur and Isparta basins are the best exposed of the SW Turkey and shed light on one of the outstanding problems of the tectono-sedimentary evolution during paleotectonic and neotectonic period. In the present paper we describe a tectonic model of the progressive foreland migration of the allochthonous units such as Lycian and Antalya nappes, initialemplacement onto stable carbonate platform in the Early Oligocene, carrying piggy-back basins and incorporating from alluvial fan to deep-marine deposits recognized in these terrigenous successions.In general, the facies and structural observations on the overall Mid-Late Eocene clastic sequences, outcropping in behind the Lycian nappes, indicate: i the alluvial fan to shallow marine settings of the Başçeşme Fm in Acıgöl, ii the Varsakyayla Fm in Burdur and iii proximal to distal flysch facies trend of the Kayıköy Fm in Isparta. The collected data allow us to hypothesize that the Mid-Late Eocene tectono-sedimentary history was characterized by a terrigenous clastics, probably lying on the constructing tectonic edifice and then deformed and covered by a piggy-back like sequence. Thetectono-sedimentary evolution of the Eocene transgressive in SW Turkey has been probably developed through a progressive migration towards the foreland basin.

  6. Geothermal structure of Australia's east coast basins

    Science.gov (United States)

    Danis, C. R.; O'Neill, C.

    2010-12-01

    The east coast sedimentary basins of Australia formed on an active margin of eastern Gondwana, and constitute an important hydrocarbon resource. The 1600km long Sydney-Gunnedah-Bowen Basin (SGBB) is largest east coast basin system, with thick Permian to Jurassic sedimentary successions overlying Palaeozoic basement rocks. The SGBB has been the focus of renewed geothermal exploration interest, however, the thermal state and geothermal potential of the system is largely unconstrained. Geothermal exploration programs require an accurate estimate of subsurface temperature information, in addition to favourable geology, to make informed decisions on potential targe developments. Primarily temperature information comes from downhole measurements, generally non-equilibrated, which are traditionally extrapolated to depth, however such extrapolation does not take into account variations in geological structure or thermal conductivity. Here we import deep 3D geological models into finite element conduction simulations, using the code Underworld, to calculate the deep thermal structure of the basin system. Underworld allows us to incorporate complex, detailed geological architecture models, incorporating different material properties for different layers, with variable temperature and depth-dependent properties. We adopt a fixed top boundary temperature on a variable topographic surface, and vary the bottom surface boundary condition, to converge of models which satisfy equilibrated downhole temperature measurement constraints. We find coal plays an important role in insulating sedimentary basins. Heat refracts around the coal interval and produces elevated temperatures beneath thick sediments, especially where thick coal intervals are present. This workflow has been formalized into an Underworld geothermal model library, enabling model centric computational workflows. Using the imported model architecture from the geology, data can be continuously updated and added to the

  7. Eridania Paleolakes Basin Floor: A new Landing Site for the next Mars 2020 Rover

    Science.gov (United States)

    Pajola, M.; Carter, J.; Rossato, S.; Baratti, E.; Mangili, C.; McBride, K. S.; Coradini, M.

    2014-07-01

    A new landing site for Mars 2020 is presented: Eridania basin. This area i) is the floor of the closed basin originating the Ma’adim Vallis; ii) shows clear clay-bearing sedimentary signatures; iii) fully respects the safety landing constraints.

  8. Technical Note: n-Alkane lipid biomarkers in loess: post-sedimentary or syn-sedimentary?

    Directory of Open Access Journals (Sweden)

    D. Faust

    2012-07-01

    Full Text Available There is an ongoing discussion whether n-alkane biomarkers – and organic matter (OM from loess in general – reflect a syn-sedimentary paleoenvironmental and paleoclimate signal or whether they are significantly a post-sedimentary feature contaminated by root-derived OM. We present first radiocarbon data for the n-alkane fraction of lipid extracts and for the first time luminescence ages for the Middle to Late Weichselian loess-paleosol sequence of Gleina in Saxony, Germany. Comparison of these biomarker ages with sedimentation ages as assessed by optically stimulated luminescence (OSL dating shows that one n-alkane sample features a syn-sedimentary age (14C: 29.2 ± 1.4 kyr cal BP versus OSL: 27.3 ± 3.0 kyr. By contrast, the 14C ages derived from the other n-alkane samples are clearly younger (20.3 ± 0.7 kyr cal BP, 22.1 ± 0.7 kyr cal BP and 29.8 ± 1.4 kyr cal BP than the corresponding OSL ages (26.6 ± 3.1 kyr, 32.0 ± 3.5 kyr and 45.6 ± 5.3 kyr. This finding suggests that a post-sedimentary n-alkane contamination presumably by roots has occurred. In order to estimate the post-sedimentary n-alkane contamination more quantitatively, we applied a 14C mass balance calculation based on the measured pMC (percent modern carbon values, the calculated syn-sedimentary pMC values and pMC values suspected to reflect likely time points of post-sedimentary contamination (current, modern, 3 kyr, 6 kyr and 9 kyr. Accordingly, current and modern root-contamination would account for up to 7%, a 3 kyr old root-contamination for up to 10%, and an Early and Middle Holocene root-contamination for up to 20% of the total sedimentary n-alkane pool. We acknowledge and encourage that these first radiocarbon results need further confirmation both from other loess-paleosol sequences and for different biomarkers, e.g. carboxylic acids or alcohols as further lipid biomarkers.

  9. Direction and Potential of Exploration for Natural Gas in Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Qaidam Basin is a large Meso-Cenozoic interior basin, which is surrounded by Qilianshan Mountains,Altun Mountains, and Kunlun Mountains, and with its geographical area, area of sedimentary rock, and maximal sedimentary thickness being 250 thousand km2, 121 thousand km2, and 17.2 thousand meters respectively. The natural gas resources is sufficiently abundant in the basin.It is estimated that the total oil and gas resources is 4.65 billion tons at present, of which natural gas resources is 2500 billion m3.

  10. Studying the NE Eridania sedimentary sequence through the Mars 2020 rover

    Science.gov (United States)

    Pajola, M.; Carter, J.; Rossato, S.; Baratti, E.; Mangili, C.; Coradini, M.; McBride, K. S.

    2014-04-01

    The landing sites we are proposing for the next Mars 2020 rover span between 28°29'30"S-28°53'0"S Latitude and 178°56'30"W°178°28'0"W Longitude, i.e. on the NE floor of a 1.1×106 km2 closed drainage basin [1]. This area, see Fig. 1, belongs to the bigger (3×106 km2) Eridania basin that gave birth to the Ma'adim Vallis through catastrophic overflow, and presenting a water table between 950 and 1250 m [1,2,3]. The crater counting chronology for this area gives an age between Early to Middle Noachian [4]. By means of OMEGA [5] and CRISM [6] data, a large clay-bearing sedimentary unit has been identified over almost the entire margin of the Eridania basin [7]. On our specific site, i.e. the NE margin of the Eridania basin, sequences of aqueous minerals are observed. Such sedimentary minerals are accessible through erosional windows into the first several tens of meters of the sedimentary sequence. The top-down mineral sequence identified on the landing sites area presents an unaltered capping unit that is overlying an Al-rich clay stratum (see Fig. 2) akin to Al-smectite and/or kaolins with a 3.8 Ga) during which liquid water was durably stable at the surface. The most valuable candidates for ancient Martian microbial life sustainability and preservation are longlasting environments, characterized by the presence of ponding water [10,11,12]: hence, the proposed site presents a high exobiological potential that is just waiting to be unveiled. Besides that, when putting into context the future results on Eridania Basin, i.e. the Ma'adim Vallis source, together with those obtained from the Spirit rover inside Gusev Crater (see Fig. 1), i.e. the Ma'adim Vallis mouth, a wide understanding of this intriguing canyon and of the Mars megaflooding age is foreseen. Besides the above scientific analysis showing than the NE side of the Eridania region fulfills entirely the Mars 2020 scientific requirements [13], the location of the proposed landing sites widely meets all the

  11. Interactions between tectonic and sedimentation related to the Rides Prérifaines in the Volubilis basin (Rif front, Morocco)

    OpenAIRE

    Roldán García, F. J.; Galindo-Zaldívar, Jesús; Chalouan, Ahmed; Anahnah, Farida; Ahmamou, M.; Ruano, P.; Constán, Ana Ruiz; Sanz de Galdeano, Carlos; Benmakhlouf, M.; Marín-Lechado, C.; López-Garrido, A. C.; Pedrera, A.

    2009-01-01

    The Volubilis Neogene basin (Morocco) was part of the South Rif Corridor that connected the Atlantic Ocean with the Mediterranean. This basin recorded the tectonic - sedimentary interactions of a foreland basin subjected to the progressive advance of the Rif mountain range front. Since the Miocene, the displacement of the Prerif to the WSW, caused the detachment of the Mesozoic and Cenozoic cover from the Variscan basement and the compartimentation of Saïss Basin. Simultaneously, ...

  12. An Analysis of Late Mesozoic Tectonic Evolution Process in Northern China:Based on Basin Sedimentary Records in Northern Taihang Mountains%华北晚中生代构造演化过程--根据太行山北部盆地沉积记录

    Institute of Scientific and Technical Information of China (English)

    王永超; 董树文; 施炜; 岑敏; 李江瑜

    2016-01-01

    The northern Taihang Mountains are located at the junction of the Yanshan tectonic belt with the Taihang Mountains belt, and their superimposed basin development process documented the basin trending conversion process from EW to NE during Jurassic to Cretaceous, which is significant for depicting the intracontinental deformation process and its dynamic background during the late Mesozoic in North China. Caogoubu basin and Zhaobai basin located in northern Taihang Mountains were selected as examples in this paper. According to the basic structural framework analysis of basins in combination with isotope chronologic data from magmatic rocks and sedimentology methods which include the detailed analysis of sediment provenance, prototype basin reconstruction and so on, tectonic evolution history of the northern Taihang Mountains during the late Mesozoic can be detected, which includes four stage evolution sequences : (1) nearly N–S contraction and flexural basin development during the late middle Jurassic, (2) nearly N–S low-magnitude extention and crust sources volcanic eruption that occurred in the late Jurassic, (3) NW–SE contraction and foreland basin development from the end of the late Jurassic to the earliest Cretaceous, and (4) NW–SE extension and mantle sources volcanic eruption during the early Cretaceous. The conversion of tectonic regimes is essentially the transformation of its geodynamic systems, and on the context of the East Asia multi-direction convergent tectonic system during the Middle–Late Jurassic, the multi-phases tectonic and basin superposition that occurred in northern Taihang Mountains during the late Mesozoic indicates the conversion process during which the Mogolia–Okhotsk tectonic system graded into the Marginal–Pacific tectonic system.%太行山北部地区处于燕山山脉和太行山山脉的交汇处,其侏罗纪—白垩纪叠加盆地发育过程记录了东西向盆地向北东向盆地转化过程,对刻画华

  13. What is the tectono-sedimentary record of hyper-extended, magma-poor rifted margins ?

    Science.gov (United States)

    Masini, Emmanuel; Manatschal, Gianreto; Mohn, Geoffroy; Lafont, François; Jammes, Suzon; Geoffroy, Laurent; Robin, Cécile

    2010-05-01

    The tectono-sedimentary record of hyper-extended, deep-water rifted margins is yet poorly understood due to the limited access to direct observations. The study of fossil analogues shows that the major change from low strain (e.g. North Sea) to high-strain rift systems is controlled by the occurrence of low-angle detachment systems associated with extensional allochthons. In such systems classical syn- to post-rift sedimentary models cannot be directly applied because the depositional geometries, the creation of space as well as the relation to potential sources are different. In our study we investigate the tectono-sedimentary record of high strain, hyper-extended deep-water rifted margins. We studied a present-day and two fossil hyper-extended rift systems, which preserve detachment systems that control the syn- to post-rift sedimentary record. The three examples are: (1) The SE Alpine Tethys (AT) rifted margin preserved in SE Switzerland. (2) The Mauléon basin in the Western Pyrenees (WP) (3) The southeastern termination of the Baja California peninsula in the Gulf of California (GC) representing a subactual system. For all three examples rift related detachment structures and their relations to pre-, syn-, and post-rift sediments can be mapped. Despite of the different plate kinematic settings (orthogonal (AT), segmented (WP), transtensional (GC)), sediment supply (starved (AT) vs. rich (WP, GC), and facies (marine (AT, WP) vs. subareal (GC)), the overall tectono-sedimentary evolution shows strong similarities and can be described as following. The detachment faulting is recorded by the generation of extensional allochthons derived from the delamination of the former hanging-wall. These syn-tectonic sediments show the progressive switch from hanging-wall to footwall derived lithologies. The sourcing change reflects the exhumation and formation of top-basement detachment systems. Sediments related to this stage represent poorly organized locally-derived tectono-sedimentary

  14. Late Neogene, Seismic stratigraphy, Biostratigraphy, Mollusca, Evolution, Pannonian basin

    OpenAIRE

    Velić, I.; Durn, G.

    1993-01-01

    The combined use of seismic stratigraphy and mollusc biostratigraphy in Late Neogene lacustrine deposits of the Pannonian basin offers three new approaches: First, the comparison of seismic facies and biofacies facilitates to make a distinction between biostratigraphic units and biofacies. Second, seismic datum levels permit crosschecking of discrete (magnetic, radiometric, and biostratigraphic) data, thus dating evolutionary events. Third, seismic monitoring of the sedimentary hi...

  15. Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East

    Institute of Scientific and Technical Information of China (English)

    Shigeyuki Suzuki; Abdul R. Ashraf; Hakuyu Okada

    2004-01-01

    Sedimentary facies of the Tsagayan Formation is distributed in the eastern Zeya-Bureya Basin has been analyzed. The formation is of the Maastrichtian to Danian in age and characterized by the cyclicity of the fining-upwards successions. Analysis of environmental changes during the K/T boundary is the focus of this study. Five facies have been identified: Facies A, thick and laterally extensive coarse-grained to medium-grained sandstone units, interpreted as channelfill deposits; Facies B, parallel-laminated to massive mudstone units interpreted as interchannel lakes and flood plain deposits; Facies C, sheet-like medium-grained to fine-grained sandstones interpreted as crevasse splay deposits;Facies D, coal to coaly mudstone beds interpreted as deposits ofpeatlands; Facies E, very poorly sorted sandy mudstone beds interpreted as debris flow deposits. Fluvial environments with the low-relief flat topography was inferred. A channel transported large volumes of clasts, and a flood basin with interchannel lakes and peatlands was deciphered. Any distinct change of sedimentary environments has not been identified throughout the Tsagayan Formation (including the K/T boundary). However, two beds of debris flow deposits were identified. The one occurs at the uppermost part of the lower Tsagayan Subformation and contains dinosaur fossils. The other is intercalated in the upper Tsagayan Subformation.

  16. Quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy: 1. Application to sedimentary rocks

    Science.gov (United States)

    Thorpe, Michael T.; Rogers, A. Deanne; Bristow, Thomas F.; Pan, Cong

    2015-11-01

    Thermal emission spectroscopy is used to determine the mineralogy of sandstone and mudstone rocks as part of an investigation of linear spectral mixing between sedimentary constituent phases. With widespread occurrences of sedimentary rocks on the surface of Mars, critical examination of the accuracy associated with quantitative models of mineral abundances derived from thermal emission spectra of sedimentary materials is necessary. Although thermal emission spectroscopy has been previously proven to be a viable technique to obtain quantitative mineralogy from igneous and metamorphic materials, sedimentary rocks, with natural variation of composition, compaction, and grain size, have yet to be examined. In this work, we present an analysis of the thermal emission spectral (~270-1650 cm-1) characteristics of a suite of 13 sandstones and 14 mudstones. X-ray diffraction and traditional point counting procedures were all evaluated in comparison with thermal emission spectroscopy. Results from this work are consistent with previous thermal emission spectroscopy studies and indicate that bulk rock mineral abundances can be estimated within 11.2% for detrital grains (i.e., quartz and feldspars) and 14.8% for all other mineral phases present in both sandstones and mudstones, in comparison to common in situ techniques used for determining bulk rock composition. Clay-sized to fine silt-sized grained phase identification is less accurate, with differences from the known ranging from ~5 to 24% on average. Nevertheless, linear least squares modeling of thermal emission spectra is an advantageous technique for determining abundances of detrital grains and sedimentary matrix and for providing a rapid classification of clastic rocks.

  17. Comparison between control factors of high quality continental reservoirs in Bohai Bay basin and Ordos basin

    Institute of Scientific and Technical Information of China (English)

    Junmao ZHENG; Jun YOU; Dongbo HE

    2008-01-01

    Bohai Bay basin,a typical extensional rift basin,and Ordos basin,an intra-craton down-warped basin,represent two important basin types in China.Because of their respective features,the main control factors for their high quality reservoirs are different.In Bohai Bay basin,the sandbody shows great variety in types and severely separated distribution and its high quality reservoirs are mostly controlled by the vertical secondary pore and vertical abnormal pressure.On the other hand,the sandbody in Ordos basin features a relative lack of variety,good continuity,indistinct vertical zone,and its reservoirs are mainly controlled bY the diagenetic differentiation caused by different sedimentation inside the sandbody.Therefore,in the Bohai Bay basin,the exploration should be based on the analysis of sedimentary facies and the favorable diagenefic zones and formations.The focus in Ordos basin,however,should be put on the relatively high permeability sandstones in a generally low permeable sandstone background.

  18. Geochemical Characteristics of Sedimentary Manganese Deposit of Guichi, Anhui Province, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The sedimentary manganese deposits occurring in Gufeng formation of the Permian in Guichi area, south Anhui Province, include manganese carbonate deposit formed by sedimentation, and manganese oxide deposit made by later oxidation. The total REE contents of these samples are relatively low ( < 250 × 10-6), belonging to LREE-enriched type,showing LREE enrichment during the process of formation of Mn deposit, especially during Mn-oxidizing process. Three normalized REE patterns and SCNA-normalized trace elements spider diagrams of the Mn-bearing sequence rocks and ores in this area reflect their same origin of ore sources, which is similar to rock-forming and ore-forming conditions. The Mnforming materials primarily came from the continent with higher mature degree and single material source. The δEu and δCe negative anomaly and Ce anomaly ( < - 0.1 ) manifest that Mn-bearing sequence of the Permian was mostly formed in marine basin and oxidative environment. The Sr and Ba anomaly, Sr/Ba and Co/Ni values reflect the Mn deposit environment was of deep water and high-salinity of marine facies. Although the Ce/La (mean 1.05), Y/Ho (25 ~ 41.5) and trace metals show a variety of correlations with Mn in the ten rock samples, which show multiple sources for the manganese, the analysis of geochemical characteristics indicate that the material sources of Mn deposit have been primarily terrestrially derived. Another source of the manganese probably comes from the seafloor volcanism in this area. Analysis of sedimentary features and geohistoric evolvement reveals that the maximum transgression of the Qixia Period, ore district is then in deep shelf-basin sedimentary setting and the Mn-bearing sequence is deposited.

  19. Cenozoic tectonics of the Tuz Gölü Basin (Central Anatolian Plateau, Turkey)

    OpenAIRE

    FERNÁNDEZ-BLANCO, David; BERTOTTI, Giovanni; ÇİNER, T. Attila

    2013-01-01

    We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of basin formation are detected during Cenozoic times. During the Palaeogene, around 2 km of basement su...

  20. Temporal Trends in Syngenetic Lipid Biomarker Signals from Proterozoic Sedimentary Organic Matter

    Science.gov (United States)

    Love, G. D.; Li, C.; Summons, R. E.

    2008-12-01

    The development of continuous-flow catalytic hydropyrolysis (HyPy) for reproducible recovery of biomarker lipid skeletons covalently-bound within kerogen has proved to be an important analytical breakthrough for ancient lipid biomarker research. The parallel analyses of free (solvent-extractable) and kerogen-bound biomarkers affords more confidence that we have correctly identified syngenetic compounds. Combining HyPy with detailed biomarker product analyzes using metastable reaction monitoring-gas chromatography mass spectrometry (MRM-GC-MS) allows detection of a large suite of biomarker compounds which are usually too low in abundance to be analyzed in detail using conventional GC-MS. Here we compare free and bound lipid biomarker records generated from Paleoproterozoic (ca. 1.7 Ga) to Late Ediacaran age (ca. 542 Ma) strata from marine basins from North and South China, Australia and Oman. Fundamental changes in eukaryotic community structure are evident after the Sturtian glaciation (ca. 713 Ma) from distinctive sterane distributions. In particular, radiations in basal animals (sponges) and chlorophyte microalgae are first apparent in Huqf sedimentary rocks from South Oman Salt Basin. Marine microbial communities were not globally homogenous in contemporaneous Proterozoic settings from comparison of biomarker profiles and this could reflect differences in ocean chemistry, affecting nutrient supply, from basin to basin.

  1. Sedimentary Features, Distribution Pattern and Accumulation Mechanism of Lakeshore Bar:Taking the Qingshankou Formation in the Southern Songliao Basin as an Example%坳陷湖盆沿岸坝沉积特征、分布规律及成藏机制——以松辽盆地南部青山口组为例

    Institute of Scientific and Technical Information of China (English)

    潘树新; 王建功; 刘彩燕; 赵志魁; 赵占银; 王立武; 梁苏娟

    2012-01-01

    基于岩心、测井、分析化验和地震等资料的综合分析,对松辽盆地南部青山口组沿岸坝的沉积特征和分布规律进行了系统研究.沿岸坝以细砂岩和粉砂岩为主;沉积构造以浪成交错层理、平行层理、透镜状层理等浅水构造为主,且沉积相序主要为反序、复合相序;粒度概率曲线以两段式为主.沿岸坝由于受到湖流和湖浪作用的改造,坝体外缘形成形态各异的斜坝和直坝沉积.时间上沿岸坝主要发育于青一段和青二段中短期旋回的下降期;平面上主要分布在各三角洲之间的湖湾区,坝体分布明显受到坡折带和湖岸线迁移的控制,西部陡坡带的坝体具有砂岩厚、相带窄的特点,南部缓坡带的坝体具有砂岩薄并呈多排展布的特点.沿岸坝是坳陷湖盆岩性油气藏勘探的重要领域之一,容易形成多种类型的原生油气藏.%Based on integrated analyze of core, well-logging, seismic and laboratory test data, sedimentary features and distribution pattern of the lakeshore bar are studied systematically. The lakeshore bar is mainly made up of fine sandstone and siltstone with such shallow water sedimentary structures as wave cross bedding, parallel and linsen bedding. Its facies sequences include the inverted and the composite. The cumulative grain-size distribution curves predominantly are two-stage. Oblique bars and orthogonal bars are formed at the bar fringe for lake current and wave kept acting on the lakeshore bars. The lakeshore bars were developed in lake-bays between deltas in descending half cycle of medium short-term strata cycles in the first and the second member of the Qingshankou Formation. Its distribution is obviously controlled by slope breaks and lake shoreline migration. The bar in the western actic region is characterized by thick sand and narrow facies belts. However, the bar in the southern gentle region is distinguished by thin sand and its multi

  2. Modelling of the Duero Sedimentary Basin and Selection of Deep Favourable Geological Formations for Supercritical CO{sub 2} Storage; Modelizacion del Subsuelo de la Cuenca del Duero y Seleccion de Formaciones Favorables para el Almacenamiento de CO{sub 2} en Estado Supercritico

    Energy Technology Data Exchange (ETDEWEB)

    Prado, A. J.; Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2008-04-10

    Currently, the Deep Geological Storage is the internationally most accepted option to store CO{sub 2}, whose main goal is to reduce the CO{sub 2} emissions to the atmosphere. This work, which has been carried out in the frame of The Strategic Singular Project entitled: CO{sub 2} generation, capture and storage advanced technologies summarizes a general methodology focused on the selection and modelling of favourable formations to store CO{sub 2} and to estimate their storage capacity. To conclude, the Duero basin suitability to allocate a CO{sub 2} storage plant has been quantified by integrating the Multi-criteria Evaluation Methods with the corresponding developed Geographical Information Systems. (Author) 45 refs.

  3. Tectonics and Petroleum Potential of the East China Sea Shelf Rift Basin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are two Cenozoic sedimentary basins in the East China Sea. They are the East China Sea shelf basin and the Okinawa Trough basin. The former can be divided into a western and an eastern rift region. The development of the shelf basin underwent continental-margin fault depression, post-rift and then tectonic inversion stages. Available exploration results show that the distribution of source rocks is controlled by the basin architecture and its tectonic evolution. In the Xihu depression, mudstones and coals are the main source rocks. The eastern rift region has good geological conditions for the formation of large oil and gas fields.

  4. Distribution of major hydrocarbon source rocks in the major oil-gas-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    LIU Luofu; ZHAO Suping; CHEN Lixin; HUO Hong

    2005-01-01

    The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Lüliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.

  5. On Implications of the Devonian Hydrothermal Sedimentary Faci es in the Qinling Orogeny%秦岭造山带泥盆系热水沉积岩相应用研究及实例

    Institute of Scientific and Technical Information of China (English)

    方维萱; 张国伟; 胡瑞忠; 刘方杰

    2001-01-01

    构造-热水沉积岩相与盆地的古地理环境, 热水沉积岩相与热水沉积成矿,热(水) 流体岩相与构造背景、构造古地理,它们之间有密切地内在联系.应用热水沉积岩相、沉积相及沉积体系分析方法,对凤县铅硐山-双石铺三级构造热水成矿盆地进行研究。%The Qinling orogenic belt is located in the central China and is one of the most important intracontinental orogeny in the world. Devonian sedimentary basins are the major accumulation structures for Au-Ag-Pb-Zn deposits in the area. Fengtai Devonian pull-apart basin, one of the accumulation basins in the Qinling orogeny, hosted a series of large-superlarge Au-Pb-Zn deposits such as Qiandongshan and Dongtangzi large Pb-Zn deposits and Baguamiao superlarge Au deposits. Lead-zinc orebodies hosted at a suite of hydrothermal depositional rocks in the three-order hydrothermal basins. Therefore, research on relationship between the hydrothermal depositional facies and the three-order hydrothermal basin is the best way to understand the relationship between metal deposits and the hydro thermal depositional basin.   The concept of hydrothermal sedimentary rock facies at the Devonian in the Qinling orogeny has been initiated. Relationships between tectonic hydrothermal sedimentary facies and paleo-geographic framework of sedimentary basin, between hydrothermal sedimentary facies and mineralization of hydrothermal depositions, and between hydrothermal sedimentary facies and tectonic geographic framework are very important in the analysis of sedimentary basin. On the basis of associat ions of the hydrothermal sedimentary facies, sedimentary lithofacies, and sedime ntary system, the Qiandongshan-Shuangshipu third-order hydrothermal deposition al basin has been analyzed in this paper. Three depositional systems are recogni zed in the Qiandongshan-Shuangshipu third-order hydrothermal depositional basin. Carbonate rock formation was formed in a shallow

  6. Incidences of polluting episodes in sedimentary media

    International Nuclear Information System (INIS)

    There exist diverse radioactivity sources in the environment coming from anthropogenic activities that alter the natural levels of radiation. The detailed study of the environmental impact of these sources is of great interest, because it provides knowledge for subsequent decontamination works and environmental control. In this work, it is analyzed the radioactive contamination caused by the radionuclide 226Ra in sedimentary media under a liquid sheet. In this way, the dumping of the radionuclide in sediment columns has been studied in laboratory, determining how its penetration in depth develops along time and for different grain sizes. For this purpose, a migration model based on the numeric resolution of the diffusion equation has been devised.

  7. Sedimentary response to ocean gateway circulation changes

    Science.gov (United States)

    Heinze, Christoph; Crowley, Thomas J.

    1997-12-01

    Previous modeling studies suggested that changes in ocean gateways may have exerted a dramatic influence on the ocean circulation. In this pilot study we extend those results to examining the potential ramifications of circulation changes on the sedimentary record. A version of the Hamburg carbon cycle/sediment model is used in these sensitivity experiments. Results indicate that internal reorganization of the ocean circulation can potentially cause very large regional changes in lysocline depth (1500-3000 m) and opal deposition. These shifts are sometimes comparable in magnitude to those imposed by changes in external forcing (e.g., climate, sea level, and weathering). Comparisons of the model response with the geologic record indicate some significant levels of first-order agreement. This exercise suggests that opportunities now exist for physically based modeling of past sediment responses to circulation and climate changes.

  8. Basin development and tectonic history of the Llanos Basin, Eastern Cordillera, and Middle Magdalena Valley, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, M.A. [PanCanadian Petroleum, Calgary, Alberta (Canada); Addison, F.T.; Alvarez, R. [BP Exploration Ltd., Bogota (Colombia)] [and others

    1995-10-01

    The Middle Magdalena Valley, Eastern Cordillera, and Llanos basin constituted a major regional sedimentary basin from the Triassic to the middle Miocene. Basin development began during the Triassic to the earliest Cretaceous with a synrift megasequence related to the separation of North and South America in the proto-Caribbean. The synrift megasequence began with deposition in a continental environment that became paralic and shallow marine in the Early Cretaceous. Basin development continued into the Cretaceous in a back-arc setting east of the Andean subduction zone. The back-arc megasequence was dominated by shallow-marine sedimentation and produced an excellent regional source rock during the Turonian-Coniacian. Marine deposition was abruptly terminated during the early Maastrichtian due to the final accretion of the Western Cordillera.

  9. The Sequence Architecture of Volcanic Basin Fillings- An Example From Xujiaweizi Faulted Depression In Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    CHENG Rihui; LIU Wanzhu; SHAN Xuanlong; WANG Pujun; CHEN Shumin; QU Yongbao

    2001-01-01

    The basin filling geometric pattern of volcanic eruptive rocks depends on both of the eruptive locations in a basin and structural styles of fault terraces. It is divided into three types by eruptive locations and occurrences of eruptive rocks, including the pattern of eruption along fault and occurrence (PEAFO), the pattern of eruption on footwall of a fault and occurrence (PEOFO) and the pattern of eruption on hangingwall of fault and occurrence (PEOHO) in Xujiaweizi fault depression of Songliao basin, Northeast of China. Those basin filling patterns of volcanic eruptive rocks are of specific geometric characteristics controlling or affecting sedimentation, geometry of sedimentary body and sequence architecture during a sequence evolution. The study shows that the volcanic rocks developed at different stages of lowstand, transgressive and highstand can give different controls or affects on the sequence architecture.

  10. Deep sedimentary structure model beneath the Osaka plain; Osaka heiya ni okeru shinbu chika kozo no model ka

    Energy Technology Data Exchange (ETDEWEB)

    Miyakoshi, K.; Kagawa, T.; Echigo, T. [Osaka Soil Test, Osaka (Japan)

    1997-05-27

    Restructuring was carried out on a sedimentary basin structure model of the Osaka plain including Osaka Bay by using newly obtained underground structural data. After the Hygoken-nanbu Earthquake of 1995, a large number of underground structure investigations have been performed in Osaka Bay and urban areas of Kobe and Osaka. However, very few surveys have been done in areas peripheral to Osaka Prefecture, such as the Ikoma area. Therefore, an attempt has been made to increase the number of measuring points to acquire underground structural data of these areas. Estimation of basic rock depths has utilized the dominant cycles in H/V spectra obtained from micro vibration survey, and good correlation of the base rock depths derived by a refraction exploration and a deep-bed boring investigation. With regard to bed division and P- and S- wave velocities in sedimentary beds in the Osaka sedimentary basin, an underground structure model was prepared, which was divided into four beds according to the refraction exploration and the micro vibration investigation. Data obtained by using this model agreed well with depth data acquired from physical exploration and other types of investigations. However, no good agreement was recognized in the data for such areas where the basic depth changes abruptly as the Rokko fault and the Osaka bay fault. 6 refs., 8 figs., 2 tabs.

  11. Distribution of subglacial sediments across the Wilkes Subglacial Basin, East Antarctica

    Science.gov (United States)

    Frederick, Bruce C.; Young, Duncan A.; Blankenship, Donald D.; Richter, Thomas G.; Kempf, Scott D.; Ferraccioli, Fausto; Siegert, Martin J.

    2016-04-01

    Topography, sediment distribution, and heat flux are all key boundary conditions governing the dynamics of the East Antarctic Ice Sheet (EAIS). EAIS stability is most at risk in Wilkes Land across vast expanses of marine-based catchments including the 1400 km × 600 km expanse of the Wilkes Subglacial Basin (WSB) region. Data from a recent regional aerogeophysical survey (Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP)/IceBridge) are combined with two historical surveys (Wilkes basin/Transantarctic Mountains System Exploration-Ice-house Earth: Stability or DYNamism? (WISE-ISODYN) and Wilkes Land Transect (WLK)) to improve our understanding of the vast subglacial sedimentary basins impacting WSB ice flow and geomorphology across geologic time. Analyzing a combination of gravity, magnetic and ice-penetrating radar data, we present the first detailed subglacial sedimentary basin model for the WSB that defines distinct northern and southern subbasin isopachs with average sedimentary basin thicknesses of 1144 m ± 179 m and 1623 m ± 254 m, respectively. Notably, more substantial southern subbasin sedimentary deposition in the WSB interior supports a regional Wilkes Land hypothesis that basin-scale ice flow and associated glacial erosion is dictated by tectonic basement structure and the inherited geomorphology of preglacial fluvial networks. Orbital, temperate/polythermal glacial cycles emanating from adjacent alpine highlands during the early Miocene to late Oligocene likely preserved critical paleoclimatic data in subglacial sedimentary strata. Substantially thinner northern WSB subglacial sedimentary deposits are generally restricted to fault-controlled, channelized basins leading to prominent outlet glacier catchments suggesting a more dynamic EAIS during the Pliocene.

  12. Elemental Characteristics of Australian Sedimentary Opals and their Implications for Opal Formation and Gemstone Fingerprinting

    Science.gov (United States)

    Dutkiewicz, A.; Landgrebe, T. C.; Rey, P. F.

    2011-12-01

    Opal consists of amorphous SiO2.nH2O comprising a network of silica spheres, which in precious opal are of similar size and form an ordered network allowing light to diffract into an array of colors. Common opal, which is often associated with precious opal, lacks this play of color as it is composed of silica spheres of variable sizes. Australia supplies over 95% of the world's precious opal. The opal is almost exclusively located within Cretaceous sedimentary rocks of the Great Artesian Basin, which experienced a major phase of uplift in the Late Cretaceous with subsequent erosion removing a package of sedimentary rock up to 3 km in thickness. Intense weathering resulted in extensive silicification at relatively shallow levels within the Tertiary regolith. However, despite a billion dollar industry and a well-constrained geological history of the basin, the formation of sedimentary opal and its uniqueness to the Australian continent are still very poorly understood. In this study we have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on precious and common opal from key opal mining areas in order to constrain the possible sources of silica fluids involved in opal genesis and to assess whether any major or trace elements could be used to determine the provenance of opal with respect to a particular mining area. A total of 123 spots, each comprising 59 elements, including rare earth elements were analyzed. Globally, volcanic and sedimentary opals can be distinguished on the basis of Ba and Ca concentrations. Although the opals from the Great Artesian Basin are all sedimentary, some show Ba concentrations consistent with volcanic opals suggesting that silica fluids from which they formed were derived from a volcanic province. The most likely source is the Cretaceous volcanic-plutonic province of central Queensland, which supplied vast amounts of volcanogenic material into the Great Artesian Basin. The weathering of feldspars from the

  13. The relationship between depositional system and ore-formation of sandstone-type uranium deposits in Dongsheng area, Ordos basin

    International Nuclear Information System (INIS)

    The analysis on depositional system plays a very important role in studying sandstone-type uranium deposits. Based on depositional system analysis and sequence stratigraphy, and through the study of depositional system characteristics and the spatial distribution of sedimentary facies, the evolution of sedimentary environments as well as the sequence stratigraphy of Zhiluo Formation in Dongsheng area, Ordos basin, authors have come to the following conclusions, (1) the spatial distribution of sand bodies is controlled by the planar distribution of sedimentary facies, which, in turn, affects the spatial distribution of ore-hosting sand bodies; (2) the evolution of sedimentary facies and sedimentary environments creates good lithofacies and lithological conditions favorable for interlayer oxidation; (3) the spatial lithologic combination of 'three layer structure' is controlled by sedimentary sequence. (authors)

  14. Crustal architecture, thermal evolution and energy resources of compressional basins (André Dumont medallist lecture 2013)

    NARCIS (Netherlands)

    Roure, F.

    2014-01-01

    Our understanding of sedimentary basins, orogens and links between deep and surface processes has greatly benefited from recent improvement of imagery techniques, including crustal scale reflection seismic and mantle tomography. ECORS profiles across the Pyrenees, the Alps and the Paris Basin for in

  15. TECTONIC ZONING OF THE SEDIMENTARY COVER OF THE SEA OF OKHOTSK BASED ON LITHOPHYSICAL, STRUCTURAL AND STRUCTURAL-LITHOPHYSICAL INDICATORS

    Directory of Open Access Journals (Sweden)

    V. P. Semakin

    2015-09-01

    Full Text Available In terms of tectonics, the Sea of Okhotsk (Fig.1 is 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.Results of tectonic zoning of the sedimentary cover based on  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].Tectonic zoning of the sedimentary cover based on structural indicators is carried out with reference to the sediment-thickness map [Sergeyev, 2006], including a significantly revised segment showing the area of the Deryugin basin [Semakin, Kochergin, 2013]. Results of such zoning are represented in the format of a structural-tectonic map (Fig. 3 showing orientations and morphology of the structural elements of the sedimentary cover, the thickness of the sedimentary cover, and amplitudes of relative uplifts and troughs.With reference to the structural-tectonic map (see Fig 3, the structural elements of different orders are grouped by their sizes, spatial positions and orientations and thus comprise tectonic sistems (Fig. 4, structural zones (Fig. 5 that unclude relative uplifts and troughs that are

  16. Tectonic Evolution of the Junggar Foreland Basin in the Late Carboniferous-Permian

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A comprehensive study has been carried out to subdivide andcorrelate the Upper Carboniferous and Permian sedimentary successions in the Junggar basin based on outcrops and drilling and geophysical data. The study results, combined with geological analyses of the basin's periphery and the basement, as well as studies of the sedimentary rocks within the basin, the unconformities, tectonic geometry, kinematics and geodynamics, lead to the conclusion that the Junggar basin was characterized by the development of foreland basin systems during the Late Carboniferous and Per mian, During that period, three foreland basin systems were developed: (1) the northwest foreland basin system, which trended nearly north-south from Mahu to the Chepaizi Palaeo-mountain during its early stage of development and thus it was also referred to as the west foreland basin system; (2) the Karamaili foreland basin system in the east and (3) the Northern Tianshan foreland basin system in the south. These systems are different in size, development stage and time of formation. The first two are developed earlier than the third, but they are smaller in size. All the structures in the Junggar basin have resulted from the integration and superposition of structural elements in the above three systems. In general, the development of the Junggar basin can be divided into four stages. Stage I was marked by the creation and evolution of the marginal western foreland and the peripheral Karamaili foreland basin systems during the Late Carboniferous-early Early Permian (C3-Pja). Stage Ⅱ was characterized by the development of complicated foreland basin systems during the mid dle-late Early Permian (Pjb-Pf) when the three foreland basin systems took their shapes. Stage Ⅲ was the integration stage of peripheral foreland basin systems during the Middle Permian (P2) in which steady and slow tectonic subsidence prevailed. Stage Ⅳ coincided with the shrinking of foreland basin development during the Late

  17. Stratigraphy and Tectonics of the East Ketungau Basin, West Kalimantan during Palaeogene

    Directory of Open Access Journals (Sweden)

    Suyono Suyono

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i4.170East Ketungau Basin is one of frontier basins in Indonesia. Some of these basins, especially those in eastern Indonesia, have been identified to possess potential of oil and gas. The existing publications of geological fieldworks and extensive exploration in the East Ketungau Basin are limited. The detailed sedimentological and biostratigraphical studies of the sedimentary succession will be used to reconstruct the tectonic and palaeogeographical history of the basin. The sedimentary Mandai Group consists of three facies such as mudstone facies, clean sand facies and alternation between thinly coal seam, coaly shale, and claystone facies. However, each facies characterizes depositional environment of barrier- island and associated strand-plain systems.

  18. Sedimentary evolution of Rio do Rastro formation (permian-triassic of the Parana Basin) at central south portion of Santa Catarina State, Brazil; Evolucao sedimentar da Formacao Rio do Rastro (Permo-Triassico da Bacia do Parana) na porcao centro sul do estado de Santa Catarina, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Lucas Verissimo; Roldan, Luis Fernando; Steiner, Samar dos Santos; Chamani, Marlei Antonio Carrari [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Programa de Pos Graduacao em Geoquimica e Geotectonica]. E-mail: lvwarren@yahoo.com; Almeida, Renato Paes de; Hachiro, Jorge; Machado, Romulo [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Geologia Sedimentar e Ambiental

    2008-06-15

    Between the Late Carboniferous and the Early Triassic, the south portion of the Gondwana Supercontinent witnessed the development of intracratonic basins related with the coeval Sanrafaelic Orogeny. The continuous subsidence and consequent generation accommodation space resulted in the formation of a large confined water body and the accumulation of a transgressive regressive sequence between the Late Permian and the Early Triassic. The progradational nature of the upper portion of this sequence, represented by de Rio do Rasto e Piramboia formations, culminated with the complete filling of the water body. In the south-eastern portion of Santa Catarina State (Southern Brazil), the Rio do Rasto Formation overlies the Teresina formation and is overlain by the Piramboia formation, both contacts being characterized by lithological transition. The lower portion of the Rio do Rasto Formation is characterized by architectural elements deposited in offshore environments subject to storm action. A marked change of the color of the pelitic facies, from gray to red and purple occurs at the top of the unit. At this stratigraphic level, there is also a predominance of deltaic and eolian architectural elements. The intercalation of near shore and offshore architectural elements can be explained by the strong auto cyclic character expected in deltaic depositional systems and by the variation of relative rates of base-level rise. The occurrence of eolian architectural elements interbedded with subaquatically deposited sediments on the second third of the unit can be considered an evidence of continentalization to the top, materialized as the transition to the Piramboia desert system. (author)

  19. The Roussillon Basin (S. France): A case-study to distinguish local and regional events between 6 and 3 Ma

    OpenAIRE

    Clauzon, Georges; Le Strat, Paul; Duvail, Cédric; Do Couto, Damien; Suc, Jean-Pierre; Molliex, Stéphane; Bache, François; Besson, David; Lindsay, Everett H.; Opdyke, Neil D.; Rubino, Jean-Loup; Popescu, Speranta-Maria; Haq, Bilal U.; Gorini, Christian

    2015-01-01

    International audience The Roussillon Basin is a non-silled Miocene sedimentary basin filling a late Oligocene–early Miocene graben. The basin was intensively impacted by the 2 Messinian fluvial erosion, as evidenced in exposed sections, in seismic profiles and in deep boreholes drilled for hydrocarbon exploration. As the basin was open to the Mediterranean Sea, the huge drop in sea level at the peak of the Messinian Salinity Crisis is clearly recorded, along with the subsequent sudden mar...

  20. Psematismenos-Maroni Basin in Cyprus: geomorphology and biostratigraphic contributions to its Tertiary geodynamic evolution

    Science.gov (United States)

    Blanpied, Christian; Mocochain, Ludovic; Müller, Carla

    2015-04-01

    The Tertiary regressive sedimentary succession which forms the sedimentary cover of the Troodos Ophiolic Massif has been studied in the Psematismenos-Maroni Basin (PMB) located in southern Cyprus. Identification of key surfaces, morphologies, and sedimentary facies permit to propose a new interpretation of the geologic history of this basin. The series of unconformity surfaces are conforted by numerous new datings, and they are related to tectonic, eustatic, and biostratigraphic hiatuses. This eventually leads to a new geologic vision of the Psematismenos-Maroni Basin from the Neogene Pakhna formation up to the first alluvial deposits of the Quaternary. In the meantime, and for what concerns the Messinian salinity crisis; similarities and differences from the 2008 Messinian consensus (Lofi et al. 2008) are highlighted.

  1. Interbasinal marker intervals——A case study from the Jurassic basins of Kachchh and Jaisalmer, western India

    Institute of Scientific and Technical Information of China (English)

    PANDEY; Dhirendra; Kumar; FüRSICH; Franz; Theodor

    2009-01-01

    The Kachchh Basin and the Jaisalmer Basin are two neighboring Mesozoic sedimentary basins at the western margin of the Indian craton. The Jurassic succession of the Kachchh Basin is more complete and more fossiliferous than that of the Jaisalmer Basin. Consequently, intrabasinal correlation of the sedimentary units has been possible in the Kachchh Basin, but not in the Jaisalmer Basin. However, some marker beds existing in the Kachchh Basin can be recognized also in the Jaisalmer Basin. Ammonite evidence shows that they are time-equivalent. The following four units form marker intervals in both basins: (1) the pebbly rudstone unit with Isastrea bernardiana and Leptosphinctes of the Kaladongar Formation (Kachchh Basin) and the Isastrea bernardiana-bearing rudstone of the Jaisalmer Formation (Jaisalmer Basin) both represent transgressive systems tract deposits dated as Late Bajocian; (2) bioturbated micrites with anomalodesmatan bivalves within the Goradongar Yellow Flagstone Member (Kachchh Basin) and bioturbated units in the Fort Member (Jaisalmer Basin) represent maximum flooding zone deposits of the Middle to Late Bathonian; (3) trough-crossbedded, sandy packto grainstones of the Raimalro Limestone Member (Kachchh Basin) and the basal limestone-sandstone unit of the Kuldhar section of the Jaisalmer Formation (Jaisalmer Basin) correspond to Late Bathonain transgressive systems tract deposits; and (4) ferruginous ooid-bearing carbonates with hardgrounds of the Dhosa Oolite member (Kachchh Basin) and the middle part of the Jajiya Member (Jaisalmer Basin) are Oxfordian transgressive systems tract deposits. The fact that in both basins similar biofacies prevailed during certain time intervals demonstrates a common control of their depositional history. As the two basins represent different tectonic settings, the most likely controlling factors were the relative sea-level changes produced by eustatic processes, a common subsidence history of the northwestern margin of

  2. Radiogenic isotope systematics of clastic sedimentary rocks - with emphasis on detrital zircon geochronology

    International Nuclear Information System (INIS)

    In the present study, the radiogenic isotope systematics of clastic sedimentary rocks are applied to provenance studies. Provenance means place of origin and is basically focused on the location and nature of sediment source areas, the pathways by which the eroded material is transferred from the source to the basin of deposition, and the factors that influence the composition of sedimentary rocks (e.g. relief, climate, tectonic setting). ICP-MS has revolutionised analytical trace element geochemistry, and micro-sampling by laser ablation makes it possible to analyse the trace element and isotope compositions of detrital mineral grains. At the time when this study was initiated, a few pilot studies on detrital zircon geochronology had been carried out. The higher sample throughput and the lower investment cost of 1CPMS compared to SIMS instrumentation, were clear advantages. The analytical challenge was to improve the lower accuracy and precision of the technique. However, new correction methods had shown promising results when applied to the analyses of zircon standards. A careful comparison of the LA-ICPMS with the SIMS technique was needed before LA-ICPMS could confidently be used for provenance studies. A comparative study of' the two techniques was therefore carried out using the NORDSIM facility and the ICPMS laboratory at Memorial University of Newfoundland. The first paper of this thesis deals with the LA-ICPMS technique, and the accuracy and precision of the method when applied to detrital zircon dating. The subsequent papers present three case studies that use the technique, 1) as a tool for terrane analyses of orogenic belts; 2) for provenance studies of a molasse basin to constrain late orogenic exhumation history; and 3) to study the provenance of offshore sediments. 4 papers are included and have titles: 1) U-Pb dating of detrital zircons for sediment provenance studies -a comparison of laser ablation ICPMS and SIMS techniques. 2) U-Pb zircon and Sm

  3. Microbial shaping of sedimentary wrinkle structures

    Science.gov (United States)

    Mariotti, G.; Pruss, S. B.; Perron, J. T.; Bosak, T.

    2014-10-01

    Wrinkle structures on sandy bed surfaces were present in some of the earliest sedimentary environments, but are rare in modern environments. These enigmatic millimetre- to centimetre-scale ridges or pits are particularly common in sediments that harbour trace fossils and imprints of early animals, and appeared in the aftermath of some large mass extinctions. Wrinkle structures have been interpreted as possible remnants of microbial mats, but the formation mechanism and associated palaeoenvironmental and palaeoecological implications of these structures remain debated. Here we show that microbial aggregates can form wrinkle structures on a bed of bare sand in wave tank experiments. Waves with a small orbital amplitude at the bed surface do not move sand grains directly. However, they move millimetre-size, light microbial fragments and thereby produce linear sand ridges and rounded scour pits at the wavelengths observed in nature within hours. We conclude that wrinkle structures are morphological biosignatures that form at the sediment-water interface in wave-dominated environments, and not beneath microbial mats as previously thought. During early animal evolution, grazing by eukaryotic organisms may have temporarily increased the abundance of microbial fragments and thus the production of wrinkle structures.

  4. Investigating Coccolithophorid Biology in the Sedimentary Laboratory

    Science.gov (United States)

    McClelland, H. L. O.; Barbarin, N.; Beaufort, L.; Hermoso, M.; Rickaby, R. E. M.

    2014-12-01

    Coccolithophores are the ocean's dominant calcifying phytoplankton; they play an important, but poorly understood, role in long-term biogeochemical climatic feedbacks. Calcite producing marine organisms are likely to calcify less in a future world where higher carbon dioxide concentrations will lead to ocean acidification (OA), but coccolithophores may be the exception. In coccolithophores calcification occurs in an intracellular vesicle, where the site of calcite precipitation is buffered from the external environment and is subject to a uniquely high degree of biological control. Culture manipulation experiments mimicking the effects of OA in the laboratory have yielded empirical evidence for phenotypic plasticity, competition and evolutionary adaptation in asexual populations. However, the extent to which these results are representative of natural populations, and of the response over timescales of greater than a few hundred generations, is unclear. Here we describe a new sediment-based proxy for the PIC:POC (particulate inorganic to particulate organic carbon ratio) of coccolithophore biomass, which is equivalent to the fractional energy contribution to calcification at constant pH, and a biologically meaningful measure of the organism's tendency to calcify. Employing the geological record as a laboratory, we apply this proxy to sedimentary material from the southern Pacific Ocean to investigate the integrated response of real ancient coccolithophore populations to environmental change over many thousands of years. Our results provide a new perspective on phenotypic change in real populations of coccolithophorid algae over long timescales.

  5. Sedimentary processes and development of the Zenisu deep-sea channel, Philippine Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Zenisu deep-sea channel originated from a volcanic arc region, Izu-Ogasawara Island Arc, and vanished in the Shikoku Basin of the Philippine Sea. According to the swath bathymetry, the deep-sea channel can be divided into three segments. They are Zenisu canyon, E-W fan channel and trough-axis channel. A lot of volcanic detritus were deposited in the Zenisu Trough via the deep-sea channel because it originated from volcanic arc settings. On the basis of the swath bathymetry, submersible and seismic reflection data, the deposits are characterized by turbidite and debrite deposits as those in the other major deep-sea channels. Erosion or few sediments were observed in the Zenisu canyon, whereas a lot of turbidites and debrites occurred in the E-W channel and trough axis channel. Cold seep communities, active fault and fluid flow were discovered along the lower slope of the Zenisu Ridge. Vertical sedimentary sequences in the Zenisu Trough consist of the four post-rift sequence units of the Shikoku Basin, among which Units A and B are two turbidite units. The development of Zenisu canyon is controlled by the N-S shear fault, the E-W fan channel is related to the E-W shear fault, and the trough-axis channel is related to the subsidence of central basin.

  6. Uranium prospecting in the Iguatu and Frade basins (Brazil)

    International Nuclear Information System (INIS)

    The Mineral Exploration Department of CNEN studied the possibilities of uranium occurences in the Iguatu and Frade Basins in the preliminary research program designated 'Small Basins of the Northeast' which contitutes the object of this report. The two basins are located in the State of Ceara. The results of geologic and radiometric researches ahowed that the possibilities for uranium mineralizations were small, since the analyses of samples from the two main anomalies showed the radioactivity came from the remains of monazite. Further analysis of sedimentologic factors indicated favorable confitions for uranium concentration, taking into consideration the large variations of vertical and lateral granulometries, which permit spectulation about the flow of uraniferous solutions. radiometric measurements of surface samples were insignificant and no uranium mineral was found. The result of research of the sedimentary Frade Basin was negative for uranium mineralization. The basin was entirely eroded, remaining as an outcrop described in this report. (F.E.)

  7. Géodynamique et évolution thermique de la matière organique: exemple du bassin de Qasbat-Tadla, Maroc centralBasin geodynamics and thermal evolution of organic material: example from the Qasbat-Tadla Basin, central Morocco

    Science.gov (United States)

    Er-Raïoui, H.; Bouabdelli, M.; Bélayouni, H.; Chellai, H.

    2001-05-01

    Seismic data analysis of the Qasbat-Tadla Basin allows the deciphering of the main tectonic and sedimentary events that characterised the Hercynian orogen and its role in the basin's structural development. The global tectono-sedimentary framework involves structural evolution of an orogenic foreland basin and was the source of rising geotherms in an epizonal metamorphic environment. The complementary effects of these parameters has led to different source rock maturity levels, ranging from oil producing to graphite domains. Different maturity levels result from three distinct structural domains within the basin, each of which exhibit characteristic geodynamic features (tectonic contraints, rate of subsidence, etc.).

  8. First seismic survey of Lake Saint-Jean (Québec, Canada): sedimentary record of the last deglaciation

    Science.gov (United States)

    Nutz, Alexis; Schuster, Mathieu; Ghienne, Jean-François; Raphaël, Certain; Nicolas, Robin; Claude, Roquin; Frédéric, Bouchette; Cousineau Pierre, A.

    2015-04-01

    The general post-glacial evolution of the Lake Saint-Jean region (Canada/Québec) was, until now, only known from onshore studies (outcrops and geomorphology). Because this lake corresponds to sediment depocentre since the area is ice free (latest Pleistocene and the entire Holocene), a comprehensive sedimentary archive could be expected from this area. As a consequence, the offshore archives of Lake Saint-Jean leave a basic, but crucial, question: can the transition from glacial to post-glacial periods be deciphered? The stratigraphy of the last deglacial sequence is investigated in Lake Saint-Jean (Québec, Canada) from 300 km of echo-sounder 2D seismic profiles. The sedimentary archive of this basin is documented from the Late Pleistocene Laurentidian ice-front recession to the present-day situation. Ten seismic units have been identified that reflect spatio-temporal variations in depositional processes characterizing different periods of the Lake Saint-Jean basin evolution. During the postglacial marine flooding, a high deposition rate of mud settling, from proglacial glacimarine and then prodeltaic plumes in the Laflamme Gulf, produced an extensive, up to 50 m thick mud sheet draping the isostatically depressed marine basin floor. Subsequently, closing of the water body due to glacio-isostatic rebound that occurred at 8.5 cal. ka BP and ice-sheet retreat outside the Saint-Jean catchment at 7.5 cal. ka BP drastically modify the hydrodynamics and sedimentation. Hyperpycnal flows appeared because fresh lake water replaced dense marine water. River sediments were transferred towards the deeper part of the lake into river-related confined lobes. The water body is also marked by the onset of a wind-driven internal circulation associating wave-related hydrodynamics and bottom currents with sedimentary features including shoreface deposits, sediment drifts, a sedimentary shelf and important erosional surfaces. The Lake Saint-Jean reveals important diversity and

  9. Flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone of the Three Gorges Reservoir, China.

    Science.gov (United States)

    Tang, Qiang; Bao, Yuhai; He, Xiubin; Fu, Bojie; Collins, Adrian L; Zhang, Xinbao

    2016-04-01

    Since the launch of the Three Gorges Dam on the Yangtze River, a distinctive reservoir fluctuation zone has been created and significantly modified by regular dam operations. Sediment redistribution within this artificial landscape differs substantially from that in natural fluvial riparian zones, due to a specific hydrological regime comprising steps of water impoundment with increasing magnitudes and seasonal water level fluctuation holding a range of sediment fluxes. This study reinterpreted post-dam sedimentary dynamics in the reservoir fluctuation zone by stratigraphy determination of a 345-cm long sediment core, and related it to impact of the hydrological regime. Seasonality in absolute grain-size composition of suspended sediment was applied as a methodological basis for stratigraphic differentiation. Sedimentary laminations with relatively higher proportions of sandy fractions were ascribed to sedimentation during the dry season when proximal subsurface bank erosion dominates source contributions, while stratigraphy with a lower proportion of sandy fractions is possibly contributed by sedimentation during the wet season when distal upstream surface erosion prevails. Chronology determination revealed non-linear and high annual sedimentation rates ranging from 21.7 to 152.1cm/yr. Although channel geomorphology may primarily determine the spatial extent of sedimentation, seasonal sedimentary dynamics was predominantly governed by the frequency, magnitude, and duration of flooding. Summer inundation by natural floods with enhanced sediment loads produced from upstream basins induced higher sedimentation rates than water impoundment during the dry season when distal sediment supply was limited. We thus conclude that flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone, though little impact on total sediment retention rate was detected. Ongoing reductions in flow and sediment supply under human disturbance may

  10. Tectonic and Sedimentary Interactions on the Initiation and the Architecture of the Accretionary Wedges in the Southwestern Edge of the Caribbean, off Panama and Colombia

    Science.gov (United States)

    Mercier De Lepinay, B. F.; Maurin, T.; Barat, F.; Auxietre, J.

    2013-12-01

    The structurally and stratigraphically complex area of North Panama deformed belt, Sinu-Uraba accretionary prism and south Caribbean deformed belt holds the key to understand the plate tectonic evolution of the southwestern margins of the Caribbean Sea. New geological fieldworks, sedimentary and structural analysis, detailed offshore and onshore seismic interpretation provide insights into the regional structural and stratigraphic evolution of those margins. Detailed results constraint the geodynamic history of these complex wedge architecture which registered successive changes of sedimentary supplies and gravity collapses. During the Paleocene and Eocene time, the southeastward subduction of the Caribbean plate below the northwestern edge of South America is characterized by the development of an accretionary wedge off the Caribbean margin of Colombia, due to the accumulation of a large amount of sediments provided by the Magdalena and the Sinu rivers. The Atrato river, at that time, was providing sediments to the basins restricted within the Panama Isthmus. During the Middle Miocene, the Panama Isthmus began to collide against South America, inducing the uplift of the San Jacinto/Sinu Belt in Colombia. As a consequence, the Magdalena river was deviated northward. The Sinu river was also deviated to the North and started to load the back of the the Sinu accretionary wedge which then began to collapse as convergence has ceased. In the same way, the uplift of the Darien Shear Zone, east of the Atrato basin, has deflected the sedimentary supply from the Chucunaque/Tuira basins to the northern margin of the isthmus, allowing the development of a sedimentary basin and the initiation of the North Panama Deformed Belt. Thus, on one hand, the structure of the Colombian Wedge, the Sinu Wedge and the North Panama Deformed belt, was controlled by the tectonic forces, a consequence of the convergence and progressive accretion of the Central American isthmus against the

  11. Vertical plate motions in the West Siberian Basin

    Science.gov (United States)

    Vibe, Yulia

    2014-05-01

    The West Siberian Basin is a sedimentary basin situated between the Ural Mountains and the Siberian Craton. The Basin has experienced several periods of subsidence and uplift since the arrival of the Siberian Traps c. 250 Ma. Although the Basin is extensively explored and hosts large reserves of Oil and Gas, the forces driving the vertical motions are poorly understood. In this work we attempt to analyse the amount, timing and location of subsidence and uplift in the Basin to shed light on the possible causes of these motions. A detailed description of sedimentary layers is published in a number of Soviet-era books and articles and serves as a basis for our research. This data is first converted into sediment grids through time. Subsequently, the sediments, the sediment load and the compaction are taken into account ('backstripping') to produce the depth of the Basin at respective time steps. With this technique we calculate the tectonic component of subsidence. Uncertainties related to uplift events are estimated by the unconformities in the stratigraphic charts. One of the possible driving forces of vertical motions is a change of force balance arising at plate boundaries. Since active plate tectonics have been absent from West Siberia since the formation of the Urengoy and Khodosey Rifts, c. 250Ma, we study the far-field tectonic effects as a potential driving mechanism. Indeed, some of the significant vertical events in the West Siberian Basin coincide with the major tectonic events around Siberia. An example is the spreading in the Arctic (Eurasian Basin) in the Eocene (56 Ma) which was synchronous with initiation of uplift events in the northern part of West Siberia. In the middle Oligocene (33 Ma), the northern and eastern parts of the basin were subjected to uplift as subsidence migrated southwards and the Basin rose above the sea level. This was coincident with the changes of plate motions in the northern North Atlantic and Indo-European collision.

  12. Paleogene-Neogene stratigraphic realm and sedimentary sequence of the Qinghai-Tibet Plateau and their response to uplift of the plateau

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the data of 1:250000 geological mapping completed by CGS and the previous literature of the Cenozoic strata, 98 remnant basins and 5 stratigraphic realms with 13 stratigraphic subrealms have been recognized on the Qinghai-Tibet Plateau and its adjacent area. Through the research of the types of remnant basins, tectonic setting, stratigraphic sequence and sedimentary characteristics, contact relationship between the strata, the formation time and evolution history of sediments, we divided the uplift process and sedimentary response of the Qinghai-Tibet Plateau into 3 stages and 8 sub-stages, namely, subduction-collision uplift stage (65-34 Ma) with three sub-stages, intercontinental convergence and compressive uplift stage (34-13 Ma) with three sub-stages, and intercontinental isostatic adjustment uplift stage (since 13 Ma) with two sub-stages.

  13. Palaeoseismicity in relation to basin tectonics as revealed from soft-sediment deformation structures of the Lower Triassic Panchet formation, Raniganj basin (Damodar valley), eastern India

    Indian Academy of Sciences (India)

    Abhik Kundu; Bapi Goswami; Patrick G Eriksson; Abhijit Chakraborty

    2011-02-01

    The Raniganj basin in the Damodar valley of eastern India is located within the riftogenic Gondwana Master-Basin. The fluvio-lacustrine deposits of the Lower Triassic Panchet Formation of the Damodar valley in the study area preserve various soft-sediment deformation structures such as slump folds, convolute laminae, flame structures, dish-and-pillar structures, sandstone dykes, pseudonodules and syn-sedimentary faults. Although such soft-sediment deformation structures maybe formed by various processes, in the present area the association of these structures, their relation to the adjacent sedimentary rocks and the tectonic and depositional setting of the formation suggest that these structures are seismogenic. Movements along the basin margin and the intra-basinal faults and resultant seismicity with moderate magnitude (2–5 on Richter scale) are thought to have been responsible for the soft-sediment deformations.

  14. Chronology and geochemistry of the volcanic rocks in Woruo Mountain region, Northern Qiangtang depression: Implications to the Late Triassic volcanic-sedimentary events

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; FU XiuGen; CHEN WenXi; WANG ZhengJiang; TAN FuWen; CHEN Ming; ZHUO JieWen

    2008-01-01

    A suite of sedimentary-volcaniclastic rocks intercalated with the volcanic rocks unconformably overlies the Triassic Xiaochaka Formation in the Woruo Mountain region, Qiangtang Basin, northern Tibet. The sents the age of the Late Triassic volcanic-sedimentary events in the Woruo Mountain region, and is consistent with that of the formation of the volcanic rocks from the Nadi Kangri Formation in the Nadigangri-Shishui River zone. There is a striking similarity in geochemical signatures of the volcanic rocks from the Woruo Mountain region and its adjacent Nadigangri-Shishui River zone, indicating that all the volcanic rocks from the Qiangtang region might have the same magmatic source and similar tectonic setting during the Late Triassic. The proper recognition of the Late Triassic large-scale volcanic eruption and volcanic-sedimentary events has important implications for the interpretation of the Late Triassic biotic extinction, climatic changes and regressive events in the eastern Tethyan domain,as well as the understanding of the initiation and nature, and sedimentary features of the Qiangtang Basin during the Late Triassic-Jurassic.

  15. Chronology and geochemistry of the volcanic rocks in Woruo Mountain region,Northern Qiangtang depression:Implications to the Late Triassic volcanic-sedimentary events

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A suite of sedimentary-volcaniclastic rocks intercalated with the volcanic rocks unconformably overlies the Triassic Xiaochaka Formation in the Woruo Mountain region, Qiangtang Basin, northern Tibet. The vitric tuff from the base of these strata gives a SHRIMP zircon U-Pb age of 216 ± 4.5 Ma, which represents the age of the Late Triassic volcanic-sedimentary events in the Woruo Mountain region, and is consistent with that of the formation of the volcanic rocks from the Nadi Kangri Formation in the Nadigangri-Shishui River zone. There is a striking similarity in geochemical signatures of the volcanic rocks from the Woruo Mountain region and its adjacent Nadigangri-Shishui River zone, indicating that all the volcanic rocks from the Qiangtang region might have the same magmatic source and similar tectonic setting during the Late Triassic. The proper recognition of the Late Triassic large-scale volcanic eruption and volcanic-sedimentary events has important implications for the interpretation of the Late Triassic biotic extinction, climatic changes and regressive events in the eastern Tethyan domain, as well as the understanding of the initiation and nature, and sedimentary features of the Qiangtang Basin during the Late Triassic-Jurassic.

  16. Pliocene-Quaternary contourites along the northern Gulf of Cadiz margin: sedimentary stacking pattern and regional distribution

    Science.gov (United States)

    Llave, Estefanía; Matias, Hugo; Hernández-Molina, F. Javier; Ercilla, Gemma; Stow, Dorrik A. V.; Medialdea, Teresa

    2011-12-01

    This study reports novel findings on the Pliocene-Quaternary history of the northern Gulf of Cadiz margin and the spatiotemporal evolution of the associated contourite depositional system. Four major seismic units (P1, P2, QI and QII) were identified in the Pliocene-Quaternary sedimentary record based on multichannel seismic profiles. These are bounded by five major discontinuities which, from older to younger, are the M (Messinian), LPR (lower Pliocene revolution), BQD (base Quaternary discontinuity), MPR (mid-Pleistocene revolution) and the actual seafloor. Unit P1 represents pre-contourite hemipelagic/pelagic deposition along the northern Gulf of Cadiz margin. Unit P2 reflects a significant change in margin sedimentation when contourite deposition started after the Early Pliocene. Mounded elongated and separated drifts were generated during unit QI deposition, accompanied by a general upslope progradation of drifts and the migration of main depocentres towards the north and northwest during both the Pliocene and Quaternary. This progradation became particularly marked during QII deposition after the mid-Pleistocene (MPR). Based on the spatial distribution of the main contourite depocentres and their thickness, three structural zones have been identified: (1) an eastern zone, where NE-SW diapiric ridges have controlled the development of two internal sedimentary basins; (2) a central zone, which shows important direct control by the Guadalquivir Bank in the south and an E-W Miocene palaeorelief structure in the north, both of which have significantly conditioned the basin-infill geometry; and (3) a western zone, affected in the north by the Miocene palaeorelief which favours deposition in the southern part of the basin. Pliocene tectonic activity has been an important factor in controlling slope morphology and, hence, influencing Mediterranean Outflow Water pathways. Since the mid-Pleistocene (MPR), the sedimentary stacking pattern of contourite drifts has been

  17. Sedimentary and crustal structure from the Ellesmere Island and Greenland continental shelves onto the Lomonosov Ridge, Arctic Ocean

    Science.gov (United States)

    Dahl-Jensen, T.; Jackson, H. R.; Lorita Working Group

    2009-04-01

    Two wide-angle refraction/reflection lines were acquired jointly by the geological surveys of Denmark and Greenland (GEUS) and Canada (GCS) on the sea ice north of Ellesmere Island and Greenland. The aim was to investigate the junction of the Lomonosov Ridge with the polar margin, crossing from the continental shelf over a bathymetric trough out onto the Lomonosov Ridge. A 14 km deep sedimentary basin consisting of two layers interpreted to be part of the Arctic Continental Terrace Wedge and under these a 9 km thick layer interpreted the to be continuation offshore of the Mesozoic to Paleozoic Sverdrup Basin sequence were found. Underneath the basin a layer with velocities consistent with metasedimentary rocks from the lower Paleozoic Franklinian Basin was modeled. The sedimentary basin and underlying metasedimentary rocks continue from the shelf out onto the Lomonosov Ridge. The underlying crust has velocities consistent with continental crust. On the shallow section of the Lomonosov Ridge, a basement high approaches the seafloor, creating the 220 km broad foot of the Ridge. Consistent with the wide-angle results, two short seismic reflection profiles in the vicinity penetrated only a thin veneer of sediments overlying basement. Furthermore, a pattern of radiating linear magnetic anomalis emanating from a circular high is coincident with the shallow basement. Onshore magnetic anomalies near north-western Ellesmere Island are reminiscent in pattern and amplitude to the anomaly on the southern end of the Ridge suggesting a similar source. In addition, the velocity structure is similar to that on the foot of the Ridge. Onshore, the anomalies are produced by the Hansen Point volcanic rocks. The proposed volcanic structure on the foot of the Ridge is by analogy to the Hansen Point volcanics and by its position in the velocity model is assumed to be intruded through continental crust, possibly as part of a failed rift zone proceeding opening of the Eurasia Basin. The

  18. General basin modeling for site suitability. Draft report 1. Baseline data

    International Nuclear Information System (INIS)

    This report summarizes work completed by Golder Associates under Task 2 - Site Suitability specifically for modeling of fluid flow and mass transport in sedimentary basins containing thick shale or salt. It also describes ongoing and future work on the above topic. The purpose of the study is to develop a general model for a nuclear waste repository situated in a deep sedimentary basin environment. The model will be used in conjunction with Golder's fluid flow and mass transport codes to study specific aspects of nuclide transport by groundwater flow

  19. Uranium prospecting in Cerro Partido Region-Encruzilhada do Sul Basin-RS, Brazil

    International Nuclear Information System (INIS)

    The Cerro Partido residual basin is a shallow (85 meters) and small (25km2) sedimentary basin, a remainder of the erosive cicle, enclosed in the pre-cambrian granitic rocks of the Rio Grande do Sul Shield. Grades of 0.2+ U3O8 were found in its upper-paleozoic sandstones and shales drilles for uranium. The small size and thicknesses of these concentrations prevent their economic mining. However, the different levels of the shield exposed by tectonics, the intrusive granitic, riolitic and syenitic rocks, the anomalous uranium contents in sedimentary and crystalline rocks recommend further investigations on the shield area

  20. The Hidden Watershed's Journals: the Informational Characteristics of Biomarkers in Sedimentary Deposits

    Science.gov (United States)

    Guerrero, F. J.; Hatten, J. A.

    2014-12-01

    The historical reconstruction of past environmental changes in watersheds is essential to understand watershed response to disturbances and how those diturbances could affect the provision of valuable goods like water. That reconstruction requires the interpretation of natural records, mainly associated to sedimentary deposits that store detailed information in the form of specific biogenic molecules (i.e. biomarkers). In forested watersheds terrestrial vegetation is an important source of biomarkers like those associated to Lignin, a complex organic polymer used by plants to provide physical support in its tissues. Through litter inputs Lignin is deposited in soils and then is transported to sedimentary environments by rivers (e.g. floodplains, lake bottoms), serving as a source of information about vegetation changes in watersheds. In spite of the critical character of the information extracted from biomarkers in sedimentary records, the very concept of information is still used in a metaphorical sense, even though it was formally defined more than 60 years ago and has been applied extensively in ecology (e.g. Shannon's diversity index). Furthermore, sophisticated techniques are being used to deliver more complex molecular data that require examination and validation as indicators for watershed historical reconstructions. My research aims to explore the applicability of some information metrics (i.e. diversity indices, information coefficients) to a diverse molecular set derived from the chemical depolymerization of lignin deposited in floodplains and lake sediments in different basins. This approach attempts to assess the informational characteristics of Lignin as an indicator of natural/human-induced perturbations in forested watersheds. The formal assessment of the informational characteristics of natural records could have a profound impact not only in our methodological approaches but also in our philosophical view about information and communication in

  1. Continental Growth and the Sedimentary Record

    Science.gov (United States)

    Dhuime, B.; Hawkesworth, C. J.; Robinson, R. A. J.; Cawood, P. A.

    2014-12-01

    Detrital sedimentary rocks provide average samples of the continental crust formed at different times and in different places. Some materials are more susceptible to erosion and/or to preservation bias than others, and one issue is to understand how the compositions of a range of source rocks are then recorded in the sediments. Here we considered two different approaches to model the growth of the continental crust: (i) The variation of Nd isotopes in continental shales with different deposition ages, which requires a correction of the bias induced by preferential erosion of younger rocks through an erosion parameter usually referred to as 'K'. The determination of K, and the extent to which it varies in different erosion systems, thus have fundamental implications for the models of continental growth based on radiogenic isotopes in continental sediments. (ii) The variations in U-Pb, Hf and O isotopes in detrital zircons, from 'modern' sediments sampled worldwide. In this approach, O isotopes are used to screen 'hybrid' Hf model ages (i.e. ages resulting from mixing processes of crustal material from different ages) from Hf model ages that represent actual crust formation ages. These two approaches independently suggest that the continental crust has been generated continuously, but with a marked decrease in the continental growth rate at ~3 Ga. The >4 Ga to ~3 Ga period is characterised by relatively high net rates of continental growth (~3.0 km3.a-1), which are similar to the rates at which new crust is generated, and destroyed, at the present time. Net growth rates are much lower since 3 Ga (~0.8 km3.a-1), which may be attributed to higher rates of destruction of continental crust. The inflexion in the continental growth curve at ~3 Ga indicates a change in the way the crust was generated and preserved. This change may be linked to onset of subduction-driven plate tectonics and discrete subduction zones.

  2. Basin formation and inversion of the back-arc, Niigata basin, central Japan: New insight from deep seismic profiling

    Science.gov (United States)

    Sato, Hiroshi; Abe, Susumu; Kawai, Nobuo; Saito, Hideo; Kato, Naoko; Shiraishi, Kazuya; Ishiyama, Tatsuya; Fukasawa, Hikaru; Inaba, Mitsuru

    2010-05-01

    Associated with the opening of the Japan Sea, rift-basins have been developed along the Japan Sea coast of northern Honshu. The Niigata basin, central Japan, is one of the such basins and filled by thick (faulting. Due to thick Neogene sediments, relationship between active faults/folds at near the surface and deep-sited seismogenic source faults is poorly understood. To reveal the crustal structure, in particular geometry of source faults, onshore-offshore integrated deep seismic profiling was undertaken along the two seismic lines in 2008 and 2009. The 2009 Aizu-Sado seismic line is a 135-km-long, onshore-offshore seismic line across Niigata basin and Sado island, which is located in the eastern part of Japan Sea. The 2008 Sanjo-Yahiko seismic line (Sato et al., 2009) is located 20 km south of the seismic line and trending parallel to it. The seismic source was air-gun (3020 cu. inch), four vibroseis trucks and explosives (cables, cable-connected-recording system and offline recorders, forming a maximum 2400 channels receiver array. The basin fill consists of early to middle Miocene volcaniclastic rocks and overlying Neogene sedimentary rocks showing upward coarsening facies deposited under bathyal to fluvial environment. Main features of basin development, such as early Miocene normal faulting, associated with the formation of Japan Sea, and shortening deformation since Pliocene, are well demonstrated on the seismic sections. Particularly, boundary between pre-Tertiary meta-sedimentary rocks and Miocene volcanics were identified by velocity profile deduced by diving wave tomography and it enabled us to identify the geometry of extensional rift-basin. It is very difficult to distinguish meta-sedimentary rocks from volcaniclastic rocks by seismic facies or pattern of reflections. Fault reactivation of Miocene normal faulting to reverse faulting is common style of deformation. The fault reactivation processes of the eastern boundary fault of the Nagaoka plane

  3. Basement faults and volcanic rock distributions in the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Volcanic rocks in the Ordos Basin are of mainly two types: one in the basin and the other along the margin of the basin. Besides those along the margin, the marginal volcanic rocks also include the volcanic rocks in the Yinshanian orogenic belt north of the basin. Based on the latest collection of gravitational and aeromagnetic data, here we interpret basement faults in the Ordos Basin and its peripheral region, compare the faults derived from aeromagnetic data with those from seismic data, and identify the geological ages of the fault development. Two aeromagnetic anomaly zones exist in the NE-trending faults of the southern basin, and they are in the volcanic basement formed in pre-Paleozoic. These NE-trending faults are the channel of volcanic material upwelling in the early age (Archean-Neoproterozoic), where igneous rocks and sedimentary rocks stack successively on both sides of the continental nucleus. In the Cambrian, the basin interior is relatively stable, but in the Late Paleozoic and Mesozoic, the basin margin underwent a number of volcanic activities, accompanied by the formation of nearly north-south and east-west basement faults in the basin periphery and resulting in accumulation of great amount of volcanic materials. Volcanic tuff from the basin periphery is discovered in the central basin and volcanic materials are exposed in the margins of the basin. According to the source-reservoir-cap rock configuration, the basin peripheral igneous traps formed in the Indosinian-Early Yanshanian and Late Hercynian are favorable exploration objectives, and the volcanic rocks in the central basin are the future target of exploration.

  4. Age, sedimentary environments, and other aspects of sandstone and related host rocks for uranium deposits

    International Nuclear Information System (INIS)

    Project II of the Uranium Geology Working Group was assigned to the study of sedimentary basins and sandstone - type uranium deposits. About 40% of the worlds's uranium resources are contained in sandstone-type deposits, which has led to extensive research. The research was carried out mainly by correspondence, and the results reported by 21 geologists from 10 nations are summarized in this report. It investigated five topics dealing with important aspects of the geology of uranium ores in sandstone host formations: age of host rock; partitioning of uranium between continental and marine sediments; latitude limitation on formation of sandstone deposits; effect of rock formation dip on sandstone ores; usefulness of stable isotope and fluid inclusion studies. The results of studies on these subjects form part of a wider programme of the Working Group, whose final results will be presented at the 27th International Geological Congress in Moscow in 1984

  5. The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

    DEFF Research Database (Denmark)

    Crooijmans, R. A.; Willems, C. J L; Nick, Hamid;

    2016-01-01

    A three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin...... and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated as a function of N...... errors in predicting the life time of low-enthalpy geothermal systems for N/G values below 70%....

  6. The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

    DEFF Research Database (Denmark)

    Crooijmans, R. A.; Willems, C. J L; Nick, Hamid;

    2016-01-01

    A three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin...... life time and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated...... lead to significant errors in predicting the life time of low-enthalpy geothermal systems for N/G values below 70%....

  7. Mars Sedimentary Geology: Key Concepts and Outstanding Questions

    OpenAIRE

    Grotzinger, John; Beaty, David; Dromart, Gilles; Gupta, Sanjeev; Harris, Mitch; Hurowitz, Joel; Kocurek, Gary; McLennan, Scott; Milliken, Ralph E.; Ori, Gian G.; Sumner, Dawn Y.

    2011-01-01

    Processes that operate at planetary surfaces have the potential to record a history of planetary evolution in the form of sedimentary rocks. This is important because our experience on Earth shows that sediments and sedimentary rocks are the dominant archive of high-resolution proxies of present and past tectonic, climatic, and biological processes. Our understanding of the evolution of Earth’s very ancient climate and paleobiological records derives from detailed exam...

  8. Sedimentary record of Earthquakes and Tsunamis in the Central Mediterranean Sea

    Science.gov (United States)

    Polonia, A.; Romano, S.; Vaiani, S. C.; Gasparotto, G.; Gasperini, L.; Nelson, C. H.

    2014-12-01

    The Ionian Sea is a landlocked basin where convergence between Africa and Eurasia produced the emplacement of two opposite verging subduction/rollback systems (i.e. the Calabrian and the Hellenic Arcs). It is one of the most seismically active regions in the Mediterranean Sea and has been struck repeatedly by destructive historical earthquakes, often associated with tsunamis. Slab tearing in a pre-collisional setting is reflected in dynamic topography with high uplift rates of the coastal mountain belts, accompanied with a great sediment discharge to the continental margins. This increases the susceptibility to mass failures implying a strong interplay between active tectonics, seismic shaking, mass flows and tsunami generation.We investigated the effects of historic earthquakes on abyssal marine sedimentation through the analysis of the turbidite record in tectonically controlled basins. Holocene resedimented units in the deep Ionian Sea represent more than 90% of the total thickness of the sedimentary record. We dated the most recent turbidite sequences using different radiometric methods and the results suggest that turbidite emplacement was triggered by major historic earthquakes and tsunamis recorded in the region (i.e. AD 365 Crete and AD 1169, 1693 and 1908 Italian earthquakes).Textural, micropaleontological, geochemical and mineralogical signatures reveal that turbidite beds are stacked sandy units, which have different compositions suggesting coeval multiple failures. They are characterized by organic-rich sandy layers, containing a mixture of lithic clasts, plant fragments and displaced benthic foraminifera derived from several sources and bathymetric ranges. Structure and composition of each turbidite unit, combined with geochemical and isotopic analysis on organic carbon, are being refined to unravel the relative contribution of seismic shaking and tsunami wave loading on mass flow processes generation.Turbidites may be considered as the sedimentary

  9. Vinna Basin

    Czech Academy of Sciences Publication Activity Database

    Honěk, J.; Franců, J.; Mikuláš, Radek; Pešek, J.; Sýkorová, Ivana; Tomanová-Petrová, P.

    Prague: Czech Geological Survey, 2014, s. 223-241 ISBN 978-80-7075-862-5 R&D Projects: GA ČR GA105/06/0653 Institutional support: RVO:67985891 ; RVO:67985831 Keywords : Tertiary basins * Czech Republic * Cenomanian and Tertiary lignite * geology * stratigraphy Subject RIV: DB - Geology ; Mineralogy

  10. Magnetic Fabrics and Paleomagnetism of Sedimentary Rocks: Examining Effects of Compaction and Deformation

    Science.gov (United States)

    Housen, B. A.

    2006-12-01

    Sedimentary rocks provide many important records of the geometry and history of the geomagnetic field, but such records are at times compromised by the effects of depositional processes, soft-sediment deformation, compaction, and tectonic strain. One productive line of research into these effects has been to utilize the well known ability of magnetic anisotropy methods to quantitatively analyze sediment fabrics that result from these processes, and to use these data to evaluate the possibility that the remanence directions in sediments and sedimentary rocks have been altered. Two approaches to this problem will be presented. The first deals with relationships between magnetic fabric shape parameters and paleomagnetic inclination error. The second approach will be to examine the shape distributions of paleomagnetic data, and compare these to the shape distributions of AMS kmin axes from the same rocks. For the first approach, analyses of magnetic fabrics and estimates of paleomagnetic inclination error in the Shikoku Basin (ODP Site 1173) sediments indicate that both initial deposition and post-depositional compaction play important roles in shallowing of inclination. The sediments down to 344 meters depth have relatively uniform flattening values and fabric-based estimates of mean inclination errors of 3.2° for a = 5, and 5.9°° for a = 2.4. The uniform flattening factors, minor inclination errors, and uniform porosity all suggest that only the initial deposition/consolidation process, rather than burial-related compaction, has influenced the paleomagnetic inclinations of the sediments within this interval. In contrast, sediments below 344 meters depth have flattening factors and calculated inclination errors that monotonically increase with depth, with mean inclination errors of 12.1° for a = 5, and 23.3° for a = 2.4. Decrease of porosity within this same depth interval suggests that burial-related compaction within these hemipelagic sediments is the dominant

  11. Tectonic evolution of Tarim basin in Cambrian-Ordovician and its implication for reservoir development, NW China

    Science.gov (United States)

    Bingsong, Yu; Zhuang, Ruan; Cong, Zhang; Yinglu, Pan; Changsong, Lin; Lidong, Wang

    2016-03-01

    In order to find the impact of regional tectonic evolution of Tarim basin on the inside distribution of sedimentary facies and reservoir development, this paper, based on the research of plate-tectonic evolution of Tarim basin, conducts an in-depth analysis on the basin's inside sedimentary response to the Eopaleozoic regional geodynamic reversion from extension to convergence around Tarim plate, and concludes that the regional geodynamic environment of surrounding areas closely contributes to the formation and evolution of paleo-uplifts, differentiation of sedimentary facies in platform, distribution of high-energy reef and bank facies belts, conversion of sedimentary base level from fall to rise, obvious change of lithology from dolomite to limestone, and formation of several unconformity surfaces in Ordovician system in the basin. A series of sedimentary responses in the basin are controlled by regional dynamic setting, which not only controls the distribution of reservoirs in reef and bank facies but also restricts the development and distribution of karst reservoirs controlled by the unconformity surfaces. This offers the macro geological evidences for us to further analyze and evaluate the distribution of favorable reservoirs.

  12. Geophysical methods for the study of sedimentary cycles

    Institute of Scientific and Technical Information of China (English)

    Xu Jingling; Liu Luofu; Wang Guiwen; Shen Jinsong; Zhang Chunhua

    2009-01-01

    We present the wavelet depth-frequency analysis and variable-scale frequency cycle analysis methods to study sedimentary cycles. The spectrum analysis, variable-scale frequency cycle analysis, and wavelet depth-frequency analysis methods are mainly discussed to distinguish sedimentary cycles of different levels. The spectrum analysis method established the relationship between the spectrum characteristics and the thickness and number of sedimentary cycles. Both the variable-scale frequency cycle analysis and the wavelet depth-frequency analysis are based on the wavelet transform. The variable-scale frequency cycle analysis is used to obtain the relationship between the periodic changes of frequency in different scales and sedimentary cycles, and the wavelet depth-frequency analysis is used to obtain the relationship between migration changes of frequency energy clusters and sedimentary cycles. We designed a software system to process actual logging data from the Changqing Oilfieid to analyze the sedimentary cycles, which verified the effectiveness of the three methods, and good results were obtained.

  13. Magmatism in rifting and basin formation

    Science.gov (United States)

    Thybo, H.

    2008-12-01

    Whether heating and magmatism cause rifting or rifting processes cause magmatic activity is highly debated. The stretching factor in rift zones can be estimated as the relation between the initial and the final crustal thickness provided that the magmatic addition to the crust is insignificant. Recent research demonstrates substantial magmatic intrusion into the crust in the form of sill like structures in the lowest crust in the presently active Kenya and Baikal rift zones and the DonBas palaeo-rift zone in Ukraine. This result may be surprising as the Kenya Rift is associated with large amounts of volcanic products, whereas the Baikal Rift shows very little volcanism. Identification of large amounts of magmatic intrusion into the crust has strong implications for estimation of stretching factor, which in the case of Baikal Rift Zone is around 1.7 but direct estimation gives a value of 1.3-1.4 if the magmatic addition is not taken into account. This may indicate that much more stretching has taken place on rift systems than hitherto believed. Wide sedimentary basins may form around aborted rifts due to loading of the lithosphere by sedimentary and volcanic in-fill of the rift. This type of subsidence will create wide basins without faulting. The Norwegian- Danish basin in the North Sea area also has subsided gradually during the Triassic without faulting, but only few rift structures have been identified below the Triassic sequences. We have identified several mafic intrusions in the form of large batholiths, typically more than 100 km long, 20-40 km wide and 20 km thick. The associated heating would have lifted the surface by about 2 km, which may have been eroded before cooling. The subsequent contraction due to solidification and cooling would create subsidence in a geometry similar to basins that developed by loading. These new aspects of magmatism will be discussed with regard to rifting and basin formation.

  14. Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Khadge, N.H.; Nabar, S.; Raghukumar, C.; Ingole, B.S.; Valsangkar, A.B.; Sharma, R.; Srinivas, K.

    An area of 0.6 km sup(2) in the manganese nodule field of the Central Indian Basin was physically disturbed and sediments discharged in the near bottom waters to simulate seabed mining and study its impact on benthic ecosystem. An estimated 2 to 3...

  15. Early Archaean collapse basins, a habitat for early bacterial life.

    Science.gov (United States)

    Nijman, W.

    For a better definition of the sedimentary environment in which early life may have flourished during the early Archaean, understanding of the basin geometry in terms of shape, depth, and fill is a prerequisite. The basin fill is the easiest to approach, namely from the well exposed, low-grade metamorphic 3.4 - 3.5 Ga rock successions in the greenstone belts of the east Pilbara (Coppin Gap Greenstone Belt and North Pole Dome) in West Australia and of the Barberton Greenstone Belt (Buck Ridge volcano-sedimentary complex) in South Africa. They consist of mafic to ultramafic volcanic rocks, largely pillow basalts, with distinct intercalations of intermediate to felsic intrusive and volcanic rocks and of silicious sediments. The, partly volcaniclastic, silicious sediments of the Buck Ridge and North Pole volcano-sedimentary complexes form a regressive-transgressive sequence. They were deposited close to base level, and experienced occasional emersion. Both North Pole Chert and the chert of the Kittys Gap volcano-sedimentary complex in the Coppin Gap Greenstone Belt preserve the flat-and-channel architecture of a shallow tidal environment. Thickness and facies distribution appear to be genetically linked to systems, i.e. arrays, of syn-depositionally active, extensional faults. Structures at the rear, front and bottoms of these fault arrays, and the fault vergence from the basin margin towards the centre characterize the basins as due to surficial crustal collapse. Observations in the Pilbara craton point to a non-linear plan view and persistence for the basin-defining fault patterns over up to 50 Ma, during which several of these fault arrays became superposed. The faults linked high-crustal level felsic intrusions within the overall mafic rock suite via porphyry pipes, black chert veins and inferred hydrothermal circulations with the overlying felsic lavas, and more importantly, with the cherty sediments. Where such veins surfaced, high-energy breccias, and in the

  16. Meso-Cenozoic basin evolution in northern Korean Peninsula

    Institute of Scientific and Technical Information of China (English)

    PAK Hyon Uk; LYANG To Jun; LIU Yongjiang; HYON Yun Su; KIM Gyong Chol

    2009-01-01

    In the Korean Peninsula the Meso-Cenozoic basins were mainly formed due to fault block and block movement. The Mesozoic fracture structures correspond basically to modern large rivers in direction. Such faults were usually developed to rift and formed lake-type tectonic basin, such as the Amrokgang-, Taedonggang-, Ryesonggang-, Hochongang-, Jangphari-, Susongchon-, Pujon-, and Nampho basins. The Mesozoic strata are considered to be divided into the Lower Jurassic Taedong System, Upper Jurassic Jasong System, Upper Jurassic- -early Lower Cretaceous Taebo System, and the Upper Cretaceous- -Paleocene (Chonjaebong, Hongwon, Jaedok Series). The Cenozoic block movement succeeded the Mesozoic fault block movement. The Kilju-Myongchon Graben and Tumangang Basin, etc, are the basins related to the fault zones developed from the Oligocene to Miocene. In addition, the Tertiary basins were formed in many areas in the Miocene (e.g. Sinhung, Oro, Hamhung, Yonghung, Anbyon, Cholwon, etc). The Cenozoic sedimentation occurred mainly from the late Oligocene to Miocene. The Kilju-Myongchon Graben was the fore deep connected to the sea and the basins inclined in the Chugaryong Fault Zone are intramountain basins. Therefore, coal-bearing beds and clastic rocks in the intramountain basins and rare marine strata and terrigenous clastic rocks are main sedimentary sequences in the Cenozoic.

  17. Gondwana basins and their coal resources in Bangladesh

    International Nuclear Information System (INIS)

    Fault bounded five Gondwana basins have been discovered in the north western Bangladesh. Among these basins show considerable amount of coal deposits. The Gondwana rocks are highly formed during the Permo-carboniferous diastrophism and later on acquired dynamic characters. In almost all basins, the Permian rocks overlie the Precambrian basement and underlie either the Tertiary or the Cretaceous sediments, structural, stratigraphic, and depositional history of these basins is more or less similar. The sedimentary sequences are composed of light to dark gray, fine to very coarse grained, sub angular to sub rounded felspathic sandstone, dark grey carbonaceous shale and sandstone, variegated conglomerate and thick coal seams (single seam max. 42.38m). The rocks are often alternated and bear the characteristics of cyclic sedimentation. The depositional environments varied from restricted drainage to open fluvial dominated low to moderate sinuous drainage system. The coal bearing basins were flanked by vegetated and swampy over bank. Age of these coals is suggested to be the late permian. Proved and probable reserves of coal in Jamalganj-Paharpur basin are 670 and 1,460 million metric tons, in Barapukuria basin 303 and 3899 million metric tons; in Barapukuria basin 303 and 389 million metric tons; and in Khalaspir basin 143 and 685 million metric tons respectively. The coal is high volatile, low sulphur, bituminous type. It can be used for different forms of thermal conversion. (author)

  18. Tectonic Evolution and Petroleum Systems in the Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    WANG Weifeng; CHEN Yequan

    2004-01-01

    The Junggar basin is located in the northern part of Xinjiang of China. It is part of the Kazakstan plate,surrounded by the Paleozoic folded mountains: the Halaart, Zayier and Chepaizi Mountains in the northwest, the Qingelidi and Karamaili Mountains in the northeast, and the Tianshan Mountains in the south. In different evolution stages, the basin's types are different, and the stratigraphy and deposition are also different. From the Carboniferous to Tertiary the basin has in turn gone through rift basin, collision foreland basin, intraplate depression basin and regenerated foreland basin. Based on an analysis of thermal evolution history and buried history of the source rocks, three major periods of oil generation are found in the basin. According to the characteristics of source rock distribution, evolution, oil-source correlation, structure and multi-phase and mixed pools, the Junggar basin could be divided into 4 composite petroleum systems. Due to the variation in sedimentary facies, difference in structural patterns and development histories, the petroleum pool-forming conditions in different areas and horizons are greatly different, so are the petroleum pool types,the accumulation mechanisms in different areas and horizons.

  19. Holocene paleoclimate characterization in Lago Fagnano (Tierra del Fuego) using sedimentary, physical and geochemical proxies

    Science.gov (United States)

    Vizcaino Marti, A.; Dunbar, R. B.; Wahl, D.; Moy, C. M.; Mucciarone, D. A.; Anderson, L.; Guilderson, T. P.

    2010-12-01

    Tierra del Fuego is the world's southernmost landmass outside of Antarctica. Two features of ocean circulation control the climate of Tierra del Fuego: the Southern Ocean circumpolar flow and the South Pacific Gyre. Together with Patagonia, Tierra del Fuego is the only terrestrial region directly influenced by the southern hemisphere westerly winds. This region is also a tectonically active area affected by volcanic and seismic activity related to South American and Scotia-Antarctic plate boundaries. Accommodated along the Magallanes-Fagnano fault system, as part of the plate boundary, the Lago Fagnano is the largest lake in Tierra del Fuego. This E-W trending lake is 100 km long and 5-15 km wide. Our investigations were carried out on the upper 4 meters of an 8.4 m long piston core obtained at 69 m water depth in Bahía Grande (LF06-PC8); a southwestern lake sub-basin separated from the main lake by a shallow sill. Our studies are based on the integration of sediment description, physical properties, pollen, and geochemical analyses including C and N isotopes (1cm interval) and XRF scan (1mm interval). The age model for the core is based on radiocarbon ages and tephrochronology. Additionally, a 800 km long grid of high resolution seismic profiles support the sedimentary analyses and allow the correlation with other cores from within the lake basin. LF06-PC8 yields continuous and high accumulation-rate sedimentary sections for Lago Fagnano. The presented sediment record corresponds to a laminated hemipelagite with presence of a single but complex mass transport deposit interval. An accurate sedimentological interpretation of the core together with the radiocarbon ages and tephra dates allow to identify and characterize the main sedimentary processes occurring in the lake over the last 8 kyr. In addition, proxy data (C and N isotopes and XRF scan data) from the laminated hemipelagic interval provide a reliable record of past variability in the westerly wind field as

  20. The impact of sedimentary alkalinity release on the water column CO2 system in the North Sea

    Science.gov (United States)

    Brenner, H.; Braeckman, U.; Le Guitton, M.; Meysman, F. J. R.

    2016-02-01

    It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO2 of seawater and hence increasing the CO2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O2), alkalinity (AT) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high AT and DIC fluxes were recorded in near-shore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of AT and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO2 dynamics of shallow coastal systems.

  1. Early middle Miocene tectonic uplift of the northwestern part of the Qinghai–Tibetan Plateau evidenced by geochemical and mineralogical records in the western Tarim Basin

    NARCIS (Netherlands)

    Wang, Chaowen; Hong, Hanlie; Abels, Hemmo A.; Li, Zhaohui; Cao, Kai; Yin, Ke; Song, Bowen; Xu, Yadong; Ji, Junliang; Zhang, Kexin

    2016-01-01

    The Tarim Basin in western China has been receiving continuous marine to lacustrine deposits during the Cenozoic as a foreland basin of the Qinghai–Tibetan Plateau (QTP). Clay mineralogy and geochemical proxy data from these sedimentary archives can shed light on climate and tectonic trends. Here we

  2. Constraining forcing factors and relative sea-level fluctuations in semi-enclosed basins : the Late Neogene demise of Lake Pannon

    NARCIS (Netherlands)

    ter Borgh, M.; Radivojević, D.; Matenco, L.

    2015-01-01

    Sedimentary basins are affected by a large number of forcing factors during their evolution and as a result, it is often difficult to isolate the contribution of each individual factor. Many forcing factors are temporally and spatially heterogeneous; they do not affect all parts of the basin in the

  3. A comparative analysis of some late carboniferous basins of Variscan Europe

    Energy Technology Data Exchange (ETDEWEB)

    Oplustil, S.; Cleal, C.J. [Charles University Prague, Prague (Czech Republic). Faculty of Science

    2007-05-15

    Vegetation diversity and pattern changes, and their relation to tectono-sedimentary histories are compared between selected Euramerican Late Palaeozoic coalfields, to understand better the controls on the dynamics of the Pennsylvanian terrestrial ecosystems and to demonstrate the problems with comparing data from various basins. The analysis is based on data from the following basins of different geotectonic and palaeogeographical positions: the cratonic Pennines Basin, the foreland South Wales and Upper Silesia basins, and the fault-related Intra Sudetic and Central and Western Bohemia basins. The analysis indicates that complex factors are responsible for changes in plant diversity and vegetation patterns. These are related to climate, tectonics, preservation potential, sampling biases and the current state of revision of the flora in each basin. Plant diversity patterns in the basins differ because of local controls and/or the character and detail of the available data. Maximum diversity varies among the basins within the Langsettian and Duckmantian substages. Two apparent step-like drops in diversity were detected within coal-bearing strata of most basins: at the Duckmantian/Bolsovian boundary and at the Bolsovian/Asturian boundary. Further and more prominent falls are related to transitions from coal-bearing to non-coal-bearing (mostly red bed) strata or vice versa during Stephanian times. Interpretation of climatic signals recorded in the sedimentary successions indicates that Westphalian and middle Stephanian times were wet intervals, whereas early and late Stephanian times were drier.

  4. Coastal climate reflected in carbon-13/carbon-12 ratio of organic carbon in varved sediment from Santa Barbara basin

    OpenAIRE

    Schimmelmann, Arndt; Tegner, Mia J.

    1991-01-01

    A 1844-1987 time-series of carbon stable isotope ratios from dated sedimentary total organic carbon from the center of the Santa Barbara basin is compared with historical climate and oceanographic records. Carbon derived from carbon-13-depleted phytoplankton and carbon-13-enriched kelp appear responsible for a large part of the isotopic variance in sedimentary total organic carbon. El Niño/Southern Oscillation events are recorded by the isotopic response of marine organic carbon in sediments.

  5. Sediment budget in the Ucayali River basin, an Andean tributary of the Amazon River

    OpenAIRE

    W. Santini; Martinez, J. -M.; Espinoza-Villar, R.; G. Cochonneau; Vauchel, P.; Moquet, J.-S.; Baby, P.; Espinoza, J.-C.; Lavado, W.; Carranza, J.; Guyot, J.-L.

    2015-01-01

    Formation of mountain ranges results from complex coupling between lithospheric deformation, mechanisms linked to subduction and surface processes: weathering, erosion, and climate. Today, erosion of the eastern Andean cordillera and sub-Andean foothills supplies over 99% of the sediment load passing through the Amazon Basin. Denudation rates in the upper Ucayali basin are rapid, favoured by a marked seasonality in this region and extreme precipitation cells above sedimentary strata, uplifted...

  6. Messinian Events: View from the Provence Basin (Gulf of Lion,Western Mediterranean)

    OpenAIRE

    Bache, François; Gorini, C.; Olivet, Jean-Louis; Rabineau, Marina; Aslanian, Daniel; Suc, J.p.

    2009-01-01

    Though the late Miocene "Messinian Salinity Crisis" has been intensely researched along the circum- Mediterranean basins, few studies have focused on the central part of the Mediterranean Basin and, especially, the pre-salt deposits. Within the Western Mediterranean, the Gulf of Lion is exceptional in that its sedimentary strata have not been significantly deformed. In addition, the Gulf of Lion is characterized by a relatively constant subsidence with continuous accommodation space for sedim...

  7. The Tortonian salinity crisis in the Fortuna Basin (southeastern Spain): Stratigraphic record, tectonic scenario and chronostratigraphy

    OpenAIRE

    Tent-Manclús, J. E.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Soria, J. M.; Departamento Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. 99, San Vicente del Raspeig, 03080 Alicante; Estévez, A.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apto. 99, 03080 San Vicente del Raspeig, Alicante, Spain; Lancis, C.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Caracuel, J. E.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apdo. Correos 99, 03080 Alicante, Spain; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Yébenes, A.; Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Apto. 99, 03080 San Vicente del Raspeig, Alicante, Spain

    2008-01-01

    The Neogene Fortuna and Bajo Segura basins are located on the northeastern end of the Trans-Alborán Shear Zone (TASZ), on the eastern Betic cordillera. The stratigraphic study of the infilling of these basins has shown two major sedimentary discontinuities. The first one, represented by an erosive surface separating open marine marls from an overlying coastal conglomeratic unit, is linked to the onset of the activity along the TASZ, which in this area indicates the beginning of the Abanilla T...

  8. Effect of the settlement of sediments on water infiltration in two urban infiltration basins

    OpenAIRE

    Lassabatere, Laurent; Angulo Jaramillo, R.; GOUTALAND, David; Letellier, Laetitia; GAUDET, JP; Winiarski, Thierry; DELOLME, C

    2010-01-01

    The sealing of surfaces in urban areas makes storm water management compulsory. The suspended solids from surface runoff water accumulate in infiltration basins and may impact on water infiltration. This paper describes a study of the effect of the settlement of sedimentary layers on the water infiltration capacity of two urban infiltrations basins. In situ water infiltration experiments were performed (1) to quantify the effect of sediment on water infiltration at local scale and (2) to deri...

  9. Chronostratigraphy and tectonic deformation of the North Ecuadorian-South Colombian offshore Manglares forearc basin

    OpenAIRE

    Marcaillou, B.; Collot, Jean-Yves

    2008-01-01

    Forearc basins in convergent margins contain a nearly continuous record of sedimentation and deformation. Their chronostratigraphy reflects the manner in which the basin accommodates loads and vertical and horizontal motion caused by eustasy, tectonics and sedimentation during plate convergence. Along the North Ecuador and South Colombia (NESC) Margin (1 degrees-3.5 degrees N), thick Cenozoic sedimentary sequences accumulated over blocks of oceanic basement that accreted between the Late Cret...

  10. Sand provenance and implications for paleodrainage in a rifted basin: the Tera Group (N. Spain)

    OpenAIRE

    González-Acebrón, L.; Arribas, J; Mas, R.

    2010-01-01

    [EN] Fluvial-fan and fluvial siliciclastic strata, developed during the rifting that generated the Cameros Basin (North Spain), record important provenance changes that reveal source areas compositions and locations, paleodrainage evolution and rift patterns. The Tera Group represents the first rifting stage in the Cameros Basin, containing fluvial-fan sediments at the lower part of the sedimentary fill that evolve to fluvial and lacustrine systems in the upper part of the record. Ou...

  11. Sand provenance and implications for paleodrainage in a rifted basin: the Tera Group (N. Spain)

    OpenAIRE

    González Acebrón, Laura; Arribas Mocoroa, José; Mas Mayoral, José Ramón

    2010-01-01

    Fluvial-fan and fluvial siliciclastic strata, developed during the rifting that generated the Cameros Basin (North Spain), record important provenance changes that reveal source areas compositions and locations, paleodrainage evolution and rift patterns. The Tera Group represents the first rifting stage in the Cameros Basin, containing fluvial-fan sediments at the lower part of the sedimentary fill that evolve to fluvial and lacustrine systems in the upper part of the record. Our qua...

  12. Geochemistry of polymetallic nodules from the Central Indian Ocean basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Khadge, N.H.; Desa, J.A.E.

    ; \\[\\] > l0 cm. Pacific Ocean; A nodules; x sediments. Average shale values from Piper (1974). POLYMETALLIC NODULES FROM THE CENTRAL INDIAN OCEAN BASIN TABLE 3A Inter-element relationship in the CIOB nodules Moisture Mn Fe Cu Ni Co Cu + Ni + Co Moisture...-242. Lyle, M., 1982. Estimating growth rates of ferromanganese nodules from chemical composition: implications for nodule formation processes. Geochim. Cosmochem. Acta., 46: 2301- 2306. Piper, D.Z., 1974. Rare earth elements and the sedimentary cycle: A...

  13. Cenozoic coupled basin-mountain and prospecting direction for sandstone-type uranium deposits in western Yunnan

    International Nuclear Information System (INIS)

    The initial forming time of Cenozoic basins in western Yunnan is at 14 Ma or so, it was coupling in the later period tectonic activity time of Lushui-Ruili arc dextral strike-slip fault belt in the eastern fringe and Nabang dextral strike-slip fault belt in the western fringe of Tengchong microplate. The evolution of Cenozoic basins is divided into two stages of sedimentary basin and reformed basin, the former was coupling in the strike-slip tectonic activity of orogen, and formed strike-slip basins, the latter was closely related with the uplift of the whole basins, and formed residual basins. It is considered that there exists two sorts of Cenozoic basins, and they are different in sedimentary evolution, volcanic activity and geographic sight etc., the metallogenic conditions of sandstone-type uranium deposits are also different. The most favourable basins for prospecting sandstone-type uranium deposits are those basins that keeps on uplifting in reformed basin stages, exists volcanic activity and deep incised low mountain-hill-river valley terraces in northern Tengchong area. (authors)

  14. Middle muschelkalk evaporitic deposits in eastern Paris basin

    Science.gov (United States)

    Geisler-Cussey, D.

    Middle Muschelkalk of the eastern Paris Basin is an extension of the large German Basin than an unit by itself. It allows us to study the effects of continental influences on evaporitic sedimentation: fresh water and detrital supplies, and salt dissolution. More or less evaporated sea water flowing into the basin causes a cyclic evolution of salinity throughout the series. The deposit is generally layered and shows millimetric to centimetric primary depositional sequences which prove the complexity of the internal organization of the filling in the basin. They reflect elementary changes in the depositional environment: fresh water supplies carring detrital particles, fresh water and sea water inflow introducing dilution, increasing evaporation rate causing precipitation of carbonates, Ca-sulfate or halite. In fact, the main factors controlling sedimentation which are working at this fine scale and the evolution at a larger sequential scale depends upon which one of these factors becomes dominant. The general evolution results in a typical sedimentary cycle.

  15. Gestures and metaphors as indicators of conceptual understanding of sedimentary systems

    Science.gov (United States)

    Riggs, E. M.; Herrera, J. S.

    2012-12-01

    Understanding the geometry and evolution of sedimentary systems and sequence stratigraphy is crucial to the development of geoscientists and engineers working in the petroleum industry. There is a wide variety of audiences within industry who require relatively advanced instruction in this area of geoscience, and there is an equally wide array of approaches to teaching this material in the classroom and field. This research was undertaken to develop a clearer picture of how conceptual understanding in this area of sedimentary geology grows as a result of instruction and how instructors can monitor the completeness and accuracy of student thinking and mental models. We sought ways to assess understanding that did not rely on model-specific jargon but rather was based in physical expression of basic processes and attributes of sedimentary systems. Advances in cognitive science and educational research indicate that a significant part of spatial cognition is facilitated by gesture, (e.g. giving directions, describing objects or landscape features). We aligned the analysis of gestures with conceptual metaphor theory to probe the use of mental image-schemas as a source of concept representation for students' learning of sedimentary processes. In order to explore image schemas that lie in student explanations, we focused our analysis on four core ideas about sedimentary systems that involve sea level change and sediment deposition, namely relative sea level, base level, and sea-level fluctuations and resulting basin geometry and sediment deposition changes. The study included 25 students from three U.S. Midwestern universities. Undergraduate and graduate-level participants were enrolled in senior-level undergraduate courses in sedimentology and stratigraphy. We used semi-structured interviews and videotaping for data collection. We coded the data to focus on deictic, iconic, and metaphoric gestures, and coded interview transcripts for linguistic metaphors using the

  16. Seismic stratigraphic framework of deep central Gulf of Mexico basin

    Energy Technology Data Exchange (ETDEWEB)

    Shaub, F.J.; Buffler, R.T.; Parsons, J.G.

    1984-11-01

    The deep Gulf of Mexico basin is underlain by up to 10 km (33,000 ft) of Jurassic(.) to Holocene layered sedimentary rocks. The multichannel reflection seismic record from the deep Gulf of Mexico was divided into six seismic stratigraphic units for study of the geologic history of this accumulation. The basal Challenger unit (Jurassic (.) to middle Cretaceous) is considered coeval with early basin formation. We interpret it as a deep marine sequence overlying oceanic crust in the central basin and as continental and shallow through deep marine rocks, including thick evaporites, over adjacent transitional crust. The next three units, Campeche, Lower Mexican Ridges and Upper Mexican Ridges, indicate that from the Late Cretaceous through middle Miocene the basin filled progressively from the west and north, most probably with siliceous turbidites interlayered with pelagic deposits. By the late Tertiary, however, salt and shale deformation within thick sedimentary sections along the western and northern margins trapped much of the incoming sediment supply on the shelves and upper slopes. The late Miocene to Pliocene Cinco de Mayo unit, therefore, represents a relatively starved interval. In contrast, the uppermost, or Sigsbee unit, includes the Mississippi Fan, an accumulation up to 3 km (10,000 ft) thick of mainly mass-transported deposits that bypassed the shelf and slope and were deposited directly onto the abyssal plain. In the western and southwestern portions of the deep basin, beyond the fan pinchout, the Pleistocene section is largely a continuation of the Pliocene suspension deposits.

  17. Discrimination of tectonic dynamism, quiescence and third order relative sea level cycles of the Cauvery Basin, South India

    Directory of Open Access Journals (Sweden)

    Ramkumar Muthuvairavasamy

    2015-01-01

    Full Text Available Application of integrated stratigraphic modeling of sedimentary basins with the help of sequence and chemostratigraphic methods for improved understanding on the relative roles of depositional pattern and history of a Barremian-Danian stratigraphic record of the Cauvery Basin, India was attempted. Through enumeration of facies characteristics, tectonic structures and geochemical characteristics of the sedimentary rocks the use of geochemical signatures in distinguishing the relative roles of major factors has been evaluated. The results indicate that the geochemical signatures of the sedimentary rocks accurately record the prevalent geological processes and an ability to distinguish them through employing stratigraphic variations of compositional values and discrimination diagrams help in understanding the basinal history better. In addition, predomination of relative sea level fluctuations and active nature of tectonic movements during few time slices, which in turn was overwhelmed by sea level fluctuations are also inferred.

  18. Macrofossils in Raraku Lake (Easter Island) integrated with sedimentary and geochemical records: towards a palaeoecological synthesis for the last 34,000 years

    Science.gov (United States)

    Cañellas-Boltà, N.; Rull, V.; Sáez, A.; Margalef, O.; Giralt, S.; Pueyo, J. J.; Birks, H. H.; Birks, H. J. B.; Pla-Rabes, S.

    2012-02-01

    Macrofossil analysis of a composite 19 m long sediment core from Rano Raraku Lake (Easter Island) was related to litho-sedimentary and geochemical features of the sediment. Strong stratigraphical patterns are shown by indirect gradient analyses of the data. The good correspondence between the stratigraphical patterns derived from macrofossil (Correspondence Analysis) and sedimentary and geochemical data (Principal Component Analysis) shows that macrofossil associations provide sound palaeolimnological information in conjunction with sedimentary data. The main taphonomic factors influencing the macrofossil assemblages are run-off from the catchment, the littoral plant belt, and the depositional environment within the basin. Five main stages during the last 34,000 calibrated years BP (cal yr BP) are characterised from the lithological, geochemical, and macrofossil data. From 34 to 14.6 cal kyr BP (last glacial period) the sediments were largely derived from the catchment, indicating a high energy lake environment with much erosion and run-off bringing abundant plant trichomes, lichens, and mosses into the centre of Raraku Lake. During the early Holocene the infilling of the lake basin and warmer conditions favoured the growth of a littoral plant belt that obstructed terrigenous input. Cladoceran remains and Solanaceae seeds are indicative of reduced run-off and higher values of N and organic C indicate increased aquatic and catchment productivity. From 8.7 to 4.5 cal kyr BP a swamp occupied the entire basin. The increase of Cyperaceae seeds reflects this swamp development and, with oribatid mites and coleopteran remains, indicates a peaty environment and more anoxic condit