WorldWideScience

Sample records for sedimentary facies model

  1. Applying and improving a sedimentary facies model for exploration of stratigraphic traps in the Austrian Molasse basin

    Energy Technology Data Exchange (ETDEWEB)

    Hinsch, R.; Kofler, N. [Rohoel-Aufsuchungs AG (RAG), Vienna (Austria); Hubbard, S. [Calgary Univ., Calgary (Canada). Dept. of Geology and Geophysics

    2007-09-13

    In the Molasse foreland basin of Upper Austria gas is produced from deep-water sandstones and conglomerates of the Puchkirchen and basal Hall formations (Oligocene-Lower Miocene). The basin is mature, with >750 wells drilled by RAG to date. An extensive 3-D seismic reflection dataset that covers much of the paleo-basin foredeep has been acquired in the study area over the last 15 years. Seismic stratigraphic analysis has revealed that deepwater sedimentation in the basin was dominated by a channel belt up to 5 km wide that transported sediment derived from the Central and Eastern Alps eastward along the basin axis (Linzer, 2001; de Ruig, 2003). Based on these findings, a detailed sedimentary facies model has been developed, outlining several distinct depositional elements that reveal numerous possible stratigraphic trap types (de Ruig and Hubbard, 2006). This depositional model is currently being applied and tested in exploration and refined by ongoing research. Channel abandonment and migration are important processes that resulted in stratigraphic configurations consisting of coarse-grained sandstones and conglomerates overlain by channel and overbank mudstones. This represents ideal reservoir architecture, including porous reservoir facies sealed by impermeable deposits. Additional stratigraphic trapping conditions can result from special spatial arrangements of depositional elements, for example a sandstone-filled tributary channel that is sealed by an overlying mudstone-filled abandonment channel. Recognizing and further improving such stratigraphic trapping configurations are important for future exploration in Upper Austria, where most of the structural traps have been drilled. (orig.)

  2. Sedimentary environments: processes, facies, and stratigraphy

    National Research Council Canada - National Science Library

    Reading, H. G; Reading, Harold G

    1996-01-01

    ... and chemical systems, 6 2.1.2 Climate, 7 2.1.3 Tectonic movements and subsidence, 11 2.1.4 Sea-level changes, 11 2.1.5 Milankovitch processes and orbital forcing, 14 2.1.6 Intrinsic sedimentary processes,...

  3. A Facies Model for Temperate Continental Glaciers.

    Science.gov (United States)

    Ashley, Gail Mowry

    1987-01-01

    Discusses the presence and dynamics of continental glaciers in the domination of the physical processes of erosion and deposition in the mid-latitudes during the Pleistocene period. Describes the use of a sedimentary facies model as a guide to recognizing ancient temperate continental glacial deposits. (TW)

  4. 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....../G, Tmin and discharge rate, while the design model for the energy recovery rate is only a function of N/G and Tmin. Both life time and recovery show a positive relation with an increasing N/G. Further our results suggest that neglecting details of process-based facies modelling may lead to significant...

  5. The investigation of sedimentary facies and stacking pattern in the Mulid River (Southeastern Qayen

    Directory of Open Access Journals (Sweden)

    Marzieh Fayazi Borujeni

    2017-03-01

    Full Text Available Introduction In the most gravel bed rivers, particle size exponentially decreases to the downstream. The study of particle size fining trend to the downstream and determination of the effective processes on it along the recent rivers is accomplished in the different parts of Iran. The river sedimentary facies are deposited in the channel and overbank areas and they are provided important information about sedimentary environment and deposition rate, the extent and development of the river channel and floodplain. These sedimentary facies that are deposited in the different depositional conditions have been achieved from variations of flow regime and/ or variation in the depositional environment in the large scale. The aim of this study is to investigate of the particle size variations and the effective controllers of fining trend to downstream, to determine of the important factors in creating sedimentary discontinuities and to study of the sedimentary facies, architectural elements, determination of depositional model and some paleohydraulic parameters of river. The Mulid River catchment with elongated shape is located in 120 km of southeast Qayen in the Southern Khorasan Province, in the 33̊ 24ʹ 44.3ʺ to 33̊ 35ʹ 11.4ʺ east latitude and 59̊ 56ʹ 42.5ʺ to 59̊ 58ʹ 44ʺ north longitude. According to the geological classification of Iran, this basin is a part of the East Iran flysch and mélange belt that is located in the east of the Lut Block.  Materials and Methods  In order to sedimentological studies, 30 sediment samples unsystematically were collected from upstream to downstream and from about 20 cm depth of the main channel bottom of river (with 30 km long. The granulometry analysis of the studied samples were achieved using the dry sieving method with 0.5 φ intervals and weight percent of gravel, sand and mud size particles were estimated. The sediment naming is done using Folk (1980 classification and the estimation of sorting

  6. Lower Tertiary Sedimentary Turbidite Facies at the Chicontepec Basin, East-Central Mexico

    Directory of Open Access Journals (Sweden)

    Santillán-Piña N.

    2011-07-01

    Full Text Available The study area comprises the northwestern portion of the Chicontepec Basin at southeastern San Luis Potosí and northeastern Hidalgo States. At the stratigraphy sequences of the Chicontepec Formation from Lower Paleocene in isolated outocrops, were herein interpreted two major sedimentary sub-environments into the fan model: the middle and the external sedimentary settings; the applied criteria for their identification were: (a lithostratigraphic (thickness, geometry and distribution; (b internal and external primary sedimentary structures, and (c intra-formational deformation structures. The sedimentary facies are composed of siliciclastic and calcareous particles sourced from the Sierra Madre Oriental, western; the Tuxpan paleo-island, eastern; and from the Teziutlan Massif, southern; the sediments were massively transported by slideing, slumping, flow debris and turbidity currents, then deposited as massive, tabular, lenticular and lobely in shape at the slope foot and on the sea marine floor.

  7. Sedimentary environment and facies of St Lucia Estuary Mouth, Zululand, South Africa

    Science.gov (United States)

    Wright, C. I.; Mason, T. R.

    The St. Lucia Estuary is situated on the subtropical, predominantly microtidal Zululand coast. Modern sedimentary environments within the estuary fall into three categories: (1) barrier environments; (2) abandoned channel environments; and (3) estuarine/lagoonal environments. The barrier-associated environment includes tidal inlet channel, inlet beach face, flood-tidal delta, ebb-tidal delta, spit, backspit and aeolian dune facies. The abandoned channel environment comprises washover fan, tidal creek tidal creek delta and back-barrier lagoon facies. The estuarine/lagoonal environment includes subtidal estuarine channel, side-attached bar, channel margin, mangrove fringe and channel island facies. Each sedimentary facies is characterised by sedimentary and biogenic structures, grain-size and sedimentary processes. Vertical facies sequences produced by inlet channel migration and lagoonal infilling are sufficiently distinct to be recognized in the geological record and are typical of a prograding shoreline.

  8. The relationship between hydrogeologic properties and sedimentary facies: an example from Pennsylvanian bedrock aquifers, southwestern Indiana

    International Nuclear Information System (INIS)

    Fisher, A.T.; Barnhill, M.; Revenaugh, J.

    1998-01-01

    The relationship between the hydrogeologic properties and sedimentary facies of shallow Pennsylvanian bedrock aquifers was examined using detailed sedimentologic descriptions, aquifer (slug) tests, and gamma ray logs. The main goal of the study was to determine if it was possible to reliably estimate near-well hydraulic conductivities using core descriptions and logging data at a complex field site, based on assignment of consistent conductivity indicators to individual facies. Lithologic information was gathered from three sources: core descriptions, simplified lithologic columns derived from the core descriptions, and drillers' logs. Gamma ray data were collected with a conventional logging instrument. Slug tests were conducted in all wells containing screened zones entirely within the Pennsylvanian facies of interest. Simplified subsets of sedimentologic facies were assembled for classification of subsurface geology, and all rocks within the screened intervals of test wells were assigned to individual facies based on visual descriptions. Slug tests were conducted to determine the bulk hydraulic conductivity (a spatial average within the screened interval) in the immediate vicinity of the wells, with measured values varying from 10 -4 m/s to 10 -8 m/s. Gamma ray logs from these wells revealed variations in raw counts above about 1.5 orders of magnitude. Data were combined using simple linear and nonlinear inverse techniques to derive relations between sedimentologic facies, gamma ray signals, and bulk hydraulic conductivities. The analyses suggest that facies data alone, even those derived from detailed core descriptions, are insufficient for estimating hydraulic conductivity in this setting to better than an order of magnitude. The addition of gamma ray data improved the estimates, as did selective filtering of several extreme values from the full data set. Better estimates might be obtained through more careful field measurements and reduction of

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

    International Nuclear Information System (INIS)

    Qi Fucheng

    1992-01-01

    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

  10. The sedimentary facies characteristics and lithofacies palaeogeography during Middle-Late Cambrian, Sichuan Basin and adjacent area

    Directory of Open Access Journals (Sweden)

    Feifan Lu

    2017-06-01

    Full Text Available Combined with the regional strata filling characteristics of Middle-Upper Cambrian, the present paper conducts a systematic research on sedimentary facies in the basin and its peripheral area by utilizing 164 field outcrops and drilling and coring data. Further, the method of “multi-factor comprehensive synthesis based on single-factor analysis” was employed to investigate the sedimentary facies and palaeogeography of the study area and establish the sedimentary facies model. Stratigraphic reveals that the study area represents the pattern of thin-northwest and thick-southeast by stretching northeast-southwest. Within the present basin, the pattern of “one thin and two thick” predominates, while outside the basin “four thin and three thick” filling feature was found. Sedimentary facies shows that the study area was featured by rimmed carbonate platform. Specifically, carbonate platform, slope and northeastern corner Qinling paleooceanic Basin and southeastern corner Jiangnan Bain was identified from the west to the east. The carbonate platform contains restricted platform, evaporation-restricted platform, semi-restricted platform and the platform margin. Single factor analysis and lithofacies palaeogeographic characteristics manifests that during Middle-Late Cambrian, the western Old land evolved into peneplain stage, and that the eastern and southwestern sub-sags remained connected to the open-sea to some extent. At the time, the shllow seawater circulation was relatively restricted, while the ancient seabed tended to be flat and evaporation characteristics significantly diminished. Secondary sea-level fluctuation intensively influenced the development of scaled grain beach. It is suggested that tide marginal beach, intraplatform shoal subfacies zone, along with Shiqian-SangZhi in southeast and Zhenba-Xinshan in northeast platform-margin beach subfacies zone to be preferable targets for the favorable reservoir facies zone and

  11. Sedimentary facies and depositional history of the Swan Islands, Honduras

    Science.gov (United States)

    Ivey, Marvin L.; Breyer, John A.; Britton, Joseph C.

    1980-10-01

    Swan Island is a Honduran possession in the western Caribbean, located on the southeastern side of the Cayman Trench. Two sedimentary assemblages are found on the island: an older bedded sequence of mid-Tertiary age (Aquitanian or Burdigalian) and a younger sedimentary sequence of Late Pleistocene age. The older sequence is composed of a series of calcarenites, calcilutites, and siliciclastic mudstones; capping these are cliff-forming reefal carbonates of the younger sequence. The rocks of the older bedded sequence accumulated in deep water. Sedimentation consisted of a constant rain of pyroclastic debris interrupted by the episodic introduction of upslope carbonate material by turbidity currents. Uplift and deformation of this sequence was initiated sometime after the Early Miocene. By the Late Pleistocene, uplift had brought the rocks into water depths conducive to coral growth. Pleistocene sedimentation on the island was controlled by the interaction between tectonic uplift and eustatic sea-level changes. The primary controlling force on the tectonic history of the island is its proximity to the boundary between the North American and Caribbean plates.

  12. Sedimentary Facies of the West Crocker Formation North Kota Kinabalu-Tuaran Area, Sabah, Malaysia

    Science.gov (United States)

    Mohamed, Azfar; Hadi Abd Rahman, Abdul; Suhaili Ismail, Mohd

    2016-02-01

    Newly outcrops exposed in the West Crocker Formation have led to the detail sedimentolgical analysis of the formation. Eight sedimentary facies have been recognised in which it was divided into three main groups: (1) sand-dominated facies (F1-F2), (2) poorly- sorted unit mixed sand and mud-dominated facies (F3), and (3) mud-dominated facies (F4-F5). These are: F1- graded sandstone (massive to planar laminated), F2-ripple-cross laminated, wavy and convolute lamination sandstone, F3-chaotic beds of mixed sandstone and mudstone blocks and clasts, F4-lenticular bedded of sandstone, and F5-shale. The studies of the formation has come out that it was deposited in a sand-rich submarine fan with specific location located at (1) inner fan channel-levee complex; (2) mid-fan channelised lobes, and (3) outer fan.

  13. Anthropogenic effects on sedimentary facies in Lake Baldeney, West Germany

    Science.gov (United States)

    Neumann-Mahlkau, Peter; Niehaus, Heinz Theo

    1983-12-01

    Analysis of well logs of Lake Baldeney, a reservoir of the Ruhr River, yields four facies factors that reflect the effect of anthropogenic processes on the sediment. First, the sedimentation rate is directly related to the subsidence caused by mining. The extent of the subsidence was such that the sediment load of the river could not compensate for the sinking of the lake bottom. Discharged sediment filled about one-fifth of the basin within 40 years. In certain areas of the basin the sedimentation rate reached up to 10 cm per year. Second, the grain-size distribution of the sediment was influenced by long-term and short-term events. During the subsidence, grain-size distribution remained relatively constant. The destruction of the Möhne River dam during World War II resulted in the presence of an extremely large grain size as evidenced by the so-called Möhnelage. The filling of the lake after 1961 was accompanied by a continual increase in medium grain size. Third, until 1975, the mode of the lake sediment reflects the effect of mining in the vicinity of the lake. High coal content can be traced to its origin. The introduction of modern production processes, modernization of coal dressing, and hydraulic hauling is documented in the sediment. Finally, the heavy metal content of the sediment corresponds to the industrial development in the drainage area the Ruhr River. The accumulation of Cd reached an extreme concentration, exceeding the natural content by a thousand times. Variation in concentration reflects an increase in industrial production, as well as measures undertaken to restore water quality.

  14. Sedimentary Facies Mapping Based on Tidal Channel Network and Topographic Features

    Science.gov (United States)

    Ryu, J. H.; Lee, Y. K.; Kim, K.; Kim, B.

    2015-12-01

    Tidal flats on the west coast of Korea suffer intensive changes in their surface sedimentary facies as a result of the influence of natural and artificial changes. Spatial relationships between surface sedimentary facies distribution and benthic environments were estimated for the open-type Ganghwa tidal flat and semi closed-type Hwangdo tidal flat, Korea. In this study, we standardized the surface sedimentary facies and tidal channel index of the channel density, distance, thickness and order. To extract tidal channel information, we used remotely sensed data, such as those from the Korea Multi-Purpose Satellite (KOMPSAT)-2, KOMPSAT-3, and aerial photographs. Surface sedimentary facies maps were generated based on field data using an interpolation method.The tidal channels in each sediment facies had relatively constant meandering patterns, but the density and complexity were distinguishable. The second fractal dimension was 1.7-1.8 in the mud flat, about 1.4 in the mixed flat, and about 1.3 in the sand flat. The channel density was 0.03-0.06 m/m2 in the mud flat and less than 0.02 m/m2 in the mixed and sand flat areas of the two test areas. Low values of the tidal channel index, which indicated a simple pattern of tidal channel distribution, were identified at areas having low elevation and coarse-grained sediments. By contrast, high values of the tidal channel index, which indicated a dendritic pattern of tidal channel distribution, were identified at areas having high elevation and fine-grained sediments. Surface sediment classification based on remotely sensed data must circumspectly consider an effective critical grain size, water content, local topography, and intertidal structures.

  15. Sedimentary facies and Holocene depositional processes of Laura Island, Majuro Atoll

    Science.gov (United States)

    Yasukochi, Toru; Kayanne, Hajime; Yamaguchi, Toru; Yamano, Hiroya

    2014-10-01

    The depositional processes that formed Laura Island, Majuro Atoll, Marshall Islands, were reconstructed based on a facies analysis of island sediments and spine ratios, and radiocarbon ages of foraminifera. Sedimentary facies were analyzed from trenches and drill cores excavated on the island and its adjacent reef flat. Depositional ages were obtained using benthic foraminifera (Calcarina) whose spines had not been abraded. The facies were classified into two types: gravelly and sandy. The initial sediments of these sites consisted of gravelly facies in the lower horizon and sandy facies in the upper horizon. Their ages were approximately 2000 cal BP and coincident with the onset of a 1.1-m decline in regional relative sea level, which enabled deposition of the gravelly facies. Half of the sand fraction of the sediment was composed of larger benthic foraminifera. The spine ratio showed that their supply source on the reef flat was located oceanside of the island. The supply source appears to have been caused by the relative sea-level fall. This indicates that the studied island was formed by a relative reduction in wave energy and enhanced foraminiferal supply, both of which were triggered by the late Holocene relative sea-level fall.

  16. Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The distribution of benthic foraminifera and sedimentary facies from Recent coastline environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the aim to: 1) provide reliable analogs for understanding and interpreting the depositional environment of ancient shallow-marine sediments from the UAE; 2) assess any modifications in the distribution of benthic environments and sedimentary facies in an area affected by significant anthropogenic activities - particular construction and land reclamation. A total of 100 sea-floor sediment samples were collected in different shallow-marine sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited the sampling sites used in several studies conducted in the middle of last century (prior to any significant anthropogenic activities) to assess temporal changes in Recent benthic foraminifera and sedimentary facies distribution during the last 50 years. Five foraminiferal assemblages were recognized in the studied area. Species with a porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. The species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples particularly in lagoons and mangal environments and have not been reported previously in the studied area. The majority of the ooid shoal sediments, the coarser sediments of the beach-front and samples collected in dredged channels

  17. Trace fossils and sedimentary facies from a Late Cambrian‐Early Ordovician tide‐dominated shelf (Santa Rosita Formation, northwest Argentina): Implications for ichnofacies models of shallow marine successions

    Science.gov (United States)

    Mángano, M. Gabriela; Buatois, Luis A.; Aceñolaza, Guillermo F.

    1996-01-01

    The Santa Rosita Formation is one the most widely distributed lower Paleozoic units of northwest Argentina. At the Quebrada del Salto Alto section, east of Purmamarca, Jujuy Province, it is represented by four sedimentary facies: thick‐bedded planar cross‐stratified quartzose sandstones (A), thin‐bedded planar cross‐stratified quartzose sandstones and mudstones (B), wave‐rippled sandstones and bioturbated mudstones (C), and black and greenish gray shales (D). Paleocurrent data, sandstone architecture, and sedimentary structures from faciès A and B indicate bipolar/bimodal paleoflows, suggesting the action of tidal currents. The succession is interpreted as that of a tide‐dominated shelf, with only secondary influence of wave processes. Trace fossils are restricted to facies B and C.The Cruziana ichnocoenosis is preserved on the soles of thin‐bedded planar cross‐stratified quartzose sandstones (faciès B). This ichnocoenosis consists of Conostichus isp., Cruziana omanica, C. semiplicata, C. cf. tortworthi, Cruziana isp. Helminthopsis abeli, Monomorphichnus bilinearis, M. multilineatus, Palaeophycus tubularis, Rusophycus carbonarias, R. latus, and R. isp. The occurrence of Cruziana semiplicata, C. omanica, C. cf. tortworthi, and Rusophycus latus supports a Late Cambrian‐Tremadoc age. Slabbing of Cruziana shows complex interactions between biologic and sedimentologic processes, and suggests a predominance of exhumed traces, washed out and recast by tractive sand deposition. Sandstone soles are densely packed with biogenic structures and exhibit distinctive clusters of Rusophycus isp. that most likely represent trilobite nesting burrows. The Cruziana ichnocoenosis records the resident fauna of a protected, lower intertidal to subtidal interbar setting.The Skolithos ichnocoenosis is represented by high to low density vertical burrows of Skolithos linearis, which extend downwards to the quartzose sandstone soles of faciès B and

  18. Sedimentary facies and lithologic characters as main factors controlling hydrocarbon accumulations and their critical conditions

    Directory of Open Access Journals (Sweden)

    Jun-Qing Chen

    2015-10-01

    Full Text Available Taking more than 1000 clastic hydrocarbon reservoirs of Bohai Bay Basin, Tarim Basin and Junggar Basin, China as examples, the paper has studied the main controlling factors of hydrocarbon reservoirs and their critical conditions to reveal the hydrocarbon distribution and to optimize the search for favorable targets. The results indicated that the various sedimentary facies and lithologic characters control the critical conditions of hydrocarbon accumulations, which shows that hydrocarbon is distributed mainly in sedimentary facies formed under conditions of a long-lived and relatively strong hydrodynamic environment; 95% of the hydrocarbon reservoirs and reserves in the three basins is distributed in siltstones, fine sandstones, lithified gravels and pebble-bearing sandstones; moreover, the probability of discovering conventional hydrocarbon reservoirs decreases with the grain size of the clastic rock. The main reason is that the low relative porosity and permeability of fine-grained reservoirs lead to small differences in capillary force compared with surrounding rocks small and insufficiency of dynamic force for hydrocarbon accumulation; the critical condition for hydrocarbon entering reservoir is that the interfacial potential in the surrounding rock (Φn must be more than twice of that in the reservoir (Φs; the probability of hydrocarbon reservoirs distribution decreases in cases where the hydrodynamic force is too high or too low and when the rocks have too coarse or too fine grains.

  19. Seismic facies; Facies sismicas

    Energy Technology Data Exchange (ETDEWEB)

    Johann, Paulo Roberto Schroeder [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao Corporativo. Gerencia de Reservas e Reservatorios]. E-mail: johann@petrobras.com.br

    2004-11-01

    The method presented herein describes the seismic facies as representations of curves and vertical matrixes of the lithotypes proportions. The seismic facies are greatly interested in capturing the spatial distributions (3D) of regionalized variables, as for example, lithotypes, sedimentary facies groups and/ or porosity and/or other properties of the reservoirs and integrate them into the 3D geological modeling (Johann, 1997). Thus when interpreted as curves or vertical matrixes of proportions, seismic facies allow us to build a very important tool for structural analysis of regionalized variables. The matrixes have an important application in geostatistical modeling. In addition, this approach provides results about the depth and scale of the wells profiles, that is, seismic data is integrated to the characterization of reservoirs in depth maps and in high resolution maps. The link between the different necessary technical phases involved in the classification of the segments of seismic traces is described herein in groups of predefined traces of two approaches: a) not supervised and b) supervised by the geological knowledge available on the studied reservoir. The multivariate statistical methods used to obtain the maps of the seismic facies units are interesting tools to be used to provide a lithostratigraphic and petrophysical understanding of a petroleum reservoir. In the case studied these seismic facies units are interpreted as representative of the depositional system as a part of the Namorado Turbiditic System, Namorado Field, Campos Basin.Within the scope of PRAVAP 19 (Programa Estrategico de Recuperacao Avancada de Petroleo - Strategic Program of Advanced Petroleum Recovery) some research work on algorithms is underway to select new optimized attributes to apply seismic facies. One example is the extraction of attributes based on the wavelet transformation and on the time-frequency analysis methodology. PRAVAP is also carrying out research work on an

  20. Sedimentary facies and depositional environments of early Mesozoic Newark Supergroup basins, eastern North America

    Science.gov (United States)

    Smoot, J.P.

    1991-01-01

    The early Mesozoic Newark Supergroup consists of continental sedimentary rocks and basalt flows that occupy a NE-trending belt of elongate basins exposed in eastern North America. The basins were filled over a period of 30-40 m.y. spanning the Late Triassic to Early Jurassic, prior to the opening of the north Atlantic Ocean. The sedimentary rocks are here divided into four principal lithofacies. The alluvial-fan facies includes deposits dominated by: (1) debris flows; (2) shallow braided streams; (3) deeper braided streams (with trough crossbeds); or (4) intense bioturbation or hyperconcentrated flows (tabular, unstratified muddy sandstone). The fluvial facies include deposits of: (1) shallow, ephemeral braided streams; (2) deeper, flashflooding, braided streams (with poor sorting and crossbeds); (3) perennial braided rivers; (4) meandering rivers; (5) meandering streams (with high suspended loads); (6) overbank areas or local flood-plain lakes; or (7) local streams and/or colluvium. The lacustrine facies includes deposits of: (1) deep perennial lakes; (2) shallow perennial lakes; (3) shallow ephemeral lakes; (4) playa dry mudflats; (5) salt-encrusted saline mudflats; or (6) vegetated mudflats. The lake margin clastic facies includes deposits of: (1) birdfoot deltas; (2) stacked Gilbert-type deltas; (3) sheet deltas; (4) wave-reworked alluvial fans; or (5) wave-sorted sand sheets. Coal deposits are present in the lake margin clastic and the lacustrine facies of Carnian age (Late Triassic) only in basins of south-central Virginia and North and South Carolina. Eolian deposits are known only from the basins in Nova Scotia and Connecticut. Evaporites (and their pseudomorphs) occur mainly in the northern basins as deposits of saline soils and less commonly of saline lakes, and some evaporite and alkaline minerals present in the Mesozoic rocks may be a result of later diagenesis. These relationships suggest climatic variations across paleolatitudes, more humid to the

  1. Barrier island facies models and recognition criteria

    Science.gov (United States)

    Mulhern, J.; Johnson, C. L.

    2017-12-01

    Barrier island outcrops record transgressive shoreline motion at geologic timescales, providing integral clues to understanding how coastlines respond to rising sea levels. However, barrier island deposits are difficult to recognize. While significant progress has been made in understanding the modern coastal morphodynamics, this insight is not fully leveraged in existing barrier island facies models. Excellent outcrop exposures of the paralic Upper Cretaceous Straight Cliffs Formation of southern Utah provide an opportunity to revise facies models and recognition criteria for barrier island deposits. Preserved barrier islands are composed of three main architectural elements (shorefaces, tidal inlets, and tidal channels) which occur independently or in combination to create larger-scale barrier island deposits. Barrier island shorefaces record progradation, while barrier island tidal inlets record lateral migration, and barrier island tidal channels record aggradation within the tidal inlet. Four facies associations are used to describe and characterize these barrier island architectural elements. Barrier islands occur in association with backarrier fill and internally contain lower and upper shoreface, high-energy upper shoreface, and tidal channel facies. Barrier islands bound lagoons or estuaries, and are distinguished from other shoreface deposits by their internal facies and geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island deposits. Existing barrier island models highlight the short term heterogeneous and dynamic nature of barrier island systems, yet overlook processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their expressions in preserved barrier island strata. This study uses characteristic outcrop expressions of barrier island successions to

  2. Late Pleistocene dune-sourced alluvial fans in coastal settings: Sedimentary facies and related processes (Mallorca, Western Mediterranean)

    Science.gov (United States)

    Pomar, F.; del Valle, L.; Fornós, J. J.; Gómez-Pujol, L.

    2018-05-01

    Aeolian-alluvial sedimentary interaction results in the formation of deposits characterized by typical alluvial sedimentary structures, but is composed of conspicuous amounts of aeolian sediments. The literature on this topic is limited and most works relate more with continental aeolian dunes or fluvial dune interference with fan bodies. Furthermore, there is a lack of examples of aeolian-alluvial sedimentary interference in coastal settings. In the western Mediterranean, there are many Pleistocene alluvial fan deposits built up partly by sediment originating from coastal dunes dismantled by alluvial streams. Very often, these deposits show a continuous sedimentary sequence through which we can derive the contribution and predominance of coastal, alluvial-colluvial and aeolian processes and their controls on landscape formation. This is an outstanding feature within coastal systems since it shows marine sediments reworked and integrated within coastal dune fields by aeolian transport, and the latter built up into alluvial fan bodies. In this sense, aeolian-alluvial interaction is the geomorphic-sedimentary expression of the coexistence and overlapping of alluvial and aeolian environments resulting in deposits sharing sedimentary features from both environments. The aim of this paper is to unravel the contribution of coastal dunes in the construction of alluvial fans bodies and identify the main sedimentary facies that constitute these deposits, as well as their climatic controls. For this reason, Es Caló fan (northern Mallorca) has been selected due to its well-exposed deposits exhibiting the alternation of aeolian, alluvial and colluvial deposits. Sedimentological and stratigraphic analyses based on 33 logs and complementary analyses demonstrate that most of the facies constituting the fan body are made up completely of marine bioclastic sands. These deposits record an alluvial fan sedimentary environment characterized by sediments inputs that do not proceed

  3. Calcareous nannofossils and sedimentary facies in the Upper Cretaceous Bozeş Formation (Southern Apuseni Mountains, Romania

    Directory of Open Access Journals (Sweden)

    Ramona Balc

    2012-02-01

    Full Text Available The lithology, sedimentology and biostratigraphy of the Bozes Formation, which crop out in the SE Metaliferi Mountains (Apuseni Mts. have been investigated in order to establish the age of the deposits and the depositional environment. The sedimentary structures and facies are interpreted as indicating a deep-water depositional environment, representing part of a submarine fan lobe. Three facies assemblages have been identified and described. Calcareous nannofossils were used to determine the age of the investigated deposits. The presence of Lucianorhabdus cayeuxii and Calculites obscurus indicates the CC17 biozone, while UC13 Zone is pointed out by the continuous occurrence of Arkhangelskiella cymbiformis and the absence of Broinsonia parca parca. Thus, the age of the studied deposits is Late Santonian -?Early Campanian.

  4. Fluvial systems and their sedimentary models

    Directory of Open Access Journals (Sweden)

    Dragomir Skabeme

    1995-12-01

    Full Text Available The Slovenian géomorphologie and sedimentologie terminology for fluvial depositional environments is not established yet. Therefore a classification and the proposal for Slovenian names of fluvial sedimentary and erosional forms and influences controlling them are discussed. Attention is given to the problems of recognition of sedimentary environments in sedimentary rocks, and to fluvial sedimentary models.

  5. Preliminary investigation on the sedimentary facies of the middle silurian uraniferous rock formations in western Qinling Region

    International Nuclear Information System (INIS)

    Mao Yunian; Min Yongming.

    1987-01-01

    The Middle Silurian stratabound uranium deposits in Western Qinling were formed due to hydrothermal modification of ground water and reconcentration of uranium from the sedimentary source rocks. The Silurian system consists of the sediments deposited in the marginal sea of the passive continent, to the south of which is the Ruoergai palaeocontinent. The Middle Silurian is divided into three formations. The lower members of each formation are composed of fine-grained clastic rocks with bay-lagoon facies, while the upper members of each formation are uraniferous rock formations consisted of carbonaceous-siliceous-limestone-argillaceous rocks. During the Middle Silurian period there occurred an island chain barrier which is roughly parallel to the palaeocoast and was formed by undersea uplifts. The uraniferous rock formations belong to the assemblage of lagoon-reef-back tidal flat-reef beach facies. Nearshore shallow water environment, abundant terrestrial fine detritus, local reduction facies and zones are three cardinal conditions for the formation of uranium-rich sediments. Uranium deposition mainly took place in the environments of the inner part of reef beach and reef-back tidal flat, which are characterized by having medium to slightly lower energy, the terrestrial fine detritus involved, and local reduction field resulting from the decomposition of organism after their massive death. Furing the process of relative slow deposition, UO 2 2+ in the sea water was formed by means of infiltration, diffusion and alternative absorption of water at the bottom into organic matter and clay

  6. REGIONAL OUTCROPS WITH DIDACTIC INTEREST AND SEDIMENTARY FACIES ASSOCIATION OF THE ITARARÉ GROUP AT SÃO PAULO (BRAZIL

    Directory of Open Access Journals (Sweden)

    Sérgio Bergamaschi

    2016-03-01

    Full Text Available The main objective of this work is to locate and identify the outcrops considered iconic and valuable as references, not only from the point of view of Cultural or Didactic Tourism, but also in paleoenvironmental reconstruction studies, based on the lithologies that comprise the Itararé Group, in the State of São Paulo, Brazil. This work also intends to relate these sites to outcrops of sedimentary facies, in an area located at south of Itu and Porto Feliz, and north of Sorocaba. The Itararé Group lies within the Paraná Basin (Paleozoic, and is composed by sedimentary sequences associated with the record of the Permo-Carboniferous glaciation event that occurred in the Gondwana supercontinent. This work is based on observations of outcrops in a macro- and mesoscopic scale, considering the characterization of external and internal aspects of the layer, the stratigraphic sequence in the outcrop, and the continuity of the layers within the mapped area. The study area has outcrops where the evidences of glaciomarine deposits predominate. Sedimentary sequences deposited in a subaquatic low-energy environment, as well as episodic deposits, in which relatively more energetic phases alternated with low hydrodynamic conditions are well-developed in the study area. There are also fluvio-deltaic environmental occurrences related to sea level oscillations linked with glacier advances and receding.

  7. Facies and sedimentary series in the La Camocha Carboniferous, (Gijon, NW Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Corrales, I; Flor, G; Pello, J; Peon, A

    1985-01-01

    The Carboniferous of La Camocha Mine consists mainly of terrigenous facies belonging to a fluvial-dominated delta system. Occasionally, as a consequence of avulsion, the area is abandoned by the distributary channels; it gives occasion for some quick marine transgression, the sediments of which being of carbonate character. This situation occurs in the lower part of the studied succession; the upper one is characterised only by sediments of the delta plain environments. 12 references.

  8. Modern sedimentary facies, depositional environments, and major controlling processes on an arid siliciclastic coast, Al qahmah, SE Red Sea, Saudi Arabia

    Science.gov (United States)

    Nabhan, Abdullah I.; Yang, Wan

    2018-04-01

    The facies and environments along the arid siliciclastic coast of Red Sea in Al Qahmah, Saudi Arabia are studied to establish a depositional model for interpretation of ancient rocks deposited in rift settings. Field and petrographic studies of 151 sediment samples in an area of 20 km2 define seven main facies types: beach, washover fan, tidal channel, dune, sabkha, delta, and wadi (seasonal stream). The wadi and delta facies are composed of poorly to moderately well-sorted, gravelly, medium-to-fine sands. Delta-front sands are redistributed by southward longshore currents to form a beach. Beach facies is composed of well-to-moderately sorted fine sands with minor gravels, which contain high concentrations of magnetite, ilmenite, garnet, pyroxene, amphibole, epidote, titanite, and apatite grains, indicating strong winnowing. Crabs and other burrowers destroy primary sedimentary structures and mix sediments in foreshore and backshore of the beaches. Wind and storm surge rework foreshore and backshore sediments to form washover fans. Sabkha facies occurs extensively in supratidal depressions behind beach, are flooded by rainstorms and spring tide, and capped by a 5-cm-thick crust composed of interlaminated halite, quartz, albite, minor gypsum and biotite, and rarely calcium carbonate. Halite occurs as thin sheets and gypsum as nodules with a chicken-wire structure. Clastic fraction in sabkha sediments ranges from coarse silt to coarse sand with moderate sorting, and is transported by currents and wind. Tidal inlets and tidal creeks assume abandoned wadis and are filled by muddy sand. Sand dunes and sand sheets are 1-7 m high and widely distributed due to variable wind directions. Fine-grained dune sands are moderately well sorted, whereas sheet sands are coarser and poorly sorted due to vegetation baffling. Most eolian sands are sourced from beach deposits. This suite of complex riverine, wave, tidal, wind, chemical, and biological processes form the facies mosaic

  9. Study on evaluation method for heterogeneous sedimentary rocks based on forward model

    International Nuclear Information System (INIS)

    Masui, Yasuhiro; Kawada, Koji; Katoh, Arata; Tsuji, Takashi; Suwabe, Mizue

    2004-02-01

    It is very important to estimate the facies distribution of heterogeneous sedimentary rocks for geological disposal of high level radioactive waste. The heterogeneousness of sedimentary rocks is due to variable distribution of grain size and mineral composition. The objective of this study is to establish the evaluation method for heterogeneous sedimentary rocks based on forward model. This study consisted of geological study for Horonobe area and the development of soft wear for sedimentary model. Geological study was composed of following items. 1. The sedimentary system for Koetoi and Wakkanai formations in Horonobe area was compiled based on papers. 2. The cores of HDB-1 were observed mainly from sedimentological view. 3. The facies and compaction property of argillaceous rocks were studied based on physical logs and core analysis data of wells. 4. The structure maps, isochrone maps, isopach maps and restored geological sections were made. The soft wear for sedimentary model to show sedimentary system on a basin scale was developed. This soft wear estimates the facies distribution and hydraulic conductivity of sedimentary rocks on three dimensions scale by numerical simulation. (author)

  10. Syn-sedimentary tectonics and facies analysis in a rift setting: Cretaceous Dalmiapuram Formation, Cauvery Basin, SE India

    Directory of Open Access Journals (Sweden)

    Nivedita Chakraborty

    2018-04-01

    transgressive systems tract motif to grow eventually passing upwards into the Karai Shale Formation, whose contact with the Dalmiapuram Formation is gradational. Keywords: Syn-sedimentary tectonics, Facies analysis, Carbonate shelf, Cretaceous, Dalmiapuram Formation, Cauvery Basin

  11. Phosphate-rich sedimentary rocks: significance for organic facies and petroleum exploration

    Energy Technology Data Exchange (ETDEWEB)

    Waples, D W

    1982-03-01

    Phosphorus-bearing rocks and sediments can be divided into two genetically distinct classes: phosphatic shales or limestones and phosphorites. Phosphatic shales are primary sediments in which phosphate nodules or micronodules have formed diagenetically by precipitation of calcium phosphates derived mainly from organic phosphorus. The nodules form in reducing environments at shallow depths within the sediments, where loss of phosphate by diffusion to the overlying water column is minimized. Highly biogenic sediments containing large amounts of organic matter and some fine clastic debris provide ideal environments for the formation of phosphate nodules. Phosphorites, in contrast, represent concentrated accumulations of reworked phosphate nodules which originated in phosphatic shales or limestones. Currents, wave action, recrystallization, and erosion and resedimentation are important mechanisms in the concentration process. Phosphatic shales and limestones may become excellent oil source rocks if thermal maturity is achieved. They are useful facies indicators for anoxic or nearly anoxic depositional environments, and are often associated with restricted basins, or, during certain geologic periods, with broad shelves developed during transgressions. Phosphorites, in contrast, are often correlated with sea-level regressions or uplifts. They are modest source rocks because of their low organic carbon contents and the fact that they were reworked under oxidizing conditions. Nevertheless, because phosphorites are derived from, and often grade into, phosphatic shales, they also are of potential utility in the search for oil source beds.

  12. Recent benthic foraminifera and sedimentary facies from mangrove swamps and channels of Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Fiorini, Flavia; Odeh, Weaam A. S. Al; Lokier, Stephen W.; Paul, Andreas

    2016-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations in several coastline environments (mangrove swamps and channels) located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of living and dead benthic foraminifera in different sedimentary facies in the mangal and in the surrounding area comprising natural environments of the upper and lower intertidal area (mud flats and channels) and areas modified by anthropogenic activities (dredged channels). The fine-grain sediments collected near mangrove (Avicenna marina) roots presented a high abundance of living and dead foraminifera tests. The assemblages in these samples show very low diversity and are almost entirely constituted of small-sized opportunistic species belonging to the genera Ammonia and Elphidium. In particular: • Samples collected on the mud flat and in ponds at the margin of the channel show a foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Triloculina, Quinqueloculina, Peneroplis and Spirolina. • Samples collected in the lower (wet) intertidal area close to Avicenna marina roots, presented a low-diversity assemblage mostly comprising opportunistic foraminifera of the genera Ammonia and Elphidium along with rare miliolidae. • Samples from the upper intertidal area (dry) close to Avicenna marina roots, produced an assemblage exclusively composed of small-sized opportunistic Ammonia and Elphidium, together with abundant specimens belonging to the genera Trochammina. Throchammina specimens have not been previously recorded from Recent sedimentary samples of

  13. The Neogene molasse deposits of the Zagros Mountains in central Dezful Embayment: facies, sedimentary environments and controls

    Directory of Open Access Journals (Sweden)

    Ali Hossein Jalilian

    2016-03-01

    Full Text Available The upper part of Neogene sequence of the Zagros Mountains consists of a clastic succession which is identified as Aghajari and Bakhtyari formations. The sequence is an excellent example of synorogenic sedimentation or molasse deposited in northern portion of the Zagros foreland basin. Sedimentological analysis of an outcrop section representing Miocene-Pliocene sediments in central Dezful Embayment resulted in recognizing 9 lithofacies and 4 architectural elements. These lithofacies include conglometate (Gt, Gh, Gmm, sandstone (Sp, Sh, Sr, St and mudstone (Fm, Fl that were deposited in meandering stream, braided river and alluvial fan environments. Paleocurrent analysis of cross-beds, channels and asymmetric ripple marks indicate that these Neogene clastics were mainly drived from Cretaceous to Paleogene highlands in the Zagros Mountains on the north. This stratigraphic record is coarsening-upward and formed by a regressive depositional megacycle under arid climate. Facies and depositional history analysis show that sedimentation of the Zagros molasse was primarily controlled by base-level changes rather than catchment lithology or climate. The sedimentary record of this regressive megacycle reveales the base-level was constantly falling down on one hand and the provenance was uplifting on the other hand. Tectonic activities and Zagros Mountains rising in the Late Miocene resulted in deposition of fining-upward point-bar and floodplain sequences of the Aghajari Formation in low-gradient meandering streams. The Lahbari Member of the Aghajari Formation represents deposition in braided rivers that composed predominantly of flood-plain deposits in the Early Pliocene. Finally, the sedimentary cycle of the Zagros molasse deposits terminated with massive conglomerates of the Bakhtyari Formation deposited in large alluvial fans near the source area.

  14. Oceanographic controls on sedimentary and geochemical facies on the Peru outer shelf and upper slope

    Science.gov (United States)

    Arthur, Michael A.; Dean, Walter E.

    2013-01-01

    Concentrations and characteristics of organic matter in surface sediments deposited under an intense oxygen-minimum zone (OMZ) on the Peru margin were mapped and studied in samples from deck-deployed box cores and push cores acquired by submersible on two east-west transects spanning depths of 75 to 1,000 meters (m) at 12°S and 13.5°S. On the basis of sampling and analyses of the top 1–2 centimeters (cm) of available cores, three main belts of sediments were identified on each transect with increasing depth: (1) muds rich in organic carbon (OC); (2) authigenic phosphatic mineral crusts and pavements; and (3) glaucony facies.Sediments rich in OC on the 12°S transect were mainly located on the outer shelf and upper slope (150–350 m), but they occurred in much shallower water (approximately 100 m) on the 13.5°S transect. The organic matter is almost entirely marine as confirmed by Rock-Eval pyrolysis and isotopic composition of OC. Concentrations of OC are highest (up to 18 percent) in sediments within the OMZ where dissolved oxygen (DO) concentrations are Peru margin can only become buried and incorporated into the geologic record once bottom currents slacken sufficiently to allow fine-grained sediment to accumulate.Glaucony-rich surface sediments, relatively undiluted by other components, were found mainly in deeper water on the 13.5°S transect (750 m to at least 1,067 m). These sediments consist almost entirely of sand-size glaucony pellets. These widespread glaucony sands formed in place and were then concentrated and reworked by strong currents that winnowed away the fine-grained matrix. Although the glaucony occurs in sand-size pellets, the pellets are made up of aggregates of authigenic, platy, micaceous clay minerals. Glaucony is predominantly a potassium (K), sodium (Na), iron (Fe), magnesium (Mg) aluminosilicate with an approximate formula of (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2. The glaucony on the 13.5°S transect forms by alteration of one or more

  15. Holocene facies analysis of the sedimentary record with anthropogenic impacts in the Ria de Vigo (NW Spain)

    Science.gov (United States)

    Rubio, B.; Garcia-Gil, S.; Vilas, F.; Garcia, A.

    2004-05-01

    The Ria de Vigo constitutes the southernmost ria of the Rias Bajas. The reconnaisance studies of this ria indicate a heterogeneous distribution of both terrigenous and carbonate sediments with a major axial deposit of cohesive sediments. These fine sediments are relatively rich in organic matter, particularly in the inner part of the ria. This is the result of a progressive change in hydrodynamic conditions along the ria. The outer parts are affected by severe storms in winter and by upwelling processes in summer, whilst the inner parts have an estuarine character throughout the year. The upwelling produces a marked increase in the biological productivity in the Ria and, consequently, these sediments have typically very high contents of organic matter. In recent years, increasing interest has been shown in the levels of heavy metals in sediments of the Galician Rias. Particularly, some of these studies showed a higher concentration of heavy metals in the muddiest surficial sediments in the Ria de Vigo. However, and despite of the important human and industrial settlement in the Galician rias, knowledge about the evolution of historical contamination along the Holocene sedimentary record is scarce. In order to ascertain this evolution have been selected 8 gravity corer located along the axial part of the ria. This evaluation was focused on the muddy sediments of the axial part of the ria due to the dependence of metal levels on grain size, resulting from the association of metals with the finer particles, as it has been demonstrated by previous studies in the ria. On these sediments, the combination of geochemical, mineralogical and sedimentological data, facies interpretations (obtained from x-ray radiography), and their integration with high resolution seismic data (Uniboom and 3.5 Khz subbottom profiler) have allowed to establish the evolution of certain heavy metals (Zn, Cu and Pb) along the Holocene recent sedimentary record in the Ria de Vigo. Sediments in the

  16. Physical stratigraphy and facies analysis of the castissent tecto-sedimentary unit

    OpenAIRE

    Poyatos-Moré, Miquel

    2014-01-01

    L'anàlisi de la sedimentologia, geometria i trajectòria de diverses clinoformes deltaiques successives en estudis d'aflorament o en bases de dades de sísmica de reflexió han estat àmpliament utilitzats com una eina per a (1) inferir canvis en el nivell del mar i per a (2) interpretar els factors de control a curt i llarg termini sobre la evolució dels marges de conca, així com en la durada i tipus de transport de sediment groller des dels continents fins als oceans. Els models deposicionals, ...

  17. Non-marine carbonate facies, facies models and palaeogeographies of the Purbeck Formation (Late Jurassic to Early Cretaceous) of Dorset (Southern England).

    Science.gov (United States)

    Gallois, Arnaud; Bosence, Dan; Burgess, Peter

    2015-04-01

    Non-marine carbonates are relatively poorly understood compared with their more abundant marine counterparts. Sedimentary facies and basin architecture are controlled by a range of environmental parameters such as climate, hydrology and tectonic setting but facies models are few and limited in their predictive value. Following the discovery of extensive Early Cretaceous, non-marine carbonate hydrocarbon reservoirs in the South Atlantic, the interest of understanding such complex deposits has increased during recent years. This study is developing a new depositional model for non-marine carbonates in a semi-arid climate setting in an extensional basin; the Purbeck Formation (Upper Jurassic - Lower Cretaceous) in Dorset (Southern England). Outcrop study coupled with subsurface data analysis and petrographic study (sedimentology and early diagenesis) aims to constrain and improve published models of depositional settings. Facies models for brackish water and hypersaline water conditions of these lacustrine to palustrine carbonates deposited in the syn-rift phase of the Wessex Basin will be presented. Particular attention focusses on the factors that control the accumulation of in-situ microbialite mounds that occur within bedded inter-mound packstones-grainstones in the lower Purbeck. The microbialite mounds are located in three units (locally known as the Skull Cap, the Hard Cap and the Soft Cap) separated by three fossil soils (locally known as the Basal, the Lower and the Great Dirt Beds) respectively within three shallowing upward lacustrine sequences. These complex microbialite mounds (up to 4m high), are composed of tabular small-scale mounds (flat and long, up to 50cm high) divided into four subfacies. Many of these small-scale mounds developed around trees and branches which are preserved as moulds (or silicified wood) which are surrounded by a burrowed mudstone-wackestone collar. Subsequently a thrombolite framework developed on the upper part only within

  18. Level-set techniques for facies identification in reservoir modeling

    Science.gov (United States)

    Iglesias, Marco A.; McLaughlin, Dennis

    2011-03-01

    In this paper we investigate the application of level-set techniques for facies identification in reservoir models. The identification of facies is a geometrical inverse ill-posed problem that we formulate in terms of shape optimization. The goal is to find a region (a geologic facies) that minimizes the misfit between predicted and measured data from an oil-water reservoir. In order to address the shape optimization problem, we present a novel application of the level-set iterative framework developed by Burger in (2002 Interfaces Free Bound. 5 301-29 2004 Inverse Problems 20 259-82) for inverse obstacle problems. The optimization is constrained by (the reservoir model) a nonlinear large-scale system of PDEs that describes the reservoir dynamics. We reformulate this reservoir model in a weak (integral) form whose shape derivative can be formally computed from standard results of shape calculus. At each iteration of the scheme, the current estimate of the shape derivative is utilized to define a velocity in the level-set equation. The proper selection of this velocity ensures that the new shape decreases the cost functional. We present results of facies identification where the velocity is computed with the gradient-based (GB) approach of Burger (2002) and the Levenberg-Marquardt (LM) technique of Burger (2004). While an adjoint formulation allows the straightforward application of the GB approach, the LM technique requires the computation of the large-scale Karush-Kuhn-Tucker system that arises at each iteration of the scheme. We efficiently solve this system by means of the representer method. We present some synthetic experiments to show and compare the capabilities and limitations of the proposed implementations of level-set techniques for the identification of geologic facies.

  19. Level-set techniques for facies identification in reservoir modeling

    International Nuclear Information System (INIS)

    Iglesias, Marco A; McLaughlin, Dennis

    2011-01-01

    In this paper we investigate the application of level-set techniques for facies identification in reservoir models. The identification of facies is a geometrical inverse ill-posed problem that we formulate in terms of shape optimization. The goal is to find a region (a geologic facies) that minimizes the misfit between predicted and measured data from an oil–water reservoir. In order to address the shape optimization problem, we present a novel application of the level-set iterative framework developed by Burger in (2002 Interfaces Free Bound. 5 301–29; 2004 Inverse Problems 20 259–82) for inverse obstacle problems. The optimization is constrained by (the reservoir model) a nonlinear large-scale system of PDEs that describes the reservoir dynamics. We reformulate this reservoir model in a weak (integral) form whose shape derivative can be formally computed from standard results of shape calculus. At each iteration of the scheme, the current estimate of the shape derivative is utilized to define a velocity in the level-set equation. The proper selection of this velocity ensures that the new shape decreases the cost functional. We present results of facies identification where the velocity is computed with the gradient-based (GB) approach of Burger (2002) and the Levenberg–Marquardt (LM) technique of Burger (2004). While an adjoint formulation allows the straightforward application of the GB approach, the LM technique requires the computation of the large-scale Karush–Kuhn–Tucker system that arises at each iteration of the scheme. We efficiently solve this system by means of the representer method. We present some synthetic experiments to show and compare the capabilities and limitations of the proposed implementations of level-set techniques for the identification of geologic facies

  20. Sedimentary facies of the upper Cambrian (Furongian; Jiangshanian and Sunwaptan) Tunnel City Group, Upper Mississippi Valley: new insight on the old stormy debate

    Science.gov (United States)

    Eoff, Jennifer D.

    2014-01-01

    New data from detailed measured sections permit a comprehensive revision of the sedimentary facies of the Furongian (upper Cambrian; Jiangshanian and Sunwaptan stages) Tunnel City Group (Lone Rock Formation and Mazomanie Formation) of Wisconsin and Minnesota. Heterogeneous sandstones, comprising seven lithofacies along a depositional transect from shoreface to transitional-offshore environments, record sedimentation in a storm-dominated, shallow-marine epicontinental sea. The origin of glauconite in the Birkmose Member and Reno Member of the Lone Rock Formation was unclear, but its formation and preserved distribution are linked to inferred depositional energy rather than just net sedimentation rate. Flat-pebble conglomerate, abundant in lower Paleozoic strata, was associated with the formation of a condensed section during cratonic flooding. Hummocky cross-stratification was a valuable tool used to infer depositional settings and relative paleobathymetry, and the model describing formation of this bedform is expanded to address flow types dominant during its genesis, in particular the importance of an early unidirectional component of combined flow. The depositional model developed here for the Lone Rock Formation and Mazomanie Formation is broadly applicable to other strata common to the early Paleozoic that document sedimentation along flooded cratonic interiors or shallow shelves.

  1. Sedimentary facies and evolution of the upper member of cretaceou Sunjiawan formation in Heishui area of western Liaoning

    International Nuclear Information System (INIS)

    Zhao Zhonghua; Xi Haiyin; Chen Debing; Wang Liming; Rao Minghui

    2010-01-01

    The upper member of Sunjiawan formation in Heishui area is mainly alluvial fan facies. From the macroscopic view, alluvial fan facies can be divided into three sub-facies of proximal end gravel braided plain, distal end gravel braided plain and pre-fan flood-plain and further into some micro-facies of debris flow, gravel braided channel, gravel dam, flood-fine and peat bog etc. The upper member of Sunjiawan formation could be divided into three sub-members. The first sub-member is retrograding dry land type fan sediment under drought-humid climate. The second sub-member is retrograding wet land type fan deposit under humid climate. Third sub-member is progradational wetland type fan sediments under humid climate. Sunjiawan formation in Heishui area experienced three evolutionary stages: the early retrograding dryland type fan deposition, the medium term retrograding wet land type fan deposition and the later progradational wetland type fan. (authors)

  2. Ground Penetrating Radar (GPR) facies delineated shallow sedimentary records along a recently prograding coastal barrier adjoining the Bay of Bengal: Paradeep, Odisha, India

    Science.gov (United States)

    Layek, M. K.; Sengupta, P.; Mukherjee, A.

    2017-12-01

    Sea-level fluctuations, triggered by progradation of beach or marine regression, can be of various time-scales. The fluctuating history of a shoreline along a coastal barrier can be identified from the sedimentary features of accretion or erosion. The necessity of the understanding of the complex barrier dynamics and subsurface along the Paradeep coast (in the state of Odisha, India), adjacent to the Bay of Bengal, has been growing since the number of the harbor industrial projects and the inhabitants of this major port city of India increases. In this study area, high resolution ground penetrating radar (GPR) survey and its interpretation by GPR facies analysis, which considers the pattern/set of reflected electromagnetic signals, has proved to be a useful method for shallow-subsurface (up to 8 m) imaging. In order to perform this task, a GPR system with 200 MHZ antenna was employed to survey along (17 profiles) and across (21 profiles) the microtidal coastal barrier of Paradeep. The shapes and sizes of the accretional and erosional features like beach-ridge deposits, washover deposits, channel-and-fill, and scour-and-fill are delineated on the radargram after processing by Radan7® software. The internal geometry of the beach ridge is mapped accurately after the radar facies analysis which suggests the longshore drift of sediments from the nearby river mouths of Mahanadi, Devi and their tributaries. This GPR facies analysis revealed the existence of two types of palaeo-tidal channels of the study area - (a) larger channels which are perpendicular to the shoreline having channel width of about 400 m with maximum depth of 4.5 m from the surface and (b) smaller channels (width up to 60 m) which flow parallel to the shoreline. In case of Paradeep coastal barrier, seaward-dipping beach progradational facies is positioned within oblique erosional surfaces (13°-36°) below the horizontal erosional surface or facies boundary. This lead to delineate the cycles of erosion

  3. Sedimentary facies analysis of the Mesozoic clastic rocks in Southern Peru (Tacna, 18°S): Towards a paleoenvironmental Redefinition and stratigraphic Reorganization

    Science.gov (United States)

    Alván, Aldo; Jacay, Javier; Caracciolo, Luca; Sánchez, Elvis; Trinidad, Inés

    2018-07-01

    The Mesozoic rocks of southern Peru comprise a Middle Jurassic to Early Cretaceous sedimentary sequence deposited during a time interval of approximately 34 Myr. In Tacna, these rocks are detrital and constitute the Yura Group (Callovian to Tithonian) and the Hualhuani Formation (Berriasian). Basing on robust interpretation of facies and petrographic analysis, we reconstruct the depositional settings of such units and provide a refined stratigraphic framework. Accordingly, nine types of sedimentary facies and six architectural elements are defined. They preserve the record of a progradational fluvial system, in which two styless regulated the dispersion of sediments: (i) a high-to moderate-sinuosity meandering setting (Yura Group), and a later (ii) incipient braided setting (Hualhuani Formation). The Yura Group (Callovian-Tithonian) represents the onset of floodplain deposits and lateral accretion of point-bar deposits sited on a semi-flat topography. Nonetheless, the progradational sequence was affected by at least two rapid marine ingressions occurred during Middle Callovian and Tithonian times. Such marine ingressions reveal the proximity of a shallow marine setting and incipient carbonate deposition. In response to increase in topographic gradient, the Hualhuani Formation (Berriasian) deposited as extensive multistory sandy channels. The mineralogy of the Mesozoic sediments suggests sediment supplies and intense recycling from a craton interior (i.e. Amazon Craton and/or plutonic sources) located eastward of the study area.

  4. Facies and sedimentary environments of the Abu Qada Formation at Gabal El-Gunna, Southeastern Sinai, Egypt

    Directory of Open Access Journals (Sweden)

    Tarek Y.M.A. El-Hariri

    2012-06-01

    Full Text Available The biostratigraphy, microfacies association, mineralogical interferences, depositional environments and geochemical properties of the Abu Qada Formation, which exposed at Gabal El-Gunna Southeastern Sinai, Egypt were delineated. It belongs to the planktonic foraminiferal Whiteinella archaeocretacea Zone of the Late Cenomanian-Early Turonian and consists of calcareous shale and limestone. The calcareous shale facies is characterized by chlorite, smectite and illite with high concentration of P2O5, Zn, Ni, V, and Cr. The carbonate rocks are characterized by foraminiferal wakestone and bioclastic grainstone. These microfacies associations are characterized by barite with high content of Sr. The facies types with faunal contents, geochemical and mineralogical studies suggest a restricted to shelf lagoon open circulation environment.

  5. The influence of freshwater and material export on sedimentary facies and benthic processes within the Fly Delta and adjacent Gulf of Papua (Papua New Guinea)

    Science.gov (United States)

    Alongi, D. M.; Christoffersen, P.; Tirendi, F.; Robertson, A. I.

    1992-02-01

    Large volumes of freshwater and suspended material debouch from the Fly River in southwestern Papua New Guinea into the Gulf of Papua, greatly influencing the hydrography and sedimentary processes within the river delta and adjacent shelf region. Sedimentary facies within the subtidal regions of the Fly Delta are composed mainly of compacted and eroded very fine black sand, and highly laminated, muddy sand and sandy mud, progressing to prodelta mud with intermixed primary and biogenic structures in the inner Gulf of Papua. These prodelta muds grade further to mixed terrigenous-carbonate deposits southwards into the northern Great Barrier Reef and Torres Strait, and to well-bioturbated, fluid mud northwards into the Gulf of Papua. The transition from physically-dominated, estuarine conditions within the delta to more quiescent, marine conditions on the shelf leads to concomitant changes in sediment chemistry, microbial activity and infaunal and epifaunal communities. Particulate (C, N, P) and dissolved inorganic and organic nutrient concentrations were a function of sediment type (higher in finer deposits) rather than location (delta vs gulf). C: N: P ratios of solid-phase nutrients varied greatly, but were usually less than those predicted by the Redfield ratio. Mean interstitial concentrations of dissolved inorganic nutrients were low (μM range), but dissolved organic carbon, nitrogen and phosphorus levels were equivalent to those found in higher latitude systems. Fluxes of dissolved inorganic nutrients were generally low (μmol m -2 day -1). Flux rates were mostly negative (into the sediment) in the delta suggesting that these deposits are a sink for nutrients. In the offshore deposits, dissolved inorganic fluxes were higher and mostly positive indicating that they are a source for dissolved nutrients. Standing crops of bacteria (range: below detection limits— 2.5 × 10 10 cells g -1 dry wt), meiofauna (range: 5-750 individuals 10 cm -2; 9-1006 μg dry wt 10

  6. 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)

    Chen Xiaolin; Xiang Weidong; Li Tiangang; Fang Xiheng; Xia Yuliang; Pang Yaqing; Zheng Jiwei; Zhang Mingyu; Zhang Zegui; Tian Shifeng

    2006-01-01

    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)

  7. Trace fossils, sedimentary facies and parasequence architecture from the Lower Cretaceous Mulichinco Formation of Argentina: The role of fair-weather waves in shoreface deposits

    Science.gov (United States)

    Wesolowski, Lindsey J. N.; Buatois, Luis A.; Mángano, M. Gabriela; Ponce, Juan José; Carmona, Noelia B.

    2018-05-01

    Shorefaces can display strong facies variability and integration of sedimentology and ichnology provides a high-resolution model to identify variations among strongly storm-dominated (high energy), moderately storm-affected (intermediate energy), and weakly storm-affected (low energy) shoreface deposits. In addition, ichnology has proved to be of help to delineate parasequences as trace-fossil associations are excellent indicators of environmental conditions which typically change along the depositional profile. Shallow-marine deposits and associated ichnofaunas from the Mulichinco Formation (Valanginian, Lower Cretaceous) in Puerta Curaco, Neuquén Basin, western Argentina, were analyzed to evaluate stress factors on shoreface benthos and parasequence architecture. During storm-dominated conditions, the Skolithos Ichnofacies prevails within the offshore transition and lower shoreface represented by assemblages dominated by Thalassinoides isp. and Ophiomorpha irregulaire. Under weakly storm-affected conditions, the Cruziana Ichnofacies is recognized, characterized by assemblages dominated by Thalassinoides isp. and Gyrochorte comosa in the offshore transition, and by Gyrochorte comosa within the lower shoreface. Storm-influenced conditions yield wider ichnologic variability, showing elements of both ichnofacies. Storm influence on sedimentation is affected by both allogenic (e.g. tectonic subsidence, sea-level, and sediment influx) and autogenic (e.g. hydrodynamic) controls at both parasequence and intra-parasequence scales. Four distinct types of parasequences were recognized, strongly storm-dominated, moderately storm-affected, moderately storm-affected - strongly fair-weather reworked, and weakly storm-affected, categorized based on parasequence architectural variability derived from varying degrees of storm and fair-weather wave influence. The new type of shoreface described here, the moderately storm-affected - strongly fair-weather reworked shoreface

  8. Footwall degradation styles and associated sedimentary facies distribution in SE Crete: Insights into tilt-block extensional basins on continental margins

    Science.gov (United States)

    Alves, Tiago M.; Cupkovic, Tomas

    2018-05-01

    Depositional facies resulting from footwall degradation in extensional basins of SE Crete are studied based on detailed geological maps, regional transects, lithological columns and outcrop photos. During an extensional episode affecting Crete in the late Miocene-early Pliocene, depocentres trending N20°E and N70°E were filled with fan deltas, submarine mass-wasting deposits, sandy turbidites and fine-grained hemipelagites sourced from both nearby and distal sediment sources. Deposition of proximal continental and shallow-marine units, and relatively deep (marine) turbidites and mass-transport deposits, occurred within a complex mosaic of tectonically controlled depocentres. The new geological maps and transects in this work reveal that depositional facies in SE Crete were controlled by: a) their relative proximity to active faults and uplifting footwall blocks, b) the relative position (depth and relative height above sea level) of hanging-wall basins, and c) the nature of the basement units eroded from adjacent footwall blocks. Distal sediment sources supplied background siliciclastic sediment ('hemipelagites'), which differ markedly from strata sourced from local footwalls. In parallel, mass-transport of sediment was ubiquitous on tectonically active slopes, and so was the presence of coarse-grained sediment with sizes varying from large blocks > 50 m-wide to heterolithic mass-transport deposits and silty-sandy turbidites. We expect similar tectono-sedimentary settings to have predominated in tectonically active Miocene basins of the eastern Mediterranean, in which hydrocarbon exploration is occurring at present, and on rifted continental margins across the world.

  9. Tracing contaminant pathways in sandy heterogeneous glaciofluvial sediments using a sedimentary depositional model

    International Nuclear Information System (INIS)

    Webb, E.K.; Anderson, M.P.

    1990-01-01

    Heterogeneous sedimentary deposits present complications for tracking contaminant movement by causing a complex advective flow field. Connected areas of high conductivity produce so-called fast paths that control movement of solutes. Identifying potential fast paths and describing the variation in hydraulic properties was attempted through simulating the deposition of a glaciofluvial deposit (outwash). Glaciofluvial deposits usually consist of several depositional facies, each of which has different physical characteristics, depositional structures and hydraulic properties. Therefore, it is unlikely that the property of stationarity (a constant mean hydraulic conductivity and a mono-modal probability distribution) holds for an entire glaciofluvial sequence. However, the process of dividing an outwash sequence into geologic facies presumably identifies units of material with similar physical characteristics. It is proposed that patterns of geologic facies determined by field observation can be quantified by mathematical simulation of sediment deposition. Subsequently, the simulated sediment distributions can be used to define the distribution of hydrogeologic parameters and locate possible fast paths. To test this hypothesis, a hypothetical glacial outwash deposit based on geologic facies descriptions contained in the literature was simulated using a sedimentary depositional model, SEDSIM, to produce a three-dimensional description of sediment grain size distributions. Grain size distributions were then used to estimate the spatial distribution of hydraulic conductivity. Subsequently a finite-difference flow model and linked particle tracking algorithm were used to trace conservative transport pathways. This represents a first step in describing the spatial heterogeneity of hydrogeologic characteristics for glaciofluvial and other braided stream environments. (Author) (39 refs., 7 figs.)

  10. STOCHASTIC FRACTURED ROCK FACIES FOR GROUNDWATER FLOW MODELING

    Directory of Open Access Journals (Sweden)

    DANIELA BLESSENT

    2013-01-01

    Full Text Available Este artículo presenta los resultados de una simulación de flujo de agua subterránea en rocas fracturadas. Se emplea un enfoque estocástico (modelo estocástico equivalente en medio poroso fracturado para construir el modelo conceptual y para usar este último en la roca de baja permeabilidad encontrada en el sitio elegido como caso de estudio (Olkiluoto, Finlandia. La roca que se investiga se encuentra localizada alrededor de un grupo de pozos de sondeo y cubre un área de algunas hectáreas. Las mediciones de campo de pruebas de interferencia hidráulica se utilizan para calibrar el modelo de flujo de agua subterránea. Múltiples combinaciones de facies estocásticos se consideran para evaluar el impacto de la distribución y del número de facies en las cargas hidráulicas y en los caudales. Este estudio cuantifica la variabilidad de los resultados numéricos, lo cual es importante para el análisis de la incertidumbre en los sistemas hidrogeológicos. Por otra parte, este estudio muestra que el modelo conceptual de facies estocásticos es una alternativa adecuada a los modelos conceptuales de redes de fracturas discretas.

  11. Cyanobacterial diversity and related sedimentary facies as a function of water flow conditions: Example from the Monasterio de Piedra Natural Park (Spain)

    Science.gov (United States)

    Berrendero, Esther; Arenas, Concha; Mateo, Pilar; Jones, Brian

    2016-05-01

    The River Piedra in the Monasterio de Piedra Natural Park (NE Spain) is a modern tufa-depositing river that encompasses various depositional environments that are inhabited by different cyanobacterial populations. Molecular (16S rDNA) and morphological analyses of the cyanobacteria from different facies showed that Phormidium incrustatum dominates in the fast-flowing water areas where the mean depositional rate is 1.6 cm/year. Stromatolites in these areas are formed of palisades of hollow calcite tubes (inner diameter of 6.0-7.5 μm, walls 2-12 μm thick) that formed through calcite encrustation around the filaments followed by decay of the trichomes. In contrast, in slow-flowing water areas with lower depositional rates (mean depositional rate of 0.3 cm/year), Phormidium aerugineo-caeruleum is the dominant species. In these areas, randomly oriented calcite tubes (inner diameter of 5-6 μm, walls 3-8 μm thick) formed by calcite encrustation, are found in thin and uneven laminae and as scattered tubes in the loose lime mud and sand-sized carbonate sediment. Although this species did not build laminated deposits, it gave cohesiveness to the loose sediment. In the stepped and low waterfalls, with intermediate deposition rates (mean depositional rate of 0.9 cm/year), both species of Phormidium are found in association with spongy moss and algal boundstones, which is consistent with the variable flow conditions in this setting. The calcite encrustations on the cyanobacteria from different environments exhibit irregular patterns that may be linked to changes in the calcite saturation index. The physicochemical conditions associated with extracellular polymeric substances may be more significant to CaCO3 precipitation in microbial mats in slow-flowing water conditions than in fast-flowing water conditions. These results show that flow conditions may influence the distribution of different cyanobacteria that, in turn, leads to the development of different sedimentary

  12. The Toarcian Bathonian succession of the Antsiranana Basin (NW Madagascar): Facies analysis and tectono-sedimentary history in the development of the East Africa-Madagascar conjugate margins

    Science.gov (United States)

    Papini, Mauro; Benvenuti, Marco

    2008-04-01

    The latest Early to Middle Jurassic succession of the Antsiranana Basin (NW Madagascar) records the complex transition from the continental rifting of Gondwana to the drifting of Madagascar-India from East Africa. The Madagascan Late Paleozoic-Mesozoic successions have been included in several paleogeographic and geodynamic models explaining the evolution of the Gondwana margins. Nevertheless, in some cases, as for the Toarcian-Bathonian deposits of the Antsiranana Basin, no significant stratigraphic revision has been carried out since the early 1970s. New field surveys allow reconsidering the stratigraphic and structural context and the palaeoenvironmental meaning of Toarcian-Bathonian successions occurring in different parts of the basin. These successions rest on the Triassic-Early Jurassic Isalo Sandstone which records pre-breakup rift events with a dominantly fluvial deposition. This situation is similar to other continental rift basins of Gondwana. After a regional Toarcian transgression the different portions of the Antsiranana Basin were characterized by significantly diversified and coeval depositional environments. The basin can be subdivided in a SW and NE part separated by a NW-SE trending structural high. In the SW part of the basin (Ampasindava sub-basin) the so-called "Jurassique paralique" [Rerat, J.C., 1964. Note sur les variations de faciès des sèries jurassiques du nord de Madagascar. Comptes Rendus Semaine gèologique, Tananarive, pp. 15-22] or " Facies Mixtes de la Presqu'ile de Ampasindava" [Besairie, H., Collignon, M., 1972. Géologie de Madagascar; I. Les terrains sédimentaires. Annales Géologiques de Madagascar, 35, 1-463], a 1500 m thick prevalently terrigenous deposit, has been subdivided into four units. They document the long-lasting development of coastal-deltaic systems in a highly subsiding area. In the NE portion of the basin (Ankarana-Analamera sub-basin), a coeval mixed carbonate-terrigenous succession subdivided in five units

  13. Lacustrine sedimentation and facies model for the last 45,000 yr in Chalco basin. Central Mexico

    Science.gov (United States)

    Ortega, B.; Lozano, S.; Caballero, M.; Herrera, D.

    2013-05-01

    Chalco basin in central Mexico (19° 15' N, 98° 58' W, 2200 m asl) is one of the most detailed lake sediment sequence analyzed in Mexico for paleoclimatic and paleoenvironmental studies. In this former lake, five drill cores up to 27 m depth were recovered in 1987-1989 by the UNAM team, and three cores covering most of the former sequence were obtained in 2008 and 2011. The upper 27 m of the Chalco lacustrine sequence contains the record of the last 45 kyr climate history in the northern American tropics. The active tectonic and volcanic setting of Chalco Lake in the Trans-Mexican Volcanic Belt, provides an opportunity to evaluate environmental (volcanic + tectonic vs. climatic) controls on lacustrine sedimentation. The establishment of a detailed time scale by 14C in pollen extracts provides an accurate chronological control. The stratigraphical and sedimentological analyses presented here provided the recognition of depositional environments and the architecture of the upper lacustrine succession. Sedimentary facies were defined on the basis of sedimentological descriptions, microscopic observation and compositional analyses. According to compositional criteria, facies were identified and groped into two main categories according to compositional criteria: 1) detrital and volcaniclastic, and 2) biogenic facies. The clastic facies includes massive to laminated, silty and clayey sediments composed of clay minerals, feldspars, amphiboles with minor amounts of quartz, opaque minerals and calcite. Diatoms are the most common biological remains in all the clastic facies. Most of the volcaniclastic deposits correspond to fall-out deposits, some of them of well documented eruptions of the nearby large stratovolcanoes Popocatepetl and Nevado de Toluca, which in turn serve as stratigraphical markers. The biogenic facies are massive to finely laminated diatom ooze and ostracod ooze layers. The sedimentary architecture of the lacustrine succession has been controlled by

  14. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology

    International Nuclear Information System (INIS)

    Alonso-Zarza, A. M.

    2013-01-01

    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.

  15. Facies and depositional model of Almada Canyon, Almada Basin, Bahia, Brazil; Facies e modelo deposicional do Canyon de Almada, Bacia de Almada, Bahia

    Energy Technology Data Exchange (ETDEWEB)

    D' Avila, Roberto Salvador Francisco; Souza Cruz, Carlos Emanoel de; Oliveira Filho, Jose Souto; Jesus, Candida Menezes de; Cesero, Pedro de; Dias Filho, Dorval Carvalho; Lima, Claudio Coelho de; Queiroz, Claudia Lima de; Santos, Saulo Ferreira; Ferreira, Eduardo Araripe [PETROBRAS, Santos, SP (Brazil). Unidade de Negocio de Exploracao]. E-mail: rdavila@petrobras.com.br

    2004-11-01

    In the continental portion of the Almada Basin outcrops of canyon filling deposits are represented by turbidite channels and associated facies from Urucutuca Formation. The canyon - semi-exhumated - eroded basement and pre-Cenomanian sedimentary rocks. The field study of the outcrops and cores obtained in adjacent perforations lead to the understanding of the facies and processes that controlled the deposition of these channeled turbidite that can be compared to the reservoirs of many oil fields in Brazil. The Almada canyon is a submarine conduct of tectonic origin that was enlarged by the repeated passing of turbidity currents. During the rift phase and the Albian period, compressive events reactivated old N E and N W faults in the basement as trans current fault systems. The continuation of these stresses, from the Cenomanian to the Maastrichtian, developed normal faults that controlled a submarine canyon that connected the continent, where an estuary was formed between the mountains, to the deep marine region of the basin. The canyon has received sediments brought by catastrophic fluvial floods coming from the surrounding mountains, which formed hyperpicnal flows that have evolved as turbidity currents, thus causing erosion of the substrate and carrying a huge volume of sediments to the basin. A part of that load was deposited in the canyon and formed turbidite channels filled by conglomerates, sandstones and shales. These moderately to highly efficient turbidite are intercalated to pro delta pelites and low density turbid plumes deposits, which have mostly been re mobilized as slump and debris flows (chaotic deposits). Pelites were accumulated mainly in the normal fluvial sedimentation phases, when the sandy sediment was retained next to the canyon head and were reworked by the tides on the upper part of the estuary. (author)

  16. Detailed facies analysis of the Upper Cretaceous Tununk Shale Member, Henry Mountains Region, Utah: Implications for mudstone depositional models in epicontinental seas

    Science.gov (United States)

    Li, Zhiyang; Schieber, Juergen

    2018-02-01

    Lower-Middle Turonian strata of the Tununk Shale Member of the greater Mancos Shale were deposited along the western margin of the Cretaceous Western Interior Seaway during the Greenhorn second-order sea level cycle. In order to examine depositional controls on facies development in this mudstone-rich succession, this study delineates temporal and spatial relationships in a process-sedimentologic-based approach. The 3-dimensional expression of mudstone facies associations and their stratal architecture is assessed through a fully integrative physical and biologic characterization as exposed in outcrops in south-central Utah. Sedimentologic characteristics from the millimeter- to kilometer-scale are documented in order to fully address the complex nature of sediment transport mechanisms observed in this shelf muddy environment. The resulting facies model developed from this characterization consists of a stack of four lithofacies packages including: 1) carbonate-bearing, silty and sandy mudstone (CSSM), 2) silt-bearing, calcareous mudstone (SCM), 3) carbonate-bearing, silty mudstone to muddy siltstone (CMS), and 4) non-calcareous, silty and sandy mudstone (SSM). Spatial and temporal variations in lithofacies type and sedimentary facies characteristics indicate that the depositional environments of the Tununk Shale shifted in response to the 2nd-order Greenhorn transgressive-regressive sea-level cycle. During this eustatic event, the Tununk shows a characteristic vertical shift from distal middle shelf to outer shelf (CSSM to SCM facies), then from outer shelf to inner shelf environment (SCM to CMS, and to SSM facies). Shifting depositional environments, as well as changes in dominant paleocurrent direction throughout this succession, indicate multiple source areas and transport mechanisms (i.e. longshore currents, offshore-directed underflows, storm reworking). This study provides a rare documentation of the Greenhorn cycle as exposed across the entire shelf setting

  17. Fluvial to Lacustrine Facies Transitions in Gale Crater, Mars

    Science.gov (United States)

    Sumner, Dawn Y.; Williams, Rebecca M. E.; Schieber, Juergen; Palucis, Marisa C.; Oehler, Dorothy Z.; Mangold, Nicolas; Kah, Linda C.; Gupta, Sanjeev; Grotzinger, John P.; Grant, John A., III; hide

    2015-01-01

    NASA's Curiosity rover has documented predominantly fluvial sedimentary rocks along its path from the landing site to the toe of the Peace Vallis alluvial fan (0.5 km to the east) and then along its 8 km traverse across Aeolis Palus to the base of Aeolis Mons (Mount Sharp). Lacustrine facies have been identified at the toe of the Peace Vallis fan and in the lowermost geological unit exposed on Aeolis Mons. These two depositional systems provide end members for martian fluvial/alluvial-lacustrine facies models. The Peace Vallis system consisted of an 80 square kilometers alluvial fan with decimeter-thick, laterally continuous fluvial sandstones with few sedimentary structures. The thin lacustrine unit associated with the fan is interpreted as deposited in a small lake associated with fan runoff. In contrast, fluvial facies exposed over most of Curiosity's traverse to Aeolis Mons consist of sandstones with common dune-scale cross stratification (including trough cross stratification), interbedded conglomerates, and rare paleochannels. Along the southwest portion of the traverse, sandstone facies include south-dipping meter-scale clinoforms that are interbedded with finer-grained mudstone facies, interpreted as lacustrine. Sedimentary structures in these deposits are consistent with deltaic deposits. Deltaic deposition is also suggested by the scale of fluvial to lacustrine facies transitions, which occur over greater than 100 m laterally and greater than 10 m vertically. The large scale of the transitions and the predicted thickness of lacustrine deposits based on orbital mapping require deposition in a substantial river-lake system over an extended interval of time. Thus, the lowermost, and oldest, sedimentary rocks in Gale Crater suggest the presence of substantial fluvial flow into a long-lived lake. In contrast, the Peace Vallis alluvial fan onlaps these older deposits and overlies a major unconformity. It is one of the youngest deposits in the crater, and

  18. Marine and fluvial facies modelling at petroleum reservoir scale; Modelisation des heterogeneites lithologiques a l'echelle du reservoir petrolier en milieu marin et fluviatile

    Energy Technology Data Exchange (ETDEWEB)

    Leflon, B.

    2005-10-15

    When modelling a petroleum reservoir, well data are very useful to model properties at a sub-seismic scale. Petrophysical properties like porosity or permeability are linked to the rock-type. Two methods based on well data have been developed to model facies. The first one is used to model marine carbonates deposits. The geometry of sedimentary layers is modelled through a special parameterization of the reservoir similar to Wheeler space. The time parameter is defined along the well paths thanks to correlations. The layer thickness is then extrapolated between wells. A given relationship between facies and bathymetry of sedimentation makes it possible to compute bathymetry along the well paths. Bathymetry is then extrapolated from wells and a reference map using the concept of accommodation. The model created this way is stratigraphically consistent. Facies simulation can then be constrained by the computed bathymetry. The second method describes a novel approach to fluvial reservoirs modelling. The core of the method lies in the association of a fairway with the channels to be simulated. Fairways are positioned so that all data are taken in account; they can be stochastic if unknown or explicitly entered if identified on seismic data. A potential field is defined within the fairway. Specifying a transfer function to map this potential field to thickness results in generating a channel inside the fairway. A residual component is stochastically simulated and added to the potential field creating realistic channel geometries. Conditioning to well data is obtained by applying the inverse transfer function at the data location to derive thickness values that will constrain the simulation of residuals. (author)

  19. Traces in the dark: sedimentary processes and facies gradients in the upper shale member of the Upper Devonian-Lower Mississippian Bakken Formation, Williston Basin, North Dakota, U.S.A.

    Science.gov (United States)

    Egenhoff, Sven O.; Fishman, Neil S.

    2013-01-01

    currents, were active across all facies belts. Suspended sediment settling from near the ocean surface, however, most likely played a role in the deposition of some of the mudstones, and was probably responsible for deposition of the radiolarites. The distribution pattern of high-TOC sediments in proximal and lower-TOC deposits in some distal facies is interpreted as a function of higher accumulation rates during radiolarian depositional events leading to a decrease in suspension-derived organic carbon in radiolarite laminae. The presence of burrows in all FAs and nearly all facies in the upper Bakken shale member indicates that dysoxic conditions prevailed during its deposition. This study shows that in intracratonic high-TOC mudstone successions such as the upper Bakken shale member bed-load processes most likely dominated sedimentation, and conditions promoted a thriving infaunal benthic community. As such, deposition of the upper Bakken shale member through dynamic processes in an overall dysoxic environment represents an alternative to conventional anoxic depositional models for world-class source rocks.

  20. Lithofacies paleogeography and sedimentary model of Sinian Dengying Fm in the Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Jingao Zhou

    2017-05-01

    Full Text Available For predicting the distribution of favorable reservoir facies belts of the super-large ancient Anyue carbonate gas field in the Sichuan Basin, through an analysis of structure and lithofacies paleogeography, the lithofacies paleogeography and sedimentary model of the Sinian Dengying Fm was reconstructed based on the field outcrop, drilling and seismic data. As a result, achievements are made in four aspects. First, the basin and its periphery resided in an extensional tectonic setting in the Sinian. Intense extension led to the formation of the Deyang–Anyue intra-platform rift. The Sichuan Basin was divided into the palaeo-geographic pattern of “two uplifts and four sags”. The “two uplifts” evolved into the platform, and the “four sags” evolved into the slope-basin environment. Second, in the depositional stage of the Deng 2 Member, some favorable reservoir belts developed, such as bioherm-shoal at the continental margin, bioherm-shoal at the rift margin, and bioherm-shoal in the platform. The bioherm-shoal at rift margin developed along both sides of the Deyang–Anyue rift, in a U-shape, with a width of about 5–40 km and a length of about 500 km. It connected with the platform margin belt at the continental margin to the west in the Shifang area, and to the north near Guangyuan area. Third, in the depositional stage of the Deng 4 Member, when the lithofacies paleogeographic features in the Deng 2 Member remained, the platform margin belt at the rift margin evolved into two parts in the east and the west as a result of the continuous southward extensional faulting of the Deyang–Anyue rift until it finally crossed the basin from north to south. The eastern platform margin belt was located in the Guangyuan–Yanting–Anyue–Luzhou area, showing NS distribution with a length of about 450 km and a width of about 4–50 km. The western platform margin belt mainly developed in the Dujiangyan

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

    International Nuclear Information System (INIS)

    Faeh, D.; Panza, G.F.

    1994-03-01

    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

  2. Fine-Grained Turbidites: Facies, Attributes and Process Implications

    Science.gov (United States)

    Stow, Dorrik; Omoniyi, Bayonle

    2016-04-01

    Within turbidite systems, fine-grained sediments are still the poor relation and sport several contrasting facies models linked to process of deposition. These are volumetrically the dominant facies in deepwater and, from a resource perspective, they form important marginal and tight reservoirs, and have great potential for unconventional shale gas, source rocks and seals. They are also significant hosts of metals and rare earth elements. Based on a large number of studies of modern, ancient and subsurface systems, including 1000s of metres of section logging, we define the principal genetic elements of fine-grained deepwater facies, present a new synthesis of facies models and their sedimentary attributes. The principal architectural elements include: non-channelised slope-aprons, channel-fill, channel levee and overbank, turbidite lobes, mass-transport deposits, contourite drifts, basin sheets and drapes. These comprise a variable intercalation of fine-grained facies - thin-bedded and very thin-bedded turbidites, contourites, hemipelagites and pelagites - and associated coarse-grained facies. Characteristic attributes used to discriminate between these different elements are: facies and facies associations; sand-shale ratio, sand and shale geometry and dimensions, sand connectivity; sediment texture and small-scale sedimentary structures; sediment fabric and microfabric; and small-scale vertical sequences of bed thickness. To some extent, we can relate facies and attribute characteristics to different depositional environments. We identify four distinct facies models: (a) silt-laminated mud turbidites, (b) siliciclastic mud turbidites, (c) carbonate mud turbidites, (d) disorganized silty-mud turbidites, and (e) hemiturbidites. Within the grainsize-velocity matrix turbidite plot, these all fall within the region of mean size < 0.063mm, maximum grainsize (one percentile) <0.2mm, and depositional velocity 0.1-0.5 m/s. Silt-laminated turbidites and many mud

  3. Inverse modeling of geochemical and mechanical compaction in sedimentary basins

    Science.gov (United States)

    Colombo, Ivo; Porta, Giovanni Michele; Guadagnini, Alberto

    2015-04-01

    We study key phenomena driving the feedback between sediment compaction processes and fluid flow in stratified sedimentary basins formed through lithification of sand and clay sediments after deposition. Processes we consider are mechanic compaction of the host rock and the geochemical compaction due to quartz cementation in sandstones. Key objectives of our study include (i) the quantification of the influence of the uncertainty of the model input parameters on the model output and (ii) the application of an inverse modeling technique to field scale data. Proper accounting of the feedback between sediment compaction processes and fluid flow in the subsurface is key to quantify a wide set of environmentally and industrially relevant phenomena. These include, e.g., compaction-driven brine and/or saltwater flow at deep locations and its influence on (a) tracer concentrations observed in shallow sediments, (b) build up of fluid overpressure, (c) hydrocarbon generation and migration, (d) subsidence due to groundwater and/or hydrocarbons withdrawal, and (e) formation of ore deposits. Main processes driving the diagenesis of sediments after deposition are mechanical compaction due to overburden and precipitation/dissolution associated with reactive transport. The natural evolution of sedimentary basins is characterized by geological time scales, thus preventing direct and exhaustive measurement of the system dynamical changes. The outputs of compaction models are plagued by uncertainty because of the incomplete knowledge of the models and parameters governing diagenesis. Development of robust methodologies for inverse modeling and parameter estimation under uncertainty is therefore crucial to the quantification of natural compaction phenomena. We employ a numerical methodology based on three building blocks: (i) space-time discretization of the compaction process; (ii) representation of target output variables through a Polynomial Chaos Expansion (PCE); and (iii) model

  4. Modeling Oligo-Miocence channel sands (Dezful Embayment, SW Iran): an integrated facies classification workflow

    International Nuclear Information System (INIS)

    Heydari, Mostafa; Maddahi, Iradj; Moradpour, Mehran; Esmaeilpour, Sajjad

    2014-01-01

    This study has been conducted on Mansuri onshore oilfield located in Dezful Embayment, south-west Iran. One of the hydrocarbon-bearing formations is a Oligo-Miocene Asmari formation—the most prolific Iranian reservoir rock. Like many other oilfields in the area, the trap in this field is deemed structural (anticline), formed during the collision of the Arabian plate with the Iranian plate and the folding of Neotethys deposits with a NW–SE trend. This study integrates three different quantitative studies from geology, geophysics and petrophysics disciplines to quantitate ‘the qualitative study of seismic facies analysis based on trace shapes and 3D multi-attribute clustering’. First, stratigraphic sequences and seismic detectable facies were derived at one well location using the available high resolution core facies analysis and depositional environment assessment reports. Paleo and petrophysical logs from other wells were subsequently used for the extrapolation of stratigraphic sequences interpreted at the first well. Utilizing lithology discrimination obtained by wire-line log interpretation, facies were extrapolated to all wells in the area. Seismic 3D attribute analysis and seismic facies classification established a 3D facies volume accordingly, which was finally calibrated to geological facies at well locations. The ultimate extracted facies-guided geobody shows that good reservoir-quality channel sands have accumulated with NW/SE elongation at the ridge of the structure. As a result, this type of geometry has created a stratigraphic/structural hydrocarbon trap in this oilfield. Moreover, seismic facies analysis shows that buried channels do not parallel the predominant Arabian plate-originated channels (with SW–NE trends) in SW Zagros and are locally swerved in this area. (paper)

  5. Neural net generated seismic facies map and attribute facies map

    International Nuclear Information System (INIS)

    Addy, S.K.; Neri, P.

    1998-01-01

    The usefulness of 'seismic facies maps' in the analysis of an Upper Wilcox channel system in a 3-D survey shot by CGG in 1995 in Lavaca county in south Texas was discussed. A neural net-generated seismic facies map is a quick hydrocarbon exploration tool that can be applied regionally as well as on a prospect scale. The new technology is used to classify a constant interval parallel to a horizon in a 3-D seismic volume based on the shape of the wiggle traces using a neural network technology. The tool makes it possible to interpret sedimentary features of a petroleum deposit. The same technology can be used in regional mapping by making 'attribute facies maps' in which various forms of amplitude attributes, phase attributes or frequency attributes can be used

  6. Tectonic controls on preservation of Middle Triassic Halfway reservoir facies, Peejay Field, northeastern British Columbia: a new hydrocarbon exploration model

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. L. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Geological Sciences; Moslow, T. F. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    1997-12-01

    The Peejay Field in northeastern British Columbia was chosen as the site of a detailed study to establish the paleogeography, geological history and genesis of reservoir facies of Middle Triassic strata. A total of 132 cores and well logs from 345 wells were examined to establish the depositional model, to identify the origin of all reservoir facies and to construct an exploration model to improve the prediction of reservoir facies. Results show that the Middle Triassic Halfway Formation of northeastern British Columbia is comprised of at least four west-southwest prograding paleoshorelines. The Lithofacies Succession One quartz-arenites paleoshore faces have less porosity and permeability and are laterally discontinuous. For these reasons shoreface facies have minimal reservoir quality. The tidal inlet fill successions were found to have the greatest observed porosity, permeability and lateral continuity in the Peejay Field. The geometry and orientation of these tidal inlet fill deposits are controlled by tectonic processes. It was suggested that the success of hydrocarbon exploration in this structurally complex area of northeastern British Columbia and west-central Alberta depends on further stratigraphic and sedimentological examination of Middle Triassic strata on a regional scale to obtain a complete understanding of the geological history of the area. 39 refs., 13 refs.

  7. A new ‘superassemblage’ model explaining proximal-to-distal and lateral facies changes in fluvial environments, based on the Proterozoic Sanjauli Formation (Lesser Himalaya, India

    Directory of Open Access Journals (Sweden)

    Ananya Mukhopadhyay

    2016-09-01

    Full Text Available Facies analysis of fluvial deposits of the Proterozoic Sanjauli Formation in the Lesser Himalaya was combined with an architectural analysis. On this basis, a model was developed that may be applied to other fluvial systems as well, whether old or recent. The new model, which might be considered as an assemblage of previous models, explains lateral variations in architecture and facies but is not in all respects consistent with the standard fluvial models. The Sanjauli fluvial model is unique in that it deals with lateral facies variations due to shifts of the base-level along with fluctuations in accommodation space owing to changes in palaeoclimate.

  8. Inverse geothermal modelling applied to Danish sedimentary basins

    Science.gov (United States)

    Poulsen, Søren E.; Balling, Niels; Bording, Thue S.; Mathiesen, Anders; Nielsen, Søren B.

    2017-10-01

    This paper presents a numerical procedure for predicting subsurface temperatures and heat-flow distribution in 3-D using inverse calibration methodology. The procedure is based on a modified version of the groundwater code MODFLOW by taking advantage of the mathematical similarity between confined groundwater flow (Darcy's law) and heat conduction (Fourier's law). Thermal conductivity, heat production and exponential porosity-depth relations are specified separately for the individual geological units of the model domain. The steady-state temperature model includes a model-based transient correction for the long-term palaeoclimatic thermal disturbance of the subsurface temperature regime. Variable model parameters are estimated by inversion of measured borehole temperatures with uncertainties reflecting their quality. The procedure facilitates uncertainty estimation for temperature predictions. The modelling procedure is applied to Danish onshore areas containing deep sedimentary basins. A 3-D voxel-based model, with 14 lithological units from surface to 5000 m depth, was built from digital geological maps derived from combined analyses of reflection seismic lines and borehole information. Matrix thermal conductivity of model lithologies was estimated by inversion of all available deep borehole temperature data and applied together with prescribed background heat flow to derive the 3-D subsurface temperature distribution. Modelled temperatures are found to agree very well with observations. The numerical model was utilized for predicting and contouring temperatures at 2000 and 3000 m depths and for two main geothermal reservoir units, the Gassum (Lower Jurassic-Upper Triassic) and Bunter/Skagerrak (Triassic) reservoirs, both currently utilized for geothermal energy production. Temperature gradients to depths of 2000-3000 m are generally around 25-30 °C km-1, locally up to about 35 °C km-1. Large regions have geothermal reservoirs with characteristic temperatures

  9. 3D modeling of stratigraphic units and simulation of seismic facies in the Lion gulf margin; Modelisation 3D des unites stratigraphiques et simulation des facies sismiques dans la marge du golfe du Lion

    Energy Technology Data Exchange (ETDEWEB)

    Chihi, H.

    1997-05-12

    This work aims at providing a contribution to the studies carried out on reservoir characterization by use of seismic data. The study mainly consisted in the use of geostatistical methods in order to model the geometry of stratigraphic units of the Golfe du Lion margin and to simulate the seismic facies from high resolution seismic data. We propose, for the geometric modelling, a methodology based on the estimation of the surfaces and calculation afterwards of the thicknesses, if the modelling of the depth is possible. On the other hand the method consists in estimating the thickness variable directly and in deducing the boundary surfaces afterwards. In order to simulate the distribution of seismic facies within the units of the western domain, we used the truncated Gaussian method. The used approach gave a satisfactory results, when the seismic facies present slightly dipping reflectors with respect to the reference level. Otherwise the method reaches its limits because of the problems of definition of a reference level which allows to follow the clino-forms. In spite of these difficulties, this simulation allows us to estimate the distribution of seismic facies within the units and then to deduce their probable extension. (author) 150 refs.

  10. Modeling the Sedimentary Infill of Lakes in the East African Rift: A Case Study of Multiple versus Single Rift Basin Segments

    Science.gov (United States)

    Zhang, C.; Scholz, C. A.

    2016-12-01

    The sedimentary basins in the East African Rift are considered excellent modern examples for investigating sedimentary infilling and evolution of extensional systems. Some lakes in the western branch of the rift have formed within single-segment systems, and include Lake Albert and Lake Edward. The largest and oldest lakes developed within multi-segment systems, and these include Lake Tanganyika and Lake Malawi. This research aims to explore processes of erosion and sedimentary infilling of the catchment area in single-segment rift (SSR) and multi-segment rift (MSR) systems. We consider different conditions of regional precipitation and evaporation, and assess the resulting facies architecture through forward modeling, using state-of-the-art commercial basin modeling software. Dionisos is a three-dimensional numerical stratigraphic forward modeling software program, which simulates basin-scale sediment transport based on empirical water- and gravity-driven diffusion equations. It was classically used to quantify the sedimentary architecture and basin infilling of both marine siliciclastic and carbonate environments. However, we apply this approach to continental rift basin environments. In this research, two scenarios are developed, one for a MSR and the other for a SSR. The modeled systems simulate the ratio of drainage area and lake surface area observed in modern Lake Tanganyika and Lake Albert, which are examples of MSRs and SSRs, respectively. The main parameters, such as maximum subsidence rate, water- and gravity-driven diffusion coefficients, rainfall, and evaporation, are approximated using these real-world examples. The results of 5 million year model runs with 50,000 year time steps show that MSRs are characterized by a deep water lake with relatively modest sediment accumulation, while the SSRs are characterized by a nearly overfilled lake with shallow water depths and thick sediment accumulation. The preliminary modeling results conform to the features

  11. Gravimetric survey and modeling of the basement morphology in the sedimentary thickness characterization, NE portion of Paraná Sedimentary Basin - Brazil

    Directory of Open Access Journals (Sweden)

    Maximilian Fries

    2017-05-01

    Full Text Available ABSTRACT: The northeast portion of the Paraná Sedimentary Basin is distinguished by structural highs as the known Pitanga Dome, an uplifted structure identified in the last century. It represents a geological and evolutionary evidence of the Paraná Sedimentary Basin and has undergone inspired studies and intense exploration surveys. This study consists of a gravimetric survey in the Pitanga Dome area, State of São Paulo, Brazil. The Bouguer gravity anomalies have been identified and related to the structural high, sedimentary thickness, and the basement morphology. Processing and enhancement techniques were used for forward modeling based on previous studies. The three models from profiles sectioning the dome have a sedimentary thickness varying from 200 to 1.250 meters. The adopted methodology has provided important results determining that the Pitanga Dome can be understood through rational 3D visualization. The area can be interpreted as an undulating basement with thinning of sedimentary rocks related to deep features (structures in the crust/mantle limit (Moho uplift. This characteristic is confirmed by the sedimentary layer thickening present throughout the surrounding area. The results also offer important insights and support for further studies concerning the genesis and evolution of this and other uplifted structures of the Paraná Sedimentary Basin.

  12. Genesis and sedimentary record of blind channel and islands of the anabranching river: An evolution model

    Science.gov (United States)

    Leli, Isabel T.; Stevaux, José C.; Assine, Mário L.

    2018-02-01

    Blind channel (BC) is a fluvial feature formed by attachment of a lateral sand bar to an island or riverbank. It consists of a 10- to 20-m wide and hundreds to thousands meters long channel, parallel to the island or bank, closed at its upstream end by accretion to the island. It is an important feature in anabranching rivers that plays an important role in both the island formation and river ecology. This paper discusses the formation processes, functioning, evolution, and the sedimentary record of a blind channel, related landforms, and its context on island development in the Upper Paraná River. The evolution of this morphologic feature involves (1) formation of a lateral or attachment bar beside an island with the development of a channel in between; (2) vertical accretion of mud deposits during the flood and vegetal development on the bar; (3) the upstream channel closure that generates the blind channel; and (4) annexation of the blind channel to the island. A blind channel is semilotic to lentic, that is not totally integrated to the dynamics of the main active channel and that acts as a nursery for fingerlings and macrophytes. The sedimentary facies succession of BCs are relatively simple and characterized by cross-stratified sand covered by organic muddy sediments. Based on facies analysis of 12 cores, we identified a succession of environments that contribute to the formation of islands: channel bar, blind channel, pond, and swamp. Blind channel formation and its related bar-island attachment are relevant processes associated with the growing of large island evolution in some anabranching rivers.

  13. Implementation of the Iterative Proportion Fitting Algorithm for Geostatistical Facies Modeling

    International Nuclear Information System (INIS)

    Li Yupeng; Deutsch, Clayton V.

    2012-01-01

    In geostatistics, most stochastic algorithm for simulation of categorical variables such as facies or rock types require a conditional probability distribution. The multivariate probability distribution of all the grouped locations including the unsampled location permits calculation of the conditional probability directly based on its definition. In this article, the iterative proportion fitting (IPF) algorithm is implemented to infer this multivariate probability. Using the IPF algorithm, the multivariate probability is obtained by iterative modification to an initial estimated multivariate probability using lower order bivariate probabilities as constraints. The imposed bivariate marginal probabilities are inferred from profiles along drill holes or wells. In the IPF process, a sparse matrix is used to calculate the marginal probabilities from the multivariate probability, which makes the iterative fitting more tractable and practical. This algorithm can be extended to higher order marginal probability constraints as used in multiple point statistics. The theoretical framework is developed and illustrated with estimation and simulation example.

  14. Estuarine Facies Model Revisited: Conceptual Model of Estuarine Sediment Dynamics During Non-Equilibrium Conditions

    Science.gov (United States)

    Elliott, E. A.; Rodriguez, A. B.; McKee, B. A.

    2017-12-01

    Traditional models of estuarine systems show deposition occurs primarily within the central basin. There, accommodation space is high within the deep central valley, which is below regional wave base and where current energy is presumed to reach a relative minimum, promoting direct deposition of cohesive sediment and minimizing erosion. However, these models often reflect long-term (decadal-millennial) timescales, where accumulation rates are in relative equilibrium with the rate of relative sea-level rise, and lack the resolution to capture shorter term changes in sediment deposition and erosion within the central estuary. This work presents a conceptual model for estuarine sedimentation during non-equilibrium conditions, where high-energy inputs to the system reach a relative maximum in the central basin, resulting in temporary deposition and/or remobilization over sub-annual to annual timescales. As an example, we present a case study of Core Sound, NC, a lagoonal estuarine system where the regional base-level has been reached, and sediment deposition, resuspension and bypassing is largely a result of non-equilibrium, high-energy events. Utilizing a 465 cm-long sediment core from a mini-basin located between Core Sound and the continental shelf, a 40-year sub-annual chronology was developed for the system, with sediment accumulation rates (SAR) interpolated to a monthly basis over the 40-year record. This study links erosional processes in the estuary directly with sediment flux to the continental shelf, taking advantage of the highly efficient sediment trapping capability of the mini-basin. The SAR record indicates high variation in the estuarine sediment supply, with peaks in the SAR record at a recurrence interval of 1 year (+/- 0.25). This record has been compared to historical storm influence for the area. Through this multi-decadal record, sediment flushing events occur at a much more frequent interval than previously thought (i.e. annual rather than

  15. Sedimentary facies analysis of a high-frequency, small-scale, peritidal carbonate sequence in the Lower Jurassic of the Tripolis carbonate unit (central western Crete, Greece: Long-lasting emergence and fossil laminar dolocretes horizons

    Directory of Open Access Journals (Sweden)

    Fotini A. Pomoni

    2016-07-01

    Full Text Available The study examines a Lower Jurassic (late Liassic cyclic lagoonal–peritidal stratigraphic unit outcropping in central western Crete (Tripolis unit, which corresponds to the eastern (internal part of the mainland Gavrovo-Tripolis platform, the most significant external platform of the Hellenides. The studied Tripolis carbonate sequence consists of meter-scale, shallowing-upward successions of restricted inner-carbonate platform facies, including cyclically repeated subtidal, intertidal and supratidal facies, that are separated by erosion surfaces (elementary cycles. Each cycle starts with relatively open-marine facies, which are overlain by shallower, more restricted facies (tidal flat progradation. The lithofacies association includes dolomitic intraclastic–peloidal–bioclastic wackestones–packstones/floatstones and grainstones/rudstones dominated by a restricted shallow-marine fauna (bivalves, gastropods, ostracods and seldom benthic foraminifers, representing a shallow subtidal to intertidal, moderately high-energy environment within an inner-platform setting (peritidal environment to restricted lagoon. This lithofacies association has been intermittently subaerially exposed and has undergone diagenetic processes in an inter- or supratidal environment, exhibiting features of vadose diagenesis and pedogenesis due to long-lasting exposure along certain horizons. The peritidal facies are capped by dolocretes controlled by root-activities (laminar dolocretes, peloidal–pisoid dolocretes and massive dolocretes, marking the end of each depositional cycle, and, thus, distinguishing the successive episodes of a prolonged subaerial exposure period and birth of paleosol horizons. Dolocretes consist a diagenetic facies, characterized by several vadose and pedogenic fabrics, including fenestral cavities with geopetal structures, “flower spar” to blocky sparry cement in primary pores, micritic coatings, crudely pelleted walls, alveolar

  16. Modeling of a sedimentary rock alternative for the siting of the radioactive waste disposal system

    International Nuclear Information System (INIS)

    Fuentes, Nestor O.

    2007-01-01

    Here are described the main concepts, the approximations, and all those simulation aspects that characterize the modeling performed using the unsaturated saturated approach for porous media. The objective of this work is to obtain a generic description of a sedimentary rock soil as an alternative site for the low and intermediate level radioactive waste disposal system. (author) [es

  17. Inverse geothermal modelling applied to Danish sedimentary basins

    DEFF Research Database (Denmark)

    Poulsen, Soren E.; Balling, Niels; Bording, Thue S.

    2017-01-01

    . The numerical model was utilized for predicting and contouring temperatures at 2000 and 3000 m depths and for two main geothermal reservoir units, the Gassum (Lower Jurassic-Upper Triassic) and Bunter/Skagerrak (Triassic) reservoirs, both currently utilized for geothermal energy production. Temperature...... gradients to depths of 2000-3000 m are generally around 25-30. degrees C km(-1), locally up to about 35. degrees C km(-1). Large regions have geothermal reservoirs with characteristic temperatures ranging from ca. 40-50. degrees C, at 1000-1500 m depth, to ca. 80-110. degrees C, at 2500-3500 m, however...

  18. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology; La Petrologia Sedimentaria: desde Sorby a la globalizacion de la Geologia Sedimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Zarza, A M

    2013-02-01

    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.

  19. Sedimentary Petrology: from Sorby to the globalization of Sedimentary Geology; La Petrologia Sedimentaria: desde Sorby a la globalizacion de la Geologia Sedimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Zarza, A. M.

    2013-02-01

    We describe here the most important milestones and contributions to Sedimentary Petrology compared to other geological disciplines. We define the main aim of our study and the scientific and economic interests involved in Sedimentary Petrology. The body of the paper focuses upon the historical development of this discipline from Henry Sorby's initial work until the present day. The major milestones in its history include: 1) initial descriptive works; 2) experimental studies; 3) the establishment of the different classifications of sedimentary rocks; 4) studies into facies and sedimentary environments; 5) advances in the study of diagenetic processes and their role in hydrocarbon prospection; and 6) the development of Sedimentary Geochemistry. Relationships and coincidences with Sedimentology are discussed. We go on to look at the advances that have taken place over the last 30 years, in which the study of sedimentary rocks is necessarily included in the wider field of Sedimentary Geology as a logical result of the proposal of global models of a changing Earth in which Sedimentary Geology plays a significant part. Finally we mention the notable contributions of Spanish sedimentary petrologists to this whole field of science. (Author) 120 refs.

  20. PROBLEMS AND METHODOLOGY OF THE PETROLOGIC ANALYSIS OF COAL FACIES.

    Science.gov (United States)

    Chao, Edward C.T.

    1983-01-01

    This condensed synthesis gives a broad outline of the methodology of coal facies analysis, procedures for constructing sedimentation and geochemical formation curves, and micro- and macrostratigraphic analysis. The hypothetical coal bed profile has a 3-fold cycle of material characteristics. Based on studies of other similar profiles of the same coal bed, and on field studies of the sedimentary rock types and their facies interpretation, one can assume that the 3-fold subdivision is of regional significance.

  1. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2006-04-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  2. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2007-08-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  3. Eclogite facies rocks

    National Research Council Canada - National Science Library

    Carswell, D. A

    1990-01-01

    .... This is the first volume to provide a coherent and comprehensive review of the conditions necessary for the formation of eclogites and eclogite facies rocks and assemblages, and a detailed account...

  4. Facies and facies architecture and depositional environments of the ...

    African Journals Online (AJOL)

    Facies and facies architecture and depositional environments of the ... PROMOTING ACCESS TO AFRICAN RESEARCH ... Depositional environments of the Yolde Formation were studied based on the analysis of facies and facies architecture. ... Senegal (6); Sierra Leone (1); South Africa (96); South Sudan (1); Sudan (3) ...

  5. 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.

  6. Reactive Transport Modeling Investigation of High Dissolved Sulfide Concentrations in Sedimentary Basin Rocks

    Science.gov (United States)

    Xie, M.; Mayer, U. K.; MacQuarrie, K. T. B.

    2017-12-01

    Water with total dissolved sulfide in excess of 1 mmol L-1is widely found in groundwater at intermediate depths in sedimentary basins, including regions of the Michigan basin in southeastern Ontario, Canada. Conversely, at deeper and shallower depths, relatively low total dissolved sulfide concentrations have been reported. The mechanisms responsible for the occurrence of these brackish sulfide-containing waters are not fully understood. Anaerobic microbial sulfate reduction is a common process resulting in the formation of high sulfide concentrations. Sulfate reduction rates depend on many factors including the concentration of sulfate, the abundance of organic substances, redox conditions, temperature, salinity and the species of sulfate reducing bacteria (SRB). A sedimentary basin-specific conceptual model considering the effect of salinity on the rate of sulfate reduction was developed and implemented in the reactive transport model MIN3P-THCm. Generic 2D basin-scale simulations were undertaken to provide a potential explanation for the dissolved sulfide distribution observed in the Michigan basin. The model is 440 km in the horizontal dimension and 4 km in depth, and contains fourteen sedimentary rock units including shales, sandstones, limestones, dolostone and evaporites. The main processes considered are non-isothermal density dependent flow, kinetically-controlled mineral dissolution/precipitation and its feedback on hydraulic properties, cation exchange, redox reactions, biogenic sulfate reduction, and hydromechanical coupling due to glaciation-deglaciation events. Two scenarios were investigated focusing on conditions during an interglacial period and the transient evolution during a glaciation-deglaciation cycle. Inter-glaciation simulations illustrate that the presence of high salinity brines strongly suppress biogenic sulfate reduction. The transient simulations show that glaciation-deglaciation cycles can have an impact on the maximum depth of

  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. Facies Constrained Elastic Full Waveform Inversion

    KAUST Repository

    Zhang, Z.

    2017-05-26

    Current efforts to utilize full waveform inversion (FWI) as a tool beyond acoustic imaging applications, for example for reservoir analysis, face inherent limitations on resolution and also on the potential trade-off between elastic model parameters. Adding rock physics constraints does help to mitigate these issues. However, current approaches to add such constraints are based on averaged type rock physics regularization terms. Since the true earth model consists of different facies, averaging over those facies naturally leads to smoothed models. To overcome this, we propose a novel way to utilize facies based constraints in elastic FWI. A so-called confidence map is calculated and updated at each iteration of the inversion using both the inverted models and the prior information. The numerical example shows that the proposed method can reduce the cross-talks and also can improve the resolution of inverted elastic properties.

  9. Facies Constrained Elastic Full Waveform Inversion

    KAUST Repository

    Zhang, Z.; Zabihi Naeini, E.; Alkhalifah, Tariq Ali

    2017-01-01

    Current efforts to utilize full waveform inversion (FWI) as a tool beyond acoustic imaging applications, for example for reservoir analysis, face inherent limitations on resolution and also on the potential trade-off between elastic model parameters. Adding rock physics constraints does help to mitigate these issues. However, current approaches to add such constraints are based on averaged type rock physics regularization terms. Since the true earth model consists of different facies, averaging over those facies naturally leads to smoothed models. To overcome this, we propose a novel way to utilize facies based constraints in elastic FWI. A so-called confidence map is calculated and updated at each iteration of the inversion using both the inverted models and the prior information. The numerical example shows that the proposed method can reduce the cross-talks and also can improve the resolution of inverted elastic properties.

  10. Mutual Dependence Between Sedimentary Organic Carbon and Infaunal Macrobenthos Resolved by Mechanistic Modeling

    Science.gov (United States)

    Zhang, Wenyan; Wirtz, Kai

    2017-10-01

    The mutual dependence between sedimentary total organic carbon (TOC) and infaunal macrobenthos is here quantified by a mechanistic model. The model describes (i) the vertical distribution of infaunal macrobenthic biomass resulting from a trade-off between nutritional benefit (quantity and quality of TOC) and the costs of burial (respiration) and mortality, and (ii) the variable vertical distribution of TOC being in turn shaped by bioturbation of local macrobenthos. In contrast to conventional approaches, our model emphasizes variations of bioturbation both spatially and temporally depending on local food resources and macrobenthic biomass. Our implementation of the dynamic interaction between TOC and infaunal macrobenthos is able to capture a temporal benthic response to both depositional and erosional environments and provides improved estimates of the material exchange flux at the sediment-water interface. Applications to literature data for the North Sea demonstrate the robustness and accuracy of the model and its potential as an analysis tool for the status of TOC and macrobenthos in marine sediments. Results indicate that the vertical distribution of infaunal biomass is shaped by both the quantity and the quality of OC, while the community structure is determined only by the quality of OC. Bioturbation intensity may differ by 1 order of magnitude over different seasons owing to variations in the OC input, resulting in a significant modulation on the distribution of OC. Our relatively simple implementation may further improve models of early diagenesis and marine food web dynamics by mechanistically connecting the vertical distribution of both TOC and macrobenthic biomass.

  11. A geostatistical model of facies-architecture and internal heterogeneity of Rotliegend-reservoirs developed from outcrop-analogues. Outcrop-analogue study Cutler Group (Utah/USA)

    Energy Technology Data Exchange (ETDEWEB)

    Irmen, A.

    2001-10-01

    The aim of this DGMK study was the collection of data that document the distribution of facies units within mixed fluvial/aeolian deposits. The Cutler Group of southeastern Utah was chosen as an outcrop analog since it contains all major lithofacies common within such deposits (aeolian dunes and interdunes, fluvial channel-films as well as lacustrine and Sabkha deposits). Because of the outstanding outcrop quality in this region, numerous detailed datasets could be collected, which allowed the visualization of size, distribution, and sedimentological inventory of the different facies in various ''paleogeographical'' maps and diagrams. A genetic model, which explains the presence of correlative horizons and cyclic patterns of deposition, could be developed. (orig.) [German] Zielsetzung dieses DGMK-Forschungsvorhabens war es, quantitative Daten zur Verteilung fazieller Einheiten innerhalb eines gemischt fluviatil/aeolischen Ablagerungsraums zu gewinnen. Die Cutler Group im Suedosten des amerikanischen Bundesstaates Utah wurde als Aufschlussanalog gewaehlt, in welchem die typischen Ablagerungen eines solchen Deposystems vorhanden sind (aeolische Duenen und -Interduenen, fluviatile Rinnenfuellungen, sowie lakustrine und Sabkha-Ablagerungen). Aufgrund der hervorragenden Aufschlusssituation konnten detaillierte Datensaetze gewonnen werden, welche die Darstellung von Groesse, bevorzugter Ausrichtung und Sedimentologie potentieller Heterogenitaetselemente entweder direkt als ''paleogeographische'' Karten, oder in statistischer Form ermoeglichten. Ein genetisches Modell erklaert die Zyklizitaet der Ablagerungen und die Anwesenheit von weitraeumig korrelierbaren Horizonten. (orig.)

  12. Uranium distribution in relation to sedimentary facies, Kern Lake, California

    International Nuclear Information System (INIS)

    Merifield, P.M.; Carlisle, D.; Idiz, E.; Anderhalt, R.; Reed, W.E.; Lamar, D.L.

    1980-04-01

    Kern Lake has served as a sink for drainage from the southern Sierra Nevada and, in lesser amounts, from the southern Temblor Range. Both areas contain significant uranium source rocks. The uranium content in Holocene Kern Lake sediments correlates best with the mud (silt and clay) fraction. It correlates less well with organic carbon. Biotite grains could account for much of the uranium in the sand fraction, and perhaps the silt fraction as well. The data suggest that fixation of uranium by adsorption on mineral grains is a dominant process in this lake system. Further work is required to determine the importance of cation-exchange of uranium on clays and micas and of organically complexed uranium adsorbed to mineral surfaces. These findings also raise the question of whether uranium transport down the Kern River occurs largely as uranium adsorbed to mineral surfaces

  13. Sedimentary facies control on mechanical and fracture stratigraphy in turbidites

    NARCIS (Netherlands)

    Ogata, Kei; Storti, Fabrizio; Balsamo, Fabrizio; Tinterri, Roberto; Bedogni, Enrico; Fetter, Marcos; Gomes, Leonardo; Hatushika, Raphael

    2017-01-01

    Natural fracture networks exert a first-order control on the exploitation of resources such as aquifers, hydrocarbons, and geothermal reservoirs, and on environmental issues like underground gas storage and waste disposal. Fractures and the mechanical stratigraphy of layered sequences have been

  14. Measurement of unsaturated hydraulic properties and evaluation of property-transfer models for deep sedimentary interbeds, Idaho National Laboratory, Idaho

    Science.gov (United States)

    Perkins, Kimberlie; Johnson, Brittany D.; Mirus, Benjamin B.

    2014-01-01

    Operations at the Idaho National Laboratory (INL) have the potential to contaminate the underlying Eastern Snake River Plain (ESRP) aquifer. Methods to quantitatively characterize unsaturated flow and recharge to the ESRP aquifer are needed to inform water-resources management decisions at INL. In particular, hydraulic properties are needed to parameterize distributed hydrologic models of unsaturated flow and transport at INL, but these properties are often difficult and costly to obtain for large areas. The unsaturated zone overlying the ESRP aquifer consists of alternating sequences of thick fractured volcanic rocks that can rapidly transmit water flow and thinner sedimentary interbeds that transmit water much more slowly. Consequently, the sedimentary interbeds are of considerable interest because they primarily restrict the vertical movement of water through the unsaturated zone. Previous efforts by the U.S. Geological Survey (USGS) have included extensive laboratory characterization of the sedimentary interbeds and regression analyses to develop property-transfer models, which relate readily available physical properties of the sedimentary interbeds (bulk density, median particle diameter, and uniformity coefficient) to water retention and unsaturated hydraulic conductivity curves.

  15. A two-dimensional model of the passive coastal margin deep sedimentary carbon and methane cycles

    Directory of Open Access Journals (Sweden)

    D. E. Archer

    2012-08-01

    Full Text Available We present a new geologic-time and basin-spatial scale model of the continental margin methane cycle. The model, SpongeBOB, is used to simulate evolution of the carbon cycle in a passive sedimentary continental margin in response to changing oceanographic and geologic forcing over a time scale of 200 million years. The geochemistry of the sediment column is altered by the addition of vertical high-permeability channels intended to mimic the effects of heterogeneity in the real sediment column due to faults, and produces results consistent with measured pore-water tracers SO42− and 129I. Pore water dissolved inorganic carbon (DIC concentrations are consistent with chemical weathering (CaCO3 formation from igneous rocks at depth within the sediment column. The carbon isotopic composition of the DIC is consistent with a methane production efficiency from particulate organic carbon (POC of 50%, which is somewhat lower than redox balance with the H / C of organic matter in the model. The hydrate inventory in the model is somewhat less sensitive to temperature than our previous results with a one-dimensional model, quite sensitive to reasonable changes in POC, and extremely sensitive to the ability of methane bubbles to rise within the sediment column, and how far gas-phase methane can get through the sediment column before it redissolves when it reaches undersaturated conditions. Hydrate formation is also sensitive to deep respiration of migrating petroleum. Other phenomena which we simulated had only a small impact on the hydrate inventory, including thermogenic methane production and production/decomposition of dissolved organic carbon.

  16. Facies analysis, sedimentology and paleocurrent of the quaternary nenering formation, Pengkalan Hulu, Malaysia

    International Nuclear Information System (INIS)

    Yuniarti Ulfa; Evonne Hooi Rong Yu; Ooi Cheng Kit

    2014-01-01

    Nenering Formation is essentially made up of semi-consolidated sediments, which are divided into basal conglomerate beds, conglomeratic sandstone, cross-bedded sandstone, and siltstone to muddy layers facies. It is overlie unconformable to the Berapit Formation, but conformable to the Kroh and Grik Formations. The stratigraphy of Nenering Formation is a fining upwards sequence where the thickness of conglomerate beds become thinner upwards and become thicker for conglomeratic sandstone. The thickness varies from 0.5 m to tenths of meters. The more sandy in the upper portion (cross-bedded sandstone) overlie with thin siltstone and mud stone facies. The clast and grain composition suggested that the material making up the sedimentary sequence were derived predominantly from the erosion of granitoid rocks and sedimentary and metamorphic rocks constitute a minor provenance. Imbrications and the trend sizes of clasts indicate that the paleo-current flow toward northeast. Cross bedding that was found in conglomerate and sandstone indicates the main channel depositional environment. The sequence stratigraphy of this area match with the Saskatchewan fluvial braided channel model. (author)

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

    Directory of Open Access Journals (Sweden)

    Richard, R. Schneider

    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.

  18. Modeling groundwater age using tritium and groundwater mineralization processes - Morondava sedimentary basin, Southwestern Madagascar

    International Nuclear Information System (INIS)

    RAMAROSON, V.

    2007-01-01

    The tritium method in the lumped parameter approach was used for groundwater dating in the Morondava sedimentary basin, Southwestern Madagascar. Tritium data were interpreted by the dispersion model. The modeling results, with P D values between 0.05 and 0.7, show that shallow groundwater age is ranging from 17 to 56 years. Different types of chemical composition were determined for these shallow ground waters, among others, Ca-HCO 3 , Ca-Na-HCO 3 , Ca-Na-Mg-HCO 3 , Ca-K-HCO 3 -NO 3 -SO 4 , Na-Cl, or Ca-Na-Mg-Cl. Likewise, deeper ground waters show various chemical type such as Ca-Na-HCO 3 , Ca-Mg-Na H CO 3 , Ca-Na-Mg-HCO 3 , Ca-Na-Mg-HCO 3 -Cl-SO 4 , Ca-Mg-HCO 3 , Na-Ca-Mg-HCO 3 -SO 4 -Cl, Na-Cl-HCO 3 or Na-HCO 3 -Cl. To evaluate the geochemical processes, the NETPATH inverse geochemical modeling type was implemented. The modeling results show that silicate minerals dissolution , including olivine, plagioclase, and pyroxene is more important than calcite or dolomite dissolution, for both shallow and deeper groundwater . In the Southern part of the study area, while halite dissolution is likely to be the source of shallow groundwater chloride concentration rise, the mineral precipitation seems to be responsible for less chloride content in deeper groundwater. Besides, ion exchange contributes to the variations of major cations concentrations in groundwater. The major difference between shallow and deep groundwater mineralization process lies in the leaching of marine aerosols deposits by local precipitation, rapidly infiltrated through the sandy formation and giving marine chemical signature to shallow groundwater [fr

  19. Facies and depositional environments for the coquinas of the Morro do Chaves Formation, Sergipe-Alagoas Basin, defined by taphonomic and compositional criteria

    Directory of Open Access Journals (Sweden)

    Ana Carolina Tavares

    Full Text Available Lacustrine carbonate rocks form important hydrocarbon accumulations along the Brazilian continental margin, some of which are contained in oil fields in which coquinas are one of the main reservoirs (viz. Campos Basin. The complexity and heterogeneity of these deposits make them a challenge in terms of reservoir description. For the necessary classification and paleoenvironmental interpretation of the coquinas, it is essential to evaluate many aspects including biological (such as carbonate productivity, sedimentological (energy regime in the depositional environment, transport of bioclasts, terrigenous supply, taphonomic (fragmentation of shells, abrasion and diagenetic processes. The facies analysis applied in this study is considered a more appropriate classification approach to understand these coquinas, since it is more flexible and comprehensive than the existing classifications for carbonate rocks. The material investigated here consists of rock samples of the coquinas from the Atol Quarry of the Morro do Chaves Formation (Barremian/Aptian, Sergipe-Alagoas Basin. These rocks that crop out in the Atol quarry complex can be considered as a case study for similar coquinas reservoirs found in the Brazilian continental margin basins. Six sedimentary facies were described, using the main taphonomic (fragmentation of shells and compositional (presence of micrite and siliciclastic matrix features as a diagnostic criteria. Two carbonate facies, two mixed carbonate-siliciclastic facies and two siliciclastic facies (mudstones were identified. From the facies succession, combined with a review of the literature on the subject, the following depositional paleoenvironments were defined: high-energy lake platform, lacustrine delta in a high-energy lake platform and lake-centre. In this paper, a new facies model for the studied coquinas succession is proposed.

  20. Sedimentary mode and reservoir distribution of the Cambrian carbonate & evaporate paragenesis system in the Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Anna Xu

    2016-11-01

    Full Text Available The Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin is made up of the Longwangmiao, Gaotai and Xixiangchi Fms. So far, great breakthrough has been made only in the Longwangmiao Fm instead of the latter two, and the Anyue Gasfield was discovered in the center of this basin. In this paper, therefore, the Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin was analyzed in terms of its structural–sedimentary setting, sequence stratigraphic framework, sedimentary facies and the distribution of evaporites by using various geologic, logging and seismic data. Then, the geological model of sedimentary facies was established and the distribution range of favorable reservoirs was predicted. Based on these studies, the following results are obtained. Firstly, the palaeotectonic framework is characterized by the style of “one depression between two uplifts” in the setting of a large SE dipping slope, and the stratigraphic filling is in the structure of “onlapping at the bottom and truncation at the top” which is thin in the west and thick in the east. Secondly, three third-order sequence cycles which, on the whole, become shallow upward are developed from bottom to top, and gypsum-salt rocks are mainly located at the high system tract (HST of third-order sequences and concentrated in the Wanzhou–Yibin sag. Thirdly, the geological model of sedimentary facies is composed of three major sedimentary structural layers from bottom to top, namely the evaporative carbonate ramp, the evaporative diamictic restricted platform and the evaporative restricted platform. The sedimentary environment changes from the open to the closed and the penesaline for a long time, and then back to the open. The distribution of shoals changes from the pattern of “dual banks” in a large area to more scattered shoals and banded shoals, while the evaporative lagoon and tidal flat shrink. Fourthly, the reservoir distribution is

  1. Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge

    DEFF Research Database (Denmark)

    Anderskouv, Kresten; Surlyk, Finn

    2011-01-01

    , including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab­sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites...... slump packages (14–18 in total) are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in slumping. The vertical succession of facies records an earliest Cenomanian facies shift from dominantly siliciclastic to chalk deposition...

  2. Sedimentary record of erg migration

    Science.gov (United States)

    Porter, M. L.

    1986-06-01

    The sedimentary record of erg (eolian sand sea) migration consists of an idealized threefold division of sand-sea facies sequences. The basal division, here termed the fore-erg, is composed of a hierarchy of eolian sand bodies contained within sediments of the flanking depositional environment. These sand bodies consist of eolian strata deposited by small dune complexes, zibars, and sand sheets. The fore-erg represents the downwind, leading edge of the erg and records the onset of eolian sedimentation. Basin subsidence coupled with erg migration places the medial division, termed the central erg, over the fore-erg strata. The central erg, represented by a thick accumulation of large-scale, cross-stratified sandstone, is the product of large draa complexes. Eolian influence on regional sedimentation patterns is greatest in the central erg, and most of the sand transported and deposited in the erg is contained within this region. Reduction in sand supply and continued erg migration will cover the central-erg deposits with a veneer of back-erg deposits. This upper division of the erg facies sequence resembles closely the fore-erg region. Similar types of eolian strata are present and organized in sand bodies encased in sediments of the upwind flanking depositional environment(s). Back-erg deposits may be thin due to limited eolian influence on sedimentation or incomplete erg migration, or they may be completely absent because of great susceptibility to postdepositional erosion. Tectonic, climatic, and eustatic influences on sand-sea deposition will produce distinctive variations or modifications of the idealized erg facies sequence. The resulting variants in the sedimentary record of erg migration are illustrated with ancient examples from western North America, Europe, southern Africa, and South America.

  3. Coupled distinct element-finite element numerical modelling of fluid circulation in deforming sedimentary basins.

    Science.gov (United States)

    Hindle, D.; Malz, A.; Donndorf, S.; Kley, J.; Kopp, H.

    2012-04-01

    We develop a coupled numerical model for fluid flow in deforming sedimentary basins. We combine a distinct element method for large deformations of crustal materials, with a finite element method for fluid flow according to a diffusion type equation. The key question in such a model is how to simulate evolving permeabilities due to upper and possibly middle crustal deformation, and the coupled issue of how localisation of deformation in faults and shear zones is itself influenced by fluid flow and fluid pressure and vice versa. Currently our knowledge of these issues is restricted, even sketchy. There are a number of hypotheses, based partly on geological and isotope geochemical observations, such as "seismic pumping" models, and fluid induced weak décollement models for thrust sheet transport which have gained quite wide acceptance. Observations around thrusts at the present day have also often been interpreted as showing deformation induced permeability. However, combining all the physics of these processes into a numerical simulation is a complicated task given the ranges of, in particular time scales of the processes we infer to be operating based on our various observations. We start this task by using an elastic fracture relationship between normal stresses across distinct element contacts (which we consider to be the equivalent of discrete, sliding fractures) and their openness and hence their transmissivity. This relates the mechanical state of the distinct element system to a discrete permeability field. Further than that, the geometry of the mechanical system is used to provide boundary conditions for fluid flow in a diffusion equation which also incorporates the permeability field. The next question we address is how to achieve a feedback between fluid pressures and deformation. We try two approaches: one treats pore space in the DEM as real, and calculates the force exerted locally by fluids and adds this to the force balance of the model; another

  4. Modelling hydrothermal venting in volcanic sedimentary basins: Impact on hydrocarbon maturation and paleoclimate

    Science.gov (United States)

    Iyer, Karthik; Schmid, Daniel W.; Planke, Sverre; Millett, John

    2017-06-01

    Vent structures are intimately associated with sill intrusions in sedimentary basins globally and are thought to have been formed contemporaneously due to overpressure generated by gas generation during thermogenic breakdown of kerogen or boiling of water. Methane and other gases generated during this process may have driven catastrophic climate change in the geological past. In this study, we present a 2D FEM/FVM model that accounts for 'explosive' vent formation by fracturing of the host rock based on a case study in the Harstad Basin, offshore Norway. Overpressure generated by gas release during kerogen breakdown in the sill thermal aureole causes fracture formation. Fluid focusing and overpressure migration towards the sill tips results in vent formation after only few tens of years. The size of the vent depends on the region of overpressure accessed by the sill tip. Overpressure migration occurs in self-propagating waves before dissipating at the surface. The amount of methane generated in the system depends on TOC content and also on the type of kerogen present in the host rock. Generated methane moves with the fluids and vents at the surface through a single, large vent structure at the main sill tip matching first-order observations. Violent degassing takes place within the first couple of hundred years and occurs in bursts corresponding to the timing of overpressure waves. The amount of methane vented through a single vent is only a fraction (between 5 and 16%) of the methane generated at depth. Upscaling to the Vøring and Møre Basins, which are a part of the North Atlantic Igneous Province, and using realistic host rock carbon content and kerogen values results in a smaller amount of methane vented than previously estimated for the PETM. Our study, therefore, suggests that the negative carbon isotope excursion (CIE) observed in the fossil record could not have been caused by intrusions within the Vøring and Møre Basins alone and that a contribution

  5. Artificial neural network modeling and cluster analysis for organic facies and burial history estimation using well log data: A case study of the South Pars Gas Field, Persian Gulf, Iran

    Science.gov (United States)

    Alizadeh, Bahram; Najjari, Saeid; Kadkhodaie-Ilkhchi, Ali

    2012-08-01

    Intelligent and statistical techniques were used to extract the hidden organic facies from well log responses in the Giant South Pars Gas Field, Persian Gulf, Iran. Kazhdomi Formation of Mid-Cretaceous and Kangan-Dalan Formations of Permo-Triassic Data were used for this purpose. Initially GR, SGR, CGR, THOR, POTA, NPHI and DT logs were applied to model the relationship between wireline logs and Total Organic Carbon (TOC) content using Artificial Neural Networks (ANN). The correlation coefficient (R2) between the measured and ANN predicted TOC equals to 89%. The performance of the model is measured by the Mean Squared Error function, which does not exceed 0.0073. Using Cluster Analysis technique and creating a binary hierarchical cluster tree the constructed TOC column of each formation was clustered into 5 organic facies according to their geochemical similarity. Later a second model with the accuracy of 84% was created by ANN to determine the specified clusters (facies) directly from well logs for quick cluster recognition in other wells of the studied field. Each created facies was correlated to its appropriate burial history curve. Hence each and every facies of a formation could be scrutinized separately and directly from its well logs, demonstrating the time and depth of oil or gas generation. Therefore potential production zone of Kazhdomi probable source rock and Kangan- Dalan reservoir formation could be identified while well logging operations (especially in LWD cases) were in progress. This could reduce uncertainty and save plenty of time and cost for oil industries and aid in the successful implementation of exploration and exploitation plans.

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

    International Nuclear Information System (INIS)

    Faeh, D.; Suhadolc, P.; Mueller, S.; Panza, G.F.

    1994-04-01

    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

  7. Combined tide and storm influence on facies sedimentation of miocene Miri Formation, Sarawak

    International Nuclear Information System (INIS)

    Yuniarta Ulfa; Nasiman Sapari; Zuhar Zahir Tuan Harith

    2011-01-01

    This study was conducted on the sedimentary rocks belonging to the Miri Formation (Middle - Late Miocene). The primary objective of the present study is to provide additional interpretation on the stratigraphy of the Miri Formation in the Miri Field based on the new information gathered from new outcrops in the area. Five outcrops were examined in detail on sedimentology and stratigraphy. Based on lithology, sedimentary structures, bedding geometry and traces fossil, the sediments of the Miri Formation were grouped into fourteen lithofacies. Influence of tide and storm during the depositional processes of the formation were indicated by the group of two main facies associations which are: (i) tide-dominated estuary; and (ii) wave-and-storm dominated facies associations. The tide-dominated estuary system of the Miri Formation are includes variety of sub environments: estuary mouth or tidal channel and sand bars (characterized by trough cross-stratified sandstone with mud drapes facies), estuary channel or upper flow regime of sand flat (characterized by parallel stratified sandstone with mud-laminas facies), mixed-tidal flat (characterized by wavy and flaser bedded sandstone facies), and mud-tidal flat (characterized by rhythmic stratified sandstone-mudstone and lenticular bedding facies). The wave-and-storm dominated varied from lower to middle shore face (characterized by hummocky cross-stratified sandstone and rhythmic parallel stratified sandstone and laminated siltstone facies), upper shore face (characterized by swaley cross-stratified sandstone), lower shore face inter bedded to bioturbated sandstone and siltstone facies), and offshore transitional (characterized by bioturbated sandstone and mudstone inter bedding with parallel to hummocky cross-stratified sandstone facies). (author)

  8. Microbial mat-induced sedimentary structures in siliciclastic sediments

    Indian Academy of Sciences (India)

    This paper addresses macroscopic signatures of microbial mat-related structures within the. 1.6Ga-old Chorhat Sandstone ... Sandstone differentiated in facies superposed one over the other and their respective structural assemblages (b). may be ..... within the classification of primary sedimentary struc- tures; J. Sed. Res.

  9. Marine habitat mapping of the Milford Haven Waterway, Wales, UK: Comparison of facies mapping and EUNIS classification for monitoring sediment habitats in an industrialized estuary

    Science.gov (United States)

    Carey, Drew A.; Hayn, Melanie; Germano, Joseph D.; Little, David I.; Bullimore, Blaise

    2015-06-01

    A detailed map and dataset of sedimentary habitats of the Milford Haven Waterway (MHW) was compiled for the Milford Haven Waterway Environmental Surveillance Group (MHWESG) from seafloor images collected in May, 2012 using sediment-profile and plan-view imaging (SPI/PV) survey techniques. This is the most comprehensive synoptic assessment of sediment distribution and benthic habitat composition available for the MHW, with 559 stations covering over 40 km2 of subtidal habitats. In the context of the MHW, an interpretative framework was developed that classified each station within a 'facies' that included information on the location within the waterway and inferred sedimentary and biological processes. The facies approach provides critical information on landscape-scale habitats including relative location and inferred sediment transport processes and can be used to direct future monitoring activities within the MHW and to predict areas of greatest potential risk from contaminant transport. Intertidal sediment 'facies' maps have been compiled in the past for MHW; this approach was expanded to map the subtidal portions of the waterway. Because sediment facies can be projected over larger areas than individual samples (due to assumptions based on physiography, or landforms) they represent an observational model of the distribution of sediments in an estuary. This model can be tested over time and space through comparison with additional past or future sample results. This approach provides a means to evaluate stability or change in the physical and biological conditions of the estuarine system. Initial comparison with past results for intertidal facies mapping and grain size analysis from grab samples showed remarkable stability over time for the MHW. The results of the SPI/PV mapping effort were cross-walked to the European Nature Information System (EUNIS) classification to provide a comparison of locally derived habitat mapping with European-standard habitat

  10. 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)

  11. Obligaciones prima facie y derrotabilidad

    OpenAIRE

    Oller, Carlos A.

    2006-01-01

    Este artículo examina algunos de los problemas que presenta el tratamiento lógico de las obligaciones prima facie en la obra de Carlos Alchourrón. Por una parte, señalaremos que su sistema para los condicionales derrotables DFT no formaliza adecuadamente la noción intuitiva de condición contribuyente que Alchourrón utiliza para elucidar la de condicional derrotable. Por otra parte, argumentaremos que la noción de deber prima facie de David Ross no queda adecuadamente formalizada en el sistema...

  12. Magma Chamber Model of Batur Caldera, Bali, Indonesia: Compositional Variation of Two Facies, Large-Volume Dacitic Ignimbrites

    Directory of Open Access Journals (Sweden)

    Igan S. Sutawidjaja

    2015-05-01

    Full Text Available DOI:10.17014/ijog.2.2.111-124Batur is one of the finest known calderas on Earth, and is the source of at least two major ignimbrite eruptions with a combined volume of some 84 km3 and 19 km3. These ignimbrites have a similar compositions, raising the question of whether they are geneticaly related. The Batur Ignimbrite-1 (BI-1 is crystal poor, containing rhyodacitic (68 - 70wt % SiO2, white to grey pumices and partly welded and unwelded. The overlying Batur Ignimbrite-2 (BI-2 is a homogeneous grey to black dacitic pumices (64 - 66 wt % SiO2, unwelded and densely welded (40 - 60% vesicularity, crystal and lithic rich. Phase equilibria indicate that the Batur magma equilibrated at temperatures of 1100 - 1300oC with melt water contents of 3 - 6 wt%. The post-eruptive Batur magma was cooler (<1100oC and it is melt more water rich (> 6 wt % H2O. A pressure of 20 kbar is infered from mineral barometry for the Batur magma chamber. Magmatic chamber model is one in which crystals and melt separate from a convecting Batur magma by density differences, resulting in a stratified magma chamber with a homogeneous central zone, a crystal-rich accumulation zone near the walls or base, and a buoyant, melt-rich zone near the top. This is consistent with the estimated magma temperatures and densities: the pre-eruptive BI-1 magma was hoter (1300oC and more volatile rich (6 wt % H2O with density 2.25 g/cm3 than the BI-2 magma (1200oC; 4 wt % H2O in density was higher (2.50 g/cm3. Batur melt characteristics and intensive parameters are consistent with a volatile oversaturation-driven eruption. However, the higher H2O content, high viscosity and low crystal content of the BI-1 magma imply an external eruption trigger.

  13. Upper Carboniferous retroarc volcanism with submarine and subaerial facies at the western Gondwana margin of Argentina

    Science.gov (United States)

    Koukharsky, M.; Kleiman, L.; Etcheverría, M.; Quenardelle, S.; Bercowski, F.

    2009-04-01

    During Late Carboniferous times a continental magmatic arc developed at the western margin of Gondwana in South America, as several marine sedimentary basins were formed at the same time in the retroarc region. North of 33°S, at Cordón Agua del Jagüel, Precordillera of Mendoza, Argentina, a volcanic sequence crops out which was emplaced in a submarine environment with some subaerial exposures, and it is intercalated in marine sediments of Agua del Jagüel Formation, which fills of one of these retroarc basins. This paper presents, for the first time, a facies analyses together with geochemical and isotopic data of this volcanic suite, suggesting its deposition in an ensialic retroarc marine basin. The volcanic succession comprises debris flows with either sedimentary or volcanic fragments, base surge, resedimented massive and laminated dacitic-andesitic hyaloclastite, pillow lava, basic hyaloclastite and dacitic-andesitic lavas and hyaloclastite facies. Its composition is bimodal, either basaltic or dacitic-andesitic. The geochemistry data indicate a subalkaline, low K calk-alkaline and metaluminous affinity. The geochemistry of the basalts points to an origin of the magmas from a depleted mantle source with some crustal contamination. Conversely, the geochemistry of the dacites-andesites shows an important participation of both crustal components and subduction related fluids. A different magmatic source for the basalts than for the dacites-andesites is also supported by Sr and Nd isotopic initial ratios and Nd model ages. The characteristics of this magmatic suite suggest its emplacement in an extensional setting probably associated with the presence of a steepened subduction zone at this latitude during Upper Carboniferous times.

  14. Multiscale heterogeneity characterization of tidal channel, tidal delta and foreshore facies, Almond Formation outcrops, Rock Springs uplift, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Schatzinger, R.A.; Tomutsa, L. [BDM Petroleum Technologies, Bartlesville, OK (United States)

    1997-08-01

    In order to accurately predict fluid flow within a reservoir, variability in the rock properties at all scales relevant to the specific depositional environment needs to be taken into account. The present work describes rock variability at scales from hundreds of meters (facies level) to millimeters (laminae) based on outcrop studies of the Almond Formation. Tidal channel, tidal delta and foreshore facies were sampled on the eastern flank of the Rock Springs uplift, southeast of Rock Springs, Wyoming. The Almond Fm. was deposited as part of a mesotidal Upper Cretaceous transgressive systems tract within the greater Green River Basin. Bedding style, lithology, lateral extent of beds of bedsets, bed thickness, amount and distribution of depositional clay matrix, bioturbation and grain sorting provide controls on sandstone properties that may vary more than an order of magnitude within and between depositional facies in outcrops of the Almond Formation. These features can be mapped on the scale of an outcrop. The products of diagenesis such as the relative timing of carbonate cement, scale of cemented zones, continuity of cemented zones, selectively leached framework grains, lateral variability of compaction of sedimentary rock fragments, and the resultant pore structure play an equally important, although less predictable role in determining rock property heterogeneity. A knowledge of the spatial distribution of the products of diagenesis such as calcite cement or compaction is critical to modeling variation even within a single facies in the Almond Fin. because diagenesis can enhance or reduce primary (depositional) rock property heterogeneity. Application of outcrop heterogeneity models to the subsurface is greatly hindered by differences in diagenesis between the two settings. The measurements upon which this study is based were performed both on drilled outcrop plugs and on blocks.

  15. FACIES PARTITIONING AND SEQUENCE STRATIGRAPHY OF A MIXED SILICICLASTIC-CARBONATE RAMP STACK IN THE GELASIAN OF SICILY (S ITALY: A POTENTIAL MODEL FOR ICEHOUSE, DISTALLY-STEEPENED HETEROZOAN RAMPS

    Directory of Open Access Journals (Sweden)

    FRANCESCO MASSARI

    2012-11-01

    Full Text Available The Gelasian succession of the Capodarso area (Enna-Caltanissetta basin, Sicily, Italy consists of an offlapping stack of cycles composed of siliciclastic units passing to carbonate heterozoan, clino-stratified wedges, developed from a growing positive tectonic structure. Identification of a number of facies tracts, based on sedimentary facies, biofacies and taphofacies, provided important information about the differentiation and characterisation of systems tracts and key stratal surfaces of sequence stratigraphy. The bulk of carbonate wedges are interpreted as representing the rapid falling-stage progradation of distally steepened ramps. The inferred highest rate of carbonate production during forced regressions was concomitant with active downramp resedimentation by storm-driven downwelling flows, leading to storing of most carbonate sediment on the ramp slope as clino-beds of the prograding bodies. Comparison of the Capodarso ramps with other icehouse carbonate ramps, with particular regard to the Mediterranean Plio-Pleistocene, provides clues for defining some common features. These are inferred to include: (1 brief, rapid episodes of progradation concomitant with orbitally-forced sea-level changes, resulting in limited ramp width; (2 preferential fostering of growth and downramp resedimentation of heterozoan carbonates during glacial hemicycles marked by enhanced atmospheric and marine circulation; (3 building out from positive features of entirely submerged distally-steepened ramps with storm-wave-graded profile and distinctive clinoforms; (4 ramp stacks generally consisting of mixed clastic-carbonate sequences showing an ordered spectrum of distinct frequencies; (5 rapid, continuous changes in environmental parameters, leading to the short-lived persistence of faunal communities, climax communities generally having insufficient time to form. 

  16. A refined model of sedimentary rock cover in the southeastern part of the Congo basin from GOCE gravity and vertical gravity gradient observations

    Science.gov (United States)

    Martinec, Zdeněk; Fullea, Javier

    2015-03-01

    We aim to interpret the vertical gravity and vertical gravity gradient of the GOCE-GRACE combined gravity model over the southeastern part of the Congo basin to refine the published model of sedimentary rock cover. We use the GOCO03S gravity model and evaluate its spherical harmonic representation at or near the Earth's surface. In this case, the gradiometry signals are enhanced as compared to the original measured GOCE gradients at satellite height and better emphasize the spatial pattern of sedimentary geology. To avoid aliasing, the omission error of the modelled gravity induced by the sedimentary rocks is adjusted to that of the GOCO03S gravity model. The mass-density Green's functions derived for the a priori structure of the sediments show a slightly greater sensitivity to the GOCO03S vertical gravity gradient than to the vertical gravity. Hence, the refinement of the sedimentary model is carried out for the vertical gravity gradient over the basin, such that a few anomalous values of the GOCO03S-derived vertical gravity gradient are adjusted by refining the model. We apply the 5-parameter Helmert's transformation, defined by 2 translations, 1 rotation and 2 scale parameters that are searched for by the steepest descent method. The refined sedimentary model is only slightly changed with respect to the original map, but it significantly improves the fit of the vertical gravity and vertical gravity gradient over the basin. However, there are still spatial features in the gravity and gradiometric data that remain unfitted by the refined model. These may be due to lateral density variation that is not contained in the model, a density contrast at the Moho discontinuity, lithospheric density stratifications or mantle convection. In a second step, the refined sedimentary model is used to find the vertical density stratification of sedimentary rocks. Although the gravity data can be interpreted by a constant sedimentary density, such a model does not correspond to

  17. Quantitative Analogue Experimental Sequence Stratigraphy : Modelling landscape evolution and sequence stratigraphy of river-shelf sedimentary systems by quantitative analogue experiments

    NARCIS (Netherlands)

    Heijst, Maximiliaan Wilhelmus Ignatius Maria van

    2000-01-01

    This thesis reports a series of flume tank experiments that were conducted to model the stratigraphic evolution of river-delta systems. Chapter 1 introduces the river-delta sedimentary system that is subject of modelling. The chapter also includes an overview of previous research and the summary and

  18. Stratigraphy and Facies Analysis of a 122 M Long Lacustrine Sequence from Chalco Lake, Central Mexico

    Science.gov (United States)

    Herrera, D. A.; Ortega, B.; Caballero, M.; Lozano, S.; Pi, T.; Brown, E. T.

    2010-12-01

    Chalco lake is located SE of the outskirts of Mexico City, at the central part of the Trans Mexican Volcanic Belt. Previous studies show the importance of this lacustrine sequence as an archive of paleoenvironmental and paleoclimatic changes. A set of five cores up to 122 m depth were drilled in the basin, in order to analyze the sedimentary record and to extent the previous knowledge of past environmental changes in central Mexico. As an initial step, in this work we present the identification and classification of sedimentary facies. Preliminary paleomagnetism analyses recognize the possible record of the Blake Event (ca. 120 kyr BP), and suggest that the sequence might span the last 240 kyr. In this case, variations in sedimentary facies could reflect the conditions of the MIS 1-7. The facies are mostly diatom ooze, carbonate mud, organic rich silt and volcaniclastic, both massive and laminated, and massive dark gray to reddish brown silt. From 1 to 8 m depth dominates the organic rich silt facies, which correlates with the MIS 1. Intercalations of reddish brown and grayish brown silt facies, between 8 to 60 m depth, indicate changes occurred during MIS 2 to 5d. Between 60-75 m depth the sequence is characterized by dark grayish silty clay facies, which possibly coincide with the MIS 5e. At 79 m depth (ca. 130 kyr BP) we found struvite (MgNH4PO4.6H2O), which may be related to dry conditions. The laminated diatom ooze facies dominates between 90 to 122 m depth and indicates rhythmic changes in the sediment deposition of the basin. The volcaniclastic facies is represented by lapilli and ash deposits in more than 100 individual tephra layers of both mafic and felsic composition. Some of them correspond to main volcanic eruptions, as the Upper Toluca Pumice (13,500 cal yr BP), from the Nevado de Toluca volcano and the Pómez con Andesita (17,700 cal yr BP) from the Popocatépetl volcano. The carbonate mud facies is composed of calcite and siderite, with frequent

  19. Evidence for new resonances in the K-barN system: A prima facie case for the even-wave harmonic-oscillator model

    International Nuclear Information System (INIS)

    Kamath, S.G.

    1978-01-01

    Arguments are presented to show that the new resonance parameters obtained by Alston-Garnjost et al. in a recent analysis of the K-barN system from 365 to 1320 MeV/c provide a prima facie case for the even-wave harmonic-oscillator theory of baryonic states in the framework of SU(6)/sub W/ x O(3). A new quantum classification of the Λ states belonging to the (70,1 - ) is also proposed

  20. Modeling of Wave Propagation in the Osaka Sedimentary Basin during the 2013 Awaji Island Earthquake (Mw5.8)

    Science.gov (United States)

    Asano, K.; Sekiguchi, H.; Iwata, T.; Yoshimi, M.; Hayashida, T.; Saomoto, H.; Horikawa, H.

    2013-12-01

    The three-dimensional velocity structure model for the Osaka sedimentary basin, southwest Japan is developed and improved based on many kinds of geophysical explorations for decades (e.g., Kagawa et al., 1993; Horikawa et al., 2003; Iwata et al., 2008). Recently, our project (Sekiguchi et al., 2013) developed a new three-dimensional velocity model for strong motion prediction of the Uemachi fault earthquake in the Osaka basin considering both geophysical and geological information by adding newly obtained exploration data such as reflection surveys, microtremor surveys, and receiver function analysis (hereafter we call UMC2013 model) . On April 13, 2013, an inland earthquake of Mw5.8 occurred in Awaji Island, which is close to the southwestern boundary of the aftershock area of the 1995 Kobe earthquake. The strong ground motions are densely observed at more than 100 stations in the basin. The ground motion lasted longer than four minutes in the Osaka urban area where its bedrock depth is about 1-2 km. This long-duration ground motions are mainly due to the surface waves excited in this sedimentary basin whereas the magnitude of this earthquake is moderate and the rupture duration is expected to be less than 5 s. In this study, we modeled long-period (more than 2s) ground motions during this earthquake to check the performance of the present UMC2013 model and to obtain a better constraint on the attenuation factor of sedimentary part of the basin. The seismic wave propagation in the region including the source and the Osaka basin is modeled by the finite difference method using the staggered grid solving the elasto-dynamic equations. The domain of 90km×85km×25.5km is modeled and discretized with a grid spacing of 50 m. Since the minimum S-wave velocity of the UMC2013 model is about 250 m/s, this calculation is valid up to the period of about 1 s. The effect of attenuation is included in the form of Q(f)=Q0(T0/T) proposed by Graves (1996). A PML is implemented in

  1. From dry to saturated thermal conductivity: mixing-model correction charts and new conversion equations for sedimentary rocks

    Science.gov (United States)

    Fuchs, Sven; Schütz, Felina; Förster, Andrea; Förster, Hans-Jürgen

    2013-04-01

    The thermal conductivity (TC) of a rock is, in collaboration with the temperature gradient, the basic parameter to determine the heat flow from the Earth interior. Moreover, it forms the input into models targeted on temperature prognoses for geothermal reservoirs at those depths not yet reached by boreholes. Thus, rock TC is paramount in geothermal exploration and site selection. Most commonly, TC of a rock is determined in the laboratory on samples that are either dry or water-saturated. Because sample saturation is time-consuming, it is desirable, especially if large numbers of samples need to be assessed, to develop an approach that quickly and reliably converts dry-measured bulk TC into the respective saturated value without applying the saturation procedure. Different petrophysical models can be deployed to calculate the matrix TC of a rock from the bulk TC and vice versa, if the effective porosity is known (e.g., from well logging data) and the TC of the saturation fluid (e.g., gas, oil, water) is considered. We have studied for a large suite of different sedimentary rocks the performance of two-component (rock matrix, porosity) models that are widely used in geothermics (arithmetic mean, geometric mean, harmonic mean, Hashin and Shtrikman mean, and effective medium theory mean). The data set consisted of 1147 TC data from three different sedimentary basins (North German Basin, Molasse Basin, Mesozoic platform sediments of the northern Sinai Microplate in Israel). Four lithotypes (sandstone, mudstone, limestone, dolomite) were studied exhibiting bulk TC in the range between 1.0 and 6.5 W/(mK). The quality of fit between measured (laboratory) and calculated bulk TC values was studied separately for the influence of lithotype, saturation fluid (water and isooctane), and rock anisotropy (parallel and perpendicular to bedding). The geometric mean model displays the best correspondence between calculated and measured bulk TC, however, the relation is not

  2. Hydro-mechanical modelling of a shaft seal in crystalline and sedimentary host rock media using COMSOL

    Energy Technology Data Exchange (ETDEWEB)

    Priyanto, D.G. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

    2011-07-01

    Shaft seals are components of the engineered barriers system considered for closure of a Deep Geological Repository (DGR). These seals would be installed in strategic locations of the shafts, where significant fracture zones (FZ) are located and would serve to limit upward flow of groundwater from the repository level towards the surface. This paper presents the results of hydro-mechanical (HM) numerical modelling exercises to evaluate the performance of a shaft seal using a finite element computer code, COMSOL. This study considered a variety of host geological media as part of generic assessments of system evolution in a variety of environments including five hypothetical sedimentary and crystalline host rock conditions. Four simulations of a shaft seal in different sedimentary rocks were completed, including: shale with isotropic permeability; shale with anisotropic permeability; limestone with isotropic permeability; and limestone with anisotropic permeability. The other simulation was a shaft seal in crystalline rock with isotropic permeability. Two different stages were considered in these HM simulations. Stages 1 and 2 simulated the groundwater flow into an open shaft and after installation of shaft sealing components, respectively. As expected, the models were able to simulate that installation of the shaft seal limits groundwater flow through the shaft. Based on the conditions and assumptions defined for the host media and fracture features examined in this study, the following conclusions can be drawn from the results of the numerical modelling exercises. A shaft that remained open for a longer time was beneficial with respect to delaying of seal saturation because it could reduce the groundwater flow rate around the fracture zone. Delaying saturation time indicates slower movement of the groundwater or other substances that may be transported with the groundwater. The core of the shaft seal (i.e., the bentonite-sand mixture (BSM)) became fully saturated

  3. Multiparameter Elastic Full Waveform Inversion with Facies-based Constraints

    Science.gov (United States)

    Zhang, Zhen-dong; Alkhalifah, Tariq; Naeini, Ehsan Zabihi; Sun, Bingbing

    2018-03-01

    Full waveform inversion (FWI) incorporates all the data characteristics to estimate the parameters described by the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion beyond improved acoustic imaging, like in reservoir delineation, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Some anisotropic parameters are insufficiently updated because of their minor contributions to the surface collected data. Adding rock physics constraints to the inversion helps mitigate such limited sensitivity, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a global constraint for the whole area. Since similar rock formations inside the Earth admit consistent elastic properties and relative values of elasticity and anisotropy parameters (this enables us to define them as a seismic facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel approach to use facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such facies using Bayesian theory and update them at each iteration of the inversion using both the inverted models and a prior information. We take the uncertainties of the estimated parameters (approximated by radiation patterns) into consideration and improve the quality of estimated facies maps. Four numerical examples corresponding to different acquisition, physical assumptions and model circumstances are used to verify the effectiveness of the proposed method.

  4. Multiparameter elastic full waveform inversion with facies-based constraints

    Science.gov (United States)

    Zhang, Zhen-dong; Alkhalifah, Tariq; Naeini, Ehsan Zabihi; Sun, Bingbing

    2018-06-01

    Full waveform inversion (FWI) incorporates all the data characteristics to estimate the parameters described by the assumed physics of the subsurface. However, current efforts to utilize FWI beyond improved acoustic imaging, like in reservoir delineation, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Some anisotropic parameters are insufficiently updated because of their minor contributions to the surface collected data. Adding rock physics constraints to the inversion helps mitigate such limited sensitivity, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a global constraint for the whole area. Since similar rock formations inside the Earth admit consistent elastic properties and relative values of elasticity and anisotropy parameters (this enables us to define them as a seismic facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel approach to use facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such facies using Bayesian theory and update them at each iteration of the inversion using both the inverted models and a priori information. We take the uncertainties of the estimated parameters (approximated by radiation patterns) into consideration and improve the quality of estimated facies maps. Four numerical examples corresponding to different acquisition, physical assumptions and model circumstances are used to verify the effectiveness of the proposed method.

  5. Multiparameter Elastic Full Waveform Inversion with Facies-based Constraints

    KAUST Repository

    Zhang, Zhendong

    2018-03-20

    Full waveform inversion (FWI) incorporates all the data characteristics to estimate the parameters described by the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion beyond improved acoustic imaging, like in reservoir delineation, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Some anisotropic parameters are insufficiently updated because of their minor contributions to the surface collected data. Adding rock physics constraints to the inversion helps mitigate such limited sensitivity, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a global constraint for the whole area. Since similar rock formations inside the Earth admit consistent elastic properties and relative values of elasticity and anisotropy parameters (this enables us to define them as a seismic facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel approach to use facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such facies using Bayesian theory and update them at each iteration of the inversion using both the inverted models and a prior information. We take the uncertainties of the estimated parameters (approximated by radiation patterns) into consideration and improve the quality of estimated facies maps. Four numerical examples corresponding to different acquisition, physical assumptions and model circumstances are used to verify the effectiveness of the proposed method.

  6. Interannual sedimentary effluxes of alkalinity in the southern North Sea: Model results compared with summer observations

    OpenAIRE

    Pätsch, Johannes; Kühn, Wilfried; Six, Katharina D.

    2018-01-01

    For the sediments of the central and southern North Sea different sources of alkalinity generation are quantified by a regional modelling system for the period 2000–2014. For this purpose a formerly global ocean sediment model coupled with a pelagic ecosystem model is adopted to shelf sea dynamics where much larger turnover rates than in the open and deep ocean occurs. To track alkalinity changes due to different nitrogen-related processes the open ocean sediment model was extended by t...

  7. Modeling of groundwater using the isotopic technique in the sedimentary aquifer of the Mahafaly basin, southwestern Madagascar

    International Nuclear Information System (INIS)

    Fareze, L.H.

    2016-01-01

    The Mahafaly sedimentary basin, southwest of Madagascar belongs to the region where the water resources management problem, such as high groundwater mineralization and dry wells lingers. In this research work, hydrochemistry and isotopes techniques are used to assess the groundwater characteristics, to determine the groundwater origin and to understand their geochemical evolution. The development of an hydrological model using Modflow software contribute to control the groundwater flow and predict the dissolved particles evolution and travel time according to their flow direction. Dissolution of halite, calcite and gypsum and cation exchange are the main sources of the groundwater mineralization in the study area. The groundwater isotopic composition indicates that the groundwaters are directly recharged by local precipitation, having a mean time of 25 years. A mixture of groundwater and Onilahy river water occurs in adjacent aquifers, of which residence time is about 60 years. A mixture of recent and old groundwaters by the upwelling of the deep waters is observed in the southern aquifer of Isalo, confirmed by the tritium concentration value, which is lower than 0,5UT. The model established indicates a high groundwater flow rate from the recharge area, located in Betioky hill. This is due to a steep slope with a hydraulic conductivity of about 10 -5 m.s -1 , although other flow directions have been identified. The model predicts a decrease of the hydraulic head during the last decades. [fr

  8. A numerical model of artificial radionuclides transfers in the English Channel. (Hydrodynamical, biological and sedimentary processes)

    International Nuclear Information System (INIS)

    Le Fur, J.

    1989-01-01

    The paper examines a method of evaluation, using numerical techniques, of the fate of radioelements released by chronic or accidental discharge into the ecosystem of the English Channel. In areas close to the reprocessing center at La Hague, a statistical study is used to establish a direct relation between quantities of ruthenium-106 released by the discharge source and concentrations of the radioelement in marine algae. A multidisciplinary model is developed for general case. The constituents studied are the liquid environment (radioelement vector), particulate matter (radioelement trap) and live macroorganisms (radioelement receptors). Dispersion of radioelements in the liquid environment is calculated using different models for estimating tidal currents (resolution of the Saint-Venant system), the transport of bodies of water and radioelement diffusion. Radioelement fixing in particulate matter is formalized using and adjustment coefficient integrated into the diffusion equation. Transfers of radioelements between the liquid phase and the organisms are modelized using a system of compartments; fluctuations in the discharge source are taken into account in the formulation. All the models are integrated into a calculation system which enables them to be used automatically in sequence. Estimates for currents and trajectories are in agreement with observations and enable short term applications of the system to be contemplated. The model of radioelement transfer to organisms is validated using a pair of experiments carried out in situ. Points remaining to be specified mainly concern the transfer to particulate matter, the calibration of the system for long term studies and certain factors to be included in the model of radioelement transfer to organisms [fr

  9. Interannual sedimentary effluxes of alkalinity in the southern North Sea: model results compared with summer observations

    Directory of Open Access Journals (Sweden)

    J. Pätsch

    2018-06-01

    Full Text Available For the sediments of the central and southern North Sea different sources of alkalinity generation are quantified by a regional modelling system for the period 2000–2014. For this purpose a formerly global ocean sediment model coupled with a pelagic ecosystem model is adapted to shelf sea dynamics, where much larger turnover rates than in the open and deep ocean occur. To track alkalinity changes due to different nitrogen-related processes, the open ocean sediment model was extended by the state variables particulate organic nitrogen (PON and ammonium. Directly measured alkalinity fluxes and those derived from Ra isotope flux observation from the sediment into the pelagic are reproduced by the model system, but calcite building and calcite dissolution are underestimated. Both fluxes cancel out in terms of alkalinity generation and consumption. Other simulated processes altering alkalinity in the sediment, like net sulfate reduction, denitrification, nitrification, and aerobic degradation, are quantified and compare well with corresponding fluxes derived from observations. Most of these fluxes exhibit a strong positive gradient from the open North Sea to the coast, where large rivers drain nutrients and organic matter. Atmospheric nitrogen deposition also shows a positive gradient from the open sea towards land and supports alkalinity generation in the sediments. An additional source of spatial variability is introduced by the use of a 3-D heterogenous porosity field. Due to realistic porosity variations (0.3–0.5 the alkalinity fluxes vary by about 4 %. The strongest impact on interannual variations of alkalinity fluxes is exhibited by the temporal varying nitrogen inputs from large rivers directly governing the nitrate concentrations in the coastal bottom water, thus providing nitrate necessary for benthic denitrification. Over the time investigated the alkalinity effluxes decrease due to the decrease in the nitrogen supply by the rivers.

  10. Understanding and analyzing the hydro-sedimentary processes in the Bay of Toulon. Contribution for modelling the dispersion of radionuclides

    International Nuclear Information System (INIS)

    Dufresne, Christiane

    2014-01-01

    This doctoral research aims to enhance knowledge of the hydro-sedimentary processes in the Bay of Toulon and to represent these processes through a post accidental managing tool, developed to simulate the dispersion of radionuclides. This work is based on a multidisciplinary strategy, using numerical modelling and in situ measurements to study the complex problem of contaminants in the marine environment. Hydrodynamic of the Bay and water mass exchanges through the channel have been studied. Results are highly linked to the atmospheric conditions and the water exchange times of the Little Bay range from two to six days, depending on wind conditions. Recorded data in the Las and Eygoutier Rivers led to the description and the estimation of the catchment yields to the Bay, poorly studied before. With one ton of particulate matter annually discharged by the Las River, the Little Bay seems to be a sedimentation area. In case of accidental release of radionuclides, this area appears to be a trapping zone. (author)

  11. Two dimentional modeling of subsurface structure over upper Benue ...

    African Journals Online (AJOL)

    The subsurface lithology obtained from 2D modelling of the residual field showed the presence of two lithological units. The sedimentary rock unit underlined by the basement rock consists of shales, sandstones, limestones, siltstones, clay and non-marine facies. The Basement rock units were composed of pegmatite, ...

  12. The Coastal Dynamics of Heterogeneous Sedimentary Environments: Numerical Modeling of Hydrodynamics and Mass Transport in Estuaries

    Science.gov (United States)

    2010-08-12

    Medina, et al. (2006). "The Prestige oil spill in Cantabria (Bay of Biscay). Part I: Operational forecasting system for quick response, risk assessment...estuaries (Kostoglidis, Pattiaratchi et al. 2005), macrotidal estuaries (Yang, Eisma et al. 2000), and estuaries with fringing mangrove swamps...the Atchafalaya Bay system (Cobb, Keen et al. 2008), and Patos Lagoon, Brazil . The model current fields used in the Papua New Guinea study (Keen, Ko

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

    OpenAIRE

    Richard, R. Schneider; J. Brad Stelfox; Stan Boutin; Shawn Wasel

    2003-01-01

    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 nex...

  14. Delineation of geological facies from poorly differentiated data

    Energy Technology Data Exchange (ETDEWEB)

    Wohlberg, Brendt [Los Alamos National Laboratory; Tartakovsky, Daniel [UCSC

    2008-01-01

    The ability to delineate geologic facies and to estima.te their properties from sparse data is essential for modeling physical and biochemical processes occurring in the 'ubsurface. If such data are poorly differentiated, this challcnrring task is complicated further by the absence of a clear distinction between different hydrofacies even at locations where data. are available. vVe consider three alt mative approaches for analysis of poorly differentiated data: a k-means clU!:iterinrr algorithm, an expectation-maximization algorithm, and a minimum-variance algorithm. Two distinct synthetically generated geological settings are used to r:tnalyze the ability of these algorithmti to as ign accurately the membership of such data in a given geologic facies. On average, the minimum-variance algorithm provides a more robust p rformance than its two counterparts and when combined with a nearest-neighbor algorithm, it also yields the most accurate reconstruction of the boundaries between the facies.

  15. A process-sedimentary framework for characterizing recent and ancient sabkhas

    Science.gov (United States)

    Handford, C.R.

    1981-01-01

    The discovery of sabkha environments during the 1960's, marked the beginning of Recent evaporite sedimentological studies and their perception as models for facies analysis. However, variation among Recent sabkhas, though recognized by the geologic community, has not been duly addressed, which has resulted in overuse of the Trucial Coast model in comparative sedimentological studies. Knowledge of the dominant physical processes which determine sabkha morphology, and of the sedimentary response to those processes, can lead to a fundamental understanding of a sabkha's origin and of how it differs from other sabkhas. Physical processes thought to be most important (besides evaporation) include those operative under: (1) marine-; (2) fluvial-lacustrine-; and (3) eolian-dominated conditions. Dominance of one or more of these in the proper settings give rise to marine coastal sabkhas, continental playas, and interdune sabkhas. Sedimentary responses to dominant physical processes lead to the development of sabkhas consisting of a combination of either: (1) terrigenous clastics; (2) carbonate-sulfate (anhydrite-gypsum) minerals; or (3) soluble salts (halite, sylvite, polyhalite, etc.). Sediment characterization can also allow discrimination of the range or compositional variety in, for example, coastal sabkhas. Where applied to the stratigraphic record, this classification system may help unravel the sedimentary history of an ancient sabkha system, and a determination of the dominant physical processes that ruled its development. ?? 1981.

  16. Development of Geostatistical Models to Estimate CO2 Storage Resource in Sedimentary Geologic Formations

    Science.gov (United States)

    Popova, Olga H.

    Dental hygiene students must embody effective critical thinking skills in order to provide evidence-based comprehensive patient care. The problem addressed in this study it was not known if and to what extent concept mapping and reflective journaling activities embedded in a curriculum over a 4-week period, impacted the critical thinking skills of 22 first and second-year dental hygiene students attending a community college in the Midwest. The overarching research questions were: what is the effect of concept mapping, and what is the effect of reflective journaling on the level of critical thinking skills of first and second year dental hygiene students? This quantitative study employed a quasi-experimental, pretest-posttest design. Analysis of Covariance (ANCOVA) assessed students' mean scores of critical thinking on the California Critical Thinking Skills Test (CCTST) pretest and posttest for the concept mapping and reflective journaling treatment groups. The results of the study found an increase in CCTST posttest scores with the use of both concept mapping and reflective journaling. However, the increase in scores was not found to be statistically significant. Hence, this study identified concept mapping using Ausubel's assimilation theory and reflective journaling incorporating Johns's revision of Carper's patterns of knowing as potential instructional strategies and theoretical models to enhance undergraduate students' critical thinking skills. More research is required in this area to draw further conclusions. Keywords: Critical thinking, critical thinking development, critical thinking skills, instructional strategies, concept mapping, reflective journaling, dental hygiene, college students.

  17. Role of sedimentary organic matter in bacterial sulfate reduction: the G model tested

    International Nuclear Information System (INIS)

    Westrich, J.T.; Berner, R.A.

    1984-01-01

    Laboratory study of the bacterial decomposition of Long Island Sound plankton in oxygenated seawater over a period of 2 years shows that the organic material undergoes decomposition via first-order kinetics and can be divided into two decomposable fractions, of considerably different reactivity, and a nonmetabolized fraction. This planktonic material, after undergoing varying degrees of oxic degradation, was added in the laboratory to anoxic sediment taken from a depth of 1 m at the NWC site of Long Island Sound and the rate of bacterial sulfate reduction in the sediment measured by the 35 S radiotracer technique. The stimulated rate of sulfate reduction was in direct proportion to the amount of planktonic carbon added. This provides direct confirmation of the first-order decomposition, or G model, for marine sediments and proves that the in situ rate of sulfate reduction is organic-matter limited. Slower sulfate reduction rates resulted when oxically degraded plankton rather than fresh plankton was added, and the results confirm the presence of the same two fractions of organic matter deduced from the oxic degradation studies. Near-surface Long Island Sound sediment, which already contains abundant readily decomposable organic matter, was also subjected to anoxic decomposition by bacterial sulfate reduction. The decrease in sulfate reduction rate with time parallels decreases in the amount of organic matter, and these results also indicate the presence of two fractions of organic carbon of distinctly different reactivity. From plots of the log of reduction rate vs. time two first-order rate constants were obtained that agree well with those derived from the plankton addition experiment. Together, the two experiments confirm the use of a simple multi-first-order rate law for organic matter decomposition in marine sediments

  18. A Three-Dimensional Model of the Marine Nitrogen Cycle during the Last Glacial Maximum Constrained by Sedimentary Isotopes

    Directory of Open Access Journals (Sweden)

    Christopher J. Somes

    2017-05-01

    Full Text Available Nitrogen is a key limiting nutrient that influences marine productivity and carbon sequestration in the ocean via the biological pump. In this study, we present the first estimates of nitrogen cycling in a coupled 3D ocean-biogeochemistry-isotope model forced with realistic boundary conditions from the Last Glacial Maximum (LGM ~21,000 years before present constrained by nitrogen isotopes. The model predicts a large decrease in nitrogen loss rates due to higher oxygen concentrations in the thermocline and sea level drop, and, as a response, reduced nitrogen fixation. Model experiments are performed to evaluate effects of hypothesized increases of atmospheric iron fluxes and oceanic phosphorus inventory relative to present-day conditions. Enhanced atmospheric iron deposition, which is required to reproduce observations, fuels export production in the Southern Ocean causing increased deep ocean nutrient storage. This reduces transport of preformed nutrients to the tropics via mode waters, thereby decreasing productivity, oxygen deficient zones, and water column N-loss there. A larger global phosphorus inventory up to 15% cannot be excluded from the currently available nitrogen isotope data. It stimulates additional nitrogen fixation that increases the global oceanic nitrogen inventory, productivity, and water column N-loss. Among our sensitivity simulations, the best agreements with nitrogen isotope data from LGM sediments indicate that water column and sedimentary N-loss were reduced by 17–62% and 35–69%, respectively, relative to preindustrial values. Our model demonstrates that multiple processes alter the nitrogen isotopic signal in most locations, which creates large uncertainties when quantitatively constraining individual nitrogen cycling processes. One key uncertainty is nitrogen fixation, which decreases by 25–65% in the model during the LGM mainly in response to reduced N-loss, due to the lack of observations in the open ocean most

  19. Pilot points method for conditioning multiple-point statistical facies simulation on flow data

    Science.gov (United States)

    Ma, Wei; Jafarpour, Behnam

    2018-05-01

    We propose a new pilot points method for conditioning discrete multiple-point statistical (MPS) facies simulation on dynamic flow data. While conditioning MPS simulation on static hard data is straightforward, their calibration against nonlinear flow data is nontrivial. The proposed method generates conditional models from a conceptual model of geologic connectivity, known as a training image (TI), by strategically placing and estimating pilot points. To place pilot points, a score map is generated based on three sources of information: (i) the uncertainty in facies distribution, (ii) the model response sensitivity information, and (iii) the observed flow data. Once the pilot points are placed, the facies values at these points are inferred from production data and then are used, along with available hard data at well locations, to simulate a new set of conditional facies realizations. While facies estimation at the pilot points can be performed using different inversion algorithms, in this study the ensemble smoother (ES) is adopted to update permeability maps from production data, which are then used to statistically infer facies types at the pilot point locations. The developed method combines the information in the flow data and the TI by using the former to infer facies values at selected locations away from the wells and the latter to ensure consistent facies structure and connectivity where away from measurement locations. Several numerical experiments are used to evaluate the performance of the developed method and to discuss its important properties.

  20. Application of organic facies in sedimentological-stratigraphical model of the Oligo-Miocene and Miocene of the Campos Basin; Aplicacao da faciologia organica no modelo sedimentologico-estratigrafico do Oligo-Mioceno e Mioceno da Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca Filho, Joao Graciano; Mendonca, Joalice de Oliveira; Oliveira, Antonio Donizeti de; Torres, Jaqueline [Universidade Federal do Rio de Janeiro (UFRJ). Centro de Ciencias Exatas e da Natureza. Inst. de Geociencias (Brazil)], e-mails: graciano@geologia.ufrj.br, donizeti@lafo.geologia.ufrj.br, joalice@lafo.geologia.ufrj.br, jaqueline@lafo.geologia.ufrj.br; Menezes, Taissa Rego [Centro de Pesquisas da Petrobras (CENPES), RJ (Brazil). P e D em Geociencias. Gerencia de Geoquimica], e-mail: taissamenezes@petrobras.com.br; Santos, Viviane Sampaio Santiago dos; Arienti, Luci Maria [Centro de Pesquisas da Petrobras (CENPES), RJ (Brazil). P e D em Geociencias. Gerencia de Sedimentologia e Estratigrafia], e-mails: vsss@petrobras.com.br, arienti@petrobras.com.br

    2010-05-15

    This study integrates palynofacies analyses and the sedimentological and stratigraphic model of the Oligo-Miocene/Miocene siliciclastic deposits from the stratigraphic interval of the shallow continental platform up to the slope/basin of the Oligo-Miocene/ Miocene of the Campos Basin proposed. The main objective of the palynofacies study was to characterize the particulate sedimentary organic matter to obtain information about the proximal-distal relationship and the sedimentary organic matter preservation and depositional environmental conditions. The 158 core samples collected in 29 wells of the 9 oil production fields (Albacora, Barracuda, Marlim Sul, Marlim, Voador, Marlim Leste, Moreia and Albacora Leste), were studied. This technique provides information about the proximal-distal relationship and the paleoenvironmental conditions of deposition and preservation of sedimentary organic matter, to facilitate the evaluation and comparisons between the associations of particulate organic components. Thus, the palynofacies technique can be used as another tool in the characterization of depositional systems, based on the spatial and temporal distribution of sedimentary intervals. In general the palynofacies assemblages showed the predominance of the Phytoclast Group (terrestrial derived organic matter) at various degradation stages due to the selective preservation process diagnosed in the studied samples. Some samples, revealed high dinocysts percentages indicative of transgressive depositional conditions. From the obtained data, it was possible to characterize the stratigraphic sequences according to the distribution of particulate organic content (e.g. influence of fluvio-deltaic systems, oxygen system, regressive-transgressive tendencies of each sequence). Additional analyses of Total Organic Carbon (% wt) showed the control of the particulate components from the Phytoclast Group on the TOC (% wt) content, suggesting that the relative sea-level variation curves

  1. Zircon (Hf, O isotopes) as melt indicator: Melt infiltration and abundant new zircon growth within melt rich layers of granulite-facies lenses versus solid-state recrystallization in hosting amphibolite-facies gneisses (central Erzgebirge, Bohemian Massif)

    Science.gov (United States)

    Tichomirowa, Marion; Whitehouse, Martin; Gerdes, Axel; Schulz, Bernhard

    2018-03-01

    In the central Erzgebirge within the Bohemian Massif, lenses of high pressure and ultrahigh pressure felsic granulites occur within meta-sedimentary and meta-igneous amphibolite-facies felsic rocks. In the felsic granulite, melt rich parts and restite form alternating layers, and were identified by petrology and bulk rock geochemistry. Mineral assemblages representing the peak P-T conditions were best preserved in melanocratic restite layers. In contrast, in the melt rich leucocratic layers, garnet and related HP minerals as kyanite are almost completely resorbed. Both layers display differences in accessory minerals: melanosomes have frequent and large monazite and Fe-Ti-minerals but lack xenotime and apatite; leucosomes have abundant apatite and xenotime while monazite is rare. Here we present a detailed petrographic study of zircon grains (abundance, size, morphology, inclusions) in granulite-facies and amphibolite-facies felsic gneisses, along with their oxygen and hafnium isotope compositions. Our data complement earlier Usbnd Pb ages and trace element data (REE, Y, Hf, U) on zircons from the same rocks (Tichomirowa et al., 2005). Our results show that the degree of melting determines the behaviour of zircon in different layers of the granulites and associated amphibolite-facies rocks. In restite layers of the granulite lenses, small, inherited, and resorbed zircon grains are preserved and new zircon formation is very limited. In contrast, new zircons abundantly grew in the melt rich leucocratic layers. In these layers, the new zircons (Usbnd Pb age, trace elements, Hf, O isotopes) best preserve the information on peak metamorphic conditions due to intense corrosion of other metamorphic minerals. The new zircons often contain inherited cores. Compared to cores, the new zircons and rims show similar or slightly lower Hf isotope values, slightly higher Hf model ages, and decreased oxygen isotope ratios. The isotope compositions (Hf, O) of new zircons indicate

  2. Acoustic Impedance Inversion To Identify Oligo-Miocene Carbonate Facies As Reservoir At Kangean Offshore Area

    Science.gov (United States)

    Zuli Purnama, Arif; Ariyani Machmud, Pritta; Eka Nurcahya, Budi; Yusro, Miftahul; Gunawan, Agung; Rahmadi, Dicky

    2018-03-01

    Model based inversion was applied to inversion process of 2D seismic data in Kangean Offshore Area. Integration acoustic impedance from wells and seismic data was expected showing physical property, facies separation and reservoir quality of carbonate rock, particularly in Kangean Offshore Area. Quantitative and qualitative analysis has been conducted on the inversion results to characterize the carbonate reservoir part of Kujung and correlate it to depositional facies type. Main target exploration in Kangean Offshore Area is Kujung Formation (Oligo-Miocene Carbonate). The type of reservoir in this area generate from reef growing on the platform. Carbonate rock is a reservoir which has various type and scale of porosity. Facies determination is required to to predict reservoir quality, because each facies has its own porosity value. Acoustic impedance is used to identify and characterize Kujung carbonate facies, also could be used to predict the distribution of porosity. Low acoustic impedance correlated with packstone facies that has acoustic impedance value below 7400 gr/cc*m/s. In other situation, high acoustic impedance characterized by wackestone facies above 7400 gr/cc*m/s. The interpretation result indicated that Kujung carbonate rock dominated by packstone facies in the upper part of build-up and it has ideal porosity for hydrocarbon reservoir.

  3. Delineating Facies Spatial Distribution by Integrating Ensemble Data Assimilation and Indicator Geostatistics with Level Set Transformation.

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, Glenn Edward; Song, Xuehang; Ye, Ming; Dai, Zhenxue; Zachara, John; Chen, Xingyuan

    2017-03-01

    A new approach is developed to delineate the spatial distribution of discrete facies (geological units that have unique distributions of hydraulic, physical, and/or chemical properties) conditioned not only on direct data (measurements directly related to facies properties, e.g., grain size distribution obtained from borehole samples) but also on indirect data (observations indirectly related to facies distribution, e.g., hydraulic head and tracer concentration). Our method integrates for the first time ensemble data assimilation with traditional transition probability-based geostatistics. The concept of level set is introduced to build shape parameterization that allows transformation between discrete facies indicators and continuous random variables. The spatial structure of different facies is simulated by indicator models using conditioning points selected adaptively during the iterative process of data assimilation. To evaluate the new method, a two-dimensional semi-synthetic example is designed to estimate the spatial distribution and permeability of two distinct facies from transient head data induced by pumping tests. The example demonstrates that our new method adequately captures the spatial pattern of facies distribution by imposing spatial continuity through conditioning points. The new method also reproduces the overall response in hydraulic head field with better accuracy compared to data assimilation with no constraints on spatial continuity on facies.

  4. Modeling geomorphic changes in sedimentary rock areas. A case study in the Boso Peninsula area, Central Japan

    International Nuclear Information System (INIS)

    Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo; Sanga, Tomoji

    2011-01-01

    For the long-term safety of geological disposal of high-level radioactive wastes, evaluation of the radionuclide migration toward the human environment associated with groundwater flow is an issue of utmost importance. Therefore, we are carrying out a program for developing methods for assessing long-term groundwater flow in regional scales. As a part of the above program, we constructed models depicting the influences of geomorphological evolution on long-term groundwater flow. This was done by reconstructing the processes of river deepening with historical simulation of the profiles of four rivers in the Boso Peninsula. This area was selected because the sedimentary rocks are widely distributed with uncomplicated topography and geological structure which enabled the acquisition of a large amount of relevant geological information. The study resulted in the sum of erosion during the past 125,000 years which is the equivalent of one glacial to interglacial cycle. Consequently, the profiles of four rivers during the last glacial age to the present were successfully reconstructed using similar parameters. Also it was found that, in this area, the profiles were sculpted in accordance with the uplifting rates with very little influence of initial topography owing to the relatively soft and easily dissected characteristics of the geological units. However, detailed investigation revealed that the effects of geomorphological evolution differ between the rivers emptying into the inner bay and the rivers emptying into the open sea. In the case of the former two rivers, the river-bed elevation hardly changed during the 125,000 years and shows an extensive concave profile including the marine area. In the latter case, the elevation changed within the range of 20-30 m during the period and a convex profile appears in the marine area where the present water depth is over 30 m. Additionally the estimates of total amount of erosion during 125,000 years in the former group were

  5. Advanced GPR imaging of sedimentary features: integrated attribute analysis applied to sand dunes

    Science.gov (United States)

    Zhao, Wenke; Forte, Emanuele; Fontolan, Giorgio; Pipan, Michele

    2018-04-01

    We evaluate the applicability and the effectiveness of integrated GPR attribute analysis to image the internal sedimentary features of the Piscinas Dunes, SW Sardinia, Italy. The main objective is to explore the limits of GPR techniques to study sediment-bodies geometry and to provide a non-invasive high-resolution characterization of the different subsurface domains of dune architecture. On such purpose, we exploit the high-quality Piscinas data-set to extract and test different attributes of the GPR trace. Composite displays of multi-attributes related to amplitude, frequency, similarity and textural features are displayed with overlays and RGB mixed models. A multi-attribute comparative analysis is used to characterize different radar facies to better understand the characteristics of internal reflection patterns. The results demonstrate that the proposed integrated GPR attribute analysis can provide enhanced information about the spatial distribution of sediment bodies, allowing an enhanced and more constrained data interpretation.

  6. Investigation of Facies Types and Associations of Kuhlan Red Bed Formation in NW Yemen: A New Hypothesis for Origin and Depositional Environment

    Directory of Open Access Journals (Sweden)

    Mohammed A. Al-Wosabi

    2006-06-01

    Full Text Available Varieties of thirteen facies types were recognized in the Kuhlan Formation represented by red bed siliciclastic sequences of argillaceous sediments. Examination of the Kuhlan stratigraphic column included sequence relationships, lithology, sedimentary characters, structures and petrography of the dominant rock types. These facies types are grouped in three distinct associations of facies. The lower unit A comprises association of facies (Distal turbidites represented by alternates of turbidity sequences including sandstone, siltstone and thick shale beds. These facies types confirm a regressive depositional environment in deep marine shelf conditions. There are three facies types which are identified as massive sandstone, cross-bedded sandstone and pebbly sandstone facies. The middle unit B association of facies (Proximal turbedites represents glaciomarine sequences displaying high lateral and vertical facies changes of glacioturbidite sediment alternates with diamictites and tillite beds. The sequences are affected by eustatic and eustatism of the glacial advance and retreat. This unit B includes eight types of facies. These are identified as; tillite, massive diamictites, stratified diamictites, laminated siltstone/shale, deformed siltstone/mudstone, graded rhythmic siltstone, massive conglomerate and cross-stratified sandy conglomerate facies. The upper unit C association of facies is represented by shallow marine shelf sequences displaying very thick massive and locally cross-bedded sand bar sandstone overlying the laminated siltstone/shale interbeds. The upward gradual changes in mineralogical composition and color confirms the start of marine transgression and later deposited platform Amran Group. Mineralogical composition of Kuhlan sandstone displays impure dirty rocks consisting of more than 30% of argillaceous matrix, 50% of cristobalite and quartz grains, more than 10% of ferruginous cement and 10% of detrital iron oxide grains, potash

  7. Geochemistry of sedimentary carbonates

    National Research Council Canada - National Science Library

    Morse, John W; Mackenzie, Fred T

    1990-01-01

    .... The last major section is two chapters on the global cycle of carbon and human intervention, and the role of sedimentary carbonates as indicators of stability and changes in Earth's surface environment...

  8. DEVELOPING A MATHEMATICAL MODEL FOR THE PROCESS OF DEVELOPING A MATHEMATICAL MODEL FOR THE PROCESS OF SEDIMENTARY TANKS

    Directory of Open Access Journals (Sweden)

    Valeria Victoria IOVANOV

    2013-05-01

    Full Text Available The model is reformulated by means of stochastic differential equations, and the parametersare estimated by a maximum likelihood method.VESILIND (1968; 1979 proposed a sludge settling velocity model of exponential form. During recent years,several refinements to the original model have been proposed, see e.g. GRIJSPEERDT et al. (1995; DUPONTand DAHL (1995 EKAMA et al. (1997. In the proposed models several layers in the settling tank areincorporated to permit the calculation of SS profiles over the tank depth and predict the SS concentrations in thereturn sludge and in the effluent from the clarifier.Here, the original VESILIND model combined with a simple suction depth model is used to enable predictionof the SS concentration in the effluent from the tank. In order to make the model applicable for real time controlpurposes, only two layers of variable height in the tank are considered

  9. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    aram bayetgoll

    2015-10-01

    Formations along the basement Kalmard Fault. In the present study, three stratigraphic sections (NW-SE transects were measured, described and sampled in the Kalmard area. In these sections, detailed considerations have been given on the lithofacies variations; bed geometry and contacts, faunal content, the potential of trace fossils as tools for reconstructing depositional conditions, sedimentary textures and structures, bounding surfaces, vertical trends and stacking patterns and lateral/vertical variations in facies and thicknesses. The observed siliciclastic facies can readily be interpreted using existing shelf sedimentation and shoreline succession models (e.g. Walker and Plint 1992 . Interpretation carbonate facies have been done on the basis the microfacies analysis (200 thin-sections, sedimentary textures and structures and faunal content (Wilson et al. 1975; Flügel 2010 . In final, internal architecture, characteristics of sedimentary facies, the overall stacking pattern and nature of sequence-bounding unconformities have been investigated to evaluate the influence of regional uplift, local tectonics and eustasy on both along-strike variations in sequence architecture and genetic complexity of sequence boundaries.     Discussion, Results and Conclusion   The Lower Ordovician Shirgesht Formation in central Iran is composed of siliciclastic and carbonate rocks deposited in diverse coastal and marine shelf environments (tidal flat, lagoon, shoreface, and offshore-shelf and carbonate ramp. Relying on the facies characteristics and stratal geometries, the siliciclastic succession are divided into five facies associations, FA1 (tidal flat, FA2 (lagoon/washoverfan, FA3 (upper shoreface-foreshore, FA4 (lower to middle shoreface, and FA5 (offshore-shelf.Carbonate succession of this formation based on lithology, sedimentary characteristics and textures divided into four facies belts, FA (tidal flat, FB (lagoon,FC (shoal/barrier island, and FD (open marine. These facies

  10. Joint inversion of geophysical data using petrophysical clustering and facies deformation wth the level set technique

    Science.gov (United States)

    Revil, A.

    2015-12-01

    Geological expertise and petrophysical relationships can be brought together to provide prior information while inverting multiple geophysical datasets. The merging of such information can result in more realistic solution in the distribution of the model parameters, reducing ipse facto the non-uniqueness of the inverse problem. We consider two level of heterogeneities: facies, described by facies boundaries and heteroegenities inside each facies determined by a correlogram. In this presentation, we pose the geophysical inverse problem in terms of Gaussian random fields with mean functions controlled by petrophysical relationships and covariance functions controlled by a prior geological cross-section, including the definition of spatial boundaries for the geological facies. The petrophysical relationship problem is formulated as a regression problem upon each facies. The inversion of the geophysical data is performed in a Bayesian framework. We demonstrate the usefulness of this strategy using a first synthetic case for which we perform a joint inversion of gravity and galvanometric resistivity data with the stations located at the ground surface. The joint inversion is used to recover the density and resistivity distributions of the subsurface. In a second step, we consider the possibility that the facies boundaries are deformable and their shapes are inverted as well. We use the level set approach to perform such deformation preserving prior topological properties of the facies throughout the inversion. With the help of prior facies petrophysical relationships and topological characteristic of each facies, we make posterior inference about multiple geophysical tomograms based on their corresponding geophysical data misfits. The method is applied to a second synthetic case showing that we can recover the heterogeneities inside the facies, the mean values for the petrophysical properties, and, to some extent, the facies boundaries using the 2D joint inversion of

  11. Dolomitization and sedimentary cyclicity of the Ordovician, Silurian, and Devonian rocks in South Estonia

    Directory of Open Access Journals (Sweden)

    Kallaste, Toivo

    2006-03-01

    Full Text Available The distribution and composition of dolomitized rocks and stoichiometry of dolomite in southern Estonia in the Ordovician, Silurian, and Devonian were studied on the background of the facies, sedimentary cyclicity (nine shallowing-up cycles, and evolution of the palaeobasins. The composition of rocks and lattice parameters of dolomite were investigated using the X-ray diffraction, X-ray fluorescence, titration and gravimetric analyses, and porosity measurements. The formation of dolostones is directly determined by the cyclic evolution of palaeobasins. Dolomitized rocks belong to the shallow-water inner shelf or tidal/lagoonal facies belt of regressive phases of sedimentary cycles. Sediments of the deep shelf/transitional environment and transgressive phases are not dolomitized. The most stoichiometric is secondary replacive dolomite of Silurian and upper Ordovician dolostones, formed during the early diagenesis of normal-marine (saline shallow-shelf calcitic sediments. The content of insoluble residue does not affect the stoichiometry. The changes in lattice parameters are induced by the Ca/Mg ratio in the dolomite lattice. The dolomite of the dolostones contacting limestone or containing calcite has an expanded lattice. The primary (syngenetic dolostone of the lagoonal or tidal flat belt has also an expanded lattice. No dolomitizing effect of the waters of the Devonian palaeobasin on the underlying rocks was revealed. The whole data set of the studied dolostones is consistent with the marine water environment in the palaeobasin at the corresponding time and shows no sign of the inflow of external fluids. It suggests that the microbial model of dolomite formation may characterize the Ordovician, Silurian, and Devonian in southern Estonia. The occurrence of dolostones between undolomitized rocks limits the time of dolomitization to the early diagenetic stage.

  12. Integration of seismic data and a triple porosity model for interpretation of tight gas formations in the Western Canada sedimentary basin

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Fernando; Aguilera, Roberto; Lawton, Don [University of Calgary (Canada)

    2011-07-01

    Due to the increased global demand for oil and gas, companies are looking to unconventional methods for exploring, drilling and refining these products. Unconventional reservoirs are found in the form of shale gas, coal bed methane and tight gas. This paper presents a model for evaluating various tight gas reservoirs in the Western Canada sedimentary basin (WCSB) by developing an equation. The proposed method integrates a triple porosity model with sonic, density and resistivity logs. The model uses petrographic data from work in the WCSB to determine the types of pores that are present in the tight rocks. The process also provides information on inter-well formation resistivity, porosity and water saturation to allow estimation of the amount of original gas in place. The results calculated from this study agreed with the actual deep resistivities of the WCSB Nikanassin group. This model can also be applied to other regions of the world that have similar characteristics to those of the WCSB.

  13. Identification of multiple detrital sources for Otway Supergroup sedimentary rocks: implications for basin models and chronostratigraphic correlations

    International Nuclear Information System (INIS)

    Mitchell, M.M.

    1997-01-01

    Correlation of apatite chlorine content (wt%) with apatite fission track age (Ma) from Lower Cretaceous Otway Supergroup sediments at present-day low temperatures, allows identification of two characteristic detrital source regions. Apatites from eroded Palaeozoic basement terrains yield low Cl content (generally 0.5 wt%) and syndepositional fission track ages. Where post-depositional thermal annealing ( > 70 degree C) has significantly reduced the fission track age, provenance information is preserved in the apatite Cl composition alone. In the Otway Supergroup, evidence for contemporaneous volcanism was found in both the Eumeralla Formation (Albian-Aptian), and Crayfish Group (Aptian-Berriasian) in samples located towards the central rift, where less sandy facies dominate. Results suggest that Crayfish Group sediments deposited along the northern margin of the basin were predominantly derived from eroding basement material, while the section located towards the central rift contains a greater proportion of volcanogenic detritus. Evidence from this study suggests that volcanogenic detritus was a distal sediment source throughout the entire early rift phase, prior to the main influx of arc-related volcanogenic material during deposition of the Eumeralla Formation. As diagenesis of volcanogenic sediments significantly reduces porosity and permeability of the sandstones, reservoir quality and petroleum potential may be significantly reduced in the Crayfish Group in deeper parts of the basin where a greater proportion of volcanogenic detritus is suggested. The results presented here provide important information regarding Lower Cretaceous Otway Basin stratigraphy and clearly indicate that this methodology may have wider application. (authors)

  14. 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)

  15. Multiparameter Elastic Full Waveform Inversion With Facies Constraints

    KAUST Repository

    Zhang, Zhendong

    2017-08-17

    Full waveform inversion (FWI) aims fully benefit from all the data characteristics to estimate the parameters describing the assumed physics of the subsurface. However, current efforts to utilize full waveform inversion as a tool beyond acoustic imaging applications, for example in reservoir analysis, faces inherent challenges related to the limited resolution and the potential trade-off between the elastic model parameters. Adding rock physics constraints does help to mitigate these issues, but current approaches to add such constraints are based on including them as a priori knowledge mostly valid around the well or as a boundary condition for the whole area. Since certain rock formations inside the Earth admit consistent elastic properties and relative values of elastic and anisotropic parameters (facies), utilizing such localized facies information in FWI can improve the resolution of inverted parameters. We propose a novel confidence map based approach to utilize the facies-based constraints in both isotropic and anisotropic elastic FWI. We invert for such a confidence map using Bayesian theory, in which the confidence map is updated at each iteration of the inversion using both the inverted models and a prior information. The numerical examples show that the proposed method can reduce the trade-offs and also can improve the resolution of the inverted elastic and anisotropic properties.

  16. The salt that wasn't there: Mudflat facies equivalents to halite of the Permian Rustler Formation, southeastern New Mexico

    International Nuclear Information System (INIS)

    Powers, D.W.; Holt, R.M.

    2000-01-01

    Four halite beds of the Permian Restler Formation in southeastern New Mexico thin dramatically over horst lateral distances to correlative classic (mudstone) beds. The mudstones have long been considered residues after post-burial dissolution (subrosion) of halite, assumed to have been deposited continuously across the area. Hydraulic properties of the Culebra Dolomite Member have often been related to Rustler subrosion. In cores and three shafts at the Waste Isolation Pilot Plant (WIPP), however, these mudstones display flat bedding, graded bedding, cross-bedding, erosional contacts, and channels filled with intraformational conglomerates. Cutans indicate early stages of soil development during subaerial exposure. Smeared intraclasts developed locally as halite was removed syndepositionally during subaerial exposure. The authors interpret these beds as facies formed in salt-pan or hypersaline-lagoon, transitional, and mudflat environments. Halite is distributed approximately as it was deposited. Breccia in limited areas along one halite margin indicates post-burial dissolution, and these breccials are key to identifying areas of subrosion. A depositional model accounts for observed sedimentary features of Restler mudstones. Marked facies and thickness changes are consistent with influence by subsidence boundaries, as found in some modern continental evaporites. A subrosion model accounts for limited brecciated zones along (depositional)halite margins, but bedding observed in the mudstones would not survive 90% reduction in rock volume. Depositional margins for these halite beds will be useful in reconstructing detailed subsidence history of the Late Permian in the northern Delaware Basin, It also no longer is tenable to attribute large variations in Culebra transmissivity to Rustler subrosion

  17. Reactive transport and mass balance modeling of the Stimson sedimentary formation and altered fracture zones constrain diagenetic conditions at Gale crater, Mars

    Science.gov (United States)

    Hausrath, E. M.; Ming, D. W.; Peretyazhko, T. S.; Rampe, E. B.

    2018-06-01

    On a planet as cold and dry as present-day Mars, evidence of multiple aqueous episodes offers an intriguing view into very different past environments. Fluvial, lacustrine, and eolian depositional environments are being investigated by the Mars Science Laboratory Curiosity in Gale crater, Mars. Geochemical and mineralogical observations of these sedimentary rocks suggest diagenetic processes affected the sediments. Here, we analyze diagenesis of the Stimson formation eolian parent material, which caused loss of olivine and formation of magnetite. Additional, later alteration in fracture zones resulted in preferential dissolution of pyroxene and precipitation of secondary amorphous silica and Ca sulfate. The ability to compare the unaltered parent material with the reacted material allows constraints to be placed on the characteristics of the altering solutions. In this work we use a combination of a mass balance approach calculating the fraction of a mobile element lost or gained, τ, with fundamental geochemical kinetics and thermodynamics in the reactive transport code CrunchFlow to examine the characteristics of multiple stages of aqueous alteration at Gale crater, Mars. Our model results indicate that early diagenesis of the Stimson sedimentary formation is consistent with leaching of an eolian deposit by a near-neutral solution, and that formation of the altered fracture zones is consistent with a very acidic, high sulfate solution containing Ca, P and Si. These results indicate a range of past aqueous conditions occurring at Gale crater, Mars, with important implications for past martian climate and environments.

  18. Comparison of four approaches to a rock facies classification problem

    Science.gov (United States)

    Dubois, M.K.; Bohling, Geoffrey C.; Chakrabarti, S.

    2007-01-01

    In this study, seven classifiers based on four different approaches were tested in a rock facies classification problem: classical parametric methods using Bayes' rule, and non-parametric methods using fuzzy logic, k-nearest neighbor, and feed forward-back propagating artificial neural network. Determining the most effective classifier for geologic facies prediction in wells without cores in the Panoma gas field, in Southwest Kansas, was the objective. Study data include 3600 samples with known rock facies class (from core) with each sample having either four or five measured properties (wire-line log curves), and two derived geologic properties (geologic constraining variables). The sample set was divided into two subsets, one for training and one for testing the ability of the trained classifier to correctly assign classes. Artificial neural networks clearly outperformed all other classifiers and are effective tools for this particular classification problem. Classical parametric models were inadequate due to the nature of the predictor variables (high dimensional and not linearly correlated), and feature space of the classes (overlapping). The other non-parametric methods tested, k-nearest neighbor and fuzzy logic, would need considerable improvement to match the neural network effectiveness, but further work, possibly combining certain aspects of the three non-parametric methods, may be justified. ?? 2006 Elsevier Ltd. All rights reserved.

  19. Sedimentary mode and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Jinhu Du

    2016-11-01

    Full Text Available The gas reservoir of the Lower Cambrian Longwangmiao Fm in the Sichuan Basin is a supergiant integral marine carbonate gas reservoir whose single scale is currently the largest in China. In order to figure out its sedimentary model and reservoir genesis, its geological structures and sedimentary settings and facies were analyzed comprehensively and the lithofacies paleographic map was plotted. It is revealed that the following sedimentary facies are successively developed in the Longwangmiao Fm from West Sichuan to Southeast Chongqing: diamictic tidal flat at the back ramp, grain bank (the upper bank at the inner/shallow ramp – interbank sea (depression, deeper open bay at the platform depression of inner ramp → evaporative lagoon → evaporative tidal flat, tempestite at the middle ramp – barrier beach – mud mound beach (the lower bank, and outer ramp – basin. Accordingly, the specific sedimentary model of dual grain banks in the Longwangmiao Fm carbonate ramp was established as follows. Firstly, in this model, dual grain banks are symmetrically developed with Wanzhou–Yibin platform depression as the axis, on whose dual sides the paleohighs have shallow water bodies with strong energy. Compared with the classical model, the new one has a new upper bank which is developed around the paleohighs covering an area of about 8 × 104 km2. Secondly, the upper bank is large for its paleogeomorphology being located at the highest position with the strongest water energy during deposition. Therefore, it is prone to dolomitization and meteoric dissolution respectively during contemporaneous–penecontemporaneous hot-dry and hot-humid periods, and especially the Caledonian–Early Hercynian denudation wedge out tends to undergo post-supergene multiphase karstification. Therefore, quality reservoirs are more developed on scale. Thirdly, the intergranular pores and vermes moldic pores were dissolved and enlarged due to the multiphase

  20. Facies interpretations and lateral variability based on correlation of conventional core in the Logan canyon and Mississauga formations of the Scotian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Piper, D.J.W. [Geological Survey of Canada (Canada); Gould, K.M.; Pe-Piper, G. [Saint Mary' s University (Canada)], email: 075353g@acadiau.ca

    2011-07-01

    In the Lower Cretaceous of the Scotian Basin in Canada, sediment facies have been interpreted mostly using vertical successions of rock. However, other studies show that the lateral extent and variability of sediment facies must be understood to assess reservoir extent and connectivity. The aim of this paper is to present the investigation of two areas of the Scotian Basin. In each area, a regional correlation was performed using gamma ray well logs and the lithology, sedimentary and biogenic structures were determined for 67 different cores. It was found that the determination of facies and vertical successions was useful for comparing and correlating across multiple wells. In addition it was shown that gamma logs are effective for regional correlation but can only correlate major changes. This paper demonstrated that gamma logs are useful for performing facies interpretations and determining lateral variability.

  1. Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran

    Energy Technology Data Exchange (ETDEWEB)

    Omidvar, M.; Safari, A.; Vaziri-Moghaddam, H.; Ghalavand, H.

    2016-07-01

    Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers. (Author)

  2. Sedimentary architecture of the distal lower freshwater molasse and its relation to the diagenesis and petrophysical properties demonstrated by the example of the Langenthal boreholes

    International Nuclear Information System (INIS)

    Keller, B.; Blaesi, H.R.; Platt, N.H.; Mozley, P.S.; Matter, A.

    1990-08-01

    Sedimentary study at outcrop and quarry exposures of distal alluvial deposits in the upper part of the Lower Freshwater Molasse ('Aquitan') has revealed four principal facies. The same facies may also be recognised in boreholes (Langenthal, Weiach, Schafisheim) penetrating the continental succession. These facies make up distinct sediment bodies or 'architectural elements'. Each architectural element may be assigned to a particular depositional setting: Meander Belt RG (MB); Crevasse Splays and Crevasse Channels DFR (CS), Levees and Distal Splays UW (LS), Overbank, Paleosols and Swamps UPS (OPS) and Lacustrine LAK (LAC). Meander belt sandstones in the distal Lower Freshwater Molasse reflect the occurrence of two types of mixed load channels. Architectural modelling permits consideration of the distal Lower Freshwater Molasse in terms of a sandy framework, comprising the channel sandstone bodies, each in contact with their associated crevasse splay and crevasse channel sandstones, and a muddy-silty matrix consisting of interbedded floodplain sediments. Comparison with the morphologies of modern alluvial systems suggests that channel sandstone bodies in the Lower Freshwater Molasse are likely to show greater longitudinal continuity, greater width and a higher degree of interconnectedness in an upstream direction. Conversely, primary depositional porosities and permeabilities of the sandstone units are likely to decrease downstream towards more distal areas in the east and at the northern margin of the basin, although regional differences in tectonic style and diagenesis will also exert a major control on the petrophysical and hydrological properties in any given area. (author) figs., tabs., 54 refs

  3. 3D Voronoi grid dedicated software for modeling gas migration in deep layered sedimentary formations with TOUGH2-TMGAS

    Science.gov (United States)

    Bonduà, Stefano; Battistelli, Alfredo; Berry, Paolo; Bortolotti, Villiam; Consonni, Alberto; Cormio, Carlo; Geloni, Claudio; Vasini, Ester Maria

    2017-11-01

    As is known, a full three-dimensional (3D) unstructured grid permits a great degree of flexibility when performing accurate numerical reservoir simulations. However, when the Integral Finite Difference Method (IFDM) is used for spatial discretization, constraints (arising from the required orthogonality between the segment connecting the blocks nodes and the interface area between blocks) pose difficulties in the creation of grids with irregular shaped blocks. The full 3D Voronoi approach guarantees the respect of IFDM constraints and allows generation of grids conforming to geological formations and structural objects and at the same time higher grid resolution in volumes of interest. In this work, we present dedicated pre- and post-processing gridding software tools for the TOUGH family of numerical reservoir simulators, developed by the Geothermal Research Group of the DICAM Department, University of Bologna. VORO2MESH is a new software coded in C++, based on the voro++ library, allowing computation of the 3D Voronoi tessellation for a given domain and the creation of a ready to use TOUGH2 MESH file. If a set of geological surfaces is available, the software can directly generate the set of Voronoi seed points used for tessellation. In order to reduce the number of connections and so to decrease computation time, VORO2MESH can produce a mixed grid with regular blocks (orthogonal prisms) and irregular blocks (polyhedron Voronoi blocks) at the point of contact between different geological formations. In order to visualize 3D Voronoi grids together with the results of numerical simulations, the functionality of the TOUGH2Viewer post-processor has been extended. We describe an application of VORO2MESH and TOUGH2Viewer to validate the two tools. The case study deals with the simulation of the migration of gases in deep layered sedimentary formations at basin scale using TOUGH2-TMGAS. A comparison between the simulation performances of unstructured and structured

  4. Sedimentary processes and depositional environments of the Horn River Shale in British Columbia, Canada

    Science.gov (United States)

    Yoon, Seok-Hoon; Koh, Chang-Seong; Joe, Young-Jin; Woo, Ju-Hwan; Lee, Hyun-Suk

    2017-04-01

    The Horn River Basin in the northeastern British Columbia, Canada, is one of the largest unconventional gas accumulations in North America. It consists mainly of Devonian shales (Horn River Formation) and is stratigraphically divided into three members, the Muskwa, Otterpark and Evie in descending order. This study focuses on sedimentary processes and depositional environments of the Horn River shale based on sedimentary facies analysis aided by well-log mineralogy (ECS) and total organic carbon (TOC) data. The shale formation consists dominantly of siliceous minerals (quartz, feldspar and mica) and subordinate clay mineral and carbonate materials, and TOC ranging from 1.0 to 7.6%. Based on sedimentary structures and micro texture, three sedimentary facies were classified: homogeneous mudstone (HM), indistinctly laminated mudstone (ILM), and planar laminated mudstone (PLM). Integrated interpretation of the sedimentary facies, lithology and TOC suggests that depositional environment of the Horn River shale was an anoxic quiescent basin plain and base-of-slope off carbonate platform or reef. In this deeper marine setting, organic-rich facies HM and ILM, dominant in the Muskwa (the upper part of the Horn River Formation) and Evie (the lower part of the Horn River Formation) members, may have been emplaced by pelagic to hemipelagic sedimentation on the anoxic sea floor with infrequent effects of low-density gravity flows (turbidity currents or nepheloid flows). In the other hand, facies PLM typifying the Otterpark Member (the middle part of the Horn River Formation) suggests more frequent inflow of bottom-hugging turbidity currents punctuating the hemipelagic settling of the background sedimentation process. The stratigraphic change of sedimentary facies and TOC content in the Horn River Formation is most appropriately interpreted to have been caused by the relative sea-level change, that is, lower TOC and frequent signal of turbidity current during the sea

  5. Polymetamorphic evolution of the granulite-facies Paleoproterozoic basement of the Kabul Block, Afghanistan

    Science.gov (United States)

    Collett, Stephen; Faryad, Shah Wali; Mosazai, Amir Mohammad

    2015-08-01

    The Kabul Block is an elongate crustal fragment which cuts across the Afghan Central Blocks, adjoining the Indian and Eurasian continents. Bounded by major strike slip faults and ophiolitic material thrust onto either side, the block contains a strongly metamorphosed basement consisting of some of the only quantifiably Proterozoic rocks south of the Herat-Panjshir Suture Zone. The basement rocks crop-out extensively in the vicinity of Kabul City and consist predominantly of migmatites, gneisses, schists and small amounts of higher-grade granulite-facies rocks. Granulite-facies assemblages were identified in felsic and mafic siliceous rocks as well as impure carbonates. Granulite-facies conditions are recorded by the presence of orthopyroxene overgrowing biotite in felsic rocks; by orthopyroxene overgrowing amphibole in mafic rocks and by the presence of olivine and clinohumite in the marbles. The granulite-facies assemblages are overprinted by a younger amphibolite-facies event that is characterized by the growth of garnet at the expense of the granulite-facies phases. Pressure-temperature (P-T) conditions for the granulite-facies event of around 850 °C and up to 7 kbar were calculated through conventional thermobarometry and phase equilibria modeling. The younger, amphibolite-facies event shows moderately higher pressures of up to 8.5 kbar at around 600 °C. This metamorphism likely corresponds to the dominant metamorphic event within the basement of the Kabul Block. The results of this work are combined with the litho-stratigraphic relations and recent geochronological dating to analyze envisaged Paleoproterozoic and Neoproterozoic metamorphic events in the Kabul Block.

  6. Integrated 3D geology modeling constrained by facies and horizontal well data for Block M of the Orinoco heavy oil belt

    Energy Technology Data Exchange (ETDEWEB)

    Longxin, M.; Baojun, X.; Shancheng, Z.; Guoqing, H. [CNPC America Ltd., Caracas (Venezuela)

    2008-10-15

    Horizontal well drilling with cold production were used to develop most of heavy oil fields in Venezuela's Orinoco heavy oil belt. This study interpreted the horizontal well logs of Block M of the Orinoco heavy oil belt in an effort to improve production from this highly porous and permeable reservoir. The reservoir is comprised primarily of non-consolidated sandstones. A porosity calculation formula for the horizontal well without porosity logs was established based on the study of horizontal well logging data of block M in the Orinoco heavy oil belt. A high quality 3-D simulation tool was used to separate the block into several different sections. A set of methods were presented in order to identify if the well track was approaching an adjacent formation, to estimate the distance between the well track and the adjacent formation, and to correct the deep resistivity of the horizontal section affected by the adjacent formation. A set of interpretation techniques were established, based on the combination of well logging data, seismic data and the oilfield development performance data. It was concluded that the development of the precise 3D geological model helped to establish a solid foundation for guiding the well position design and the drilling of the horizontal well. It also contributed to the reservoir numerical simulation and the effective development of the oil field. 6 refs., 2 tabs., 14 figs.

  7. Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea

    Directory of Open Access Journals (Sweden)

    Finn Surlyk

    2011-12-01

    Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

  8. Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea: Plate 1

    Directory of Open Access Journals (Sweden)

    Surlyk, Finn

    2011-12-01

    Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

  9. Optimum and robust 3D facies interpolation strategies in a heterogeneous coal zone (Tertiary As Pontes basin, NW Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Falivene, Oriol; Cabrera, Lluis; Saez, Alberto [Geomodels Institute, Group of Geodynamics and Basin Analysis, Department of Stratigraphy, Paleontology and Marine Geosciences, Universitat de Barcelona, c/ Marti i Franques s/n, Facultat de Geologia, 08028 Barcelona (Spain)

    2007-07-02

    Coal exploration and mining in extensively drilled and sampled coal zones can benefit from 3D statistical facies interpolation. Starting from closely spaced core descriptions, and using interpolation methods, a 3D optimum and robust facies distribution model was obtained for a thick, heterogeneous coal zone deposited in the non-marine As Pontes basin (Oligocene-Early Miocene, NW Spain). Several grid layering styles, interpolation methods (truncated inverse squared distance weighting, truncated kriging, truncated kriging with an areal trend, indicator inverse squared distance weighting, indicator kriging, and indicator kriging with an areal trend) and searching conditions were compared. Facies interpolation strategies were evaluated using visual comparison and cross validation. Moreover, robustness of the resultant facies distribution with respect to variations in interpolation method input parameters was verified by taking into account several scenarios of uncertainty. The resultant 3D facies reconstruction improves the understanding of the distribution and geometry of the coal facies. Furthermore, since some coal quality properties (e.g. calorific value or sulphur percentage) display a good statistical correspondence with facies, predicting the distribution of these properties using the reconstructed facies distribution as a template proved to be a powerful approach, yielding more accurate and realistic reconstructions of these properties in the coal zone. (author)

  10. Facies-related fracturing in turbidites: insights from the Marnoso-Arenacea Fm. (Northern Apennines, Italy)

    Science.gov (United States)

    Ogata, Kei; Storti, Fabrizio; Balsamo, Fabrizio; Bedogni, Enrico; Tinterri, Roberto; Fetter, Marcos; Gomes, Leonardo; Hatushika, Raphael

    2016-04-01

    Natural fractures deeply influence subsurface fluid flow, exerting a primary control on resources like aquifers, hydrocarbons and geothermal reservoirs, and on environmental issues like CO2 storage and nuclear waste disposal. In layered sedimentary rocks, depositional processes-imprinted rock rheology favours the development of both mechanical anisotropy and heterogeneity on a wide range of scales, and are thus expected to strongly influence location and frequency of fractures. To better constrain the contribution of stratigraphic, sedimentological and petrophysical attributes, we performed a high-resolution, multidisciplinary study on a selected stratigraphic interval of jointed foredeep turbidites in the Miocene Marnoso-arenacea Formation (Northern Apennines, Italy), which are characterised by a great lateral and vertical variability of grain-size and depositional structures. Statistical relationships among field and laboratory data significantly improve when the single facies scale is considered, and, for similar facies recording different evolutionary stages of the parent turbidity currents, we observed a direct correlation between the three-dimensional anisotropies of rock hardness tensors and the normalized fracture frequencies, testifying for the primary sedimentary flow-related control on fracture distributions.

  11. First direct observations linking confined supercritical turbidity currents to their depositional architecture and facies characteristics

    Science.gov (United States)

    Hage, S.; Cartigny, M.; Hughes Clarke, J. E.; Clare, M. A.; Sumner, E.; Hubbard, S. M.; Talling, P.; Lintern, G.; Stacey, C.; Vardy, M. E.; Hunt, J.; Vendettuoli, D.; Yokokawa, M.; Hizzett, J. L.; Vellinga, A. J.; Azpiroz, M.

    2017-12-01

    Turbidity currents transfer globally significant amounts of sediment via submarine channels from the continental margin to deep submarine fans. Submarine channel inception is thought to result from erosive, supercritical turbidity currents that are common in proximal settings of the marine realm. Recent monitoring of submarine processes have provided the first measurements of supercritical turbidity currents (Hughes Clarke, 2016), demonstrating that they drive the upstream migration of crescentic bedforms in confined submarine channels. Although upstream-migrating bedforms are common in confined channels across the world's oceans, there is considerable debate over the type of deposits that they produce. It is important to understand what types of deposit record these supercritical bedforms to potentially identify them from geological archives. For the first time, we combine direct measurements from supercritical field-scale turbidity currents with the facies and depositional architecture resulting from such flows. We show how the subsurface architecture evolves in a highly active channel at Squamish submarine delta, British Columbia, Canada. Repeated upstream migration of bedforms is found to create two main deposit geometries. First, regular back-stepping beds result from flow deceleration on the slightly-inclined sides of the bedforms. Second, lens-shaped scour fills composed of massive deposits result from erosion of the back-stepping beds by subsequent turbidity currents. We relate our findings to a range of ancient outcrop studies to demonstrate that supercritical flows are common in proximal settings through the geological record. This study provides the first direct observation-based model to identify confined supercritical turbidity currents and their associated upslope-migrating bedforms in the sedimentary record. This is important for correctly identifying the proximal sites of ancient submarine channels that served as past conduits for globally

  12. Model-based classification of CPT data and automated lithostratigraphic mapping for high-resolution characterization of a heterogeneous sedimentary aquifer.

    Science.gov (United States)

    Rogiers, Bart; Mallants, Dirk; Batelaan, Okke; Gedeon, Matej; Huysmans, Marijke; Dassargues, Alain

    2017-01-01

    Cone penetration testing (CPT) is one of the most efficient and versatile methods currently available for geotechnical, lithostratigraphic and hydrogeological site characterization. Currently available methods for soil behaviour type classification (SBT) of CPT data however have severe limitations, often restricting their application to a local scale. For parameterization of regional groundwater flow or geotechnical models, and delineation of regional hydro- or lithostratigraphy, regional SBT classification would be very useful. This paper investigates the use of model-based clustering for SBT classification, and the influence of different clustering approaches on the properties and spatial distribution of the obtained soil classes. We additionally propose a methodology for automated lithostratigraphic mapping of regionally occurring sedimentary units using SBT classification. The methodology is applied to a large CPT dataset, covering a groundwater basin of ~60 km2 with predominantly unconsolidated sandy sediments in northern Belgium. Results show that the model-based approach is superior in detecting the true lithological classes when compared to more frequently applied unsupervised classification approaches or literature classification diagrams. We demonstrate that automated mapping of lithostratigraphic units using advanced SBT classification techniques can provide a large gain in efficiency, compared to more time-consuming manual approaches and yields at least equally accurate results.

  13. Model-based classification of CPT data and automated lithostratigraphic mapping for high-resolution characterization of a heterogeneous sedimentary aquifer.

    Directory of Open Access Journals (Sweden)

    Bart Rogiers

    Full Text Available Cone penetration testing (CPT is one of the most efficient and versatile methods currently available for geotechnical, lithostratigraphic and hydrogeological site characterization. Currently available methods for soil behaviour type classification (SBT of CPT data however have severe limitations, often restricting their application to a local scale. For parameterization of regional groundwater flow or geotechnical models, and delineation of regional hydro- or lithostratigraphy, regional SBT classification would be very useful. This paper investigates the use of model-based clustering for SBT classification, and the influence of different clustering approaches on the properties and spatial distribution of the obtained soil classes. We additionally propose a methodology for automated lithostratigraphic mapping of regionally occurring sedimentary units using SBT classification. The methodology is applied to a large CPT dataset, covering a groundwater basin of ~60 km2 with predominantly unconsolidated sandy sediments in northern Belgium. Results show that the model-based approach is superior in detecting the true lithological classes when compared to more frequently applied unsupervised classification approaches or literature classification diagrams. We demonstrate that automated mapping of lithostratigraphic units using advanced SBT classification techniques can provide a large gain in efficiency, compared to more time-consuming manual approaches and yields at least equally accurate results.

  14. Depositional environment of the Onverwacht sedimentary rocks Barberton greenstone belt, South Africa

    Science.gov (United States)

    Paris, I. A.

    The Onverwacht Group is the basal part of the ca 3.5 Ga succession forming the Barberton greenstone belt. It comprises a volcanic pile overlain by a thin layer of volcaniclastic sediments which, due to silicification, are extremely well preserved. There has been a controversy as to how and in what environment these sediments were formed, different sets of data being presented to reach opposite conclusions. The Onverwacht Group has been extensively repeated tectonically and here for the first time, sediments from different structural levels are studied together. Three separate facies have been recognised, a distal and proximal turbidite facies and a subaerial facies. Deposition of Onverwacht Group sedimentary rocks occurred in an oceanic basin characterised by the presence of emergent volcanic islands. After eruption, material was deposited both subaerially and in a shallow submarine environment on the volcanic slopes and, as a result of pyroclastic flow, in the deeper parts of the basin.

  15. A hydro-sedimentary modeling system for flash flood propagation and hazard estimation under different agricultural practices

    Science.gov (United States)

    Kourgialas, N. N.; Karatzas, G. P.

    2014-03-01

    A modeling system for the estimation of flash flood flow velocity and sediment transport is developed in this study. The system comprises three components: (a) a modeling framework based on the hydrological model HSPF, (b) the hydrodynamic module of the hydraulic model MIKE 11 (quasi-2-D), and (c) the advection-dispersion module of MIKE 11 as a sediment transport model. An important parameter in hydraulic modeling is the Manning's coefficient, an indicator of the channel resistance which is directly dependent on riparian vegetation changes. Riparian vegetation's effect on flood propagation parameters such as water depth (inundation), discharge, flow velocity, and sediment transport load is investigated in this study. Based on the obtained results, when the weed-cutting percentage is increased, the flood wave depth decreases while flow discharge, velocity and sediment transport load increase. The proposed modeling system is used to evaluate and illustrate the flood hazard for different riparian vegetation cutting scenarios. For the estimation of flood hazard, a combination of the flood propagation characteristics of water depth, flow velocity and sediment load was used. Next, a well-balanced selection of the most appropriate agricultural cutting practices of riparian vegetation was performed. Ultimately, the model results obtained for different agricultural cutting practice scenarios can be employed to create flood protection measures for flood-prone areas. The proposed methodology was applied to the downstream part of a small Mediterranean river basin in Crete, Greece.

  16. Model-based analysis of δ34S signatures to trace sedimentary pyrite oxidation during managed aquifer recharge in a heterogeneous aquifer

    Science.gov (United States)

    Seibert, Simone; Descourvieres, Carlos; Skrzypek, Grzegorz; Deng, Hailin; Prommer, Henning

    2017-05-01

    The oxidation of pyrite is often one of the main drivers affecting groundwater quality during managed aquifer recharge in deep aquifers. Data and techniques that allow detailed identification and quantification of pyrite oxidation are therefore crucial for assessing and predicting the adverse water quality changes that may be associated with this process. In this study, we explore the benefits of combining stable sulphur isotope analysis with reactive transport modelling to improve the identification and characterisation of pyrite oxidation during an aquifer storage and recovery experiment in a chemically and physically heterogeneous aquifer. We characterise the stable sulphur isotope signal (δ34S) in both the ambient groundwater and the injectant as well as its spatial distribution within the sedimentary sulphur species. The identified stable sulphur isotope signal for pyrite was found to vary between -32 and +34‰, while the signal of the injectant ranged between +9.06 and +14.45‰ during the injection phase of the experiment. Both isotope and hydrochemical data together suggest a substantial contribution of pyrite oxidation to the observed, temporally variable δ34S signals. The variability of the δ34S signal in pyrite and the injectant were both found to complicate the analysis of the stable isotope data. However, the incorporation of the data into a numerical modelling approach allowed to successfully employ the δ34S signatures as a valuable additional constraint for identifying and quantifying the contribution of pyrite oxidation to the redox transformations that occur in response to the injection of oxygenated water.

  17. 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

  18. Sedimentary condensation and authigenesis

    Science.gov (United States)

    Föllmi, Karl

    2016-04-01

    Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin ( 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and paleoenvironmental change themselves.

  19. Prima facie questions in quantum gravity

    Science.gov (United States)

    Isham, C. J.

    The long history of the study of quantum gravity has thrown up a complex web of ideas and approaches. The aim of this article is to unravel this web a little by analysing some of the {\\em prima facie\\/} questions that can be asked of almost any approach to quantum gravity and whose answers assist in classifying the different schemes. Particular emphasis is placed on (i) the role of background conceptual and technical structure; (ii) the role of spacetime diffeomorphisms; and (iii) the problem of time.

  20. 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

  1. Pore-Scale Study of Transverse Mixing Induced CaCO 3 Precipitation and Permeability Reduction in a Model Subsurface Sedimentary System

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Changyong; Dehoff, Karl; Hess, Nancy; Oostrom, Mart; Wietsma, Thomas W.; Valocchi, Albert J.; Fouke, Bruce W.; Werth, Charles J.

    2010-10-15

    A microfluidic pore structure etched into a silicon wafer was used as a two-dimensional model subsurface sedimentary system (i.e., a micromodel) to study mineral precipitation and permeability reduction relevant to groundwater remediation and geological carbon sequestration. Solutions containing CaCl2 and Na2CO3 at four different saturation states (Ω = [Ca2+] [CO32-] / KspCaCO3) were introduced through two separate inlets and they mixed by diffusion transverse to the main flow direction along the center of the micromodel resulting in CaCO3 precipitation. Precipitation rates increased and the total amount of precipitates decreased with increasing saturation state, and only vaterite and calcite crystals were formed (no aragonite). The relative amount of vaterite increased from 80% at the lowest saturation (Ωv = 2.8 for vaterite) state to 95% at the highest saturation state (Ωv = 4.5). Fluorescent tracer tests conducted before and after CaCO3 precipitation indicate that pore spaces were completely occluded by CaCO3 precipitates along the transverse mixing zone, thus significantly reducing porosity and permeability, and potentially limiting transformation from vaterite to the more stable calcite. The results suggest that mineral precipitation along plume margins can decrease both reactant mixing during groundwater remediation, and injection and storage efficiency during CO2 sequestration.

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

    Science.gov (United States)

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

    2015-12-01

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

  3. 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)

  4. Tectono-sedimentary evolution of the Permian-Triassic extension event in the Zagros basin (Iran): results from analogue modelling

    Science.gov (United States)

    Madani-kivi, M.; Zulauf, G.

    2015-12-01

    Since the 1970s, the largest oil and gas reservoirs have been discovered in the Permian-Early Triassic formationsin Saudi Arabia. Thus, this time period is important for the discovery of new oil reserves in Iran. The Arabian passivecontinental margin has undergone lithospheric extension during the Permian-Triassic, which led to the formation of theNeo-Tethys. The aim of this paper is to describe the development of the continental rift basin in the Zagros region basedon the tectono-sedimentological evolution. We have studied well-log data to specify the distribution of synrift depositsin the Zagros and have related this information to the modelling. Environmental changes indicated by various sedimentarysequences, from a siliciclastic basin to a carbonate platform setting, are described. The Cambrian Hormuz salt, whichoverlies the metamorphosed Precambrian basement, becomes effective as a basal detachment layer influencing the styleof overburden deformation during the Permian-Triassic extension event. We have investigated the formation of variousstructures linked to the presence or absence of the Hormuz layer by analogue modelling and relating these structures to theLate Palaeozoic sedimentation. Based on results of the analogue modelling, we argue that the basal detachment layer (Hormuzseries) has contributed to the various structural styles of the extensional basin development in the Fars domain and theLorestan domain.

  5. Sedimentary Processes. Quantification Using Radionuclides

    International Nuclear Information System (INIS)

    Carroll, J.; Lerche, I.

    2003-01-01

    The advent of radionuclide methods in geochronology has revolutionized our understanding of modern sedimentary processes in aquatic systems. This book examines the principles of the method and its use as a quantitative tool in marine geology, with emphasis on the Pb-210 method. The assumptions and consequences of models and their behaviour are described providing the necessary background to assess the advantages and trade-offs involved when choosing a particular model for application. One of the purposes of this volume is to disentangle the influences of complicating factors, such as sediment flux variations, post-depositional diffusion of radionuclides, and bio-irrigation of sediments, to arrive at sediment ages and to properly assess the attendant data uncertainty. Environmental impacts of chemical, nuclear, or other waste material are of concern in a variety of areas around the world today. A number of relevant examples are included, demonstrating how dating models are useful for determining sources of contaminants and interpreting their influence on the environment. The book is set at a level so that an able student or professional should have no difficulty in following the procedures and methods developed. Each chapter includes case histories showing the strengths and weaknesses of a given procedure with respect to a data example. Included with this volume is the computer source code of a new generation of modelling tools based on inverse numerical analysis techniques. This first generation of the modelling tool is included, along with detailed instructions and examples for its use, in an appendix

  6. The role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities: an example from the southern North Sea.

    Directory of Open Access Journals (Sweden)

    Michaela Schratzberger

    Full Text Available We combined sediment and faunal data to explore the role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities at Broken Bank and Swarte Bank, in the southern North Sea. A variety of sediment transport processes occur in the area, differing in the frequency and magnitude of sediment mobility, and the continuum between erosion, translation and sediment accumulation. The seabed contained a variety of bedforms, including longitudinal furrows, and small to very large sandwaves. The bed sediments were dominated by fine and medium sands, with admixtures of silt and gravel. Based on sedimentary bedforms and grain size analysis, a total of 11 sedimentary facies were delineated, of which 8 were analysed in detail for their relationships with the meiofauna. The sedimentary facies fell clearly into groups of facies, respectively representing high, high-moderate and moderate, and episodic sediment mobility. For those sedimentary facies where daily movement of sediments and bedforms occurred ('high' sediment mobility, the resulting spatially homogeneous environments were dominated by an impoverished nematode community comprising small deposit feeders and large predators. Resistance to sediment movement and the ability to exploit alternative food sources were prominent functional features of the successful colonisers. Those facies characterised by relatively infrequent sediment mobility ('episodic' and 'high-moderate and moderate' sediment mobility comprised a heterogeneous suite of benthic habitats, containing taxonomically and functionally diverse assemblages of nematodes of various sizes, feeding types and reproductive potential. Faunal distribution patterns here indicated trade-offs between the resistance to sediment movement, environmental tolerance and competitive abilities. Our focus on diverse assemblages of organisms with high turnover times, inhabiting highly

  7. The Role of the Sedimentary Regime in Shaping the Distribution of Subtidal Sandbank Environments and the Associated Meiofaunal Nematode Communities: An Example from the Southern North Sea

    Science.gov (United States)

    Schratzberger, Michaela; Larcombe, Piers

    2014-01-01

    We combined sediment and faunal data to explore the role of the sedimentary regime in shaping the distribution of subtidal sandbank environments and the associated meiofaunal nematode communities at Broken Bank and Swarte Bank, in the southern North Sea. A variety of sediment transport processes occur in the area, differing in the frequency and magnitude of sediment mobility, and the continuum between erosion, translation and sediment accumulation. The seabed contained a variety of bedforms, including longitudinal furrows, and small to very large sandwaves. The bed sediments were dominated by fine and medium sands, with admixtures of silt and gravel. Based on sedimentary bedforms and grain size analysis, a total of 11 sedimentary facies were delineated, of which 8 were analysed in detail for their relationships with the meiofauna. The sedimentary facies fell clearly into groups of facies, respectively representing high, high-moderate and moderate, and episodic sediment mobility. For those sedimentary facies where daily movement of sediments and bedforms occurred (‘high’ sediment mobility), the resulting spatially homogeneous environments were dominated by an impoverished nematode community comprising small deposit feeders and large predators. Resistance to sediment movement and the ability to exploit alternative food sources were prominent functional features of the successful colonisers. Those facies characterised by relatively infrequent sediment mobility (‘episodic’ and ‘high-moderate and moderate’ sediment mobility) comprised a heterogeneous suite of benthic habitats, containing taxonomically and functionally diverse assemblages of nematodes of various sizes, feeding types and reproductive potential. Faunal distribution patterns here indicated trade-offs between the resistance to sediment movement, environmental tolerance and competitive abilities. Our focus on diverse assemblages of organisms with high turnover times, inhabiting highly dynamic

  8. Facies analysis of tuffaceous volcaniclastics and felsic volcanics of Tadpatri Formation, Cuddapah basin, Andhra Pradesh, India

    Science.gov (United States)

    Goswami, Sukanta; Dey, Sukanta

    2018-05-01

    The felsic volcanics, tuff and volcaniclastic rocks within the Tadpatri Formation of Proterozoic Cuddapah basin are not extensively studied so far. It is necessary to evaluate the extrusive environment of felsic lavas with associated ash fall tuffs and define the resedimented volcaniclastic components. The spatial and temporal bimodal association were addressed, but geochemical and petrographic studies of mafic volcanics are paid more attention so far. The limited exposures of eroded felsic volcanics and tuffaceous volcaniclastic components in this terrain are highly altered and that is the challenge of the present facies analysis. Based on field observation and mapping of different lithounits a number of facies are categorized. Unbiased lithogeochemical sampling have provided major and selective trace element data to characterize facies types. Thin-section studies are also carried out to interpret different syn- and post- volcanic features. The facies analysis are used to prepare a representative facies model to visualize the entire phenomenon with reference to the basin evolution. Different devitrification features and other textural as well as structural attributes typical of flow, surge and ash fall deposits are manifested in the middle, lower and upper stratigraphic levels. Spatial and temporal correlation of lithologs are also supportive of bimodal volcanism. Felsic and mafic lavas are interpreted to have erupted through the N-S trending rift-associated fissures due to lithospheric stretching during late Palaeoproterozoic. It is also established from the facies model that the volcaniclastics were deposited in the deeper part of the basin in the east. The rifting and associated pressure release must have provided suitable condition of decompression melting at shallow depth with high geothermal gradient and this partial melting of mantle derived material at lower crust must have produced mafic magmas. Such upwelling into cold crust also caused partial heat

  9. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    reza Mousavi-Harami

    2015-09-01

    Rahdar (Devonian Formations along the basement Kalmard Fault. In the present study, three stratigraphic sections (NW-SE transects were measured, described and sampled in the Kalmard area. In these sections, detailed considerations have been given on the lithofacies variations bed geometry and contacts, faunal content, the potential of trace fossils as tools for reconstructing depositional conditions, sedimentary textures and structures, bounding surfaces, vertical trends and stacking patterns and lateral/vertical variations in facies and thicknesses. The observed siliciclastic facies can readily be interpreted using existing shelf sedimentation and shoreline succession models (e.g. Walker and Plint 1992 . Interpretation carbonate facies have been done on the basis the microfacies analysis (200 thin-sections, sedimentary textures and structures and faunal content (Wilson et al. 1975 Flügel 2010 . In final, internal architecture, characteristics of sedimentary facies, the overall stacking pattern and nature of sequence-bounding unconformities have been investigated to evaluate the influence of regional uplift, local tectonics and eustasy on both along-strike variations in sequence architecture and genetic complexity of sequence boundaries.     Discussion, Results and Conclusion   The Lower Ordovician Shirgesht Formation in central Iran is composed of siliciclastic and carbonate rocks deposited in diverse coastal and marine shelf environments (tidal flat, lagoon, shoreface, and offshore-shelf and carbonate ramp. Relying on the facies characteristics and stratal geometries, the siliciclastic succession are divided into five facies associations, FA1 (tidal flat, FA2 (lagoon/washoverfan, FA3 (upper shoreface-foreshore, FA4 (lower to middle shoreface, and FA5 (offshore-shelf.Carbonate succession of this formation based on lithology, sedimentary characteristics and textures divided into four facies belts, FA (tidal flat, FB (lagoon,FC (shoal/barrier island, and FD

  10. Felsic granulite with layers of eclogite facies rocks in the Bohemian Massif; did they share a common metamorphic history?

    Science.gov (United States)

    Jedlicka, Radim; Faryad, Shah Wali

    2017-08-01

    High pressure granulite and granulite gneiss from the Rychleby Mountains in the East Sudetes form an approximately 7 km long and 0.8 km wide body, which is enclosed by amphibolite facies orthogneiss with a steep foliation. Well preserved felsic granulite is located in the central part of the body, where several small bodies of mafic granulite are also present. In comparison to other high pressure granulites in the Bohemian Massif, which show strong mineral and textural re-equilibration under granulite facies conditions, the mafic granulite samples preserve eclogite facies minerals (garnet, omphacite, kyanite, rutile and phengite) and their field and textural relations indicate that both mafic and felsic granulites shared common metamorphic history during prograde eclogite facies and subsequent granulite facies events. Garnet from both granulite varieties shows prograde compositional zoning and contains inclusions of phengite. Yttrium and REEs in garnet show typical bell-shaped distributions with no annular peaks near the grain rims. Investigation of major and trace elements zoning, including REEs distribution in garnet, was combined with thermodynamic modelling to constrain the early eclogite facies metamorphism and to estimate pressure-temperature conditions of the subsequent granulite facies overprint. The first (U)HP metamorphism occurred along a low geothermal gradient in a subduction-related environment from its initial stage at 0.8 GPa/460 °C and reached pressures up to 2.5 GPa at 550 °C. The subsequent granulite facies overprint (1.6-1.8 GPa/800-880 °C) affected the rocks only partially; by replacement of omphacite into diopside + plagioclase symplectite and by compositional modification of garnet rims. The mineral textures and the preservation of the eclogite facies prograde compositional zoning in garnet cores confirm that the granulite facies overprint was either too short or too faint to cause recrystallisation and homogenisation of the eclogite

  11. 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.

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

    Science.gov (United States)

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

    2016-09-01

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

  13. Facies architecture of heterolithic tidal deposits : The Holocene Holland Tidal Basin

    NARCIS (Netherlands)

    Donselaar, M.E.; Geel, C.R.

    2007-01-01

    The size, shape and spatial position of lithofacies types (or facies architecture) in a tidal estuarine basin are complex and therefore difficult to model. The tidal currents in the basin concentrate sand-sized sediment in a branching pattern of tidal channels and fringing tidal flats. Away from the

  14. Statistics and Title VII Proof: Prima Facie Case and Rebuttal.

    Science.gov (United States)

    Whitten, David

    1978-01-01

    The method and means by which statistics can raise a prima facie case of Title VII violation are analyzed. A standard is identified that can be applied to determine whether a statistical disparity is sufficient to shift the burden to the employer to rebut a prima facie case of discrimination. (LBH)

  15. Prima facie evidence against spin-two Higgs impostors

    Science.gov (United States)

    Ellis, John; Sanz, Verónica; You, Tevong

    2013-10-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

  16. Prima Facie Evidence against Spin-Two Higgs Impostors

    CERN Document Server

    Ellis, John; You, Tevong

    2013-01-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

  17. Prima facie evidence against spin-two Higgs impostors

    International Nuclear Information System (INIS)

    Ellis, John; Sanz, Verónica; You, Tevong

    2013-01-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models

  18. Prima facie evidence against spin-two Higgs impostors

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [Theoretical Particle Physics and Cosmology Group, Physics Department, King' s College London, London WC2R 2LS (United Kingdom); TH Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Sanz, Verónica, E-mail: vsanz@yorku.ca [TH Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); You, Tevong [Theoretical Particle Physics and Cosmology Group, Physics Department, King' s College London, London WC2R 2LS (United Kingdom)

    2013-10-07

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

  19. The intrusive complexof the Island of Giglio: geomagnetic characteristics of plutonic facies with low susceptibility contrast

    Directory of Open Access Journals (Sweden)

    R. Cavallini

    1998-06-01

    Full Text Available Two main plutonic facies characterize the intrusive complex of the Island of Giglio, and the trend of their contact at depth has been modelled using a 2D½ analysis based on a detailed geomagnetic survey in order to verify the geological hypothesis of the subsurface geometry of this contact. The magnetic anomaly connected with the discontinuity is quite low, due to the small difference between the magnetic susceptibilities of the two granitic facies. Development of this model of inversion of the magnetic field, which is in good agreement with the geological interpretation, was made possible by: 1 accurate control of the geomagnetic time variations and consequent temporal reduction, 2 a very low level of the artificial magnetic noise, 3 high density of the magnetic survey, 4 detailed knowledge of the mapped geologic contact between facies and of their petrologic characteristics, and 5 direct local measurements of the magnetic susceptibilities of the key lithologies. The model shows the trends of the geological contact, as projected in three E-W sections, that dips eastward in the range between 210 and 540, supporting the geologic hypothesis that the Pietrabona facies represents an external shell of the shallowly emplaced Giglio monzogranite intrusion.

  20. The Archaen volcanic facies in the Migori segment, Nyanza greenstone belt, Kenya: stratigraphy, geochemistry and mineralisation

    Science.gov (United States)

    Ichang'l, D. W.; MacLean, W. H.

    The Migori segment is an 80 by 20 km portion of the Nyanza greenstone belt which forms the northern part of the Archean Tanzanian Craton in western Kenya, northern Tanzania and southeastern Uganda. It consists of two volcanic centres, each with central, proximal and distal volcanic facies, comprising the Migori Group, the Macalder and Lolgorien Subgroups, and eleven volcano-sedimentary formations. The centres are separated by a basin of tuffs and greywacke turbidites. The volcanics are bimodal mafic basalt and dolerite ( Zr/Y = 3.8 - 6.5, La N/Yb N = 1.0 - 2.4) , and felsic calc-alkaline dacite-rhyolite ( Zr/Y = 10 - 21, La N/Yb N = 19 - 42 ) and high-K dacite ( Zr/Y = 9 - 16, La N/Yb N = 21 - 22 ). Felsic units form approximately three-fourths of the volcanic stratigraphy. Basalts, calc-alkaline dacites and rhyolites were deposited in a submarine environment, but the voluminous high-K dacites were erupted subaerially. The turbidites contain units of iron-formations. Granitic intrusions are chemically continuous with the high-K dacites. The felsic volcanics are anologous to those found at modern volcanic arc subduction settings involving continental crust. The Macalder ZnCuAuAg volcanogenic massive sulphide deposits is in central facies basalts-greywacke-rhyolite. Gold mineralisation occurs in proximal facies tuffs and iron formation, and in oblique and semi-conformable quartz veins. Greenstones in the Nyanza belt are dominated by calc-alkaline felsic volcanics in constrast to the komatiite-tholeiitic basalt volcanism in the Kaapvaal Craton of South Africa, and a mixture of the two types in the Zimbabwe Craton.

  1. Facies volcánicas del depósito de avalancha de detritos del volcán Tata Sabaya, Andes Centrales Volcanic facies of the debris avalanche deposit of Tata Sabaya Volcano, Central Andes

    Directory of Open Access Journals (Sweden)

    Benigno Godoy

    2012-09-01

    evolution of a volcano. These flows are formed by edifice instability, which could be due to several factors such as the presence of hydrother-mally altered areas, climatic changes, earthquakes, shallow magma intrusions (cryptodomes and/or dykes and/or fault activity beneath or close to the volcano. The final product of this avalanche flow, known as debris avalanche deposit (DAD shows typical hummocky and closed drainage morphologies. More than 14 volcanic centers of the Central Andes have volcanic DAD's, being Tata Sabaya (Bolivia one of them. The collapse that has originated the deposit could have been generated by a combination of magmatic and seismic activity in the volcano. The deposit associated to the partial collapse of Tata Sabaya volcano is distributed on its lower southern flank and partially fills the north-western part of the Salar de Coipasa basin. The deposit covers a minimum area of 230 km² and has an estimated minimum volume of 6±1 km³. The deposit is formed by 6 different types of hummocks, according to their compositions: lavic, pyroclastic, sedimentary, mixed, pyroclastic breccia and basaltic-andesitic hummocks. Based on the predominant hummock type and the spatial distribution, the deposit has been divided into 6 different facies (Toreva Block Facies, Volcanic Hummocks Facies, Central Facies, Sedimentary Hummocks Facies, Mixed Facies and Pyroclastic Breccia Hummocks Facies. Taking into account the facies distribution and their characteristics, we infer the pre-collapse structure of the volcano.

  2. Compaction and sedimentary basin analysis on Mars

    Science.gov (United States)

    Gabasova, Leila R.; Kite, Edwin S.

    2018-03-01

    Many of the sedimentary basins of Mars show patterns of faults and off-horizontal layers that, if correctly understood, could serve as a key to basin history. Sediment compaction is a possible cause of these patterns. We quantified the possible role of differential sediment compaction for two Martian sedimentary basins: the sediment fill of Gunjur crater (which shows concentric graben), and the sediment fill of Gale crater (which shows outward-dipping layers). We assume that basement topography for these craters is similar to the present-day topography of complex craters that lack sediment infill. For Gunjur, we find that differential compaction produces maximum strains consistent with the locations of observed graben. For Gale, we were able to approximately reproduce the observed layer orientations measured from orbiter image-based digital terrain models, but only with a >3 km-thick donut-shaped past overburden. It is not immediately obvious what geologic processes could produce this shape.

  3. Relative role of transfer zones in controlling sequence stacking patterns and facies distribution: insights from the Fushan Depression, South China Sea

    Science.gov (United States)

    Liu, Entao; Wang, Hua; Li, Yuan; Huang, Chuanyan

    2015-04-01

    In sedimentary basins, a transfer zone can be defined as a coordinated system of deformational features which has good prospects for hydrocarbon exploration. Although the term 'transfer zone' has been widely applied to the study of extensional basins, little attention has been paid to its controlling effect on sequence tracking pattern and depositional facies distribution. Fushan Depression is a half-graben rift sub-basin, located in the southeast of the Beibuwan Basin, South China Sea. In this study, comparative analysis of seismic reflection, palaeogeomorphology, fault activity and depositional facies distribution in the southern slope indicates that three different types of sequence stacking patterns (i.e. multi-level step-fault belt in the western area, flexure slope belt in the central area, gentle slope belt in the eastern area) were developed along the southern slope, together with a large-scale transfer zone in the central area, at the intersection of the western and eastern fault systems. Further analysis shows that the transfer zone played an important role in the diversity of sequence stacking patterns in the southern slope by dividing the Fushan Depression into two non-interfering tectonic systems forming different sequence patterns, and leading to the formation of the flexure slope belt in the central area. The transfer zone had an important controlling effect on not only the diversity of sequence tracking patterns, but also the facies distribution on the relay ramp. During the high-stand stage, under the controlling effect of the transfer zone, the sediments contain a significant proportion of coarser material accumulated and distributed along the ramp axis. By contrast, during the low-stand stage, the transfer zone did not seem to contribute significantly to the low-stand fan distribution which was mainly controlled by the slope gradient (palaeogeomorphology). Therefore, analysis of the transfer zone can provide a new perspective for basin analysis

  4. Mathematical modeling of the formation of sedimentary acid precipitation in the atmosphere in view of the evaporation of moisture from their surface

    Directory of Open Access Journals (Sweden)

    Gvozdyakov Dmitry

    2017-01-01

    Full Text Available The article presents the results of numeric simulation of the formation of sedimentary acid precipitation in the atmosphere taking into account the evaporation of moisture from their surfaces. It is established that the joint condensation of vapors of sulfuric anhydride and water vapor, given the flow of solar energy and the evaporation process significantly slows the growth of drops. The possibility of achieving the underlying surface by the formed sediments is analyzed.

  5. Sedimentary architecture and depositional controls of a Pliocene river-dominated delta in the semi-isolated Dacian Basin, Black Sea

    Science.gov (United States)

    Jorissen, Elisabeth L.; de Leeuw, Arjan; van Baak, Christiaan G. C.; Mandic, Oleg; Stoica, Marius; Abels, Hemmo A.; Krijgsman, Wout

    2018-06-01

    Sedimentological facies models for (semi-)isolated basins are less well developed than those for marine environments, but are critical for our understanding of both present-day and ancient deltaic sediment records in restricted depositional environments. This study considers an 835 m thick sedimentary succession of mid-Pliocene age, which accumulated in the Dacian Basin, a former embayment of the Black Sea. Detailed sedimentological and palaeontological analyses reveal a regression from distal prodelta deposits with brackish water faunas to delta-top deposits with freshwater faunas. Sediments contain frequent hyperpycnal plumes and an enrichment in terrestrial organic material, ichnofossils and in situ brackish and freshwater faunas. Deltaic progradation created thin, sharply-based sand bodies formed by multiple terminal distributary channels, covering a wide depositional area. The system experienced frequent delta-lobe switching, resulting in numerous thin parasequences. Parasequences are overlain by erosive reddish oxidized sand beds, enriched in broken, abraded brackish and freshwater shells. These beds were formed after sediment starvation, on top of abandoned delta lobes during each flooding event. A robust magnetostratigraphic time frame allowed for comparison between the observed sedimentary cyclicity and the amplitude and frequency of astronomical forcing cycles. Our results indicate that parasequence frequencies are significantly higher than the number of time equivalent astronomical cycles. This suggests that delta-lobe switching was due to autogenic processes. We consider the observed facies architecture typical for a delta prograding on a low-gradient slope into a shallow, brackish, protected, semi-isolated basin. Furthermore, in the absence of significant wave and tidal influence, sediment progradation in such a protected depositional setting shaped a delta, strongly river-dominated.

  6. Multinomial Logistic Regression & Bootstrapping for Bayesian Estimation of Vertical Facies Prediction in Heterogeneous Sandstone Reservoirs

    Science.gov (United States)

    Al-Mudhafar, W. J.

    2013-12-01

    Precisely prediction of rock facies leads to adequate reservoir characterization by improving the porosity-permeability relationships to estimate the properties in non-cored intervals. It also helps to accurately identify the spatial facies distribution to perform an accurate reservoir model for optimal future reservoir performance. In this paper, the facies estimation has been done through Multinomial logistic regression (MLR) with respect to the well logs and core data in a well in upper sandstone formation of South Rumaila oil field. The entire independent variables are gamma rays, formation density, water saturation, shale volume, log porosity, core porosity, and core permeability. Firstly, Robust Sequential Imputation Algorithm has been considered to impute the missing data. This algorithm starts from a complete subset of the dataset and estimates sequentially the missing values in an incomplete observation by minimizing the determinant of the covariance of the augmented data matrix. Then, the observation is added to the complete data matrix and the algorithm continues with the next observation with missing values. The MLR has been chosen to estimate the maximum likelihood and minimize the standard error for the nonlinear relationships between facies & core and log data. The MLR is used to predict the probabilities of the different possible facies given each independent variable by constructing a linear predictor function having a set of weights that are linearly combined with the independent variables by using a dot product. Beta distribution of facies has been considered as prior knowledge and the resulted predicted probability (posterior) has been estimated from MLR based on Baye's theorem that represents the relationship between predicted probability (posterior) with the conditional probability and the prior knowledge. To assess the statistical accuracy of the model, the bootstrap should be carried out to estimate extra-sample prediction error by randomly

  7. Mapping Depositional Facies on Great Bahama Bank: An Integration of Groundtruthing and Remote Sensing Methods

    Science.gov (United States)

    Hariss, M.; Purkis, S.; Ellis, J. M.; Swart, P. K.; Reijmer, J.

    2013-12-01

    Great Bahama Bank (GBB) has been used in many models to illustrate depositional facies variation across flat-topped, isolated carbonate platforms. Such models have served as subsurface analogs at a variety of scales. In this presentation we have integrated Landsat TM imagery, a refined bathymetric digital elevation model, and seafloor sample data compiled into ArcGIS and analyzed with eCognition to develop a depositional facies map that is more robust than previous versions. For the portion of the GBB lying to the west of Andros Island, the facies map was generated by pairing an extensive set of GPS-constrained field observations and samples (n=275) (Reijmer et al., 2009, IAS Spec Pub 41) with computer and manual interpretation of the Landsat imagery. For the remainder of the platform, which lacked such rigorous ground-control, the Landsat imagery was segmented into lithotopes - interpreted to be distinct bodies of uniform sediment - using a combination of edge detection, spectral and textural analysis, and manual editing. A map was then developed by assigning lithotopes to facies classes on the basis of lessons derived from the portion of the platform for which we had rigorous conditioning. The new analysis reveals that GBB is essentially a very grainy platform with muddier accumulations only in the lee of substantial island barriers; in this regard Andros Island, which is the largest island on GBB, exerts a direct control over the muddiest portion of GBB. Mudstones, wackestones, and mud-rich packstones cover 7%, 6%, and 15%, respectively, of the GBB platform top. By contrast, mud-poor packstones, grainstones, and rudstones account for 19%, 44%, and 3%, respectively. Of the 44% of the platform-top classified as grainstone, only 4% is composed of 'high-energy' deposits characterized by the development of sandbar complexes. The diversity and size of facies bodies is broadly the same on the eastern and western limb of the GBB platform, though the narrower eastern

  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. Las facies Keuper al SW de la provincia de Soria

    Directory of Open Access Journals (Sweden)

    Hernando, S.

    1988-08-01

    Full Text Available This paper deals with the sedimentological analysis of the materials that correspond to the Keuper facies in the area situated between the Iberian Ranges and the Central System. Acording to the obtained data, two main aspects are emphasized: - During the Upper Triassic, a c1ear retreat of the roast line towards the East took place, since this area constituted the litoral zone during the sedimentation of the Rot and Muschelkalk. - Facies change lateraly from West to East as proximal alluvial Can sediments pass into facies interpreted as distal alluvial fans and continental sabkha environment.Se analizan, desde el punto de vista sedimentológico, unos materiales correspondientes a las facies Keuper entre la Cordillera Ibérica y el Sistema Central. Dos aspectos resaltan tras este análisis: - Desplazamiento de la línea de costa (que durante la sedimentación del Rot y del Muschelkalk estaba situada en esta zona hacia el Este. - Marcado cambio lateral de facies desde el Oeste hacia el Este, pasando de unas facies proximales-medias de abanico aluvial a unas facies distales y ambiente de sabkha continental.

  10. The Totumo mud volcano and its near-shore marine sedimentological setting (North Colombia) - From sedimentary volcanism to epithermal mineralization

    Science.gov (United States)

    Dill, H. G.; Kaufhold, S.

    2018-04-01

    The Holocene mud volcano exposed at Totumo (younger than 4150 ± 50 yr BP) lines up together with some other landforms of its kind along the Caribbean Coast in northern Colombia. It currently vents a mud of the silicate-phosphate-bearing sulfur-sodium chloride type. The mud volcanoes evolved in an active continental margin setting of the South American Cordillera with high seismicity and affected by pervasive neotectonic structural disturbances. During the Neogene and Quaternary linear terrigenous shoreline sediments alternating with delta deposits evolved on this mobile crustal segment between the Andes and ancient Precambrian cratons. Meso- to microtidal sedimentary settings during transgression and progradation created meta- to instable sedimentary and petrophysical conditions (e.g. overpressure and gas-bearing bubble sands), favorable for the formation of mud volcanoes, whose lithofacies is subdivided into (1) footwall facies (detritus from metabasic, -pelitic source rocks), (2) mud volcano plus lateral facies (material from deep-seated hydrothermal sources, hydrocarbon plays, and brine reflux from the sea), (3) hanging wall facies, sand characterized by a strong longshore drift. The sedimentary volcanism in the area is characterized by different temperatures of formation: (1) pre-stage (oxides, garnet, alumosilicates, tourmaline, zircon, barite, Fe sulfides and -sulfates), light (Ca sulfates, calcite, quartz, feldspar) and clay minerals (kaolinite, mica, pyrophyllite, chlorite, vermiculite) are efficient tools to determine the source of mud, to subdivide the mud volcano system as to its facies and describe its physical-chemical regime as to the temperature of formation, pH and Eh values. The mud volcano system of Totumo bridges the gap between sedimentary "volcanism" and epithermal hot spring deposits of intermediate to high sulfidation and forms a useful "guide" to hydrocarbon accumulation.

  11. Ichnofabrics and Facies in the Paleocene of Chicxulub: A Record of the Recovery of Life Post-Impact

    Science.gov (United States)

    Whalen, M. T.; O'Malley, K.; Lowery, C. M.; Rodriguez-Tovar, F. J.; Gulick, S. P. S.; Morgan, J. V.

    2017-12-01

    IODP/ICDP Expedition 364 recovered 829 m of core at Site M0077 including 110 m of post-impact, (hemi)pelagic Paleogene sedimentary rocks overlying the Chicxulub impact crater peak ring formed from suevite, melt rock, and granitic basement. The transition between suevite and Paleocene limestone (Unit 1F) is a remarkable fining upward package of gravel to sand-sized suevite (Unit 2A) overlain by the laminated carbonate-rich Unit 1G that records deposition of fine-grained material post-impact and contains a mix of Late Cretaceous and earliest Danian taxa. This study concentrates on the overlying Unit 1F. The ichnofabric index (ii, 1-6 indicating no bioturbation to complete homogenization), provides a semiquantitative estimate of burrow density to help assess the return of life to the crater. Unit 1F is 10 m thick with a sharp contact at the base of a green claystone (ii 2) that overlies Unit 1G. It consists of cm-dm interbedded blue-gray marlstone (ii 2) grading upward into gray to blue-gray wacke/packstone (ii 3-5). Contacts between facies are mostly gradational due to burrowing. The upper 3 m of the unit is a yellow-brown burrowed packstone (ii 4) intercalated with gray marlstone (ii 2). The uppermost 7.5 cm is calcite cemented with 1 cm wide burrows (ii 3-4) and fine to coarse sand size clasts including foraminifera. The upper surface of the unit is a hardground with an 2 Myr unconformity overlain by Eocene rocks. The first well-defined burrows occur in the upper 30 cm of Unit 1G. Unequivocal burrows (ii 2) that disturb sedimentary facies occur in overlying Unit 1F with values of 3-5 recorded in the overlying 10 cm indicating significant disruption of primary sedimentary structures. The iis in Unit 1F vary between 2 and 5 with rare laminated intervals without bioturbation (ii 1). Values of ii correlate well with facies changes, i.e. marlstones display lower iis than more carbonate-rich facies, implying a depth and/or redox control on burrower distribution. The ii

  12. Parts-based geophysical inversion with application to water flooding interface detection and geological facies detection

    Science.gov (United States)

    Zhang, Junwei

    I built parts-based and manifold based mathematical learning model for the geophysical inverse problem and I applied this approach to two problems. One is related to the detection of the oil-water encroachment front during the water flooding of an oil reservoir. In this application, I propose a new 4D inversion approach based on the Gauss-Newton approach to invert time-lapse cross-well resistance data. The goal of this study is to image the position of the oil-water encroachment front in a heterogeneous clayey sand reservoir. This approach is based on explicitly connecting the change of resistivity to the petrophysical properties controlling the position of the front (porosity and permeability) and to the saturation of the water phase through a petrophysical resistivity model accounting for bulk and surface conductivity contributions and saturation. The distributions of the permeability and porosity are also inverted using the time-lapse resistivity data in order to better reconstruct the position of the oil water encroachment front. In our synthetic test case, we get a better position of the front with the by-products of porosity and permeability inferences near the flow trajectory and close to the wells. The numerical simulations show that the position of the front is recovered well but the distribution of the recovered porosity and permeability is only fair. A comparison with a commercial code based on a classical Gauss-Newton approach with no information provided by the two-phase flow model fails to recover the position of the front. The new approach could be also used for the time-lapse monitoring of various processes in both geothermal fields and oil and gas reservoirs using a combination of geophysical methods. A paper has been published in Geophysical Journal International on this topic and I am the first author of this paper. The second application is related to the detection of geological facies boundaries and their deforation to satisfy to geophysica

  13. Paragenetic evolution of reservoir facies, Middle Triassic Halfway Formation, PeeJay Field, northeastern British Columbia: controls on reservoir quality

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M. L. [Alberta Univ., Dept. of Earth and Atmospheric Sciences, Edmonton, AB (Canada); Moslow, T. F. [Ulster Petroleum Ltd., Calgary, AB (Canada)

    1998-09-01

    Because of the obvious importance of reservoir quality to reservoir performance, diagenetic controls on reservoir quality of Middle Triassic reservoir facies are investigated by comparing two reservoir lithofacies. The implications of porosity structure on the efficiency of primary and secondary hydrocarbon recovery are also assessed. Halfway reservoir facies are composed of bioclastic grainstones (lithofacies G) and litharenites/sublitharenites (lithofacies H), both of which are interpreted as tidal inlet fills. Although paragenetic evolution was similar for the two reservoir facies, subtle differences in reservoir quality are discernible. These are controlled by sedimentary structures, porosity type, grain constituents, and degree of cementation. Reservoir quality in lithofacies G is a function of connectivity of the pore network. In lithofacies H, secondary granular porosity creates a more homogeneous interconnected pore system, wide pore throats and low aspect ratios. The high porosity and low permeability values of the bioclastic grainstones are suspected to cause inefficient flushing of hydrocarbons during waterflooding. However, it is suggested that recovery may be enhanced by induced hydraulic fracturing and acidization of lower permeability calcareous cemented zones. 52 refs., 15 figs.

  14. Western Canada Sedimentary Basin competitiveness

    International Nuclear Information System (INIS)

    Millar, R.H.G.

    1996-01-01

    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

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

    International Nuclear Information System (INIS)

    Pecoits, E.; Aubet, N.; Oyhantcabal, P.; Sanchez Bettucci, L.

    2004-01-01

    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.

  16. Facies analysis, depositional environments and paleoclimate of the Cretaceous Bima Formation in the Gongola Sub - Basin, Northern Benue Trough, NE Nigeria

    Science.gov (United States)

    Shettima, B.; Abubakar, M. B.; Kuku, A.; Haruna, A. I.

    2018-01-01

    Facies analysis of the Cretaceous Bima Formation in the Gongola Sub -basin of the Northern Benue Trough northeastern Nigeria indicated that the Lower Bima Member is composed of alluvial fan and braided river facies associations. The alluvial fan depositional environment dominantly consists of debris flow facies that commonly occur as matrix supported conglomerate. This facies is locally associated with grain supported conglomerate and mudstone facies, representing sieve channel and mud flow deposits respectively, and these deposits may account for the proximal alluvial fan region of the Lower Bima Member. The distal fan facies were represented by gravel-bed braided river system of probably Scot - type model. This grade into sandy braided river systems with well developed floodplains facies, forming probably at the lowermost portion of the alluvial fan depositional gradient, where it inter-fingers with basinal facies. In the Middle Bima Member, the facies architecture is dominantly suggestive of deep perennial sand-bed braided river system with thickly developed amalgamated trough crossbedded sandstone facies fining to mudstone. Couplets of shallow channels are also locally common, attesting to the varying topography of the basin. The Upper Bima Member is characterized by shallow perennial sand-bed braided river system composed of successive succession of planar and trough crossbedded sandstone facies associations, and shallower channels of the flashy ephemeral sheetflood sand - bed river systems defined by interbedded succession of small scale trough crossbedded sandstone facies and parallel laminated sandstone facies. The overall stacking pattern of the facies succession of the Bima Formation in the Gongola Sub - basin is generally thinning and fining upwards cycles, indicating scarp retreat and deposition in a relatively passive margin setting. Dominance of kaolinite in the clay mineral fraction of the Bima Formation points to predominance of humid sub - tropical

  17. Elastic properties of granulite facies rocks of Mahabalipuram, Tamil ...

    Indian Academy of Sciences (India)

    the granulite facies rocks have helped us to under- stand the metamorphic ... imperative need to make new and accurate lab- .... the driving side and a digital storage oscilloscope ..... propagation in rocks and other lossy media: An experi-.

  18. MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Albert C. Reynolds; Dean S. Oliver; Fengjun Zhang; Yannong Dong; Jan Arild Skjervheim; Ning Liu

    2003-01-01

    Knowledge of the distribution of permeability and porosity in a reservoir is necessary for the prediction of future oil production, estimation of the location of bypassed oil, and optimization of reservoir management. But while the volume of data that can potentially provide information on reservoir architecture and fluid distributions has increased enormously in the past decade, it is not yet possible to make use of all the available data in an integrated fashion. While it is relatively easy to generate plausible reservoir models that honor static data such as core, log, and seismic data, it is far more difficult to generate plausible reservoir models that honor dynamic data such as transient pressures, saturations, and flow rates. As a result, the uncertainty in reservoir properties is higher than it could be and reservoir management can not be optimized. The goal of this project is to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem is necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management. Facies (defined here as regions of relatively uniform petrophysical properties) are common features of all reservoirs. Because the flow properties of the various facies can vary greatly, knowledge of the location of facies boundaries is of utmost importance for the prediction of reservoir performance and for the optimization of reservoir management. When the boundaries between facies are fairly well known, but flow properties are poorly known, the average properties for all facies can be determined using traditional techniques. Traditional history matching honors dynamic data by adjusting petrophysical properties in large areas, but in the process of adjusting the reservoir model ignores the static data and often results in implausible reservoir

  19. Sedimentary structures of tidal flats

    Indian Academy of Sciences (India)

    Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone ...

  20. 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.

  1. Sedimentary petrography of the Early Proterozoic Pretoria Group, Transvaal Sequence, South Africa: implications for tectonic setting

    Science.gov (United States)

    Schreiber, U. M.; Eriksson, P. G.; van der Neut, M.; Snyman, C. P.

    1992-11-01

    Sandstone petrography, geochemistry and petrotectonic assemblages of the predominantly clastic sedimentary rocks of the Early Proterozoic Pretoria Group, Transvaal Sequence, point to relatively stable cratonic conditions at the beginning of sedimentation, interrupted by minor rifting events. Basement uplift and a second period of rifting occurred towards the end of Pretoria Group deposition, which was followed by the intrusion of mafic sill swarms and the emplacement of the Bushveld Complex in the Kaapvaal Craton at about 2050 Ma, the latter indicating increased extensional tectonism, and incipient continental rifting. An overall intracratonic lacustrine tectonic setting for the Pretoria Group is supported by periods of subaerial volcanic activity and palaeosol formation, rapid sedimentary facies changes, significant arkosic sandstones, the presence of non-glacial varves and a highly variable mudrock geochemistry.

  2. Depositional environment and sedimentary of the basinal sediments in the Eibiswalder Bucht (Radl Formation and Lower Eibiswald Beds), Miocene Western Styrian Basin, Austria

    Science.gov (United States)

    Stingl, K.

    1994-12-01

    The Eibiswald Bucht is a small subbasin of the Western Styrian Basin exposing sediments of Lower Miocene age. In the past the entire sequence exposed in the Eibiswalder Bucht has been interpreted as being of fluvial/lacustrine origin; here, results are presented of detailed sedimentological investigations that lead to a revision of this concept. The lowermost siliciclastic sedimentary unit of the Eibiswalder Bucht sequence is the Radl Formation. It is overlain by the Eibiswald Beds, which are subdivided into the Lower, Middle and Upper Eibiswald Beds. The Radl Formation and the Lower Eibiswald Beds are interpreted as a fan delta complex deposited along NNW-SSE striking faults. Based on the sedimentary facies this fan delta can be subdivided into a subaerial alluvial fan facies group, a proximal delta facies group and a distal delta/prodelta facies group. The Radl Formation comprises the alluvial fan and proximal delta facies groups, the Lower Eibiswald Beds the distal delta/prodelta facies group. The alluvial fan and the proximal delta consist of diverse deposits of gravelly flows. The distal delta/prodelta consists of wave-reworked, bioturbated, low density turbidites intercalated with minor gravelly mass flows. The prodelta can be regarded as as the basin facies of the small and shallow Eibiswalder Bucht, where marine conditions prevailed. The basin was probably in part connected with the Eastern Styrian Basin, the contemporary depositional environment of the Styrian Schlier (mainly turbiditic marine offshore sediments in the Eastern Styrian Basin). Analysis of the clast composition, in conjunction with the paleotransport direction of the coarse delta mass flows of the Radl Formation, shows that the source rocks were exclusively crystalline rocks ranging from greenschists to eclogites.

  3. Tide-Dominated Tract (TDT) as a key sedimentary zone characterizing tide-dominated large-river delta and estuary systems

    Science.gov (United States)

    Saito, Y.

    2017-12-01

    sediments (inclusive of tidal thythmite), distributed over 200 km in the valley, inside of the paleo-shoreline. Similarly, such well-preserved sediments are formed in a TDT of a large-river transgressive estuarine system. An estuarine facies model for large-river systems is the need of the hour. cf. references Gugliotta et al., Process regime, salinity, morphological, and sedimentary trends along the fluvial to marine transition zone of the mixed-energy Mekong River delta, Vietnam. Continental Shelf Research. http://dx.doi.org/10.1016/j.csr.2017.03.001. Hori et al., 2001. Sedimentary facies of the tide-dominated paleo-Changjiang (Yangtze) estuary during the last transgression. Marine Geology, 177, 331-351.

  4. Sorption and migration of neptunium in porous sedimentary materials

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Mukai, Masayuki; Nakayama, Shinichi

    2005-01-01

    Column migration experiments of neptunium were conducted for porous sedimentary materials: coastal sand, tuffaceous sand, ando soil, reddish soil, yellowish soil and loess, and migration behavior, sorption mechanisms and chemical formation of Np were investigated. The migration behavior of Np in each material was much different each other, due to chemical formation in solution and/or sorption mechanism of Np. Mathematical models of different concepts were applied to the experimental results to interpret the sorption mechanism and the migration behavior. It can be concluded that both of instantaneous equilibrium sorption and sorption-desorption kinetics have to be considered to model the Np migration in sedimentary materials. (author)

  5. Tacuari formation (Nov. Nom.): Lithostratigraphy, facies, environment, age and geological significance (Cerro Largo - Uruguay)

    International Nuclear Information System (INIS)

    Veroslavsky, G.; De Santa Ana, H.; Daners, G.

    2006-01-01

    The definition of the Tacuari formation is proposed to group a set of glacial and fossiliferous siliciclastic rock deposited during the Upper proterozoic in the northeast of Uruguay. Up to this paper these lithologies were included in the San Gregorio formation (Carboniferous - Permian - Norte Basin). However, Leiosphaeridia tenuissima, L, minutissima, Myxcocooides distola, M, siderophila, Soldadophycus bossil and S. major were recorded in these rocks.This finded motivated the accomplishment of geological surveys that allowed to ferify the glacial origin of the Tacuari formation, to define its stratigraphic relationships and to corroborate its affectation by the Sierra Ballena shear zone. Two association of facies were recognized in the Tacuari formation: the base is represented by facies association A (outwash plains), characterized diamictites, sandostones and pelites; at the top, the facies association B (glaciomarine) includes a package of rhythmites with dropstones. On account of the tectonic setting, nature of sedimentation, age, and fossils, the definition of Tacuari formation constitutes a novel contribution to the regional evolutionary model of the Upper proterozoic. discussion of posible stratigraphc correlations with other neoproterozoic units of Western wondwana is also attempted

  6. The evolution of the Danube gateway between Central and Eastern Paratethys (SE Europe): Insight from numerical modelling of the causes and effects of connectivity between basins and its expression in the sedimentary record

    Science.gov (United States)

    Leever, K. A.; Matenco, L.; Garcia-Castellanos, D.; Cloetingh, S. A. P. L.

    2011-04-01

    The Pannonian and Dacic Basins in SE Europe are presently connected by the Danube River across the South Carpathians, to which they are in a back-arc and foreland position respectively. Part of the Paratethys realm during the Neogene, open water communication between the basins was interrupted by the Late Miocene uplift of the Carpathians. Different mechanisms have been proposed for the formation of the Danube gateway: capture of the upstream lake or an upstream river or incision of an antecedent river. Estimates on its age range from Late Miocene to Quaternary. A related issue is the effect of the large Mediterranean sea level fall related to the Messinian Salinity Crisis on the Paratethys subbasins, specifically the "isolated" Pannonian Basin. In a synthetic numerical modelling study, using a pseudo-3D code integrating tectonics, surface processes and isostasy, we addressed the causes and effects of changes in connectivity between two large sedimentary basins separated by an elevated barrier. Specifically, we aimed to find the expression of connectivity events in the sedimentary record in general and the consequences for the evolution of the Pannonian-Dacic area in particular. We studied a range of parameters including the geometry and uplift rate of the barrier, downstream sea level change and lithosphere rigidity. We found that changes in connectivity are expressed in the sedimentary record through their effect on base level in the upstream basin and supply in the downstream basin. The most important factors controlling the response are the elevation difference between the basins and the upstream accommodation space at the time of reconnection. The most pronounced effect of reconnection through lake capture is predicted for a large elevation difference and limited upstream accommodation space. Downstream increase in sediment supply is dependent on the latter rather than the reconnection event itself. Of the parameters we tested, the rigidity of the lithosphere

  7. Uranium, rare metals, and granulite-facies metamorphism

    Directory of Open Access Journals (Sweden)

    Michel Cuney

    2014-09-01

    The Tranomaro metasomatized marbles recrystallizing under granulite-facies conditions represent a demonstrative example of fluid transfer from granulite-facies supracrustals to traps represented by regional scale skarns. Such fluids may be at the origin of the incompatible element enrichment detected in leucosomes of migmatites from St Malo in Brittany (France and Black Hills in South Dakota. The northern French Massif Central provides us with an example of a potential association between incompatible element enrichment of granitic melts and granulite-facies metamorphism. U- and F-enriched fine-grained granites are emplaced along a crustal scale shear zone active during the emplacement within the St Sylvestre peraluminous leucogranitic complex. We propose that during granulite-facies metamorphism dominated by carbonic waves in a deep segment of the continental crust, these shear zones control: (i the percolation of F-, LILE-, rare metal-rich fluids liberated primarily by the breakdown of biotite; (ii the enhancement of partial melting by F-rich fluids at intermediate crustal levels with the generation of F-, LILE-, rare metal-rich granitic melts; (iii their transfer through the crust with protracted fractionation facilitated by their low viscosity due to high F-Li contents; and finally (iv their emplacement as rare metal intrusions at shallow crust levels.

  8. Late Permian (Zechstein) carbonate-facies maps, the Netherlands

    NARCIS (Netherlands)

    Geluk, M.C.

    2000-01-01

    The Late Permian Zechstein carbonates in the Southern Permian Basin were deposited under marine conditions. The carbonates form part of a largely progradational infill, with a gradual northward facies shift. The paleogeography of the Zechstein carbonate deposits has been reviewed recently on the

  9. Facies analysis and paleoenvironments of the upper cretaceous ...

    African Journals Online (AJOL)

    The Bida Basin is located in central Nigeria and it is perpendicular to the main axis of the Benue Trough. Due to its large areal extent and facies variation, the basin is often geographically divided into northern and southern Bida Basins. Whereas, aspects of the mineral resource and sedimentation history of the sediments in ...

  10. Sedimentary Geothermal Feasibility Study: October 2016

    Energy Technology Data Exchange (ETDEWEB)

    Augustine, Chad [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zerpa, Luis [Colorado School of Mines, Golden, CO (United States)

    2017-01-01

    The objective of this project is to analyze the feasibility of commercial geothermal projects using numerical reservoir simulation, considering a sedimentary reservoir with low permeability that requires productivity enhancement. A commercial thermal reservoir simulator (STARS, from Computer Modeling Group, CMG) is used in this work for numerical modeling. In the first stage of this project (FY14), a hypothetical numerical reservoir model was developed, and validated against an analytical solution. The following model parameters were considered to obtain an acceptable match between the numerical and analytical solutions: grid block size, time step and reservoir areal dimensions; the latter related to boundary effects on the numerical solution. Systematic model runs showed that insufficient grid sizing generates numerical dispersion that causes the numerical model to underestimate the thermal breakthrough time compared to the analytic model. As grid sizing is decreased, the model results converge on a solution. Likewise, insufficient reservoir model area introduces boundary effects in the numerical solution that cause the model results to differ from the analytical solution.

  11. Facies-controlled reservoir properties in ramp-fan and slope-apron deposits, Miocene Puente Formation, Los Angeles basin

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, K.T.; Geving, R.L.; Suchecki, R.K.

    1989-03-01

    The Miocene Puente Formation in outcrops of the eastern Los Angeles basin is interpreted as a succession of slope-apron and ramp-fan deposits that accumulated in a prism-rise wedge. The principal depositional components of this dominantly base-of-slope and ramp system are ramp-fan channels and lobes, and slope-channel and slope-apron channel/interchannel deposits. Facies-specific textural, compositional, and diagenetic attributes observed in thin section assist in the classification of depositional facies. Specifically, occurrence of carbonate cement, clay mineralogy, and abundance of organic material vary as a function of component facies architecture of the depositional system. Slope and ramp-fan channel-fill sandstones are characterized by pervasive carbonate cements, including poikilotopic and fine-grained calcite, fine-grained and baroque dolomite, and minor siderite. Diagenetic clays predate carbonate cements, and dolomite predates coarser, void-filling calcite. Ramp-fan lobe and interchannel deposits are carbonate free but are rich in detrital clay and organic matter. Diagenetic clays include mixed-layer illite/smectite and kaolinite. Sediments deposited in slope-apron channel fill are virtually cement free except for small amounts of authigenic illite/smectite. Slope-apron interchannel deposits are characterized by high content of organic matter and clay-rich matrix. Potential reservoir characteristics, such as grain size, sorting, and abundance of depositional clay matrix, are related to the primary sedimentary properties of depositional architectural components in the ramp-fan and slope-apron system. Additional diagenetic modifications, without consideration of compaction, were controlled by precipitation reactions associated with fluid flow along pathways related to the depositional architectural framework.

  12. Epigenetic alteration of sedimentary rocks at hydrogenic uranium deposit

    International Nuclear Information System (INIS)

    Ding Wanlie; Shen Kefeng

    2001-01-01

    The author introduces the concept, the recognition criteria, the genesis and classification of the epigenetic alteration of sedimentary rocks in brief, and expounds the mineral-geochemical indications and characteristics of oxidation and reduction alterations in different geochemical zones in detail, and proposes the two models of ore-controlling zonation of epigenetic alteration. The authors finally introduce research methods of epigenetic alteration

  13. Discussion on the origin of sedimentary rock resistivity

    International Nuclear Information System (INIS)

    Dong Gangjian

    2012-01-01

    Conduction current way of sedimentary rock sedimentary rock is caused by the internal structure of sedimentary rock sedimentary rock pore resistance depends on the salinity of pore water and clay content and distribution. Resistivity of sedimentary rock sedimentary rock major factor in mineral composition, water resistance, oil resistance. and sedimentary structures. In practice, we should give full attention to the difference between lithology and physical properties. (author)

  14. Prograding coastal facies associations in the Vryheid formation (Permian) at Effingham quarries near Durban, South Africa

    Science.gov (United States)

    Tavener-Smith, R.

    1982-05-01

    This paper describes and interprets a flat-lying, sandstone—siltstone sequence 70 m thick in three disused quarries. The beds comprise the lowest part of the Vryheid Formation (middle Ecca) in the Durban vicinity. The sequence is conveniently divisible into two parts: the Lower Division constitutes a prograding beach barrier association, while the upper one represents a back barrier lagoonal complex. Fourteen sedimentary facies are described and interpreted to represent a range of depositional environments including open water shelf silts, sandy shoreface and littoral deposits, organic-rich muds and peats of lagoonal origin, a tidal inlet, washover fans and a fluvial channel sand. Among the conclusions reached are that the local middle Ecca coastline extended in a northwest to southeast direction and that progradation was towards the southwest; that the coastline was microtidal and that stormy conditions were common with prevalent palaeowinds from the northwest. The absence of invertebrate body fossils in these strata is attributed to penecontemporaneous solution of shelly remains. This is the first time that a coastal sequence has been identified on the southeast margin of the Main Karoo Basin of South Africa

  15. Facies analysis of an Upper Jurassic carbonate platform for geothermal reservoir characterization

    Science.gov (United States)

    von Hartmann, Hartwig; Buness, Hermann; Dussel, Michael

    2017-04-01

    objects, like lagoons or reefs and reef mounts. Faults within this area seem to be influenced by the facies distribution and otherwise, the deformation along the faults also depended on different lithologies. The reconstruction of the development of the carbonate platform can give hints also to erosional and karst processes. The results will be included into a numerical modelling of the geothermal reservoir to analyze the interaction of geothermal wells.

  16. Depositional facies mosaics and their time lines in Lower Ordovician carbonates of central Appalachians

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, C.T.; Goldhammer, R.K.; Hardie, L.A.

    1985-02-01

    A comparative sedimentology and facies stratigraphy study of the Lower Ordovician carbonate of the central Appalachians (Beekmantown Group and equivalents) has been carried out. Our approach used subfacies (rock record of subenvironments) as the basin units of section measurement. The authors differentiated related sets of subfacies into larger facies units (rock record of environments). Facies were then correlated from section to section using fossils and lithostratigraphy to make a 3-dimensional facies mosaic. Within this mosaic, time lines were constructed using onlap-offlap tongues and cyclic sequences. These time lines cut across facies boundaries. Using this approach, the authors have established that the lower 600 m of the Lower Ordovician carbonate sequence is made up of 4 main facies: (1) cyclic laminite facies composed of a package of shoaling-upward shelf lagoon-peritidal cycles, (2) thin-bedded grainstone facies deposited in a shelf lagoon, (3) Renalcis bioherm facies recording a shelf lagoon patch-reef environment, and (4) Epiphyton bioherm facies recording a shelf-edge reef system. The distribution of these facies along time lines across the strike of the central Appalachians is markedly zoned. Epiphyton bioherm facies dominate the eastern margin while cyclic laminite facies dominate the western margin, with thin-bedded grainstone and Renalcis bioherm facies making up the central belt. This zonation of facies is a typical shallow carbonate shelf system with fringing reefs along the eastern, seaward margin and tidal flats along the western, landward margin. Vertical distribution of these facies across strike records 3 major sea level changes during deposition of the lower 600 m of this extensive Lower Ordovician carbonate shelf.

  17. Thermal conductivity of sedimentary rocks as function of Biot’s coefficient

    DEFF Research Database (Denmark)

    Orlander, Tobias; Pasquinelli, Lisa; Asmussen, J.J.

    2017-01-01

    A theoretical model for prediction of effective thermal conductivity with application to sedimentary rocks is presented. Effective thermal conductivity of sedimentary rocks can be estimated from empirical relations or theoretically modelled. Empirical relations are limited to the empirical...... conductivity of solids is typically orders of magnitude larger than that of fluids, grain contacts constituting the solid connectivity governs the heat transfer of sedi-mentary rocks and hence should be the basis for modelling effective thermal con-ductivity. By introducing Biot’s coefficient, α, we propose (1...... – α) as a measure of the solid connectivity and show how effective thermal conductivity of water saturated and dry sandstones can be modelled....

  18. Building a Bridge to Deep Time: Sedimentary Systems Across Timescales

    Science.gov (United States)

    Romans, B.; Castelltort, S.; Covault, J. A.; Walsh, J. P.

    2013-12-01

    It is increasingly important to understand the complex and interdependent processes associated with sediment production, transport, and deposition at timescales relevant to civilization (annual to millennial). However, predicting the response of sedimentary systems to global environmental change across a range of timescales remains a significant challenge. For example, a significant increase in global average temperature at the Paleocene-Eocene boundary (55.8 Ma) is interpreted to have occurred over millennial timescales; however, the specific response of sedimentary systems (e.g., timing and magnitude of sediment flux variability in river systems) to that forcing is debated. Thus, using such environmental perturbations recorded in sedimentary archives as analogs for ongoing/future global change requires improved approaches to bridging across time. Additionally, the ability to bridge timescales is critical for addressing other questions about sedimentary system behavior, including signal propagation and signal versus ';noise' in the record. The geologic record provides information that can be used to develop a comprehensive understanding of process-response behavior at multiple timescales. The geomorphic ';snapshot' of present-day erosional and depositional landscapes can be examined to reconstruct the history of processes that created the observable configurations. Direct measurement and monitoring of active processes are used to constrain conceptual and numerical models and develop sedimentary system theory. But real-time observations of active Earth-surface processes are limited to the very recent, and how such processes integrate over longer timescales to transform into strata remains unknown. At longer timescales (>106 yr), the stratigraphic record is the only vestige of ancient sedimentary systems. Stratigraphic successions contain a complex record of sediment deposition and preservation, as well as the detrital material that originated in long since denuded

  19. Geologic processes and sedimentary system on Mars

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, A S

    1988-01-01

    The subject is covered under following headings: (1) morphology and processes at the martian surface (impact craters, water and ice, landslide, aeolian processes, volcanism, chemical weathering); (2) the sedimentary system (martian geologic documentation, sedimentary balance, regolith, pyroclastics, erosion phenomena, deposit and loss of sediments) as well as (3) summary and final remarks. 72 refs.

  20. Characterizing Geological Facies using Seismic Waveform Classification in Sarawak Basin

    Science.gov (United States)

    Zahraa, Afiqah; Zailani, Ahmad; Prasad Ghosh, Deva

    2017-10-01

    Numerous effort have been made to build relationship between geology and geophysics using different techniques throughout the years. The integration of these two most important data in oil and gas industry can be used to reduce uncertainty in exploration and production especially for reservoir productivity enhancement and stratigraphic identification. This paper is focusing on seismic waveform classification to different classes using neural network and to link them according to the geological facies which are established using the knowledge on lithology and log motif of well data. Seismic inversion is used as the input for the neural network to act as the direct lithology indicator reducing dependency on well calibration. The interpretation of seismic facies classification map provides a better understanding towards the lithology distribution, depositional environment and help to identify significant reservoir rock

  1. Petrology of blueschist facies metamorphic rocks of the Meliata Unit

    Directory of Open Access Journals (Sweden)

    Faryad Shah Wali

    1997-06-01

    Full Text Available Meliata blueschists originated from basalts, limestones, pelites, psammitic and amphibolite facies basement rocks. Compositionally, the metabasalts have a geochemical signature mostly indicative of a transitional arc-MORB origin, but some mafic rocks having affinity with within plate basalts also present. The mafic blueschists consist of blue amphibole, epidote and albite, rarely also garnet, Na-pyroxene and chloritoid. Apart from phengite and quartz the metapelites and metapsammites contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, occasionally also Na-pyroxene and garnet. Amphibolite facies rocks contain relic garnet, plagioclase and hornblende, the latter two replaced by albite and blue amphibole, respectively. The zoning patterns of blue amphibole, garnet and chloritoid suggest their formation during prograde stage of metamorphism. P-T conditions of meta-morphism are estimated to be about 350-460 oC and 10-12 kbar.

  2. Coal facies evolution of the main minable coal-bed in the Heidaigou Mine, Jungar Coalfield, Inner Mongolia, northern China

    Energy Technology Data Exchange (ETDEWEB)

    Dai, S.F.; Ren, D.Y.; Li, S.S.; Zhao, L.; Zhang, Y. [China University of Mining & Technology, Beijing (China)

    2007-11-15

    The No. 6 Coal-bed from the Heidaigou Mine, Jungar Coalfield, Inner Mongolia is a super-large Ga deposit. The dominant carrier of Ga is boehmite in coal. The study of coal facies may provide genetic enrichment information of Ga and its carrier (boehmite) in the Ga deposit. On the basis of study on coal petrology and mineralogy, it was found that the No. 6 Coal-bed from the Heidaigou Mine of Jungar was enriched in inertinites and the microlithotypes were dominated by clarodurite. The maceral morphological features and association indicate that the coal-bed was formed in a dry sedimentary environment or in a periodic dry sedimentary environment caused by the alternating variations of groundwater level. The optimum conditions for the enrichment of Ga and its particular carrier (boehmite) were dominated by four transitional conditions: (1) the upper delta plain which was the transitional zone between alluvial and lower delta plains, (2) the transitional zone between the dry and wet forest swamps, being slightly apt to the dry one, (3) the transitional tree density between the thick and loose ones, and (4) the low moor that was the transitional zone between two high moors during peat accumulation.

  3. Post-depositional reactivity of the plutonium in different sediment facies from the English channel - an experimental approach

    International Nuclear Information System (INIS)

    Gouzy, A.; Boust, D.; Klein, A.

    2004-01-01

    The plutonium discharged into sea (in particular resulting from the activity of the reprocessing plants of nuclear fuels) presents a great affinity for the sedimentary particles. In the English Channel, the weakness of the plutonium concentrations met in the natural environment makes very difficult a direct study of the diagenetic phenomena which influences on the behavior of this radionuclide after its incorporation to the sedimentary column. On the scale of the all English Channel, the stock of plutonium immobilized in the sediments is significant (some TBq), this fact justifies the study of its becoming. With this intention, we constructed a set of experiments on series marine sediments with various sedimentological facies, which have been spiked with plutonium. After a one-month incubation period, various parameters describing the behavior of plutonium were given: (1) distribution of plutonium between the particulate phases and the pore waters; (2) quantification of plutonium associated with reactive sulphides; (3) distribution of plutonium between the particles and the seawater during a sediment resuspension episode. (author)

  4. Additional aspects of facies determination of the Souza Formation

    International Nuclear Information System (INIS)

    Vasconcelos, E.C.; Mabesoone, J.M.

    1984-01-01

    By means of geochemical analysis of total sample and trace elements, x-ray and DTA investigation of the clay fractions, and microfanes study, obtained by the facies determination of the Souza Formation, some additional aspects giving evidence of the sequence of events responsable by origin, deposition and formation of sediments of this middle unit of the Rio do Peixe group were established. (Author) [pt

  5. Technique for large-scale structural mapping at uranium deposits i in non-metamorphosed sedimentary cover rocks

    International Nuclear Information System (INIS)

    Kochkin, B.T.

    1985-01-01

    The technique for large-scale construction (1:1000 - 1:10000), reflecting small amplitude fracture plicate structures, is given for uranium deposits in non-metamorphozed sedimentary cover rocks. Structure drill log sections, as well as a set of maps with the results of area analysis of hidden disturbances, structural analysis of iso-pachous lines and facies of platform mantle horizons serve as sour ce materials for structural mapplotting. The steps of structural map construction are considered: 1) structural carcass construction; 2) reconstruction of structure contour; 3) time determination of structure initiation; 4) plotting of an additional geologic load

  6. Supercritical sedimentary structures and bedforms and criteria for recognition in the field: insights from the Middle Eocene deep-marine Morillo and Guaso systems, Ainsa Basin, Spanish Pyrenees

    Science.gov (United States)

    Torley, John; Pickering, Kevin

    2017-04-01

    It has long been acknowledged that for most submarine slopes with gradients > 0.5, common to many deep-water environments, they should contain abundant evidence of supercritical flows and their deposits. However, it is common for deep-marine sands/sandstones to be routinely modelled using the Bouma (1962) sequence for turbidites. Recently, the importance of supercritical flows has been highlighted from seafloor observations, with numerical and physical experiments. Such experiments have produced previously unrecognised bedforms which fail to be interpreted adequately by Bouma's model, including antidunes, chutes-and-pools, and cyclic steps. Fieldwork in the Middle Eocene Ainsa Basin, Spanish Pyrenees, has been undertaken in the Morillo and Guaso systems of the Upper Hecho Group. Approximately 5,000 beds were measured and documented in detail, e.g., grain size, sedimentary structures, bedforms and facies. Collectively, this data can be used to understand supercritical versus subcritical flow. The relative importance of supercritical flow can then be compared and contrasted within individual ancient deep-marine systems. The Morillo System is relatively coarse-grained, compared with the Guaso System. The results of this research contribute to an improved understanding of the processes in deep-marine systems, and directly benefit the hydrocarbon industry by providing better constraints to predict deep-water reservoir composition and architecture.

  7. Geochronology of the Jequie-Itabuna granulitic belt and of the Contendas-Mirante volcano-sedimentary belt

    International Nuclear Information System (INIS)

    Marinho, Moacyr M.; Barbosa, Johildo S.F.; Sabate, Pierre

    1995-01-01

    The Jequie-Itabuna Granulitic Belt is divided here into the Jequie-Mutuipe-Maracas Domain and the Atlantic Coast Domain. The paper analyzes the geochronological data from the Jequie-Mutuipe-Maracas Domain in two parts: plutonic rocks equilibrated in granulite facies, including the charno-enderbitic rocks from the Laje-Mutuipe region and the charnockitic rocks from the Maracas region; and ortho- and paraderived rocks metamorphosed in granulite facies, with the data obtained from rocks collected at the Jequie quarry and from homogeneous rocks collected at the western outskirts of the Jequirica town. The available geochronological data for the Atlantic Coast Domain is discussed, and due to the lack of petrologic control of the analyzed rocks, the geological significance of the ages between 2.0 and 2.3 is obtained in several line regressions. The paper identifies the following domains within the Contendas-Mirante volcano-sedimentary belt: the the basement dones, the volcano-sedimentary sequence and the intrusive rocks. The basement domes is the domain of the ancient gray gneisses (ca 3.4 Ga), to TTG (tonalite-trondhjemite-granodiorite) terrains and among the different massifs that crop out in the SE sector of the volcano-sedimentary belt, those of Sete Voltas and Boa Vista/Mata Verde have geochronological data available. The volcano-sedimentary sequence is divided into a lower, a middle and an upper unit and its available isotopic data are analyzed. The item referent to the intrusive rocks deals with the following plutons: The Lagoa Morro da Velha granitoid, the Pe da Serra granite, the Rio Jacare sill and the Transamazonian granites. 31 figs., 5 tabs

  8. Carbon and oxygen isotope compositions of the carbonate facies

    Indian Academy of Sciences (India)

    The Vindhyan sedimentary succession in central India spans a wide time bracket from the Paleopro- terozoic to the Neoproterozoic period.Chronostratigraphic significance of stable carbon and oxygen isotope ratios of the carbonate phase in Vindhyan sediments has been discussed in some recent studies.However,the ...

  9. Sedimentary phosphorus dynamics and the evolution of bottom-water hypoxia: A coupled benthic­pelagic model of a coastal system

    NARCIS (Netherlands)

    Reed, D.C.; Slomp, C.P.; Gustafsson, B.G.

    2011-01-01

    The present study examines oxygen and phosphorus dynamics at a seasonally hypoxic site in the Arkona basin of the Baltic Sea. A coupled benthic–pelagic reactive-transport model is used to describe the evolution of bottom-water solute concentrations, as well as pore-water and sediment profiles.

  10. Model-based classification of CPT data and automated lithostratigraphic mapping for high-resolution characterization of a heterogeneous sedimentary aquifer

    OpenAIRE

    Rogiers, Bart; Mallants, Dirk; Batelaan, Okke; Gedeon, Matej; Huysmans, Marijke; Dassargues, Alain

    2017-01-01

    Cone penetration testing (CPT) is one of the most efficient and versatile methods currently available for geotechnical, lithostratigraphic and hydrogeological site characterization. Currently available methods for soil behaviour type classification (SBT) of CPT data however have severe limitations, often restricting their application to a local scale. For parameterization of regional groundwater flow or geotechnical models, and delineation of regional hydro- or lithostratigraphy, regional SBT...

  11. Verification and Improvement of the Three-Dimensional Basin Velocity Structure Model in the Osaka Sedimentary Basin, Japan Using Interstation Green's Functions and H/V Spectral Ratios of Microtremors

    Science.gov (United States)

    Asano, K.; Iwata, T.; Sekiguchi, H.; Somei, K.; Nishimura, T.; Miyakoshi, K.; Aoi, S.; Kunugi, T.

    2012-12-01

    The Osaka sedimentary basin is filled by the Plio-Pleistocene Osaka group, terrace deposits, and alluvium deposits with thickness of 1 to 2 km over the bedrock, and it is surrounded by active fault systems. The Uemachi active fault system underlies the Osaka urban area. In order to predict the strong ground motions for future events of the Uemachi fault and others, the precise basin velocity structure model is indispensable as well as the detailed source fault model. The velocity structure of the Osaka basin has been extensively investigated by using various techniques such as gravity anomaly measurements, reflection surveys, boring explorations, and microtremor measurements. Based on these surveys and ground motion simulations for observed events, the three-dimensional velocity structure models of the Osaka basin have been developed and improved for decades (e.g., Kagawa et al., 1993; Horikawa et al., 2003; Iwata et al., 2008; Iwaki and Iwata, 2011). Now we are trying to verify the velocity structure model of the Osaka basin and to improve it incorporating new data sets. We have conducted two kinds of observations in the Osaka basin. The first observation is continuous microtremor observation. We have temporarily installed three-component velocity sensors at 15 sites covering the Osaka basin to record microtremors continuously for more than one year. The seismic interferometry technique (e.g. Shapiro and Campillo, 2004) is applied to retrieve interstation Green's function for analyzing the wave propagation characteristics inside the sedimentary basin. Both Rayleigh- and Love-wave type signals are identified in 0.1-0.5 Hz from observed interstation Green's functions. The group velocities of Rayleigh and Love waves propagating between two stations are estimated from them using the multiple filter analysis method, and they are compared with the theoretical group-velocities of the model. For example, estimated Love-wave group velocity along a line inside the basin is

  12. Zeolite facies and regional rank of bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Kisch, H J

    1966-01-01

    The author has correlated diagnostic analcime-, heulandite-, and laumontite-bearing mineral assemblages from four areas in the Upper Carboniferous and the Permian of New South Wales with the rank of the associated coals, represented by the carbon content of vitrinite. The results show that lowest-grade regional metamorphism of the zeolite facies reflects at least in part the same physical conditions of metamorphism as the increase in degree of coalification (rank) in the bituminous coal range. Degree of coalification is probably independent of partial pressures of H/sub 2/O and CO/sub 2/: it is controlled mainly by maximum depth of burial, its duration, and the geothermal gradient.

  13. Facies architecture and diagenesis of Belgian Late Frasnian carbonate mounds

    OpenAIRE

    Boulvain, Frédéric

    2001-01-01

    Late Frasnian Petit-Mont Member carbonate mounds occur in the southern pail of the Dinant Synclinorium and in the Philippeville Anticline (SW Belgium). These mounds are 30 to 80 m thick and 100 to 250 m in diameter. They are embedded in shale, nodular shale and argillaceous limestone. Based on facies mapping of 14 buildups and related off-mound sediments, these mounds typically started from below the photic and storm wave base zones and builtup into shallow water environments. Above an argill...

  14. Trace fossil analysis of lacustrine facies and basins

    Science.gov (United States)

    Buatois, L.A.; Mangano, M.G.

    1998-01-01

    Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the Mermia ichnofacies are complicated by the wide variability of lacustrine systems. Detected proximal-distal trends are useful within particular lake basins, but commonly difficult to extrapolate to other lakes. Other potential ichnofacies include the typically marine Skolithos ichnofacies for high-energy zones of lakes and substrate-controlled, still unnamed ichnofacies, associated to lake margin deposits. Trace fossils are useful for sedimentologic analysis of event beds. Lacustrine turbidites are characterized by low-diversity suites, reflecting colonization by opportunistic organisms after the turbidite event. Underflow current beds record animal activity contemporaneous with nearly continuous sedimentation. Ichnologic studies may also help to distinguish between marine and lacustrine turbidites. Deep-marine turbidites host the Nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids, recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea. Deep lacustrine environments contain the Mermia ichnofacies, which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems. The lower diversity of lacustrine ichnofaunas in comparison with deep-sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions. Increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of

  15. Prima facie evidence against spin-two Higgs impostors

    OpenAIRE

    Ellis, John; Sanz, Veronica; You, Tevong

    2013-01-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too s...

  16. Estimation of sedimentary proxy records together with associated uncertainty

    OpenAIRE

    Goswami, B.; Heitzig, J.; Rehfeld, K.; Marwan, N.; Anoop, A.; Prasad, S.; Kurths, J.

    2014-01-01

    Sedimentary proxy records constitute a significant portion of the recorded evidence that allows us to investigate paleoclimatic conditions and variability. However, uncertainties in the dating of proxy archives limit our ability to fix the timing of past events and interpret proxy record intercomparisons. While there are various age-modeling approaches to improve the estimation of the age–depth relations of archives, relatively little focus has been placed on the propagation...

  17. A combined morphometric, sedimentary, GIS and modelling analysis of flooding and debris flow hazard on a composite alluvial fan, Caveside, Tasmania

    Science.gov (United States)

    Kain, Claire L.; Rigby, Edward H.; Mazengarb, Colin

    2018-02-01

    Two episodes of intense flooding and sediment movement occurred in the Westmorland Stream alluvial system near Caveside, Australia in January 2011 and June 2016. The events were investigated in order to better understand the drivers and functioning of this composite alluvial system on a larger scale, so as to provide awareness of the potential hazard from future flood and debris flow events. A novel combination of methods was employed, including field surveys, catchment morphometry, GIS mapping from LiDAR and aerial imagery, and hydraulic modelling using RiverFlow-2D software. Both events were initiated by extreme rainfall events (events on the farmland appeared similar; however, there were differences in sediment source and transport processes that have implications for understanding recurrence probabilities. A debris flow was a key driver in the 2011 event, by eroding the stream channel in the forested watershed and delivering a large volume of sediment downstream to the alluvial fan. In contrast, modelled flooding velocities suggest the impacts of the 2016 event were the result of an extended period of extreme stream flooding and consequent erosion of alluvium directly above the current fan apex. The morphometry of the catchment is better aligned with values from fluvially dominated fans found elsewhere, which suggests that flooding represents a more frequent future risk than debris flows. These findings have wider implications for the estimation of debris flow and flood hazard on alluvial fans in Tasmania and elsewhere, as well as further demonstrating the capacity of combined hydraulic modelling and geomorphologic investigation as a predictive tool to inform hazard management practices in environments affected by flooding and sediment movement.

  18. Sedimentología y petrología de los abanicos aluviales y facies adyacentes en el Neogeno de Paracuellos de Jarama (Madrid

    Directory of Open Access Journals (Sweden)

    Alonso, M.

    1986-06-01

    Full Text Available Lateral and vertical variations of middle Miocene lithofacies (Lower and Intermediate Units of the Miocene of the Madrid Basin have been analyzed in the Paracuellos de Jarama area, near Madrid. A complete transition from medial to distal alluvial fan facies and palustrinelshaltow 1acustrine deposits can be observed. This sedimentary evolution is inferred from the detailed sedimentological. analysis carried out in each of the previously defined lithostratigraphic units: a1 Green shale and dolomite Unit, a2 Brown clays, arkosic and carbonate Unit; these two units are linked together into a Lower Group. b Coarse Arkosic Unit (Upper Group. Facies relationsbips within the Lower Group show a lateral change pattern between alluvial fan deposits, and palustrine deposits. Also the former ones gradually prograde over the palustrine deposits, as deduced from vertical evolution in the southernmost parts of the area. Upper Group represents a sudden progradation of the alluvial fan systems, that extensively overlie the distal facies observed in the Lower Group.
    Wide development of calcretes, sepiolite deposits, and nodular chert is an outstanding feature in the most distal parts of the alluvial fan bodies. They are studied in some detail provided the scarcity of well described examples of facies relationships in the kinds of deposits.

    Se estudia en este trabajo la variación lateral y vertical de las litofacies del Mioceno medio (Unidades Inferior e Intermedia en el área de Paracuellos de Jarama, próxima a Madrid, quedando representada en este área una transición completa entre depósitos de facies medias de abenícos aluviales y depósitos de ámbitos palustres. Estas conclusiones se extraen a partir del análisis sedimentológico realizado en cada una de las unidades previamente definidas: a Unidad de arcillas verdes y carbonatos y Unidad de arcillas pardas, arcillas y carbonatos en el Conjunto Inferior; b Unidad de

  19. Global Drainage Patterns to Modern Terrestrial Sedimentary Basins and its Influence on Large River Systems

    Science.gov (United States)

    Nyberg, B.; Helland-Hansen, W.

    2017-12-01

    Long-term preservation of alluvial sediments is dependent on the hydrological processes that deposit sediments solely within an area that has available accomodation space and net subsidence know as a sedimentary basin. An understanding of the river processes contributing to terrestrial sedimentary basins is essential to fundamentally constrain and quantify controls on the modern terrestrial sink. Furthermore, the terrestrial source to sink controls place constraints on the entire coastal, shelf and deep marine sediment routing systems. In addition, the geographical importance of modern terrestrial sedimentary basins for agriculture and human settlements has resulted in significant upstream anthropogenic catchment modification for irrigation and energy needs. Yet to our knowledge, a global catchment model depicting the drainage patterns to modern terrestrial sedimentary basins has previously not been established that may be used to address these challenging issues. Here we present a new database of 180,737 global catchments that show the surface drainage patterns to modern terrestrial sedimentary basins. This is achieved by using high resolution river networks derived from digital elevation models in relation to newly acquired maps on global modern sedimentary basins to identify terrestrial sinks. The results show that active tectonic regimes are typically characterized by larger terrestrial sedimentary basins, numerous smaller source catchments and a high source to sink relief ratio. To the contrary passive margins drain catchments to smaller terrestrial sedimentary basins, are composed of fewer source catchments that are relatively larger and a lower source to sink relief ratio. The different geomorphological characteristics of source catchments by tectonic setting influence the spatial and temporal patterns of fluvial architecture within sedimentary basins and the anthropogenic methods of exploiting those rivers. The new digital database resource is aimed to help

  20. Stochastic fractured rock facies for groundwater flow modeling

    OpenAIRE

    BLESSENT, DANIELA

    2014-01-01

    Este artículo presenta los resultados de una simulación de flujo de agua subterránea en rocas fracturadas. Se emplea un enfoque estocástico (modelo estocástico equivalente en medio poroso fracturado) para construir el modelo conceptual y para usar este último en la roca de baja permeabilidad encontrada en el sitio elegido como caso de estudio (Olkiluoto, Finlandia). La roca que se investiga se encuentra localizada alrededor de un grupo de pozos de sondeo y cubre un área de algunas hectáreas. ...

  1. Tectonic and climatic controls on continental depositional facies in the Karoo Basin of northern Natal, South Africa

    Science.gov (United States)

    Turner, Brian R.

    1986-02-01

    The eastern Karoo Basin, South Africa, contains a thick sequence of terrigenous clastic sediments comprising a meanderbelt facies, braided channel facies divided into coarse and fine subfacies, fluviolacustrine facies and aeolian facies. Depositional trends and changes in fluvial style reflect a progressive increase in aridity of the climate under stable tectonic conditions, interrupted by two phases of source area tectonism and the development of fine and coarse clastic wedges of the braided channel subfacies; the latter signifying a short interlude of cool, wet conditions. The fine braided channel subfacies occurs in the upper part of the meanderbelt facies, which was deposited by ephemeral, meandering mixed-load streams of variable discharge and sinuosity, under dry, semi-arid climatic conditions. These deposited complex, internally discordant channel sands and well-developed levee deposits. Following deposition of the coarse braided channel subfacies semi-arid conditions returned and fluvial deposition was dominated by ephemeral, straight to slightly sinuous mixed load streams characterised by simple channel sand bodies. As the aridity of the climate increased, the streams became more localised and carried an increasing proportion of fines. Interbedded with and overlying the fluvial deposits is a mudstone-dominated lacustrine sequence grading up into aeolian sands suggesting a playa lake-type situation. The general absence of evaporites from these sediments is attributed to the fresh nature of the lake waters, as evidenced by the freshwater aquatic organisms and clay-mineral suite, the lack of adequate inflow for solute accumulation and the removal of dust impregnated by salts from the surface of the dry lake bed during the dry season by superheated, upward-spiralling columns of air. Broadly similar environments to the fluvio-lacustrine and aeolian facies sequence are to be found in the Lake Eyre Basin of central Australia and the Okavango "delta" of northern

  2. Lavalleja group (Uruguay) a neoproterozoic metavolcanic-sedimentary sequence: ore deposits

    International Nuclear Information System (INIS)

    Sanchez Bettucci, L.; Preciozzi, F.; Ramos, V.

    2003-01-01

    The Lavalleja meta volcano-sedimentary Group, exposed along the Dom Feliciano Belt, is located in the southeast of Uruguay and formed by meta gabbros, basic and acid meta volcanic rocks. It was developed during late Proterozoic-Early Paleozoic Brasiliano orogeny. Based on the geochemical signature, Sánchez-Bettucci et al. (2001) suggested a back-arc basin tectonic setting. The metamorphic grade increases to the southeast, ranging from very low grade to lower green schist facies in the Minas formation, to lower amphibolite facies in the Fuente del Puma and Zanja del Tigre Formations (Sánchez-Bettucci et al., 2001). The metamorphic mineral assemblages correspond to a low-pressure regional metamorphism associated with a high thermal gradient (Sánchez-Bettucci et al., 2001).A compressive deformational event, that probably corresponds to the basin closure of the Lavalleja Group during a continental collision was recognized. The petrology, geochemistry, metamorphism grade, and tectonic setting are consistent with a back-arc basin as suggested by Sánchez-Bettucci et al. (2001)

  3. Facies architecture of basin-margin units in time and space: Lower to Middle Miocene Sivas Basin, Turkey

    Science.gov (United States)

    Çiner, A.; Kosun, E.

    2003-04-01

    The Miocene Sivas Basin is located within a collision zone, forming one of the largest basins in Central Turkey that developed unconformably on a foundered Paleozoic-Mesozoic basement and Eocene-Oligocene deposits. The time and space relationships of sedimentary environments and depositional evolution of Lower to Middle Miocene rocks exposed between Zara and Hafik towns is studied. A 4 km thick continuous section is subdivided into the Agilkaya and Egribucak Formations. Each formation shows an overall fining upward trend and contains three members. Although a complete section is present at the western part (near Hafik) of the basin, to the east the uppermost two members (near Zara) are absent. The lower members of both formations are composed of fluvial sheet-sandstone and red mudstone that migrate laterally on a flood basin within a semi-arid fan system. In the Agilkaya Formation that crops out near Zara, alluvial fans composed of red-pink volcanic pebbles are also present. The middle members are composed of bedded to massive gypsum and red-green mudstone of a coastal and/or continental sabkha environment. While the massive gypsum beds reach several 10’s of m in Hafik area, near Zara, they are only few m thick and alternate with green mudstones. In Hafik, bedded gypsums are intercalated with lagoonal dolomitic limestone and bituminous shale in the Agilkaya Formation and with fluvial red-pink sandstone-red mudstone in the Egribucak Formation. The upper members are made up of fossiliferous mudstone and discontinuous sandy limestone beds with gutter casts, HCS, and 3-D ripples. They indicate storm-induced sedimentation in a shallow marine setting. The disorganized accumulations of ostreid and cerithiid shells, interpreted as coquina bars, are the products of storm generated reworking processes in brackish environments. Rapid vertical and horizontal facies changes and the facies associations in both formations reflect the locally subsiding nature of this molassic

  4. Geothermal reservoir simulation of hot sedimentary aquifer system using FEFLOW®

    Science.gov (United States)

    Nur Hidayat, Hardi; Gala Permana, Maximillian

    2017-12-01

    The study presents the simulation of hot sedimentary aquifer for geothermal utilization. Hot sedimentary aquifer (HSA) is a conduction-dominated hydrothermal play type utilizing deep aquifer, which is heated by near normal heat flow. One of the examples of HSA is Bavarian Molasse Basin in South Germany. This system typically uses doublet wells: an injection and production well. The simulation was run for 3650 days of simulation time. The technical feasibility and performance are analysed in regards to the extracted energy from this concept. Several parameters are compared to determine the model performance. Parameters such as reservoir characteristics, temperature information and well information are defined. Several assumptions are also defined to simplify the simulation process. The main results of the simulation are heat period budget or total extracted heat energy, and heat rate budget or heat production rate. Qualitative approaches for sensitivity analysis are conducted by using five parameters in which assigned lower and higher value scenarios.

  5. Sedimentary paleoenvironments of the Candeleros Formation(Rio Limay Subgroup)upper cretaceous, Ezequiel Ramos Mexia, Neuquen, Argentina daming west, Argentina

    International Nuclear Information System (INIS)

    Sanchez, M.

    2004-01-01

    Sedimentary facies from the Candeleros Formation (Rio Limay Subgroup), cropping out at the El Escondido creek, at the Ezequiel Ramos Mexia dam, are analyzed and interpreted in this paper. A sedimentological detailed section was measured to get the main goal of this paper which is the sedimentary paleoenvironment. The outcroppings were pictured and a section was measured, geometries and espacial relation between them were analyzed. Eight lithofacies were identified which are: coarse sandstone facies (Se), sandstones (Sm, St, Sp, Sh t Sr), siltstones and shales (Fl and Fr). These lithofacies were agrupated into eight facies associations (FA). AFA constitutes the registration of multiepisodic events of sheet floods; AFB, C and D are product of the depositation in a braided channel belt, AFE represents units of lateral accretion, AFF is assigned deposits of crevasse splay and AFG and H are assigned to plain of flood. The distribution of these associations in the column defines an terminal fan paleoenvironment where is represented of base to top: distal (AFA, B and G) and proximal area (AFD and G) of the distributary plain; zone of feeding of the system (AFC, And, F and G), media-proximal distributary plain (AFD and F), proximal distributary plain (AFC, And, F and G); and flood basin (AFF, G and H) [es

  6. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    International Nuclear Information System (INIS)

    1993-07-01

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries

  7. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries.

  8. High resolution reservoir geological modelling using outcrop information

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others

    1997-08-01

    This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

  9. Sedimentary modelling and nuclear-waste disposal

    International Nuclear Information System (INIS)

    Van Loon, A.J.

    1982-01-01

    Nuclear energy is an important source of energy. Recently a slow down is experienced in its growth rate, due to the following factors: a) the supposed shortage of uranium; b) the fear for the consequences of nuclear accident, and c) the problem of nuclear wastes. Two types of waste are distinguished: a) fission products and actinides, and b) operational waste. The United States have started a program that must lead in 1989 to the first final storage of such waste in salt. Open-pit mines and oil-well drilling are discussed as possible solutions for operational waste storage

  10. Tectono-sedimentary analysis using the anisotropy of magnetic susceptibility: a study of the terrestrial and freshwater Neogene of the Orava Basin

    Science.gov (United States)

    Łoziński, Maciej; Ziółkowski, Piotr; Wysocka, Anna

    2017-10-01

    The Orava Basin is an intramontane depression filled with presumably fine-grained sediments deposited in river, floodplain, swamp and lake settings. The basin infilling constitutes a crucial record of the neoalpine evolution of the Inner/Outer Carpathian boundary area since the Neogene, when the Jurassic-Paleogene basement became consolidated, uplifted and eroded. The combination of sedimentological and structural studies with anisotropy of magnetic susceptibility (AMS) measurements provided an effective tool for recognition of terrestrial environments and deformations of the basin infilling. The lithofacies-oriented sampling and statistical approach to the large dataset of AMS specimens were utilized to define 12 AMS facies based on anisotropy degree (P) and shape (T). The AMS facies allowed a distinction of sedimentary facies ambiguous for classical methods, especially floodplain and lacustrine sediments, as well as revealing their various vulnerabilities to tectonic modification of AMS. A spatial analysis of facies showed that tuffites along with lacustrine and swamp deposits were generally restricted to marginal and southern parts of the basin. Significant deformations were noticed at basin margins and within two intrabasinal tectonic zones, which indicated the tectonic activity of the Pieniny Klippen Belt after the Middle Miocene. The large southern area of the basin recorded consistent N-NE trending compression during basin inversion. This regional tectonic rearrangement resulted in a partial removal of the southernmost basin deposits and shaped the basin's present-day extent.

  11. Deposits related to supercritical flows in glacifluvial deltas and subaqueous ice-contact fans: Integrating facies analysis and ground-penetrating radar

    Science.gov (United States)

    Lang, Joerg; Sievers, Julian; Loewer, Markus; Igel, Jan; Winsemann, Jutta

    2017-04-01

    transition of a supercritical plane-wall efflux-jet and is characterised by deposits of chutes-and-pools, antidunes and humpback dunes (Lang & Winsemann, 2013). In the GPR-sections, long wavelength (2 to 40 m) sinusoidal reflectors with lateral extents of up to 175 m represent the dominant radar facies, which is interpreted as deposits of stationary aggrading antidunes. This radar facies is associated with lenses (2 to 15 m wide, 0.5 to 1.5 m thick) filled with planar upflow-dipping reflectors, and sheet-like sigmoidal downflow-dipping reflectors, which are interpreted as deposits of chutes-and-pools and humpback dunes, respectively. Facies transitions occur from cyclic steps or chutes-and-pools to antidunes and from antidunes to humpback dunes, and are interpreted as related to the evolution of bedforms under spatially and temporarily changing flow conditions. References: Lang, J. & Winsemann, J. (2013) Lateral and vertical facies relationships of bedforms deposited by aggrading supercritical flows: from cyclic steps to humpback dunes. Sedimentary Geology 296, 36-54. Winsemann, J., Lang, J., Loewer, M., Polom, U., Pollok, L., Igel, J. & Brandes, C. (in review) Forced regressive ice-marginal deltas in glacial lake basins: geomorphology, facies variability and large-scale depositional architecture.

  12. Spatial and temporal modelling of fluvial aggradation in the Hasli Valley (Swiss Alps) during the last 1300 years

    Science.gov (United States)

    Llorca, Jaime; Schulte, Lothar; Carvalho, Filipe

    2016-04-01

    The Haslital delta (upper Aare River catchment, Bernese Alps) progradated into the Lake Brienz after the retreat of the Aare Glacier (post-LGM). Present delta plain geomorphology and spatial distribution of sedimentary facies result from historical fluvial dynamics and aggradation. Over centuries, local communities have struggled to control the Aare floods and to mitigate their effects on the floodplain (by means of raising artificial levees, channelizing the course, creating an underground drainage network, constructing dams at the basin headwaters). This study focuses on the spatial and temporal evolution of sediment dynamics of the floodplain by analyzing fluvial sedimentary records . The internal variability of lithostratigraphic sequences is a key issue to understand hydrological processes in the basin under the effect of environmental and anthropogenic changes of the past. The floodplain lithostratigraphy was reconstructed by coring alongside four cross-sections; each one is composed of more than 25 shallow boreholes (2 m deep) and two long drillings (variable depth, up to 9 m). The chronostratigraphical models were obtained by AMS 14C dating, and information of paleofloods and channel migration were reconstructed from historical sources (Schulte et al., 2015). The identification of different sedimentary facies, associated with the fluvial architecture structures, provides information on variations of vertical and lateral accretion processes (Houben, 2007). The location and geometry of buried channel-levee facies (gravel and coarse sand layers) indicate a significant mobility of the riverbed of the Hasli-Aare river, following an oscillatory pattern during the last millennia. Furthermore, fine sedimentary deposits and peat layers represent the existence of stable areas where floods have a low incidence. Once the different types of deposits were identified, aggradation rates were estimated in order to determine the spatial variability of the accumulation

  13. Detailed facies analyses within the Bluell and Sherwood Members, Mission Canyon Formation, North Dakota, USA - Facies stacking patterns, sequence stratigraphy and porosity relationship, consequences for reservoir distribution

    OpenAIRE

    Sjöstedt, Tony

    2017-01-01

    Detailed core analysis from seven wells with cores cut within the overall carbonate succession that makes up the Bluell and Sherwood Members of the Mission Canyon Formation located in Renville County, North Dakota, resulted in the identification of eleven depositional facies. These facies that reflect a range in depositional conditions from inner to back ramp, that is shallow fair-weather to uppermost intertidal and supratidal conditions. Systematic core analysis using a highly detailed digit...

  14. Morphology and modern sedimentary deposits of the macrotidal Marapanim Estuary (Amazon, Brazil)

    Science.gov (United States)

    Araújo da Silva, Cléa; Souza-Filho, Pedro Walfir M.; Rodrigues, Suzan W. P.

    2009-03-01

    The northern Brazilian coast, east of the Amazon River is characterized by several macrotidal estuarine systems that harbor large mangrove areas with approximately 7600 km 2. The Marapanim Estuary is influenced by macrotidal regime with moderate waves influence. Morphologic units were investigated by using remote sensing images (i.e., Landsat-7 ETM+, RADARSAT- 1 Wide and SRTM) integrated with bathymetric data. The modern sedimentary deposits were analyzed from 67 cores collected by Vibracore and Rammkersonde systems. Analysis of morphology and surface sedimentary deposits of the Marapanim River reveal they are strongly influenced by the interaction of tidal, wave and fluvial currents. Based on these processes it was possible to recognize three distinct longitudinal facies zonation that revels the geological filling of a macrotidal estuary. The estuary mouth contain fine to medium marine sands strongly influenced by waves and tides, responsible for macrotidal sandy beaches and estuarine channel development, which are characterized by wave-ripple bedding and longitudinal cross-bedding sands. The estuary funnel is mainly influenced by tides that form wide tidal mudflats, colonized by mangroves, along the estuarine margin, with parallel laminations, lenticular bedding, root fragments and organic matter lenses. The upstream estuary contains coarse sand to gravel of fluvial origin. Massive mud with organic matter lenses, marks and roots fragments occur in the floodplain accumulates during seasonal flooding providing a slowly aggrading in the alluvial plain. This morphologic and depositional pattern show easily a tripartite zonation of a macrotidal estuary, that are in the final stage of filling.

  15. Study on flow and mass transport through fractured soft sedimentary rocks (Contact research)

    International Nuclear Information System (INIS)

    Shimo, Michito; Kumamoto, Sou; Maekawa, Keisuke

    2007-03-01

    It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground accurately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. The objective of this study is to establish a conceptual model for flow and mass transport in fractured soft sedimentary rock. In previous study, a series of laboratory hydraulic and tracer tests and numerical analyses were carried out using sedimentary rock specimens obtained from Koetoi and Wakkanai formation. Single natural fractured cores and rock block specimen were used for the tests and analyses. The results indicated that the matrix diffusion played an important role for mass transport in the fractured soft sedimentary rocks. In this study, the following two tasks were carried out: (1) laboratory hydraulic and tracer experiments of rock cores of Koetoi and Wakkanai formation obtained at HDB-9, HDB-10 and HDB-11 boreholes and a rock block specimen, Wakkanai formation, obtained at an outcrop in the Horonobe area, (2) a numerical study on the conceptual model of flow and mass transport through fractured soft sedimentary rocks. Non-sorbing tracer experiments using naturally fractured cores and rock block specimens were carried out. Pottasium iodide was used as a tracer. The obtained breakthrough curves were interpreted and fitted by using a numerical simulator, and mass transport parameters, such as longitudinal dispersivity, matrix diffusion coefficient, transport aperture, were obtained. Mass transport simulations using a fracture network model, a continuum model and a double porosity model were performed to study the applicability of continuum model and double porosity model for transport in fractured sedimentary rock. (author)

  16. 17 CFR 270.3a-1 - Certain prima facie investment companies.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Certain prima facie investment companies. 270.3a-1 Section 270.3a-1 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-1 Certain prima facie investment...

  17. Two-point versus multiple-point geostatistics: the ability of geostatistical methods to capture complex geobodies and their facies associations—an application to a channelized carbonate reservoir, southwest Iran

    International Nuclear Information System (INIS)

    Hashemi, Seyyedhossein; Javaherian, Abdolrahim; Ataee-pour, Majid; Khoshdel, Hossein

    2014-01-01

    Facies models try to explain facies architectures which have a primary control on the subsurface heterogeneities and the fluid flow characteristics of a given reservoir. In the process of facies modeling, geostatistical methods are implemented to integrate different sources of data into a consistent model. The facies models should describe facies interactions; the shape and geometry of the geobodies as they occur in reality. Two distinct categories of geostatistical techniques are two-point and multiple-point (geo) statistics (MPS). In this study, both of the aforementioned categories were applied to generate facies models. A sequential indicator simulation (SIS) and a truncated Gaussian simulation (TGS) represented two-point geostatistical methods, and a single normal equation simulation (SNESIM) selected as an MPS simulation representative. The dataset from an extremely channelized carbonate reservoir located in southwest Iran was applied to these algorithms to analyze their performance in reproducing complex curvilinear geobodies. The SNESIM algorithm needs consistent training images (TI) in which all possible facies architectures that are present in the area are included. The TI model was founded on the data acquired from modern occurrences. These analogies delivered vital information about the possible channel geometries and facies classes that are typically present in those similar environments. The MPS results were conditioned to both soft and hard data. Soft facies probabilities were acquired from a neural network workflow. In this workflow, seismic-derived attributes were implemented as the input data. Furthermore, MPS realizations were conditioned to hard data to guarantee the exact positioning and continuity of the channel bodies. A geobody extraction workflow was implemented to extract the most certain parts of the channel bodies from the seismic data. These extracted parts of the channel bodies were applied to the simulation workflow as hard data

  18. Pennsylvanian coniferopsid forests in sabkha facies reveal the nature of seasonal tropical biome

    Science.gov (United States)

    Falcon-Lang, H. J.; Jud, N.A.; John, Nelson W.; DiMichele, W.A.; Chaney, D.S.; Lucas, S.G.

    2011-01-01

    Pennsylvanian fossil forests are known from hundreds of sites across tropical Pangea, but nearly all comprise remains of humid Coal Forests. Here we report a unique occurrence of seasonally dry vegetation, preserved in growth position along >5 km of strike, in the Pennsylvanian (early Kasimovian, Missourian) of New Mexico (United States). Analyses of stump anatomy, diameter, and spatial density, coupled with observations of vascular traces and associated megaflora, show that this was a deciduous, mixed-age, coniferopsid woodland (~100 trees per hectare) with an open canopy. The coniferopsids colonized coastal sabkha facies and show tree rings, confirming growth under seasonally dry conditions. Such woodlands probably served as the source of coniferopsids that replaced Coal Forests farther east in central Pangea during drier climate phases. Thus, the newly discovered woodland helps unravel biome-scale vegetation dynamics and allows calibration of climate models. ?? 2011 Geological Society of America.

  19. The sedimentary environment of the Beaufort Group Uranium Province in the vicinity of Beaufort West, South Africa

    International Nuclear Information System (INIS)

    Stear, W.M.

    1980-12-01

    Most of the Beaufort Group uranium deposits in the southwestern Karoo are located near the contact of the Abrahamskraal Formation and the Teekloof Formation within a stratigraphic interval of about 500 meters. Rocks of the Lower Beaufort uranium province in the Beaufort West study area occur in thick, fining upwards megacyclic sequences, each of which consists of an arenaceous zone overlain by an argillaceous zone. The morphology and internal geometry of selected channel sandstone bodies are described in plan and cross-section. Lateral and vertical profile diagrams are used to illustrate the salient features of fluvial style in the Abrahamskraal Formation and to compare these characteristics with recognised fluvial facies models. The Abrahamskraal Formation provides a local facies model of an ancient, interior drainage system characterised by a continuously shifting, ephemeral fluvio-lacustrine complex. Semi-arid climatic conditions in the depositional environment promoted the formation of uranium mineralization. The geologic structure and stratigraphy of the area, the facies and their distribution, the channel facies association as well as the geometry of the channel sandstone bodies and the interchannel facies association are discussed

  20. 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.

  1. Facies-succession and architecture of the third-order sequences and their stratigraphic framework of the Devonian in Yunnan-Guizhou-Guangxi area, South China

    Directory of Open Access Journals (Sweden)

    Mei Mingxiang

    2013-01-01

    Full Text Available The Caledonian orogeny at the end of the Silurian resulted in great changes in the palaeogeography in the Yunnan-Guizhou-Guangxi area of South China; the continental area of the Early Paleozoic evolved into the extensive Dian-Qian-Gui Sea in the Late Paleozoic. Early in the Devonian, as a result of a major transgression, seawater encroached gradually from the south to the north and clastic facies were deposited. Carbonate deposition was then established in the Yunnan-Guizhou-Guangxi area, with a palaeogeography marked by attached platforms, isolated platforms and narrow basins. As a result of the Ziyun movement towards the end of the Devonian, the Upper Devonian strata are regressive and thin out from the open-sea to the land areas. A study of the nature and distribution of sedimentary facies in space and time recognises 13 third-order sequences in the Devonian strata in Yunnan-Guizhou-Guangxi area, and these form two second-order sequences. The strata of the Lower Devonian comprise 5 third-order sequences (SQ1 to SQ5, which are dominated by transgressive clastics. 4 third-order sequences (SQ6 to SQ9 in the Middle Devonian are characterized by alternations of transgressive clastics and highstand carbonates. In the Upper Devonian, carbonates constitute 4 third-order sequences (SQ10 to SQ13, which are generally marked by the transgressive limestones and highstand dolomites. On the basis of earlier biostratigraphic studies, sea-level changes represented by the third-order sequences with their different facies successions are explored, and the sequence stratigraphic framework is established. Therefore, the Devonian strata in the study area provide an example for further understanding of depositional trends within the sequence-stratigraphic framework.

  2. Cenozoic uplift of the Tibetan Plateau: Evidence from the tectonic–sedimentary evolution of the western Qaidam Basin

    Directory of Open Access Journals (Sweden)

    Yadong Wang

    2012-03-01

    Full Text Available Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into (a the southern fault terrace zone, (b a central Yingxiongling orogenic belt, and (c the northern fold-thrust belt; divided by the XI fault (Youshi fault and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India–Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene–Early Miocene (Xia Ganchaigou Fm. and Shang Ganchaigou Fm., 43.8–22 Ma, and peaked in the Early Oligocene (Upper Xia Ganchaigou Fm., 31.5 Ma. The second phase occurred between the Middle Miocene and the Present (Shang Youshashan Fm. and Qigequan Fm., 14.9–0 Ma, and was stronger than the first phase. The tectonic–sedimentary evolution and the orientation of surface structures in the western Qaidam Basin resulted from the Tibetan

  3. Magnetic susceptibility evolution and sedimentary environments on carbonate platform sediments and atolls, comparison of the Frasnian from Belgium and Alberta, Canada

    Science.gov (United States)

    da Silva, Anne-Christine; Potma, Ken; Weissenberger, John A. W.; Whalen, Michael T.; Humblet, Marc; Mabille, Cédric; Boulvain, Frédéric

    2009-02-01

    Magnetic susceptibility (MS) measurements on carbonate rocks are considered as a proxy for impurities delivered to the carbonate environments. In the absence of strong climatic or tectonic variations, bulk MS values have been linked to sea level variations, because sea-level fall increases clastic supply and therefore increases in magnetic mineral deposition. In this paper we explore the relationship between the average magnitude of bulk MS, with shallowing-up sequences and facies evolution in different Devonian carbonate complexes. Similarities and differences between these parameters have been scrutinized in carbonate attached platform and detached platforms (mounds and/or atolls) from Belgium and Canada. In the carbonate attached platforms from Belgium and Canada, the MS patterns are directly related to depositional environment. Mean MS values increase from the most distal towards the most proximal facies and towards the top of the majority of fourth-order shallowing-up sequences. These trends are in agreement with theoretical background (MS increases with regression). In the Belgian detached platform, the average MS pattern generally shows an opposite behaviour to that observed in the attached carbonate platforms. Average MS decreases towards the most proximal facies and towards the top of a majority of the fourth-order shallowing-up sequences. This behaviour can be explained by the influence of sedimentary rate and water agitation during deposition. A high sedimentary rate will dilute the magnetic minerals in the atoll facies and the high water agitation during deposition may be expected to have prevented the deposition of the magnetic grains. So, the combination of these two effects will result in the observed low values in the atoll crown and lagoonal facies. In the Canadian detached platform, MS is mainly negative. This means that the limestones are very pure. The technique does not appear to be appropriate in these rocks. The variations of average MS

  4. Assessing Biogenecity of Stromatolites: Return to the Facies

    Science.gov (United States)

    Shapiro, R. S.; Jameson, S.; Rutter, A.; McCarthy, K.; Planavsky, N. J.; Severson, M.

    2013-12-01

    The discovery of richly microfossiliferous cherty stromatolites near Schreiber and Kakabeka Falls, Ontario, in the 1.9 Ga Gunflint Iron Formation, firmly established the field of pre-Cambrian paleontology. In the half-century since this discovery, paradigm shifts in the ecology of the microfossils as well as the utility of stromatolites as biological markers has caused a re-evaluation of our understanding of the pre-Cambrian fossil record. This research summarizes facies evaluation of the two stromatolite marker beds in the Gunflint-correlative Biwabik Iron Formation of Minnesota. The centimeter-scale microstratigraphy of cores drilled through the central and eastern Mesabi Iron Range was coupled with field descriptions of outcrops and mines in both the Biwabik and Gunflint iron formations. Eight lithologic facies associated with the stromatolites are identified: A) Pebble conglomerate clasts ranging in size of 0.5-3 cm, syneresis cracks, and septarian nodules with medium to coarse grain matrix; B) siltstone with subparallel sub-mm to 5 cm magnetitic and non-magnetic bands; C) stromatolitic boundstone comprising stratiform, pseudocolumnar, domal, undulatory, flat-laminated, dendritic, columnar, and mico-digitate forms and oncoids 0.5 to 2 cm diameter; D) grainstone with medium to coarse siliceous and carbonate ooids and peloids; E) massive green crystalline beds with bands of magnetite, quartz, calcite, disseminated pyrite and localized ankerite; F) autobreccicated fabric of 0.3 to 10 mm clasts; G) medium to coarse sandstone; H) quartzite. Correlation between 11 cores near Hoyt Lakes and 9 cores through the basal stromatolite layer at the MinnTac Mine near Virginia revealed that stromatolites formed both on conglomerate and medium quartz sandstone. Multiple forms of stromatolite may occur in a vertical succession (flat-laminated to undulatory to psuedocolumnar to columnar) or a core may be dominated by one type, typically columnar-stratiform. Where stromatolites do

  5. Stratigraphy, facies analysis and depositional environments of the Upper Unit of Abu Roash "E" member in the Abu Gharadig field, Western Desert, Egypt

    Science.gov (United States)

    Hewaidy, Abdel Galil; Elshahat, O. R.; Kamal, Samy

    2018-03-01

    Abu Roach "E" member is of an important hydrocarbon reservoir-producing horizon in the Abu Gharadig Field (north Western Desert, Egypt). This study is used to build facies analysis and depositional environments model for the Upper Unit of the Abu Roash "E" member in Abu Gharadig Field. This target has been achieved throughout the sedimentological, wire line logs, lithostratigraphic and biostratigraphic analyses of more than 528 feet cores. The high-resolution biostratigraphic analysis provides a calibration for the paleo-bathymetry and depositional environmental interpretations. Biozonation and lithostratigraphic markers are used to constrain stratigraphic correlation. Integration between the core description and petorographic microfacies analysis by microscope examination provide an excellent indication for the rock types and depositional environments. Five depositional facies types are detected including carbonate inner ramp, tidal flats, tidal channels, supra-tidal and tide dominated delta facies. This model helps in the understanding of the Upper Unit of Abu Roash "E" member reservoir distribution as well as lateral and vertical facies changes that contribute to the development strategy for the remaining hydrocarbon reserves for this important oil reservoir.

  6. The geological basis and the representation of spatial variability in sedimentary heterogeneous media

    International Nuclear Information System (INIS)

    Cliffe, K.A.; Franklin, D.J.; Jones, P.I.R.; Macleod, E.J.; Porter, J.D.

    1998-01-01

    The impact of different conceptual models was investigated of the heterogeneity of the Sherwood Sandstone Group (SSG) at Sellafield on calculations of flow and transport. Detailed models of the heterogeneity of the Undifferentiated St Bees Sandstone (USBS) of the SSG were produced. The models took into account directly the geological structures at the facies level. The software package STORM (STOchastic Reservoir Modelling), was used to construct the models. The data required by the model are those that characterise the geometry of the channel bodies and the properties of the various sub-facies within the channels. It was found that for the case in which all of the variability was within channels, the larger scale permeabilities did not exhibit any significant correlation structure. The up-scaled effective permeabilities also exhibited correlation lengths that were comparable with the channel dimensions. Flow and transport calculations were also performed on 90 realizations of a detailed facies scale three-dimensional representation of a larger block of the USBS. The results are broadly consistent with the analytical results for transport through a random permeability field. (R.P.)

  7. Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

    Science.gov (United States)

    Farrell, K. M.

    2001-02-01

    This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution

  8. Hidrogeoquímica de los manantiales sulfhídricos y ferruginosos de las facies Purbeck-Weald del noroeste de la Cordillera Iberica (provincia de Soria

    Directory of Open Access Journals (Sweden)

    Sanz Pérez, E.

    1994-08-01

    Full Text Available The goal of this article is to study the chemical composition of the sulfide-bearingand iron-rich springs in Soria. These springs are mainly located on sedimentary rocks of the Purbeck-Weald facies and most precisely in the Oncala group materials. Sulfide-bearing spring water belongs to calcium sulfate facies. It pH is basic or neutral. This kind of springs is mainly in the eastern area of Oncala group. Sulfate reduction with presence of organic matter seems to be the most common ORIGIN of the H2S. lronrich springs are more often located in the westside of Oncala group. Water of these springs has calcium bicarbonate character, very low salinity and acid pH. These differences on major ion chemical composition likely show the influence of the lithologic and mineralogic changes in the Oncala group. It presents low soluble terrigenous sediments in the western area whereas eastward there is a facies lateral change with the appearance of carbonates and sulfates. On the other hand, none of the iron-rich springs contains H2S and coversely Fe is never detected in the sulfide-bearing springs, although sometimes they appear together. This fact is in accordance with the plot of the two water types have in the pH/Eh diagrams.El objetivo de este trabajo consiste en el estudio de la composición química de las aguas de los manantiales sulfhídricos y ferruginosos existentes en la provincia de Soria. Este tipo de surgencias se encuentran principalmente en los materiales de las facies Purbeck-Weald, y más concretamente en los afloramientos del grupo Oncala. Los manantiales sulfhídricos son de facies sulfatada cá1cica, pH neutro o básico, y se concentran en el sector oriental del grupo Oncala; en la mayoría de los casos, el origen del H2S parece deberse a procesos de reducción de sulfatos en presencia de materia orgánica. Los manantiales ferruginosos tienden a ser más frecuentes en el sector oeste del grupo Oncala, donde presentan un car

  9. Stratigraphy, structure, and lithofacies relationships of Devonian through Permian sedimentary rocks: Paradox Basin and adjacent areas - southeastern Utah. Technical report

    International Nuclear Information System (INIS)

    McCleary, J.; Rogers, T.; Ely, R.

    1983-08-01

    Geophysical well log analysis, literature review, and field work were conducted to develop isopach, structure contour, outcrop, and facies maps and cross sections for the Devonian through Permian strata of a 14,586-km 2 (5632-square-mile) area in southeastern Utah. The study area includes part of the Paradox Basin, the salt deposits of which are of interest in siting studies for a nuclear waste repository. For this reason hydrologic models of this area are needed. This study, part of which included the development of a three-dimensional stratigraphic computer model utilizing Geographic Information System software, can serve as a base for hydrologic or other models for this area. Within and adjacent to the study area, 730 wells were screened to select the 191 wells analyzed for the study. It was found that the Elbert through Molas formations did not exhibit noticeable facies changes within the study area. The Pinkerton Trail Formation exhibits moderate changes: anhydrite and shale become somewhat more abundant toward the northeast. Facies changes in the Paradox Formation are more dramatic. Thick saline facies deposits are present in the northeast, grading to thinner anhydrite and then to carbonate facies in the south and west. The lithology of the Honaker Trail Formation appears to be fairly uniform throughout the area. Facies changes in the Cutler Group are numerous and sometimes dramatic, and generally correspond to the named formations of the group. Other factors that could affect groundwater flow, such as stratigraphic cover of fine-grained rocks, area of formation outcrops, and fracturing and faulting are discussed and delineated on maps

  10. Middle Eocene seagrass facies from Apennine carbonate platforms (Italy)

    Science.gov (United States)

    Tomassetti, Laura; Benedetti, Andrea; Brandano, Marco

    2016-04-01

    Two stratigraphic sections located in the Latium-Abruzzi (Monte Porchio, Central Apennines, Central Italy) and in the Apulian carbonate platform (S. Cesarea-Torre Tiggiano, Salento, Southern Italy) were measured and sampled to document the sedimentological characteristic and the faunistic assemblages of Middle Eocene seagrass deposits. The faunistic assemblages are dominated by porcellaneous foraminifera Orbitolites, Alveolina, Idalina, Spiroloculina, Quinqueloculina, Triloculina and abundant hooked-shaped gypsinids, associated with hooked red algae and green algae Halimeda. Fabiania, rotaliids and textulariids as well as nummulitids are subordinated. The samples were assigned to Lutetian (SBZ13-16) according to the occurrence of Nummulites cf. lehneri, Alveolina ex. gr. elliptica, Idalina berthelini, Orbitolites complanatus, Slovenites decastroi and Medocia blayensis. At Santa Cesarea reticulate nummulites occur in association with Alveolina spp. and Halkyardia minima marking the lower Bartonian (SBZ17). Three main facies associations have been recognised: I) larger porcellaneous foraminiferal grainstones with orbitolitids and alveolinids deposited into high-energy shallow-water settings influenced by wave processes that reworked the sediments associated with a seagrass; II) grainstone to packstone with small porcellaneous foraminifera and abundant permanently-attached gypsinids deposited in a more protected (e.g., small embayment) in situ vegetated environment; III) bioclastic packstone with parautochthonous material reworked from the seagrass by rip currents and accumulated into rip channels in a slightly deeper environment. The biotic assemblages suggest that the depositional environment is consistent with tropical to subtropical vegetated environments within oligotrophic conditions.

  11. Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization

    Directory of Open Access Journals (Sweden)

    Cailey B. Condit

    2018-04-01

    Full Text Available We present coupled textural observations and trace element and geochronological data from metasomatic monazite and zircon, to constrain the timing of high-grade Na-metasomatism (albitization of an Archean orthogneiss in southwest Montana, USA. Field, mineral textures, and geochemical evidence indicate albitization occurred as a rind along the margin of a ~3.2 Ga granodioritic orthogneiss (Pl + Hbl + Kfs + Qz + Bt + Zrn exposed in the Northern Madison range. The metasomatic product is a weakly deformed albitite (Ab + Bt + OAm + Zrn + Mnz + Ap + Rt. Orthoamphibole and biotite grew synkinematically with the regional foliation fabric, which developed during metamorphism that locally peaked at upper amphibolite-facies during the 1800–1710 Ma Big Sky orogeny. Metasomatism resulted in an increase in Na, a decrease in Ca, K, Ba, Fe, and Sr, a complete transformation of plagioclase and K-feldspar into albite, and loss of quartz. In situ geochronology on zoned monazite and zircon indicate growth by dissolution–precipitation in both phases at ~1750–1735 Ma. Trace element geochemistry of rim domains in these phases are best explained by dissolution–reprecipitation in equilibrium with Na-rich fluid. Together, these data temporally and mechanistically link metasomatism with high-grade tectonism and prograde metamorphism during the Big Sky orogeny.

  12. Recent Sedimentary Processes Along the Western Continental Margin of the South Korea Plateau, East Sea of Korea

    Science.gov (United States)

    Cukur, D.; Um, I. K.; Bahk, J. J.; Chun, J. H.; Lee, G. S.; Soo, K. G.; Horozal, S.; Kim, S. P.

    2017-12-01

    The continental margins of the marginal seas is largely shaped by a complex interplay of sediment transport processes directed both downslope and along-slope. Factors influence the sediment transport from shelf to the deep basin include: (i) seabed morphology, (ii) climate, (iii) sea level changes, (iv) slope stability, (v) oceanographic regime, and (vi) sediment sources. In order to understand the recent sedimentary processes along the western margin of the South Korea Plateau in the East Sea, we collected multiple geophysical datasets including the subbottom profiler and multibeam echosounder as well as geological sampling. Twelve echo types have been defined and interpreted as deposits formed by shallow marine, hemipelagic sedimentation, bottom currents, combined- (mass-movement/hemipelagic and hemipelagic/turbidites) and mass-movement-processes. Hemipelagic sedimentation, which is reflected as undisturbed layered sediments, appears to have been the primary sedimentary process throughout the study area. Two major slope-parallel channels appear to have acted as major conduits for turbidity currents from shallower shelf into the deep basins. Bottom current deposits, which is expressed as undulating seafloor morphology, are prevalent in the southern mid-slope at water depths between 250 to 450 m. Mass-transport deposits, consisting of chaotic seismic facies, occur in the upper and lower parts of the continental slope. Piston cores confirm the presence of MTDs that are characterized by mud clasts of variable size and shape. Multibeam bathymetry data show that these MTDs chiefly initiate on lower-slopes (400-600 m) where the gradient is up to 3°. In addition, subbottom profiles suggest the presence of numerous faults in close vicinity of headwall scarps; some are extending to the seafloor suggesting their recent activity. Earthquakes associated with tectonic activity are considered as the main triggering mechanism for these MTDs. Overall, the acoustic facies

  13. Pore water colloid properties in argillaceous sedimentary rocks.

    Science.gov (United States)

    Degueldre, Claude; Cloet, Veerle

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  14. Epigenetic alterations of sedimentary rocks at deposits

    International Nuclear Information System (INIS)

    Komarova, G.V.; Kondrat'eva, I.A.; Zelenova, O.I.

    1980-01-01

    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

  15. Pore water colloid properties in argillaceous sedimentary rocks

    Energy Technology Data Exchange (ETDEWEB)

    Degueldre, Claude, E-mail: c.degueldre@lancaster.ac.uk [Engineering Department, University of Lancaster, LA1 4YW Lancaster (United Kingdom); ChiAM & Institute of Environment, University of Geneva, 1211 Genève 4, Swizerland (Switzerland); Earlier, NES, Paul Scherrer Institute, 5232 Villigen (Switzerland); Cloet, Veerle [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland)

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  16. Analysis for preliminary evaluation of discrete fracture flow and large-scale permeability in sedimentary rocks

    International Nuclear Information System (INIS)

    Kanehiro, B.Y.; Lai, C.H.; Stow, S.H.

    1987-05-01

    Conceptual models for sedimentary rock settings that could be used in future evaluation and suitability studies are being examined through the DOE Repository Technology Program. One area of concern for the hydrologic aspects of these models is discrete fracture flow analysis as related to the estimation of the size of the representative elementary volume, evaluation of the appropriateness of continuum assumptions and estimation of the large-scale permeabilities of sedimentary rocks. A basis for preliminary analysis of flow in fracture systems of the types that might be expected to occur in low permeability sedimentary rocks is presented. The approach used involves numerical modeling of discrete fracture flow for the configuration of a large-scale hydrologic field test directed at estimation of the size of the representative elementary volume and large-scale permeability. Analysis of fracture data on the basis of this configuration is expected to provide a preliminary indication of the scale at which continuum assumptions can be made

  17. A Sedimentary Carbon Inventory for a Scottish Sea Loch

    Science.gov (United States)

    Smeaton, Craig; Austin, William; Davies, Althea; Baltzer, Agnes

    2015-04-01

    biogeochemical methodology and how it was applied to Loch Sunart. The methodology was applied to seismic geophysics data collected in 2009 (Baltzer et al. 2010,) and data compiled through biogeochemical analysis of sediment cores collected from Loch Sunart. Through the combination of these datasets we have undertaken calculations to quantify the total sediment mass and the percentage of carbon contained in that sediment. Through this work we have created the first holistic sedimentary carbon inventory for a sea loch; which is the first step to tackling the larger questions around coastal carbon. Baltzer, A, Bates, R, Mokeddem, Z, Clet-Pellerin, M, Walter-Simonnet, A-V, Bonnot-Courtois, C and Austin, WEN 2010, Using seismic facies and pollen analyses to evaluate climatically driven change in a Scottish sea loch (fjord) over the last 20 ka, Geological Society, London, Special Publications, 344, (1), pp. 355-369. Bauer, JE, Cai, W-J, Raymond, P a, Bianchi, TS, Hopkinson, CS and Regnier, P a G 2013, The changing carbon cycle of the coastal ocean., Nature, 504, (7478), pp. 61-70.

  18. Field-scale forward modelling of a shallow marine carbonate ramp: the Upper Jurassic Arab Formation (onshore Abu Dhabi - UAE)

    Science.gov (United States)

    Marchionda, Elisabetta; Deschamps, Rémy; Nader, Fadi H.; Ceriani, Andrea; Di Giulio, Andrea; Lawrence, David; Morad, Daniel J.

    2017-04-01

    The stratigraphic record of a carbonate system is the result of the interplay of several local and global factors that control the physical and the biological responses within a basin. Conceptual models cannot be detailed enough to take into account all the processes that control the deposition of sediments. The evaluation of the key controlling parameters on the sedimentation can be investigated with the use of stratigraphic forward models, that permit dynamic and quantitative simulations of the sedimentary basin infill. This work focuses on an onshore Abu Dhabi field (UAE) and it aims to provide a complete picture of the stratigraphic evolution of Upper Jurassic Arab Formation (Fm.). In this study, we started with the definition of the field-scale conceptual depositional model of the Formation, resulting from facies and well log analysis based on five wells. The Arab Fm. could be defined as a shallow marine carbonate ramp, that ranges from outer ramp deposits to supratidal/evaporitic facies association (from bottom to top). With the reconstruction of the sequence stratigraphic pattern and several paleofacies maps, it was possible to suggest multiple directions of progradations at local scale. Then, a 3D forward modelling tool has been used to i) identify and quantify the controlling parameters on geometries and facies distribution of the Arab Fm.; ii) predict the stratigraphic architecture of the Arab Fm.; and iii) integrate and validate the conceptual model. Numerous constraints were set during the different simulations and sensitivity analyses were performed testing the carbonate production, eustatic oscillations and transport parameters. To verify the geological consistency the 3D forward modelling has been calibrated with the available control points (five wells) in terms of thickness and facies distribution.

  19. The Adversarial Principle in Prima Facie Judgments of the Legal Thesis Firmed in the Trial of Repetitive Cases

    Directory of Open Access Journals (Sweden)

    Juliana Provedel Cardoso

    2016-10-01

    Full Text Available The present articles objective is to analyse the highly effective adversarial principle from the Constitutional Democratic State of Law and the cooperative process structure. In this sense, an analysis of the repetitive cases model is made with special relevance to the Civil Procedure Codice 2015, put in evidence the preliminary injunction, the repetitive appeals and the resolution incident repetitive demands. With the establishment of the premises, an analysis of the adversarial principle is made on prima facie judgments of the legal thesis firmed in the trial of repetitive cases, in view of the motivation of the court decision (speech of the case and law (speech of the precedents.

  20. [Burden of proof in medical cases--presumption of fact and prima facie evidence. II. Presumption of fact and prima facie evidence].

    Science.gov (United States)

    Sliwka, Marcin

    2004-01-01

    The aim of this paper was to present the main rules concerning the burden of proof in polish civil trials, including medical cases. The standard rules were presented with all the important exclusions such as presumption of law and fact or prima facie evidence. The author analyses the effect of these institutions on burden of proof in medical cases. The difference between presumptions of fact and prima facie evidence was analysed and explained. This paper also describes the importance of the res ipsa loquitur rule in United Kingdom and USA. This paper includes numerous High Court sentences on evidential and medical issues.

  1. 3D mechanical stratigraphy of a deformed multi-layer: Linking sedimentary architecture and strain partitioning

    Science.gov (United States)

    Cawood, Adam J.; Bond, Clare E.

    2018-01-01

    Stratigraphic influence on structural style and strain distribution in deformed sedimentary sequences is well established, in models of 2D mechanical stratigraphy. In this study we attempt to refine existing models of stratigraphic-structure interaction by examining outcrop scale 3D variations in sedimentary architecture and the effects on subsequent deformation. At Monkstone Point, Pembrokeshire, SW Wales, digital mapping and virtual scanline data from a high resolution virtual outcrop have been combined with field observations, sedimentary logs and thin section analysis. Results show that significant variation in strain partitioning is controlled by changes, at a scale of tens of metres, in sedimentary architecture within Upper Carboniferous fluvio-deltaic deposits. Coupled vs uncoupled deformation of the sequence is defined by the composition and lateral continuity of mechanical units and unit interfaces. Where the sedimentary sequence is characterized by gradational changes in composition and grain size, we find that deformation structures are best characterized by patterns of distributed strain. In contrast, distinct compositional changes vertically and in laterally equivalent deposits results in highly partitioned deformation and strain. The mechanical stratigraphy of the study area is inherently 3D in nature, due to lateral and vertical compositional variability. Consideration should be given to 3D variations in mechanical stratigraphy, such as those outlined here, when predicting subsurface deformation in multi-layers.

  2. MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

    Energy Technology Data Exchange (ETDEWEB)

    Albert C. Reynolds; Dean S. Oliver; Yannong Dong; Ning Liu; Guohua Gao; Fengjun Zhang; Ruijian Li

    2004-12-01

    Knowledge of the distribution of permeability and porosity in a reservoir is necessary for the prediction of future oil production, estimation of the location of bypassed oil, and optimization of reservoir management. The volume of data that can potentially provide information on reservoir architecture and fluid distributions has increased enormously in the past decade. The techniques developed in this research will make it easier to use all the available data in an integrated fashion. While it is relatively easy to generate plausible reservoir models that honor static data such as core, log, and seismic data, it is far more difficult to generate plausible reservoir models that honor dynamic data such as transient pressures, saturations, and flow rates. As a result, the uncertainty in reservoir properties is higher than it could be and reservoir management can not be optimized. In this project, we have developed computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Specifically, we have developed methods for adjusting porosity and permeability fields to match both production and time-lapse seismic data and have also developed a procedure to adjust the locations of boundaries between facies to match production data. In all cases, the history matched rock property fields are consistent with a prior model based on static data and geologic information. Our work also indicates that it is possible to adjust relative permeability curves when history matching production data.

  3. Fluvial facies reservoir productivity prediction method based on principal component analysis and artificial neural network

    Directory of Open Access Journals (Sweden)

    Pengyu Gao

    2016-03-01

    Full Text Available It is difficult to forecast the well productivity because of the complexity of vertical and horizontal developments in fluvial facies reservoir. This paper proposes a method based on Principal Component Analysis and Artificial Neural Network to predict well productivity of fluvial facies reservoir. The method summarizes the statistical reservoir factors and engineering factors that affect the well productivity, extracts information by applying the principal component analysis method and approximates arbitrary functions of the neural network to realize an accurate and efficient prediction on the fluvial facies reservoir well productivity. This method provides an effective way for forecasting the productivity of fluvial facies reservoir which is affected by multi-factors and complex mechanism. The study result shows that this method is a practical, effective, accurate and indirect productivity forecast method and is suitable for field application.

  4. Distinguishing fluvio-deltaic facies by bulk geochemistry and heavy minerals: an example from the Miocene of Denmark

    DEFF Research Database (Denmark)

    Olivarius, Mette; Rasmussen, Erik S.; Siersma, Volkert Dirk

    2011-01-01

    Interpretations of seismic profiles, gamma-ray logs and sediment descriptions were used to classify seven facies in Miocene fluvio-deltaic deposits ofDenmark. An impartial approach was adopted by not including analytical data in the facies definition. This approach allowed identification of signi......Interpretations of seismic profiles, gamma-ray logs and sediment descriptions were used to classify seven facies in Miocene fluvio-deltaic deposits ofDenmark. An impartial approach was adopted by not including analytical data in the facies definition. This approach allowed identification...... grain size of quartz and heavy minerals from the channel facies towards the delta shoreface facies and further along the coast to the spit shoreface facies is associated with an increase in sorting and textural maturity. This trend is related to longshore drift. Increasing heavy mineral grain size...... is found from the delta slope facies offshore to the delta toe and shelf facies. This trend is interpreted as a result of sorting by turbidity currents. The mixed origin of the transgressive lag facies is shown by the poorer sorting in this facies. By indicating the amount of alteration the sediments have...

  5. Facies analysis of the Balta Formation: Evidence for a large late Miocene fluvio-deltaic system in the East Carpathian Foreland

    Science.gov (United States)

    Matoshko, Anton; Matoshko, Andrei; de Leeuw, Arjan; Stoica, Marius

    2016-08-01

    Deposits of the Balta Fm are preserved in a large arcuate sediment body that covers about 60,000 km2 and is up to 350 m thick. The Balta Fm spans ca. 5 Ma as constrained by underlying Tortonian (Bessarabian) and overlying Messinian (early Pontian) Paratethys strata. It contains frequent terrestrial mammal fossils and fresh- as well as brackish-water (Paratethys) molluscs and ostracods. Over the past 140 years our understanding of the sedimentary architecture of the formation and its origins has remained in its infancy, which has limited insight into the evolution of the East Carpathian Foreland. Here, we provide the first modern sedimentary facies analysis of the Balta Fm, which is integrated with an extensive review of previously published local literature. It is supported with micropalaeontological results and a wealth of historical borehole information. We show that the Balta Fm has a tripartite vertical division. Its lowermost part is clay dominated and consists of subordinate delta front sand bodies interspersed between muds. The middle unit contains separate delta plain channels or channel belts encased in thick muds. These are overlain by a unit with amalgamated delta plain channel deposits with only minor amounts of associated mud. The abundance of upper flow regime sedimentary structures in channel sands, the absence of peats (or coals) and the presence of calcareous nodules suggest a strongly seasonal and relatively dry climate with a flashy discharge regime. Deposition of the Balta Fm in an area previously characterized by distal shelf and prodelta environments indicates large-scale progradation triggered by high sediment volume from the uplifting Carpathian Orogen and enhanced by a general lowering of Paratethys sea-level. The tripartite internal architecture of the Balta Fm indicates that progradation continued during deposition. Its wedge-shaped geometry suggests that tectonic activity in the Carpathians generated a 300 km wide foreland basin that

  6. Inferred Early Permian Arc Rifting in Bogda Mountain, Southernmost of the Central Asia Orogenic Belt: Evidence from a Peperite Bearing Volcano-Sedimentary Succession

    Science.gov (United States)

    Memtimin, M.; Guo, Z.

    2017-12-01

    Late Paleozoic tectonic history, especially Carboniferous-Permian periods, of the Central Asia Orogenic Belt (CAOB) is considered to be the turning point for the termination of terrane amalgamation and closure of the Paleoasian Ocean. However, the debate about the paleoenvironment and tectonic setting of the region during the period is still not resolved. In this study, we report a set of volcano-sedimentary sequence in the Bogda Mountain of the southernmost of CAOB, which is associated with contemporaneous subaqueous emplacement of and interaction between mafic lava and carbonate sediments. The succession contains four distinct facies including closely packed pillow basalts, pillow basalts with interstitial materials, hyaloclastites and peperites. We discuss their formation and emplacement mechanism, interaction between hot magma-water/unconsolidated sediments and thermal metamorphism during the interaction. Textural features of the sequence, especially hyaloclastites and peperites, provide clear evidence for in situ autofragmentation of lava flows, synvolcanic sedimentation of carbonates, fuel coolant interaction when hot magma bulldozed into wet unconsolidated sediments, and represent autochthonous origin of the succession. Lateral transition of the lithofacies indicate a progressively deepening subaqueous environment, resembling a stepwise evolution from early stage of volcanic intrusion with lower lava flux in shallower water level to increasingly subsiding basin with more lava flux in greater depth. Previous studies determined that the mafic magma was intruded around the Carboniferous-Permian boundary ( 300Ma), and geochemical studies showed the magma was originated from dry depleted mantle with little crustal contamination. Nevertheless, the succession was thought to be fault related allochthones formation which was transferred in as part of a Carboniferous intraplate arc. Combining our findings with the previous study results, we propose a new model to

  7. Lateral and vertical facies relationships of bedforms deposited by aggrading supercritical flows: From cyclic steps to humpback dunes

    Science.gov (United States)

    Lang, Jörg; Winsemann, Jutta

    2013-10-01

    The preservation of bedforms related to supercritical flows and hydraulic jumps is commonly considered to be rare in the geologic record, although these bedforms are known from a variety of depositional environments. This field-based study presents a detailed analysis of the sedimentary facies and stacking pattern of deposits of cyclic steps, chutes-and-pools, antidunes and humpback dunes from three-dimensional outcrops. The well exposed Middle Pleistocene successions from northern Germany comprise glacilacustrine ice-contact subaqueous fan and glacial lake-outburst flood deposits. The studied successions give new insights into the depositional architecture of bedforms related to supercritical flows and may serve as an analogue for other high-energy depositional environments such as fluvial settings, coarse-grained deltas or turbidite systems. Deposits of cyclic steps occur within the glacial lake-outburst flood succession and are characterised by lenticular scours infilled by gently to steeply dipping backsets. Cyclic steps formed due to acceleration and flow thinning when the glacial lake-outburst flood spilled over a push-moraine ridge. These bedforms are commonly laterally and vertically truncated and alternate with deposits of chutes-and-pools and antidunes. The subaqueous fan successions are dominated by laterally extensive sinusoidal waveforms, which are interpreted as deposits of aggrading stationary antidunes, which require quasi-steady flows at the lower limit of the supercritical flow stage and high rates of sedimentation. Humpback dunes are characterised by downflow divergent cross-stratification, displaying differentiation into topsets, foresets and bottomsets, and are interpreted as deposited at the transition from subcritical to supercritical flow conditions or vice versa. Gradual lateral and vertical transitions between humpback dunes and antidune deposits are very common. The absence of planar-parallel stratification in all studied successions

  8. 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.

    1 Author version: Environ. Monit. Assess., vol.184; 2012; 2829-2844 Monitoring the sedimentary carbon in an artificially disturbed deep-sea sedimentary environment B. Nagender Nath * , N.H. Khadge, Sapana Nabar, C. Raghu Kumar, B.S. Ingole... community two years after an artificial rapid deposition event. Publication of Seto Marine Biological Laboratory, 39(1), 17-27. Gage, J.D. (1978). Animals in deep-sea sediments. Proceedings of Royal Society of Edinburgh, 768, 77-93. Gage, J.D., & Tyler...

  9. Evolution of sedimentary architecture in retro-foreland basin: Aquitaine basin example from Paleocene to lower Eocene.

    Science.gov (United States)

    Ortega, Carole; Lasseur, Eric; Guillocheau, François; Serrano, Olivier; Malet, David

    2017-04-01

    The Aquitaine basin located in south western Europe, is a Pyrenean retro-foreland basin. Two main phases of compression are recorded in this retro-foreland basin during the Pyrenean orogeny. A first upper Cretaceous phase corresponding to the early stage of the orogeny, and a second one usually related to a Pyrenean paroxysmal phase during the middle Eocene. During Paleocene to lower Eocene deformations are less pronounced, interpreted as a tectonically quiet period. The aim of the study is to better constrain the sedimentary system of the Aquitaine basin during this period of Paleocene-lower Eocene, in order to discuss the evolution of the sedimentary architecture in response of the Pyrenean compression. This work is based on a compilation of a large set of subsurface data (wells logs, seismic lines and cores logs) represented by isopachs and facies map. Three main cycles were identified during this structural quiet period: (1) The Danian cycle, is recorded by the aggradation of carbonate reef-rimmed platform. This platform is characterized by proximal facies (oncoid carbonate and mudstone with thalassinoides) to the north, which leads to distal deposit facies southern (pelagic carbonate with globigerina and slump facies) and present a significant thickness variation linked to the platform-slope-basin morphology. (2) The upper Selandian-Thanetian cycle follows a non-depositional/erosional surface associated with a Selandian hiatus. The base of this cycle marked the transition between the last reef rimmed platform and a carbonate ramp. The transgressive cycle is characterized by proximal lagoon facies to the north that leads southward to distal hemipelagic facies interfingered by turbiditic Lowstand System Tracks (LST). The location of these LST is strongly controlled by inherited Danian topography. The regressive cycle ends with a major regression associated with an erosional surface. This surface is linked with a network of canyons in the north, an important

  10. Application of GPR in the study of shallow subsurface sedimentary ...

    Indian Academy of Sciences (India)

    The study of its ever-changing physiography and stratigraphy provides a wealth of information on its .... associated with the rivers like Kharod, Rukmavati,. Phot, Nagavanti .... small scale reflectors containing radar facies which dip in different ...

  11. Plio-Pleistocene facies environments from the KBS Member, Koobi Fora Formation: implications for climate controls on the development of lake-margin hominin habitats in the northeast Turkana Basin (northwest Kenya).

    Science.gov (United States)

    Lepre, Christopher J; Quinn, Rhonda L; Joordens, Josephine C A; Swisher, Carl C; Feibel, Craig S

    2007-11-01

    Climate change is hypothesized as a cause of major events of Plio-Pleistocene East African hominin evolution, but the vertically discontinuous and laterally confined nature of the relevant geological records has led to difficulties with assessing probable links between the two. High-resolution sedimentary sequences from lacustrine settings can provide comprehensive data of environmental changes and detailed correlations with well-established orbital and marine records of climate. Hominin-bearing deposits from Koobi Fora Ridge localities in the northeast Turkana Basin of Kenya are an archive of Plio-Pleistocene lake-margin sedimentation though significant developmental junctures of northern African climates, East African environments, and hominin evolution. This study examines alluvial channel and floodplain, nearshore lacustrine, and offshore lacustrine facies environments for the approximately 136-m-thick KBS Member (Koobi Fora Formation) exposed at the Koobi Fora Ridge. Aspects of the facies environments record information on the changing hydrosedimentary dynamics of the lake margin and give insights into potential climatic controls. Seasonal/yearly climate changes are represented by the varve-like laminations in offshore mudstones and the slickensides, dish-shaped fractures, and other paleosol features overprinted on floodplain strata. Vertical shifts between facies environments, however, are interpreted to indicate lake-level fluctuations deriving from longer-term, dry-wet periods in monsoonal rainfall. Recurrence periods for the inferred lake-level changes range from about 10,000 to 50,000 years, and several are consistent with the average estimated timescales of orbital precession ( approximately 20,000 years) and obliquity ( approximately 40,000 years). KBS Member facies environments from the Koobi Fora Ridge document the development of lake-margin hominin habitats in the northeast Turkana Basin. Environmental changes in these habitats may be a result of

  12. Study on flow and mass transport through fractured sedimentary rocks (2)

    International Nuclear Information System (INIS)

    Shimo, Michito; Kumamoto, Sou; Karasaki, Kenzi; Sato, Hisashi; Sawada, Atsushi

    2009-03-01

    It is important for safety assessment of HLW geological disposal to understand hydro-geological conditions at the investigation area, and to evaluate groundwater flow and mass transport model and parameters, at each investigation phase. Traditionally, for Neogene sedimentary rock, the grain spacing of sediments has been considered as the dominant migration path. However, fractures of sedimentary rock could act as dominant paths, although they were soft sedimentary rocks. In this study, as part of developing groundwater flow and mass transport evaluation methodologies of such a fractured sedimentary rock' distributed area, we conducted two different scale of studies; 1) core rock sample scale and 2) several kilometer scale. For the core rock sample scale, some of laboratory hydraulic and tracer experiments have conducted using the rock cores with tailored parallel fracture, obtained at pilot borehole drilled in the vicinity of ventilation shaft. From the test results, hydraulic conductivity, diffusion coefficient, transport aperture, dispersion length and etc. was evaluated. Based on these test results, the influence of these parameters onto mass transport behavior of fractures sedimentary rocks was examined. For larger scale, such as several kilometer scale, the regional scale groundwater flow was examined using temperature data observed along the boreholes at Horonobe site. The results show that the low permeable zone between the boreholes might be estimated. (author)

  13. Sedimentary dynamics and high-frequency sequence stratigraphy of the southwestern slope of Great Bahama Bank

    Science.gov (United States)

    Wunsch, Marco; Betzler, Christian; Eberli, Gregor P.; Lindhorst, Sebastian; Lüdmann, Thomas; Reijmer, John J. G.

    2018-01-01

    New geophysical data from the leeward slope of Great Bahama Bank show how contour currents shape the slope and induce re-sedimentation processes. Along slope segments with high current control, drift migration and current winnowing at the toe of slope form a deep moat. Here, the slope progradation is inhibited by large channel incisions and the accumulation of large mass transport complexes, triggered by current winnowing. In areas where the slope is bathed by weaker currents, the accumulation of mass transport complexes and channel incision is rather controlled by the position of the sea level. Large slope failures were triggered during the Mid-Pleistocene transition and Mid-Brunhes event, both periods characterized by changes in the cyclicity or the amplitude of sea-level fluctuations. Within the seismic stratigraphic framework of third order sequences, four sequences of higher order were identified in the succession of the upper Pleistocene. These higher order sequences also show clear differences in function of the slope exposure to contour currents. Two stochastic models emphasize the role of the contour currents and slope morphology in the facies distribution in the upper Pleistocene sequences. In areas of high current influence the interplay of erosional and depositional processes form a complex facies pattern with downslope and along strike facies alterations. In zones with lower current influence, major facies alternations occur predominately in downslope direction, and a layer-cake pattern characterizes the along strike direction. Therefore, this study highlights that contour currents are an underestimated driver for the sediment distribution and architecture of carbonate slopes.

  14. Stability of IRSL signals from sedimentary K-feldspar samples

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Murray, A.S.; Jain, Mayank

    2011-01-01

    for potassium-rich sedimentary feldspars. We show that the natural post-IR IRSL (pIRIR) signal from a 3.6 Ma old sample is in apparent saturation on a laboratory generated dose response curve, i.e. it does not show detectable fading in nature although a low fading rate is observed on laboratory time scales. We...... be explained in terms of either a single- or multiple-trap model. We present evidence that may suggest that at least part of pIRIR signal is derived from a high temperature trap (∼550°C thermoluminescence (TL) peak), although again the data can also be explained in terms of a single-trap model. Finally, we...

  15. Shaler: in situ analysis of a fluvial sedimentary deposit on Mars

    Science.gov (United States)

    Edgar, Lauren; Gupta, Sanjeev; Rubin, David M.; Lewis, Kevin W.; Kocurek, Gary A.; Anderson, Ryan; Bell, James F.; Dromart, Gilles; Edgett, Kenneth S.; Grotzinger, John P.; Hardgrove, Craig; Kah, Linda C.; LeVeille, Richard A.; Malin, Michael C.; Mangold, Nicholas; Milliken, Ralph E.; Minitti, Michelle; Palucis, Marisa C.; Rice, Melissa; Rowland, Scott K.; Schieber, Juergen; Stack, Kathryn M.; Sumner, Dawn Y.; Wiens, Roger C.; Williams, Rebecca M.E.; Williams, Amy J.

    2018-01-01

    This paper characterizes the detailed sedimentology of a fluvial sandbody on Mars for the first time, and interprets its depositional processes and palaeoenvironmental setting. Despite numerous orbital observations of fluvial landforms on the surface of Mars, ground-based characterization of the sedimentology of such fluvial deposits has not previously been possible. Results from the NASA Mars Science Laboratory Curiosity rover provide an opportunity to reconstruct at fine scale the sedimentary architecture and palaeomorphology of a fluvial environment on Mars. This work describes the grain size, texture, and sedimentary facies of the Shaler outcrop, reconstructs the bedding architecture, and analyses cross-stratification to determine palaeocurrents. On the basis of bedset geometry and inclination, grain-size distribution, and bedform migration direction, this study concludes that the Shaler outcrop likely records the accretion of a fluvial barform. The majority of the outcrop consists of large-scale trough cross-bedding of coarse sand and granules. Palaeocurrent analyses and bedform reconstruction indicate that the beds were deposited by bedforms that migrated towards the northeast, across the surface of a bar that migrated southeast. Stacked cosets of dune cross-bedding suggest aggradation of multiple bedforms, which provides evidence for short periods of sustained flow during Shaler deposition. However, local evidence for aeolian reworking and the presence of potential desiccation cracks within the outcrop suggests that fluvial deposition may have been intermittent. The uppermost strata at Shaler are distinct in terms of texture and chemistry, and are inferred to record deposition from a different sediment dispersal system with a contrasting provenance. The outcrop as a whole is a testament to the availability of liquid water on the surface of Mars in its early history.

  16. Mineralogical Characterization of The Alteration Facies at Gabal El-Missikat Area, Central Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    El-Sherif, A.M.

    2013-01-01

    The present study deals with the petrographical, mineralogical and geochemical characteristics of the alteration facies zones recognized around the shear zone at Gabal El-Missikat area, Central Eastern Desert, Egypt. Petrographically, the fresh granitic samples are composed mainly of quartz, K-feldspars (microcline and microcline perthite), plagioclase, biotite. The secondary minerals are sericite, kaolinite, muscovite, chlorite and epidote as well as zircon, apatite, fluorite, titanite and iron oxides as accessory minerals. Two alteration facies zones are recognized and namely as propylitic and advanced argillic. The propylitic facies zone is composed mainly of sericite with minor kaolinite, muscovite, quartz, relics of plagioclases, chlorite and rare epidote as well as zircon, hematite, goethite, magnetite, ilmenite, ilmenorutile, rutile, titanite, apatite, columbite and fluorite and secondary uranium minerals, the advanced argillic facies zone is composed mainly of kaolinite with minor sericite, quartz, muscovite, chlorite and rare epidote as well as zircon, hematite, goethite, magnetite, ilmenite, ilmenorutile, rutile, titanite, apatite and garnet of spessartine type as accessory minerals. The identified minerals in the studied two alteration facies zones can be grouped into three mineral groups which are: the primary minerals (pyrite, magnetite, galena, columbite and gold), the secondary minerals (uranophane, kasolite and wulfenite) and the gangue minerals (anhydrite, barite, celestine, hematite, goethite and fluorite). The identified mineral assemblage of the studied propylitic alteration facies zone may be attributed to strongly alkaline hydrothermal solutions at ph value of more than 7 with temperature varying between 350 and 450°C, while the advanced argillic alteration facies zone is essentially associated with strongly acidic hydrothermal solutions at ph value less than 7 with temperature varying between 150 and 400°C

  17. Mineralogical and Micro-fabric investigation of the Sandy Facies of Opalinus Clay (Mont Terri)

    International Nuclear Information System (INIS)

    Kaufhold, Annette; Siegesmund, Siegfried; Dohrmann, Reiner; Graesle, Werner; Plischke, Ingo

    2013-01-01

    In the field of geological disposal of radioactive waste in many countries argillaceous formations are considered as potential host rock. For the understanding of the long-term behaviour of clay host rock, it is important to understand the interaction between mechanical behaviour, micro-fabric, and mineral composition. Previous publications showed that particularly the carbonate content and the arrangement of the carbonate grains (as cement in the matrix or as shells) determines the mechanical strength of Opalinus Clay and Callovo-Oxfordian Clay specimens, respectively. Klinkenberg et al. (2009) studied the shaly facies of Opalinus Clay, however, the actual deposit is planned to be built in the sandy facies of Opalinus Clay. The aim of the present study is to investigate the relation between micro-fabric, mineral composition, and mechanical properties of different samples derived from the sandy facies (BLT-A2). Image analysis showed that the carbonates in the sandy facies mainly occur as 1) matrix which in turn acts as cement. Carbonates also occur 2) in the fine sand fraction and 3) biogenic carbonates as traces. The carbonates of the sandy facies, therefore, appear to be similar to the carbonates of the Callovo-Oxfordian Clay with respect to their possible influence on failure strength. The mechanical testing showed that the shear strength increases with increasing carbonate content. This phenomenon was also observed for the samples of the Callovo-Oxfordian Clay, while the opposite relation was found for the shaly facies of the Opalinus Clay. Preliminary results presented here, indicate that the sandy facies (drilling BLT-A2) and Callovo-Oxfordian Clay show similar mechanical properties - in detail: 1) Micro-fabric: carbonates predominate in the matrix, 2) Mineralogy: high carbonate content and 3) Mechanical testing: shear strength increases with increasing carbonate content, where the type of carbonates which controls the increase of strength has to be

  18. Age and duration of eclogite-facies metamorphism, North Qaidam HP/UHP terrane, Western China

    Science.gov (United States)

    Mattinson, C.G.; Wooden, J.L.; Liou, J.G.; Bird, D.K.; Wu, C.L.

    2006-01-01

    Amphibolite-facies para-and orthogneisses near Dulan, at the southeast end of the North Qaidam terrane, enclose minor eclogite and peridotite which record ultra-high pressure (UHP) metamorphism associated with the Early Paleozoic continental collision of the Qilian and Qaidam microplates. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. SHRIMP-RG U-Pb and REE analyses of zircons from four eclogites yield weighted mean ages of 449 to 422 Ma, and REE patterns (flat HREE, no Eu anomaly) and inclusions of garnet, omphacite, and rutile indicate these ages record eclogite-facies metamorphism. The coherent field relations of these samples, and the similar range of individual ages in each sample suggests that the ???25 m.y. age range reflects the duration of eclogite-facies conditions in the studied samples. Analyses from zircon cores in one sample yield scattered 433 to 474 Ma ages, reflecting partial overlap on rims, and constrain the minimum age of eclogite protolith crystallization. Inclusions of Th + REE-rich epidote, and zircon REE patterns are consistent with prograde metamorphic growth. In the Lu??liang Shan, approximately 350 km northwest in the North Qaidam terrane, ages interpreted to record eclogite-facies metamorphism of eclogite and garnet peridotite are as old as 495 Ma and as young as 414 Ma, which suggests that processes responsible for extended high-pressure residence are not restricted to the Dulan region. Evidence of prolonged eclogite-facies metamorphism in HP/UHP localities in the Northeast Greenland eclogite province, the Western Gneiss Region of Norway, and the western Alps suggests that long eclogite-facies residence may be globally significant in continental subduction/collision zones.

  19. 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.; Khalid, Perveiz; Jadoon, Khan; Jouini, Mohamed Soufiane

    2014-01-01

    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

  20. A novel methodology improves reservoir characterization models using geologic fuzzy variables

    Energy Technology Data Exchange (ETDEWEB)

    Soto B, Rodolfo [DIGITOIL, Maracaibo (Venezuela); Soto O, David A. [Texas A and M University, College Station, TX (United States)

    2004-07-01

    One of the research projects carried out in Cusiana field to explain its rapid decline during the last years was to get better permeability models. The reservoir of this field has a complex layered system that it is not easy to model using conventional methods. The new technique included the development of porosity and permeability maps from cored wells following the same trend of the sand depositions for each facie or layer according to the sedimentary facie and the depositional system models. Then, we used fuzzy logic to reproduce those maps in three dimensions as geologic fuzzy variables. After multivariate statistical and factor analyses, we found independence and a good correlation coefficient between the geologic fuzzy variables and core permeability and porosity. This means, the geologic fuzzy variable could explain the fabric, the grain size and the pore geometry of the reservoir rock trough the field. Finally, we developed a neural network permeability model using porosity, gamma ray and the geologic fuzzy variable as input variables. This model has a cross-correlation coefficient of 0.873 and average absolute error of 33% compared with the actual model with a correlation coefficient of 0.511 and absolute error greater than 250%. We tested different methodologies, but this new one showed dramatically be a promiser way to get better permeability models. The use of the models have had a high impact in the explanation of well performance and workovers, and reservoir simulation models. (author)

  1. Advancements in Exploration and In-Situ Recovery of Sedimentary-Hosted Uranium

    International Nuclear Information System (INIS)

    Maerten, Horst; Marsland-Smith, Andrea; Ross, Jonathan; Haschke, Michael; Kalka, Harald; Schubert, Jens

    2014-01-01

    Context and Outline: • ISR feasibility – determining factors: – What counts?; • High-resolution shallow seismic: – Methodology from ‘oil & gas hunting’ adapted to mineral exploration in sedimentary basins; • New down-hole logging tool: – Advanced PFN technology combined with lithologic logging; • Moving theory to practice: – Reactive-transport modelling for optimizing ISR

  2. Continental sedimentary successions exposed in Centinela del Mar, Buenos Aires, Argentina (Lower Pleistocene - Holocene); Las sucesiones sedimentarias continentales expuestas en Centinela del Mar, provincia de Buenos Aires, Argentina (Pleistoceno Inferior-Holoceno)

    Energy Technology Data Exchange (ETDEWEB)

    Cenizo, M. M.

    2011-07-01

    In the present paper, the geomorphologic and sedimentary characteristics of the continental sequences exposed on the coastal cliffs and surrounding areas of the Centinela del Mar locality are described and interpreted. Fourteen lithofacies are defined, their relation, geometry and structure are represented using transversal and longitudinal detailed profiles. In the basal and medium sector of the profile, facies of different degrees of transport and aqueous rework were recognized. In the superior sector, a succession of marine peri-coastal facies corresponding to the Belgranense transgression (=Fm. Pascua) were identified, ending the sequence with relictual eolic facies. The different historical interpretations are discussed, homologating the units referred previously with the ones proposed on this paper. These units are correlated with those defined in the allostratigrapic scheme proposed by other authors for the area covered between Playa San Carlos and Arroyo Chapadmalal. This allowed recognize for the area under study the presence of the Punta San Andres and Arroyo Loberia Alloformations (basal-medium and superior sector, respectively). Between these two entities, a association of well defined progradant marine facies are found and named on this paper as Centinela del Mar Alloformation. Finally, periferithe information gathered here (magnetostratigraphy, radiometric dating, stratigraphic correlations, etc) indicates, at least preliminarily, that the sequence of Centinela del Mar corresponds to the Ensenadense- Lujanense interval (Lower Pleistocene - Holocene). (Author) 73 refs.

  3. Mesozoic Alpine facies deposition as a result of past latitudinal plate motion.

    Science.gov (United States)

    Muttoni, Giovanni; Erba, Elisabetta; Kent, Dennis V; Bachtadse, Valerian

    2005-03-03

    The fragmentation of Pangaea as a consequence of the opening of the Atlantic Ocean is documented in the Alpine-Mediterranean region by the onset of widespread pelagic sedimentation. Shallow-water sediments were replaced by mainly pelagic limestones in the Early Jurassic period, radiolarian cherts in the Middle-Late Jurassic period, and again pelagic limestones in the Late Jurassic-Cretaceous period. During initial extension, basin subsidence below the carbonate compensation depth (CCD) is thought to have triggered the transition from Early Jurassic limestones to Middle-Late Jurassic radiolarites. It has been proposed that the transition from radiolarites to limestones in the Late Jurassic period was due to an increase in calcareous nannoplankton abundance when the CCD was depressed below the ocean floor. But in modern oceans, sediments below the CCD are not necessarily radiolaritic. Here we present palaeomagnetic samples from the Jurassic-Cretaceous pelagic succession exposed in the Lombardian basin, Italy. On the basis of an analysis of our palaeolatitudinal data in a broader palaeogeographic context, we propose an alternative explanation for the above facies tripartition. We suggest that the Lombardian basin drifted initially towards, and subsequently away from, a near-equatorial upwelling zone of high biosiliceous productivity. Our tectonic model for the genesis of radiolarites adds an essential horizontal plate motion component to explanations involving only vertical variations of CCD relative to the ocean floor. It may explain the deposition of radiolarites throughout the Mediterranean and Middle Eastern region during the Jurassic period.

  4. Towards the definition of AMS facies in the deposits of pyroclastic density currents

    Science.gov (United States)

    Ort, M.H.; Newkirk, T.T.; Vilas, J.F.; Vazquez, J.A.; Ort, M.H.; Porreca, Massimiliano; Geissman, J.W.

    2014-01-01

    Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate–strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.

  5. Geologic-seismic models, prediction of shallow-water lacustrine delta sandbody and hydrocarbon potential in the Late Miocene, Huanghekou Sag, Bohai Bay Basin, northern China

    Directory of Open Access Journals (Sweden)

    Hao Liu

    2018-01-01

    Full Text Available The Huanghekou Sag is located at the southeast part of the Bohai Bay Basin, northern China. Large-scale shallow lake delta developed in the Neogene provided suitable geological conditions for the formation of a subtle oil-gas reservoir in this area. The key for analyzing sandstone reservoir and sedimentary facies is by using seismic attributes (amplitude to establish the relationship between lithology combination and seismic attributes. The lower unit of Late Miocene Minghuazhen Formation at the BZ34 block in the Huanghekou Sag was subdivided into 10 parasequence sets (PSS. Thicker sandstones mainly occurred in PSS1 and PSS10, whereas thin sandstones are mostly observed within other parasequence sets. This study presents statistics and analyses of lithology, i.e., statistics of root-mean-square (RMS amplitude and lithology of well locations in different parasequence sets of the study area, as well as 1-D forward seismic models of 7 types of lithology combinations, the establishment of a spatial distribution of 2-D sandbody, forward seismic models etc. Our study indicates that high amplitude peaks correspond to thicker sandbodies, while low amplitude indicates non-development of sandbodies (generally less than 2 m, and medium amplitude agrees well with large sets of mudstones interbedded with medium and thinner sandstones. Different sand–mudstone combinations genetically reflect a combination of multiple micro-facies, therefore, amplitude features can predict sandbodies as well as facies characteristics.

  6. Atmospheric methane from organic carbon mobilization in sedimentary basins — The sleeping giant?

    Science.gov (United States)

    Kroeger, K. F.; di Primio, R.; Horsfield, B.

    2011-08-01

    The mass of organic carbon in sedimentary basins amounts to a staggering 10 16 t, dwarfing the mass contained in coal, oil, gas and all living systems by ten thousand-fold. The evolution of this giant mass during subsidence and uplift, via chemical, physical and biological processes, not only controls fossil energy resource occurrence worldwide, but also has the capacity for driving global climate: only a tiny change in the degree of leakage, particularly if focused through the hydrate cycle, can result in globally significant greenhouse gas emissions. To date, neither climate models nor atmospheric CO 2 budget estimates have quantitatively included methane from thermal or microbial cracking of sedimentary organic matter deep in sedimentary basins. Recent estimates of average low latitude Eocene surface temperatures beyond 30 °C require extreme levels of atmospheric CO 2. Methane degassing from sedimentary basins may be a mechanism to explain increases of atmospheric CO 2 to values as much as 20 times higher than pre-industrial values. Increased natural gas emission could have been set in motion either by global tectonic processes such as pulses of activity in the global alpine fold belt, leading to increased basin subsidence and maturation rates in the prolific Jurassic and Cretaceous organic-rich sediments, or by increased magmatic activity such as observed in the northern Atlantic around the Paleocene-Eocene boundary. Increased natural gas emission would have led to global warming that was accentuated by long lasting positive feedback effects through temperature transfer from the surface into sedimentary basins. Massive gas hydrate dissociation may have been an additional positive feedback factor during hyperthermals superimposed on long term warming, such as the Paleocene-Eocene Thermal Maximum (PETM). As geologic sources may have contributed over one third of global atmospheric methane in pre-industrial time, variability in methane flux from sedimentary

  7. Geologically based model of heterogeneous hydraulic conductivity in an alluvial setting

    Science.gov (United States)

    Fogg, Graham E.; Noyes, Charles D.; Carle, Steven F.

    Information on sediment texture and spatial continuity are inherent to sedimentary depositional facies descriptions, which are therefore potentially good predictors of spatially varying hydraulic conductivity (K). Analysis of complex alluvial heterogeneity in Livermore Valley, California, USA, using relatively abundant core descriptions and field pumping-test data, demonstrates a depositional-facies approach to characterization of subsurface heterogeneity. Conventional textural classifications of the core show a poor correlation with K; however, further refinement of the textural classifications into channel, levee, debris-flow, and flood-plain depositional facies reveals a systematic framework for spatial modeling of K. This geologic framework shows that most of the system is composed of very low-K flood-plain materials, and that the K measurements predominantly represent the other, higher-K facies. Joint interpretation of both the K and geologic data shows that spatial distribution of K in this system could not be adequately modeled without geologic data and analysis. Furthermore, it appears that K should not be assumed to be log-normally distributed, except perhaps within each facies. Markov chain modeling of transition probability, representing spatial correlation within and among the facies, captures the relevant geologic features while highlighting a new approach for statistical characterization of hydrofacies spatial variability. The presence of fining-upward facies sequences, cross correlation between facies, as well as other geologic attributes captured by the Markov chains provoke questions about the suitability of conventional geostatistical approaches based on variograms or covariances for modeling geologic heterogeneity. Résumé Les informations sur la texture des sédiments et leur continuité spatiale font partie des descriptions de faciès sédimentaires de dépôt. Par conséquent, ces descriptions sont d'excellents prédicteurs potentiels des

  8. Mining of sedimentary-type ore deposits

    International Nuclear Information System (INIS)

    Bruha, J.; Slovacek, T.; Berka, J.; Sadilek, P.

    1992-01-01

    A procedure is proposed for mining sedimentary-type ore deposits, particularly uranium deposits, using the stope-pillar technique. The stope having been mined out, the free room is filled with hydro-setting gob from the surface. A precondition for the application of this technique is horizontal ore mineralization in sediments where the total thickness of the mineralized ore layer is at least 3 to 5 m. Mining losses do not exceed 5%. For thicknesses greater than 5 m, the roof is reinforced and the walls are secured with netting. The assets of the technique include higher labor productivity of the driving, lower material demands in reinforcing and filling, lower power consumption, and reduced use of explosives. (Z.S.). 3 figs

  9. Possible zircon U-Pb evidence for Pan-African granulite-facies metamorphism in the Mozambique belt of southern Tanzania

    International Nuclear Information System (INIS)

    Coolen, J.J.M.M.M.

    1982-01-01

    Four zircon fractions of garnet-bearing two-pyroxene granulite, from the Furua granulite complex of southern Tanzania, plot very close to concordia. A discordia yields a lower intercept at 652 +- 10 Ma, an age slightly higher than the Rb-Sr whole-rock and mineral ages reported from the surrounding amphibolite-facies rocks. The U-Pb systematics indicate the presence of a very small amount of older (2-3 Ga) radiogenic lead. The zircon data may be interpreted as indicating an event of granulite-facies metamorphism during the Pan-African thermotectonic episode. This interpretation is at variance with current models postulating that the granulite complexes in the Mozambique belt are relicts of older, possibly Archaean events of metamorphism. (Auth.)

  10. Permanganate diffusion and reaction in sedimentary rocks.

    Science.gov (United States)

    Huang, Qiuyuan; Dong, Hailiang; Towne, Rachael M; Fischer, Timothy B; Schaefer, Charles E

    2014-04-01

    In situ chemical oxidation using permanganate has frequently been used to treat chlorinated solvents in fractured bedrock aquifers. However, in systems where matrix back-diffusion is an important process, the ability of the oxidant to migrate and treat target contaminants within the rock matrix will likely determine the overall effectiveness of this remedial approach. In this study, a series of diffusion experiments were performed to measure the permanganate diffusion and reaction in four different types of sedimentary rocks (dark gray mudstone, light gray mudstone, red sandstone, and tan sandstone). Results showed that, within the experimental time frame (~2 months), oxidant migration into the rock was limited to distances less than 500 μm. The observed diffusivities for permanganate into the rock matrices ranged from 5.3 × 10(-13) to 1.3 × 10(-11) cm(2)/s. These values were reasonably predicted by accounting for both the rock oxidant demand and the effective diffusivity of the rock. Various Mn minerals formed as surface coatings from reduction of permanganate coupled with oxidation of total organic carbon (TOC), and the nature of the formed Mn minerals was dependent upon the rock type. Post-treatment tracer testing showed that these Mn mineral coatings had a negligible impact on diffusion through the rock. Overall, our results showed that the extent of permanganate diffusion and reaction depended on rock properties, including porosity, mineralogy, and organic carbon. These results have important implications for our understanding of long-term organic contaminant remediation in sedimentary rocks using permanganate. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates Fields, Kansas, USA

    Science.gov (United States)

    Ohl, Derek; Raef, Abdelmoneam

    2014-04-01

    Higher resolution rock formation characterization is of paramount priority, amid growing interest in injecting carbon dioxide, CO2, into subsurface rock formations of depeleting/depleted hydrocarbon reservoirs or saline aquifers in order to reduce emissions of greenhouse gases. In this paper, we present a case study for a Mississippian carbonate characterization integrating post-stack seismic attributes, well log porosities, and seismic petrophysical facies classification. We evaluated changes in petrophysical lithofacies and reveal structural facies-controls in the study area. Three cross-plot clusters in a plot of well log porosity and acoustic impedance corroborated a Neural Network petrophysical facies classification, which was based on training and validation utilizing three petrophysically-different wells and three volume seismic attributes, extracted from a time window including the wavelet of the reservoir-top reflection. Reworked lithofacies along small-throw faults has been revealed based on comparing coherency and seismic petrophysical facies. The main objective of this study is to put an emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2 carbon geosequestration in a depleting reservoir and also in the deeper saline aquifer of the Arbuckle Group, south central Kansas. The 3D seismic coherency attribute, we calculated from a window embracing the Mississippian top reflection event, indicated anomalous features that can be interpreted as a change in lithofacies or faulting effect. An Artificial Neural Network (ANN) lithofacies modeling has been used to better understand these subtle features, and also provide petrophysical classes, which will benefit flow-simulation modeling and/or time-lapse seismic monitoring feasibility analysis. This paper emphasizes the need of paying greater attention to small-scale features when embarking upon characterization of a reservoir or saline-aquifer for CO2

  12. Facies discrimination in a mixed fluvio-eolian setting using elemental whole rock geochemistry

    DEFF Research Database (Denmark)

    Svendsen, Johan; Friis, Henrik; Stollhofen, Harald

    2007-01-01

    -eolian successions. The method is developed on the modern fluvio-eolian sediments from the Skeleton Coast dune field, Namibia. The examined sediments comprise eight different facies types; eolian dune sands, inter dune fluvial channel sands, intra erg mass flow deposits, intra erg hyperconcentrated flow deposits......, fluvial channel sands, fluvial mud, lacustrine heterolithic sand and lacustrine heterolithic mud. The contrasting provenance of the fluvial and eolian sediments results in a distinct source fingerprint which can be discriminated using elemental whole rock geochemistry. Multivariate statistical technique...... performed on the geochemical data has enabled discrimination of seven of the eight facies types. Furthermore, the facies discrimination method allowed a quantitative estimate of the degree of fluvial reworking of eolian sand. We believe that the method presented here, when calibrated to a reference well...

  13. Hydrogeologic framework of fractured sedimentary rock, Newark Basin, New Jersey

    Science.gov (United States)

    Lacombe, Pierre J.; Burton, William C.

    2010-01-01

    delineate the lithostratigraphy from multiple wells. Gamma-ray logs and rock cores were correlated to develop a 13-layer gamma-ray stratigraphy and 41-layer lithostratigraphy throughout the fractured sedimentary rock research site. Detailed hydrogeologic framework shows that black carbon-rich laminated mudstones are the most hydraulically conductive. Water-quality and aquifer-test data indicate that groundwater flow is greatest and TCE contamination is highest in the black, carbon- and clay-rich laminated mudstones. Large-scale groundwater flow at the NAWC research site can be modeled as highly anisotropic with the highest component of permeability occurring along bedding planes.

  14. 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

  15. Archaen to Recent aeolian sand systems and their sedimentary record

    DEFF Research Database (Denmark)

    Rodríguez-López, Juan Pedro; Clemmensen, Lars B; Lancaster, Nick

    2014-01-01

    The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand-sea or dunefield (erg) deposits, whereas coastal systems are ...

  16. Determining the Accuracy of Paleomagnetic Remanence and High-Resolution Chronostratigraphy for Sedimentary Rocks using Rock Magnetics

    Science.gov (United States)

    Kodama, K. P.

    2017-12-01

    The talk will consider two broad topics in rock magnetism and paleomagnetism: the accuracy of paleomagnetic remanence and the use of rock magnetics to measure geologic time in sedimentary sequences. The accuracy of the inclination recorded by sedimentary rocks is crucial to paleogeographic reconstructions. Laboratory compaction experiments show that inclination shallows on the order of 10˚-15˚. Corrections to the inclination can be made using the effects of compaction on the directional distribution of secular variation recorded by sediments or the anisotropy of the magnetic grains carrying the ancient remanence. A summary of all the compaction correction studies as of 2012 shows that 85% of sedimentary rocks studied have enjoyed some amount of inclination shallowing. Future work should also consider the effect of grain-scale strain on paleomagnetic remanence. High resolution chronostratigraphy can be assigned to a sedimentary sequence using rock magnetics to detect astronomically-forced climate cycles. The power of the technique is relatively quick, non-destructive measurements, the objective identification of the cycles compared to facies interpretations, and the sensitivity of rock magnetics to subtle changes in sedimentary source. An example of this technique comes from using rock magnetics to identify astronomically-forced climate cycles in three globally distributed occurrences of the Shuram carbon isotope excursion. The Shuram excursion may record the oxidation of the world ocean in the Ediacaran, just before the Cambrian explosion of metazoans. Using rock magnetic cyclostratigraphy, the excursion is shown to have the same duration (8-9 Myr) in southern California, south China and south Australia. Magnetostratigraphy of the rocks carrying the excursion in California and Australia shows a reversed to normal geomagnetic field polarity transition at the excursion's nadir, thus supporting the synchroneity of the excursion globally. Both results point to a

  17. Importance of separating sedimentation facies in prospecting for oil and gas pools confined to sloping structures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B

    1984-01-01

    The Shuantotszi field which is in the southeast part of the Sunlyalo oil and gas basin was discovered in 1962. For a long time the correlation of the main factors controlling the oil and gas distribution remained obscure. It has been established in recent years that the main volume of oil and gas is confined to facies in the channels of the second order, arranged between the facies of the main channel and the perlite deposits of the delta. It was established that formation of the accumulation is associated with redistribution and secondary migration of hydrocarbons.

  18. Microfacies, Sedimentary Environment and Relative Sea Level Changes of the Ruteh Formation, Sangsar and Makaroud Sections, Central Alborz

    Directory of Open Access Journals (Sweden)

    Leili Bastami

    2016-12-01

    -red S solution according to Dickson (1965 method. The grain and matrix percentages were estimated using visual percentage charts of Bacelle and Bosellini (1965. Dunham (1962 classification were used for carbonate facies nomenclature. Based on lithological and textural characteristics, fossil content, abiotic allochems, facies succession and their comparision with well studied environments by Flugel (2010, microfacies and their subenvironments have been identified. In this study investigation of relative sea level changes is on the basis of field observations and facies analysis. Based on the vertical succession of microfacies and sedimentary paleoenvironmental features, Systems tracts and sedimentary sequences have been recognized. Discussion of Results & Conclusions Field and petrographic studies at the Sangsar and Makaroud sections, indicate that the Ruteh Formation sediments consist of 19 carbonate microfacies and one siliciclastic petrofacies that during the Middle Permian times deposited in tidal flat to open marine facies belts of a bioclastic homoclinal carbonate ramp on the southern passive margin of the Paleotethys located on the northern Gondwana Supercontinent in a tropical region. Tidal flat facies belt includes: Dolomitic mudstone, lime mudstone to sandy lime mudstone, pelloid intraclast packstone and one quartzarenite siliciclastic petrofacies. Lagoon facies belt includes: bioclast mudstone, dasycladacea wackestone, foraminifera pelloid wackestone, bioclast pelloid wackestone,  bioclast tubiphytes wackestone, bioclast algal wackestone/packstone. Shoal facies belt includes: ooid pelloid packstone/grainstone, bioclast pelloid packstone/grainstone, pelloid bioclast grainstone and algal packstone/grainstone. Open marine facies belt includes: tubiphytes gymnocodiacea wackestone, gymnocodiacea packstone, bioclast gymnocodiacea wackestone, sponge spicule bioclast wackestone, crinoid mudstone/wackestone and bioclast mudstone.  The Ruteh Formation at both

  19. Questioning the Sedimentary Paradigm for Granites

    Science.gov (United States)

    Glazner, A. F.; Bartley, J. M.; Coleman, D. S.; Boudreau, A.; Walker, J. D.

    2007-12-01

    A critical question regarding volcano-pluton links is whether plutons are samples of magma that passed through on its way to eruption, or residues left behind after volcanic rocks were extracted. A persistent theme of recent work on granites sensu lato is that many are sedimentary accumulations of crystals that lost significant volumes of magmatic liquid. This view is based on observations of structures that clearly seem to reflect deposition on a magma chamber floor (e.g., flows of chilled mafic magma into silicic magma) and on the inference that many other structures, such as modal layering, truncated layering, and crystal accumulations, reflect crystal sedimentation on such chamber floors. There are significant physical and geochemical reasons to question this view, based on observations in the Sierra Nevada of California and similar results from other batholiths. First, few granites show the enrichments in Ba, Sr, and relative Eu that feldspar accumulation should produce. Second, sedimentary features such as graded bedding and cross-bedding form in highly turbulent flows, but turbulence is unachievable in viscous silicic liquids, where velocities on the order of 104 m/s would be required to induce turbulence in a liquid with η=104 Pa s. Third, tabular modally layered domains commonly cut surrounding modal layering on both sides, and orientations of modal layering and of the troughs of "ladder dikes" commonly scatter widely within hectare-sized areas; it is difficult to reconcile these features with gravity-driven settling. Fourth, accumulations of K-feldspar megacrysts are typically inferred to be depositional, but this is precluded by crystallization of most K- feldspar after rheologic lock-up occurs. Finally, accumulations of K-feldspar and hornblende are typically packed too tightly to be depositional. With analogy to layered mafic intrusions, many features attributed to crystal sedimentation in granites may be better explained by crystal aging and other in

  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. Mantle convective support, drainage patterns and sedimentary flux: Examples from the West Africa passive margin

    Science.gov (United States)

    Lodhia, B. H.; Roberts, G. G.; Fraser, A.; Goes, S. D. B.; Fishwick, S.; Jarvis, J.

    2017-12-01

    Sedimentary flux measurements, regional subsidence patterns, inversion of drainage patterns, tomographic models and simple isostatic calculations are combined to constrain the history of sub-plate support of North West Africa. Backstripping of 8 commercial wells and mapping of 53,000 line-km of 2D seismic reflection data show that rapid ( 0.03 mm a-1) Neogene-Recent subsidence occurred in a 500 x 500 km region offshore Mauritania. 0.4-0.8 km of water-loaded subsidence occurred in the center of the basin during the last 23 Ma. Salt withdrawal, thin-skinned tectonics, glacio-eustasy and flexure of the lithosphere due to the emplacement of Cape Verde cannot explain the timing or magnitude of this phase of subsidence. Instead, conversion of shear wave velocities into temperature and simple isostatic calculations indicate that asthenospheric temperatures determine bathymetry from Cape Verde to West Africa. Our results indicate that asthenospheric flow from Cape Verde to Mauritania generated a bathymetric gradient of 1/300 at a wavelength of 103 km during the last 23 Ma. We explore the relationship between uplift and erosion onshore and measured solid sedimentary flux offshore. First, the history of sedimentary flux to the margin was determined by depth-converting and decompacting biostratigraphically-dated isopachs. Compaction and velocity errors, determined using check-shot data, were propagated into calculated sedimentary flux history. Solid-sedimentary flux rates of 0.2-0.1+0.2 ×103 km3 /Ma between 23.8-5.6 Ma, and 1.9-1.4+2.0 ×103 km3 /Ma from 5.6-0 Ma are observed. Secondly, a calibrated stream power erosional model was used to invert 14700 river profiles for a history of regional uplift rate. Incision rates were integrated along best-fitting theoretical river profiles to predict sedimentary flux at mouths of the rivers draining NW Africa. Our predicted history of sedimentary flux increases in two stages towards the present-day, in agreement with our offshore

  2. 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.

  3. 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.

  4. Unsupervised seismic facies analysis with spatial constraints using regularized fuzzy c-means

    Science.gov (United States)

    Song, Chengyun; Liu, Zhining; Cai, Hanpeng; Wang, Yaojun; Li, Xingming; Hu, Guangmin

    2017-12-01

    Seismic facies analysis techniques combine classification algorithms and seismic attributes to generate a map that describes main reservoir heterogeneities. However, most of the current classification algorithms only view the seismic attributes as isolated data regardless of their spatial locations, and the resulting map is generally sensitive to noise. In this paper, a regularized fuzzy c-means (RegFCM) algorithm is used for unsupervised seismic facies analysis. Due to the regularized term of the RegFCM algorithm, the data whose adjacent locations belong to same classification will play a more important role in the iterative process than other data. Therefore, this method can reduce the effect of seismic data noise presented in discontinuous regions. The synthetic data with different signal/noise values are used to demonstrate the noise tolerance ability of the RegFCM algorithm. Meanwhile, the fuzzy factor, the neighbour window size and the regularized weight are tested using various values, to provide a reference of how to set these parameters. The new approach is also applied to a real seismic data set from the F3 block of the Netherlands. The results show improved spatial continuity, with clear facies boundaries and channel morphology, which reveals that the method is an effective seismic facies analysis tool.

  5. Spectral properties and ASTER-based alteration mapping of Masahim volcano facies, SE Iran

    Science.gov (United States)

    Tayebi, Mohammad H.; Tangestani, Majid H.; Vincent, Robert K.; Neal, Devin

    2014-10-01

    This study applies Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and the Mixture Tuned Matched Filtering (MTMF) algorithm to map the sub-pixel distribution of alteration minerals associated with the Masahim volcano, SE Iran for understanding the spatial relationship between alteration minerals and volcano facies. Investigations of the alteration mineralogy were conducted using field-spectroscopy, X-ray diffraction (XRD) analysis and ASTER Short Wave Infrared (SWIR) spectral data. In order to spectrally characterize the stratovolcano deposits, lithological units and alteration minerals, the volcano was divided into three facies: the Central, Proximal, and Medial-distal facies. The reflectance spectra of rock samples show absorption features of a number of minerals including white mica, kaolinite, montmorillonite, illite, goethite, hematite, jarosite, opal, and chlorite. The end-members of key alteration minerals including sericite (phyllic zone), kaolinite (argillic zone) and chlorite (propylitic zone) were extracted from imagery using the Pixel Purity Index (PPI) method and were used to map alteration minerals. Accuracy assessment through field observations was used to verify the fraction maps. The results showed that most prominent altered rocks situated at the central facies of volcano. The alteration minerals were discriminated with the coefficient of determination (R2) of 0.74, 0.81, and 0.68 for kaolinite, sericite, and chlorite, respectively. The results of this study have the potential to refine the map of alteration zones in the Masahim volcano.

  6. Hierarchy of facies of pyroclastic flow deposits generated by Laacher See type eruptions

    Science.gov (United States)

    Freundt, A.; Schmincke, H.-U.

    1985-04-01

    The upper Quaternary pyroclastic flow deposits of Laacher See volcano show compositional and structural facies variations on four different scales: (1) eruptive units of pyroclastic flows, composed of many flow units; (2) depositional cycles of as many as five flow units; flow units containing (3) regional intraflow-unit facies; and (4) local intraflow-unit subfacies. These facies can be explained by successively overlapping processes beginning in the magma column and ending with final deposition. The pyroclastic flow deposits thus reflect major aspects of the eruptive history of Laacher See volcano: (a) drastic changes in eruptive mechanism due to increasing access of water to the magma chamber and (b) change in chemical composition and crystal and gas content as evacuation of a compositionally zoned magma column progressed. The four scales of facies result from four successive sets of processes: (1) differentiation in the magma column and external factors governing the mechanism of eruption; (2) temporal variations of factors inducing eruption column collapse; (3) physical conditions in the eruption column and the way in which its collapse proceeds; and (4) interplay of flow-inherent and morphology-induced transport mechanics.

  7. Variations in vitrinite reflectance with organic facies - examples from Pennsylvanian cyclothems of the Midcontinent, USA

    Energy Technology Data Exchange (ETDEWEB)

    Wenger, L M; Baker, D R

    1987-01-01

    Significant variations in vitrinite reflectance (% R/sub o/) with organic facies have been demonstrated from Pennsylvanian -aged cyclothems of the Midcontinent, USA. Thermal alteration index (TAI) and Rock-Eval T/sub m/ax values remain relatively constant through these thin lithologic successions, regardless of facies, and are in reasonable agreement with R/sub o/ measurements on interbedded coal. Organic-rich black and phosphatic black-shales, which contain significant component of liptinitic organic matter of presumed marine algal derivation, display R/sub o/ values which are suppressed relative to the coal benchmark. A distinct correlation between increased hydrogen index (HI) and liptinite content with suppressed reflectivities is apparent. More oxic facies (e.g. calcareous and fossiliferous gray shales and limestones) often display R/sub o/'s that are considerably higher than for coal. Soxhlet extraction prior to maceration yielded no variation in reflectance compared to non-extracted kerogens suggesting bitumen adsorption was not the cause of the apparent suppression in the organic-rich black-shales. Lower total organic carbon (TOC)-normalized bitumen contents and Rock-Eval transformations ratios in liptinite-rich facies suggest differential reaction kinetics for kerogen types, with terrestrial organic matter 'maturing' at an earlier stage than hydrogen-rich marine-derived organic matter. 8 refs., 6 figs., 1 tab.

  8. Getting to First Base: Prima Facie Arguments for Propositions of Value.

    Science.gov (United States)

    Tuman, Joseph S.

    1987-01-01

    Argues that few clear standards exist for value debate. Defines values as instrumental or terminal, and identifies four prima facie burdens necessary for affirming a value resolution: value identification; value criteria; value hierarchy; and topicality through relevance. Examines the role of presumption and burden of proof in value debate. (MM)

  9. The Burger Court and the Prima Facie Case in Employment Discrimination Litigation: A Critique.

    Science.gov (United States)

    Friedman, Joel William

    1979-01-01

    The unprincipled and contrived reasoning running through these opinions manifests an intentional effort by the Court to impede litigants' ability to secure their rights to equal employment opportunity by raising the requirements of the prima facie case. Available from Fred B. Rothman & Co., 10368 West Centennial Road, Littleton, CO 80123; sc…

  10. Cataplectic facies: clinical marker in the diagnosis of childhood narcolepsy-report of two cases.

    Science.gov (United States)

    Prasad, Manish; Setty, Gururaj; Ponnusamy, Athi; Hussain, Nahin; Desurkar, Archana

    2014-05-01

    Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood and/or adolescence. The full spectrum of clinical manifestations, namely excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis, is usually not present at disease onset, delaying diagnosis during childhood. Mean delay in diagnosis since symptom onset is known to be several years. Initial manifestations can sometimes be as subtle as only partial drooping of eyelids leading to confusion with a myasthenic condition. We present two children who presented with "cataplectic facies," an unusual facial feature only recently described in children with narcolepsy with cataplexy. The diagnosis of narcolepsy was confirmed by multiple sleep latency test along with human leukocyte antigen typing and cerebrospinal fluid hypocretin assay. The diagnosis of narcolepsy with cataplexy at onset can be challenging in young children. With more awareness of subtle signs such as cataplectic facies, earlier diagnosis is possible. To date, only 11 children between 6 and 18 years of age presenting with typical cataplectic facies have been reported in the literature. We present two patients, one of whom is the youngest individual (4 years old) yet described with the typical cataplectic facies. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Metre-scale cyclicity in Middle Eocene platform carbonates in northern Egypt: Implications for facies development and sequence stratigraphy

    Science.gov (United States)

    Tawfik, Mohamed; El-Sorogy, Abdelbaset; Moussa, Mahmoud

    2016-07-01

    The shallow-water carbonates of the Middle Eocene in northern Egypt represent a Tethyan reef-rimmed carbonate platform with bedded inner-platform facies. Based on extensive micro- and biofacies documentation, five lithofacies associations were defined and their respective depositional environments were interpreted. Investigated sections were subdivided into three third-order sequences, named S1, S2 and S3. Sequence S1 is interpreted to correspond to the Lutetian, S2 corresponds to the Late Lutetian and Early Bartonian, and S3 represents the Late Bartonian. Each of the three sequences was further subdivided into fourth-order cycle sets and fifth-order cycles. The complete hierarchy of cycles can be correlated along 190 km across the study area, and highlighting a general "layer-cake" stratigraphic architecture. The documentation of the studied outcrops may contribute to the better regional understanding of the Middle Eocene formations in northern Egypt and to Tethyan pericratonic carbonate models in general.

  12. Modern foraminiferal facies in a subtropical estuarine channel, Bertioga, São Paulo, Brazil

    Science.gov (United States)

    Eichler, P.P.B.; Eichler, B.B.; De Miranda, L. B.; Rodrigues, A.R.

    2007-01-01

    Numerical analyses of modern foraminiferal abundance and environmental data from the Bertioga Channel (Sa??o Paulo, Brazil) reveal multiple biofacies within an overall paralic setting. Despite its fisheries, mariculture and attraction to tourists, the environmental state of Bertioga Channel remains poorly studied. The present investigation is an attempt to partly fill this gap; the parameters examined include depth, salinity, temperature, organic carbon, sulfur content and bottom sediment type. Muddy sediments with high organic carbon content derived from land drainage are found in the inner parts of the channel, whereas sandy sediment dominates the areas adjacent to the Atlantic Ocean. In the eastern entrance to the channel, sandy sediment contain species of Rotaliida from Facies 1 (including Elphidium discoidale, Elphidium poeyanum, Hanzawaia boueana, Pararotalia cananeiaensis and Nonionella atlantica), reflecting normal marine salinity. Sediments with high percentages of silt and clay in polyhaline and eurybaline environments of the eastern part and Itapanhau?? River contain Facies 2, which includes Ammonia beccarii and Pararotalia cananeiaensis. In the western entrance and central, western and eastern parts, where salinities vary from 18 to 30 psu and the sediments contain both low and high organic carbon, the foraminifera from Facies 3 are dominated by Quinqueloculina milletti, Arenoparrella mexicana, Pararotalia cananeiaensis, Ammonia beccarii, Buliminella elegantissima, Elphidium sp., Elphidium excavatum, Elphidium gunteri and Elphidium poeyanum. In mesohaline and polyhaline waters of the central part, the organic-carbon-rich silt and clay contain Facies 4, which includes Ammonia beccarii, Pararotalia cananeiaensis, Elphidium excavatum and Elphidium sp. Most of organic-carbon-enriched, silty-clay substrates that are subject to the highest fresh-water discharge and high bottom temperatures support two different assemblages: one of mostly Rotaliina and the

  13. Supercritical flows and their control on the architecture and facies of small-radius sand-rich fan lobes

    Science.gov (United States)

    Postma, George; Kleverlaan, Kick

    2018-02-01

    New insights into flow characteristics of supercritical, high-density turbidity currents initiated renewed interest in a sand-rich lobe complex near the hamlet of Mizala in the Sorbas Basin (Tortonian, SE Spain). The field study was done using drone-made images taken along bed strike in combination with physical tracing of bounding surfaces and section logging. The studied lobe systems show a consistent built-up of lobe elements of 1.5-2.0 m thick, which form the building 'blocks' of the lobe system. The stacking of lobe elements shows lateral shift and compensational relief infill. The new model outlined in this paper highlights three stages of fan lobe development: I. an early aggradational stage with lobe elements characterized by antidune and traction-carpet bedforms and burrowed mud intervals (here called 'distal fan' deposits); II. a progradational stage, where the distal fan deposits are truncated by lobe elements of amalgamated sandy to gravelly units characterized by cyclic step bedform facies (designated as 'supra fan' deposits). The supra fan is much more channelized and scoured and of higher flow energy than the distal-fan. Aggradation of the supra-fan is terminated by a 'pappy' pebbly sandstone and by substrate liquefaction, 'pappy' referring to a typical, porridge-like texture indicating rapid deposition under conditions of little-to-no shear. The facies-bounded termination of the supra-fan is here related to its maximum elevation, causing the lobe-feeding supercritical flow to choke and to expand upwards by a strong hydraulic jump at the channel outlet; III. a backfilling stage, characterized by backfilling of the remaining relief with progressively thinning and fining of turbidite beds and eventually with mud. The three-stage development for fan-lobe building is deducted from reoccurring architectural and facies characteristics in three successive fan-lobes. The validity of using experimental, supercritical-flow fan studies for understanding the

  14. Facies-constrained FWI: Toward application to reservoir characterization

    KAUST Repository

    Kamath, Nishant

    2017-11-01

    The most common approach to obtaining reservoir properties from seismic data exploits the amplitude variation with offset response of reflected waves. However, structural complexity and errors in the velocity model can severely reduce the quality of the inverted results. Full-waveform inversion (FWI) has shown a lot of promise in obtaining high-resolution velocity models for depth imaging. We propose supplementing FWI with rock-physics constraints obtained from borehole data to invert for reservoir properties. The constraints are imposed by adding appropriately weighted regularization terms to the objective function. The advantages of this technique over conventional FWI algorithms are shown by conducting synthetic tests for both isotropic and VTI (transversely isotropic with a vertical symmetry axis) models. The medium parameterization for FWI is selected using radiation (scattering) patterns of perturbations in the model parameters.

  15. Facies analysis of the Codó Formation (Late Aptian in the Grajaú Area, Southern São Luís-Grajaú Basin

    Directory of Open Access Journals (Sweden)

    Rossetti Dilce F.

    2004-01-01

    Full Text Available Facies descriptions of the Codó Formation in the Grajaú area are provided for the first time, and its sedimentary characteristics compared to those from the Codó area to allow paleoenvironmental reconstructions. Deposits in the Grajaú area include evaporites, limestones and argillites bearing features indicative of a shallow, low energy, subaqueous, saline environment exposed to meteoric and/or capillary conditions. Flooding-evaporative concentration-desiccation cycles suggest a saline pan complex surrounded by extensive evaporitic mudflats. The location of the system, whether coastal or inland, is a matter open for debate. However, the later hypothesis is favored considering: 1. Sr isotopic data, with values higher than those expected for Late Aptian marine waters; 2. calcitic composition of limestones (instead of dolomitic and/or magnesitic as expected in coastal settings; and 3. presence of continental ostracods and lack of marine fauna. This interpretation is consistent with that proposed for UpperAptian deposits of the Codó area, but the depositional system there was one dominated by more stable, well-stratified, anoxic waters and evaporite precipitation in central lacustrine areas, while in the Grajaú area the salt pan was more oxygenated and ephemeral, with salt precipitation mainly in marginal areas or along surrounding mudflats.

  16. Petrographic changes induced by artificial coalification of peat: comparison of two planar facies (Rhizophora and Cladium) from the Everglades-mangrove complex of Florida and a domed facies (Cyrilla) from the Okefenokee Swamp of Georgia

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, A.D.; Bailey, A.M. [University of South Carolina, Columbia, SC (United States). Dept. of Geological Sciences

    1997-12-01

    Petrographic changes during coalification of three peat samples were investigated by artificial coalification experiments using a semi-open reactor system. Compressions of from 83 to 88% produced dark brown to black, shiny, flattened pellets exhibiting microscopic banding. Overall amounts of compression inversely correlated with the framework to matrix ratios (F/M) although certain tissue fragments remained relatively uncompressed due to the presence of tanniferous cell fillings. The most distinct microscopic banding (longest and widest bands) developed in samples of the dome-formed peat facies. The planar, root-dominated, Rhizophora facies showed the greatest change in microbanding character during coalification, with greater compressions roots having disappeared. This could explain why roots are significant components of many modern peats (and ancient coal ball concretions) but are difficult to recognize in bituminous coals. Similarly, separation of cuticles from leaves in modern peat-forming environments partially explains why leaf remains are also difficult to recognize in most coals, even those with abundant cutinites. Macerals were also affected. These petrographic results, along with previously reported chemical results, all suggest that the methods used in these experiments have produced changes that might reasonably be expected to occur during natural coalification (despite speeding up). Although more work needs to be done to verify and refine these results and to establish a correlation between these artificial `coalification steps` and true coalification, the new observations and conclusions from these studies might still be helpful in constructing models to predict or interpret coal seam characteristics and to establish the timing and release-potential of gaseous or liquid hydrocarbons from coals. 69 refs., 28 figs., 5 tabs.

  17. Eclogite facies relics and a multistage breakdown in metabasites of the KTB pilot hole, NE Bavaria: implications for the Variscan tectonometamorphic evolution of the NW Bohemian Massif

    Science.gov (United States)

    O'Brien, Patrick J.; Röhr, Christian; Okrusch, Martin; Patzak, Margarete

    1992-11-01

    approach to domainal equilibrium show that both the eclogite facies and early breakdown occurred above 10 kb. As the metamorphic unit hosting these particular metabasites is generally characterized by pressures below 10 kb these results have important implications for understanding the tectonometamorphic evolution of the region. The relationship between the studied rocks and other units in the NW Bohemian Massif exhibiting a multistage metamorphic evolution is discussed and possible tectonic models evaluated.

  18. Facies-constrained FWI: Toward application to reservoir characterization

    KAUST Repository

    Kamath, Nishant; Tsvankin, Ilya; Naeini, Ehsan Zabihi

    2017-01-01

    of the inverted results. Full-waveform inversion (FWI) has shown a lot of promise in obtaining high-resolution velocity models for depth imaging. We propose supplementing FWI with rock-physics constraints obtained from borehole data to invert for reservoir

  19. Alteration of Sedimentary Clasts in Martian Meteorite Northwest Africa 7034

    Science.gov (United States)

    McCubbin, F. M.; Tartese, R.; Santos, A. R.; Domokos, G.; Muttik, N.; Szabo, T.; Vazquez, J.; Boyce, J. W.; Keller, L. P.; Jerolmack, D. J.; hide

    2014-01-01

    The martian meteorite Northwest Africa (NWA) 7034 and pairings represent the first brecciated hand sample available for study from the martian surface [1]. Detailed investigations of NWA 7034 have revealed substantial lithologic diversity among the clasts [2-3], making NWA 7034 a polymict breccia. NWA 7034 consists of igneous clasts, impact-melt clasts, and "sedimentary" clasts represented by prior generations of brecciated material. In the present study we conduct a detailed textural and geochemical analysis of the sedimentary clasts.

  20. Sedimentary Geology Context and Challenges for Cyberinfrastructure Data Management

    Science.gov (United States)

    Chan, M. A.; Budd, D. A.

    2014-12-01

    A cyberinfrastructure data management system for sedimentary geology is crucial to multiple facets of interdisciplinary Earth science research, as sedimentary systems form the deep-time framework for many geoscience communities. The breadth and depth of the sedimentary field spans research on the processes that form, shape and affect the Earth's sedimentary crust and distribute resources such as hydrocarbons, coal, and water. The sedimentary record is used by Earth scientists to explore questions such as the continental crust evolution, dynamics of Earth's past climates and oceans, evolution of the biosphere, and the human interface with Earth surface processes. Major challenges to a data management system for sedimentary geology are the volume and diversity of field, analytical, and experimental data, along with many types of physical objects. Objects include rock samples, biological specimens, cores, and photographs. Field data runs the gamut from discrete location and spatial orientation to vertical records of bed thickness, textures, color, sedimentary structures, and grain types. Ex situ information can include geochemistry, mineralogy, petrophysics, chronologic, and paleobiologic data. All data types cover multiple order-of-magnitude scales, often requiring correlation of the multiple scales with varying degrees of resolution. The stratigraphic framework needs dimensional context with locality, time, space, and depth relationships. A significant challenge is that physical objects represent discrete values at specific points, but measured stratigraphic sections are continuous. In many cases, field data is not easily quantified, and determining uncertainty can be difficult. Despite many possible hurdles, the sedimentary community is anxious to embrace geoinformatic resources that can provide better tools to integrate the many data types, create better search capabilities, and equip our communities to conduct high-impact science at unprecedented levels.

  1. Sedimentology, eruptive mechanism and facies architecture of basaltic scoria cones from the Auckland Volcanic Field (New Zealand)

    Science.gov (United States)

    Kereszturi, Gábor; Németh, Károly

    2016-09-01

    Scoria cones are a common type of basaltic to andesitic small-volume volcanoes (e.g. 10- 1-10- 5 km3) that results from gas-bubble driven explosive eruptive styles. Although they are small in volume, they can produce complex eruptions, involving multiple eruptive styles. Eight scoria cones from the Quaternary Auckland Volcanic Field in New Zealand were selected to define the eruptive style variability from their volcanic facies architecture. The reconstruction of their eruptive and pyroclastic transport mechanisms was established on the basis of study of their volcanic sedimentology, stratigraphy, and measurement of their pyroclast density, porosity, Scanning Electron Microscopy, 2D particle morphology analysis and Visible and Near Visible Infrared Spectroscopy. Collection of these data allowed defining three end-member types of scoria cones inferred to be constructed from lava-fountaining, transitional fountaining and Strombolian type, and explosive Strombolian type. Using the physical and field-based characteristics of scoriaceous samples a simple generalised facies model of basaltic scoria cones for the AVF is developed that can be extended to other scoria cones elsewhere. The typical AVF scoria cone has an initial phreatomagmatic phases that might reduce the volume of magma available for subsequent scoria cone forming eruptions. This inferred to have the main reason to have decreased cone volumes recognised from Auckland in comparison to other volcanic fields evolved dominantly in dry eruptive condition (e.g. no external water influence). It suggests that such subtle eruptive style variations through a scoria cone evolution need to be integrated into the hazard assessment of a potentially active volcanic field such as that in Auckland.

  2. Mechanisms for Fe(III) oxide reduction in sedimentary environments

    Science.gov (United States)

    Nevin, Kelly P.; Lovely, Derek R.

    2002-01-01

    Although it was previously considered that Fe(III)-reducing microorganisms must come into direct contact with Fe(III) oxides in order to reduce them, recent studies have suggested that electron-shuttling compounds and/or Fe(III) chelators, either naturally present or produced by the Fe(III)-reducing microorganisms themselves, may alleviate the need for the Fe(III) reducers to establish direct contact with Fe(III) oxides. Studies with Shewanella alga strain BrY and Fe(III) oxides sequestered within microporous beads demonstrated for the first time that this organism releases a compound(s) that permits electron transfer to Fe(III) oxides which the organism cannot directly contact. Furthermore, as much as 450 w M dissolved Fe(III) was detected in cultures of S. alga growing in Fe(III) oxide medium, suggesting that this organism releases compounds that can solublize Fe(III) from Fe(III) oxide. These results contrast with previous studies, which demonstrated that Geobacter metallireducens does not produce electron-shuttles or Fe(III) chelators. Some freshwater aquatic sediments and groundwaters contained compounds, which could act as electron shuttles by accepting electrons from G. metallireducens and then transferring the electrons to Fe(III). However, other samples lacked significant electron-shuttling capacity. Spectroscopic studies indicated that the electron-shuttling capacity of the waters was not only associated with the presence of humic substances, but water extracts of walnut, oak, and maple leaves contained electron-shuttling compounds did not appear to be humic substances. Porewater from a freshwater aquatic sediment and groundwater from a petroleum-contaminated aquifer contained dissolved Fe(III) (4-16 w M), suggesting that soluble Fe(III) may be available as an electron acceptor in some sedimentary environments. These results demonstrate that in order to accurately model the mechanisms for Fe(III) reduction in sedimentary environments it will be necessary

  3. 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.

  4. 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.

  5. Sedimentary fabrics of the macrotidal, mud-dominated, inner estuary to fluvio-tidal transition zone, Petitcodiac River estuary, New Brunswick, Canada

    Science.gov (United States)

    Shchepetkina, Alina; Gingras, Murray K.; Zonneveld, John-Paul; Pemberton, S. George

    2016-03-01

    The study provides a detailed description of mud-dominated sedimentary fabrics and their application for the rock record within the inner estuary to the fluvial zone of the Petitcodiac River estuary, New Brunswick, Canada. Sedimentological characteristics and facies distributions of the clay- and silt-rich deposits are reported. The inner estuary is characterized by thick accumulations of interbedded silt and silty clay on intertidal banks that flank the tidally influenced channel. The most common sedimentary structures observed are parallel and wavy lamination, small-scale soft-sediment deformation with microfaults, and clay and silt current ripples. The tidal channel contains sandy silt and clayey silt with planar lamination, massive and convolute bedding. The fluvio-tidal transition zone is represented by interbedded trough cross-stratified sand and gravel beds with planar laminated to massive silty mud. The riverine, non-tidal reach of the estuary is characterized by massive, planar tabular and trough cross-stratified gravel-bed deposits. The absence of bioturbation within the inner estuary to the fluvio-tidal transition zone can be explained by the following factors: low water salinities (0-5 ppt), amplified tide and current speeds, and high concentrations of flocculated material in the water body. Notably, downstream in the middle and outer estuary, bioturbation is seasonally pervasive: in those locales the sedimentary conditions are similar, but salinity is higher. In this study, the sedimentological (i.e., grain size, bedding characters, sedimentary structures) differences between the tidal estuary and the fluvial setting are substantial, and those changes occur over only a few hundred meters. This suggests that the widely used concept of an extensive fluvio-tidal transition zone and its depositional character may not be a geographically significant component of fluvial or estuary deposits, which can go unnoticed in the study of the ancient rocks.

  6. Sedimentary architecture and depositional controls of a Pliocene river-dominated delta in the semi-isolated Dacian Basin, Black Sea

    NARCIS (Netherlands)

    Jorissen, Elisabeth L.; de Leeuw, A.; van Baak, Christiaan G.C.; Mandic, Oleg; Stoica, Marius; Abels, Hemmo A.; Krijgsman, Wout

    Sedimentological facies models for (semi-)isolated basins are less well developed than those for marine environments, but are critical for our understanding of both present-day and ancient deltaic sediment records in restricted depositional environments. This study considers an 835 m thick

  7. A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D∕H ratios

    Directory of Open Access Journals (Sweden)

    O. Rach

    2017-07-01

    Full Text Available Past climatic change can be reconstructed from sedimentary archives by a number of proxies. However, few methods exist to directly estimate hydrological changes and even fewer result in quantitative data, impeding our understanding of the timing, magnitude and mechanisms of hydrological changes. Here we present a novel approach based on δ2H values of sedimentary lipid biomarkers in combination with plant physiological modeling to extract quantitative information on past changes in relative humidity. Our initial application to an annually laminated lacustrine sediment sequence from western Europe deposited during the Younger Dryas cold period revealed relative humidity changes of up to 15 % over sub-centennial timescales, leading to major ecosystem changes, in agreement with palynological data from the region. We show that by combining organic geochemical methods and mechanistic plant physiological models on well characterized lacustrine archives it is possible to extract quantitative ecohydrological parameters from sedimentary lipid biomarker δ2H data.

  8. Biostratigraphy, facies and sequence stratigraphy of the Sarvak Formation in the Ahwaz Oil Field, North Dezful Embayment Zone

    Directory of Open Access Journals (Sweden)

    Mohammad Hasan Kazemzadeh

    2016-08-01

    Full Text Available Paleontological studies lead to recognition of 21 genera and 16 species of benthic foraminifera, 5 genera and 6 species of planktonic foraminifera and 3 genera and 3 species of oligosteginids. The vertical distribution of fauna lead to identification of 5 biozones including: Favusella washitensis Range Zone, Oligostegina Assemblage Zone, Rudist debris Zone, Nezzazata-Alveolinids Assemblage Zone, Nezzazatinella-Dicyclina Assemblage Zone. Based on the indicated biozones, the age of the Sarvak Formation is Late Albian to Early Turonian in the study area. Eleven carbonate facies belonging to four environments including tidal flat, restricted and semi-restricted lagoon, shoal and open marine are recognized. The identified facies are deposited on the homoclinal ramp setting. Based on the vertical changes of facies and recognized depositional environments, four third-order depositional sequences are represented. The transgressive systems tracts mainly comprises of open marine facies including sponge spicule, oligosteginid, echinoid and benthic foraminifera, while the highstand systems tracts mainly consists of shoal facies rich in bioclast, and restricted and semi-restricted lagoon facies rich in porcellaneous and hyaline benthic foraminifera and peloid. The maximum flooding surface represented by open marine facies including echinoid and planktonic foraminifera

  9. Chemistry of decomposition of freshwater wetland sedimentary organic material during ramped pyrolysis

    Science.gov (United States)

    Williams, E. K.; Rosenheim, B. E.

    2011-12-01

    Ramped pyrolysis methodology, such as that used in the programmed-temperature pyrolysis/combustion system (PTP/CS), improves radiocarbon analysis of geologic materials devoid of authigenic carbonate compounds and with low concentrations of extractable authochthonous organic molecules. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves (Rosenheim et al., 2008) and constrained the carbon sequestration potential of suspended sediments in the lower Mississippi River (Roe et al., in review). Although ramped pyrolysis allows for separation of sedimentary organic material based upon relative reactivity, chemical information (i.e. chemical composition of pyrolysis products) is lost during the in-line combustion of pyrolysis products. A first order approximation of ramped pyrolysis/combustion system CO2 evolution, employing a simple Gaussian decomposition routine, has been useful (Rosenheim et al., 2008), but improvements may be possible. First, without prior compound-specific extractions, the molecular composition of sedimentary organic matter is unknown and/or unidentifiable. Second, even if determined as constituents of sedimentary organic material, many organic compounds have unknown or variable decomposition temperatures. Third, mixtures of organic compounds may result in significant chemistry within the pyrolysis reactor, prior to introduction of oxygen along the flow path. Gaussian decomposition of the reaction rate may be too simple to fully explain the combination of these factors. To relate both the radiocarbon age over different temperature intervals and the pyrolysis reaction thermograph (temperature (°C) vs. CO2 evolved (μmol)) obtained from PTP/CS to chemical composition of sedimentary organic material, we present a modeling framework developed based upon the ramped pyrolysis decomposition of simple mixtures of organic compounds (i.e. cellulose, lignin, plant fatty acids, etc.) often found in sedimentary

  10. Sedimentary basins reconnaissance using the magnetic Tilt-Depth method

    Science.gov (United States)

    Salem, A.; Williams, S.; Samson, E.; Fairhead, D.; Ravat, D.; Blakely, R.J.

    2010-01-01

    We compute the depth to the top of magnetic basement using the Tilt-Depth method from the best available magnetic anomaly grids covering the continental USA and Australia. For the USA, the Tilt-Depth estimates were compared with sediment thicknesses based on drilling data and show a correlation of 0.86 between the datasets. If random data were used then the correlation value goes to virtually zero. There is little to no lateral offset of the depth of basinal features although there is a tendency for the Tilt-Depth results to be slightly shallower than the drill depths. We also applied the Tilt-Depth method to a local-scale, relatively high-resolution aeromagnetic survey over the Olympic Peninsula of Washington State. The Tilt-Depth method successfully identified a variety of important tectonic elements known from geological mapping. Of particular interest, the Tilt-Depth method illuminated deep (3km) contacts within the non-magnetic sedimentary core of the Olympic Mountains, where magnetic anomalies are subdued and low in amplitude. For Australia, the Tilt-Depth estimates also give a good correlation with known areas of shallow basement and sedimentary basins. Our estimates of basement depth are not restricted to regional analysis but work equally well at the micro scale (basin scale) with depth estimates agreeing well with drill hole and seismic data. We focus on the eastern Officer Basin as an example of basin scale studies and find a good level of agreement between previously-derived basin models. However, our study potentially reveals depocentres not previously mapped due to the sparse distribution of well data. This example thus shows the potential additional advantage of the method in geological interpretation. The success of this study suggests that the Tilt-Depth method is useful in estimating the depth to crystalline basement when appropriate quality aeromagnetic anomaly data are used (i.e. line spacing on the order of or less than the expected depth to

  11. Mid amphibolite facies metamorphism of harzburgites in the Neoproterozoic Cerro Mantiqueiras Ophiolite, southernmost Brazil

    Directory of Open Access Journals (Sweden)

    HARTMANN LÉO A.

    2003-01-01

    Full Text Available Valuable information is retrieved from the integrated investigation of the field relationships, microstructure and mineral compositions of harzburgites from the Neoproterozoic Cerro Mantiqueiras Ophiolite. This important tectonic marker of the geological evolution of southernmost Brazilian Shield was thoroughly serpentinized during progressive metamorphism, because the oldest mineral assemblage is: olivine + orthopyroxene + tremolite + chlorite + chromite. This M1 was stabilized in mid amphibolite facies - 550-600ºC as calculated from mineral equilibria. No microstructural (e.g. ductile deformation of olivine or chromite or compositional (e.g. mantle spinel remnant of mantle history was identified. A metamorphic event M2 occurred in the low amphibolite facies along 100 m-wide shear zones, followed by intense serpentinization (M3 and narrow 1-3 m-wide shear zones (M4 containing asbestos.

  12. Sedimentary tectonic evolution and reservoir-forming conditions of the Dazhou–Kaijiang paleo-uplift, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Yueming Yang

    2016-12-01

    Full Text Available Great breakthrough recently achieved in the Sinian–Lower Paleozoic gas exploration in the Leshan–Longnüsi paleo-uplift, Sichuan Basin, has also made a common view reached, i.e., large-scale paleo-uplifts will be the most potential gas exploration target in the deep strata of this basin. Apart from the above-mentioned one, the other huge paleo-uplifts are all considered to be the ones formed in the post-Caledonian period, the impact of which, however, has rarely ever been discussed on the Sinian–Lower Paleozoic oil and gas reservoir formation. In view of this, based on outcrops, drilling and geophysical data, we analyzed the Sinian–Lower Paleozoic tectonic setting and sedimentary background in the East Sichuan Basin, studied the distribution rules of reservoirs and source rocks under the control of paleo-uplifts, and finally discussed, on the basis of structural evolution analysis, the conditions for the formation of Sinian–Lower Paleozoic gas reservoirs in this study area. The following findings were achieved. (1 The Dazhou–Kaijiang inherited uplift in NE Sichuan Basin which was developed before the Middle Cambrian controlled a large area of Sinian and Cambrian beach-facies development. (2 Beach-facies reservoirs were developed in the upper part of the paleo-uplift, while in the peripheral depression belts thick source rocks were developed like the Upper Sinian Doushantuo Fm and Lower Cambrian Qiongzhusi Fm, so there is a good source–reservoir assemblage. (3 Since the Permian epoch, the Dazhou–Kaijiang paleo-uplift had gradually become elevated from the slope zone, where the Permian oil generation peak occurred in the slope or lower and gentle uplift belts, while the Triassic gas generation peak occurred in the higher uplift belts, both with a favorable condition for hydrocarbon accumulation. (4 The lower structural layers, including the Lower Cambrian and its underlying strata, in the East Sichuan Basin, are now equipped with a

  13. THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

    Science.gov (United States)

    Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

    2011-12-01

    Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] macrophyte, nutrient-limited lakes (BiomEpiV macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance. © 2011 Phycological Society of America.

  14. Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

    Science.gov (United States)

    Kunz, Barbara E.; Regis, Daniele; Engi, Martin

    2018-03-01

    Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U-Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P-T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U-Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure.

  15. Regional facies variations in the Vempalle formation of Cuddapah Basin: implications on uranium exploration

    International Nuclear Information System (INIS)

    Rajaraman, H.S.; Mukundhan, A.R.; Ramesh Kumar, K.; Achar, K.K.; Umamaheswar, K.

    2012-01-01

    Strata-bound large tonnage uranium deposit hosted by the Grey-impure-dolostone of Vempalle Formation of Cuddapah Basin is known in Tummalapalle-Rachakuntapalle sector. Deposition of rocks of Cuddapah Basin commenced with Papaghni Group, which comprises Clastic - Gulcheru Formation and Chemogenic - Vempalle Formation. The Vempalle Formation is developed over 280 km stretch from south to north along the western margin of Cuddapah Basin with maximum thickness of about 2.1 km. Recent studies helped in classifying the Vempalle Formation into five major lithofacies viz. Massive Dolostone, Conglomerate, Grey-impure-dolostone (host rock for uranium mineralization), Purple shale and Cherty Dolostone. The lithofacies studies along selected traverses from Tummalapalle in south to Dhone in north revealed the development of all five facies upto Narpala near Chitravati River whereas towards its north, the Grey-impure-dolostone and Cherty Dolostone dominate. The study also revealed over lapping nature of Cherty Dolostone in North of Nossam-Peddapaya lineament; where it directly rests above the Gulcheru Formation. Environment of deposition for these facies of Vempalle Formation place this in a Shallowing-upward carbonate depositional system with characteristic tidal flat environment. The Grey-impure-dolostone facies hosting uranium is interpreted to be developed in Supratidal environment with a narrow pH range of 7.0 - 7.5 in a reducing environment along with precipitation of phosphate. Since the tidal flats have later extension over several kilometers, favorable environment of Grey-impure-dolostone may exist over wide area in northern part also. The search for Grey-impure-dolostone hosted uranium, therefore has a bearing an understanding the regional facies variations in Vempalle Formation. The paper presents the studies carried out in this direction and results thereof. (author)

  16. The use of anion geochemistry in mapping groundwater facies in the ...

    African Journals Online (AJOL)

    The groundwater system of the Port Harcourt area is home to three anion facies, the Cl – SO4, the Cl – SO4 – HCO3 and the HCO3 – Cl – SO4. The first two types exist in both shallow – and deep – groundwater environments while the third is restricted to the deep environment. Although there are natural intermittent and, ...

  17. Constraining Depositional Slope From Sedimentary Structures in Sandy Braided Streams

    Science.gov (United States)

    Lynds, R. M.; Mohrig, D.; Heller, P. L.

    2003-12-01

    Determination of paleoslopes in ancient fluvial systems has potentially broad application to quantitatively constraining the history of tectonics and paleoclimate in continental sequences. Our method for calculating paleoslopes for sandy braided streams is based upon a simple physical model that establishes depositional skin-frictional shear stresses from assemblages of sedimentary structures and their associated grain size distributions. The addition of a skin-frictional shear stress, with a geometrically determined form-drag shear stress results in a total boundary shear stress which is directly related to water-surface slope averaged over an appropriate spatial scale. In order to apply this model to ancient fluvial systems, it is necessary to measure the following: coarsest suspended sediment size, finest grain size carried in bed load, flow depth, dune height, and dune length. In the rock record, suspended load and bed load can be accurately assessed by well-preserved suspended load deposits ("low-energy" ripples) and bed load deposits (dune foresets). This model predicts an average slope for the North Loup River near Taylor, Nebraska (modern case study) of 2.7 x 10-3. The measured reach-averaged water surface slope for the same reach of the river is 1.37 x 10-3. We suggest that it is possible to calculate the depositional slope of a sandy fluvial system by a factor of approximately two. Additionally, preliminary application of this model to the Lower Jurassic Kayenta Formation throughout the Colorado Plateau provides a promising and consistent evaluation of paleoslope in an ancient and well-preserved, sandy braided stream deposit.

  18. The transgressive-regressive cycle of the Romualdo Formation (Araripe Basin): Sedimentary archive of the Early Cretaceous marine ingression in the interior of Northeast Brazil

    Science.gov (United States)

    Custódio, Michele Andriolli; Quaglio, Fernanda; Warren, Lucas Veríssimo; Simões, Marcello Guimarães; Fürsich, Franz Theodor; Perinotto, José Alexandre J.; Assine, Mario Luis

    2017-08-01

    Geologic events related to the opening of the South Atlantic Ocean deeply influenced the sedimentary record of the Araripe Basin. As consequence, upper stratigraphic units of the basin record a marine ingression in northeastern Brazil during the late Aptian. The timing and stratigraphic architecture of these units are crucial to understand the paleogeography of Gondwana and how the proto-Atlantic Ocean reached interior NE Brazil during the early Cretaceous. This marine ingression is recorded in the Araripe Basin as the Romualdo Formation, characterized by a transgressive-regressive cycle bounded by two regional unconformities. In the eastern part of the basin, the Romualdo depositional sequence comprises coastal alluvial and tide-dominated deposits followed by marine transgressive facies characterized by two fossil-rich intervals: a lower interval of black shales with fossil-rich carbonate concretions (Konservat-Lagerstätten) and an upper level with mollusk-dominated shell beds and shelly limestones. Following the marine ingression, an incomplete regressive succession of marginal-marine facies records the return of continental environments to the basin. The stratigraphic framework based on the correlation of several sections defines a transgressive-regressive cycle with depositional dip towards southeast, decreasing in thickness towards northwest, and with source areas located at the northern side of the basin. The facies-cycle wedge-geometry, together with paleocurrent data, indicates a coastal onlap towards NNW. Therefore, contrary to several paleogeographic scenarios previously proposed, the marine ingression would have reached the western parts of the Araripe Basin from the SSE.

  19. The Salinas formation in the type-area, Northeastern Minas Gerais: a proposal to review the stratigraphy of the Aracuai belt on sedimentary, metamorphic and U-Pb SHRIMP evidences

    International Nuclear Information System (INIS)

    Lima, Sirlene A. de Abreu; Pedrosa Soares, Antonio C.; Cordani, Umberto G.; Nutman, Allen

    2002-01-01

    The Salinas Formation has been considered to be a stratigraphic unit of the Macaubas Group. This group comprises the rift to passive margin sequences of the precursor basin of the Neo proterozoic Aracuai Orogeny, eastern Brazil. However, new road cuts show extensive and spectacular outcrops with very well-preserved sedimentary structures, allowing detailed studies in the type-locality of this formation, located in the Salinas town and surroundings, northeast Minas Gerais State. In its type-locality, the Salinas Formation consists of graywacke, pelite and clast-supported conglomerate, metamorphosed in the green schist facies. The sedimentary lithofacies are grouped into three facies association (shelf, slope and deep-sea), indicating sedimentation from shelf deposits to deep-water turbidites. The shelf sedimentation was influenced by storm-wave during deposition. The slump and deep-sea deposits were generated by gravitational flows and high- to low-concentration turbidity currents. Shelf sandstone, clast-supported conglomerate and proximal to distal turbidites outline a submarine fan system. U-Pb SHRIMP data from detrital zircons of graywacke samples indicate a maximum sedimentation age of ca. 568 Ma. Thus, the Salinas Formation is much younger than the Macaubas Group, and represents late orogenic deposits (ca. 568- 500 Ma). The distal, passive margin unit of the Macaubas Group is now called Ribeirao da Folha Formation (ca. 800 Ma). (author)

  20. Hydrothermal dolomite reservoir facies in the Sinian Dengying Fm, central Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Yuqiang Jiang

    2017-07-01

    Full Text Available The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD, filled saddle dolomite (FSD (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.. Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.

  1. In defence of moral imperialism: four equal and universal prima facie principles.

    Science.gov (United States)

    Dawson, A; Garrard, E

    2006-04-01

    Raanan Gillon is a noted defender of the four principles approach to healthcare ethics. His general position has always been that these principles are to be considered to be both universal and prima facie in nature. In recent work, however, he has made two claims that seem to present difficulties for this view. His first claim is that one of these four principles, respect for autonomy, has a special position in relation to the others: he holds that it is first among equals. We argue that this claim makes little sense if the principles are to retain their prima facie nature. His second claim is that cultural variation can play an independent normative role in the construction of our moral judgments. This, he argues, enables us to occupy a middle ground between what he sees as the twin pitfalls of moral relativism and (what he calls) moral imperialism. We argue that there is no such middle ground, and while Gillon ultimately seems committed to relativism, it is some form of moral imperialism (in the form of moral objectivism) that will provide the only satisfactory construal of the four principles as prima facie universal moral principles.

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

    International Nuclear Information System (INIS)

    Wei Sanyuan; Qin Mingkuan; Li Yuexiang; He Zhongbo; Chen Anping; Shen Kefeng; Cao Jianying

    2006-01-01

    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)

  3. 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.

  4. 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

  5. Seasonal variations and sources of sedimentary organic carbon in Tokyo Bay

    International Nuclear Information System (INIS)

    Kubo, Atsushi; Kanda, Jota

    2017-01-01

    Total organic carbon (TOC), total nitrogen (TN) contents, their stable C and N isotope ratio (δ 13 C and δ 15 N), and chlorophyll a ([Chl a] sed ) of surface sediments were investigated monthly to identify the seasonal variations and sources of organic matter in Tokyo Bay. The sedimentary TOC (TOC sed ) and TN (TN sed ) contents, and the sedimentary δ 13 C and δ 15 N (δ 13 C sed and δ 15 N sed ) values were higher in summer than other seasons. The seasonal variations were controlled by high primary production in the water column and hypoxic water in the bottom water during summer. The fraction of terrestrial and marine derived organic matter was estimated by Bayesian mixing model using stable isotope data and TOC/TN ratio. Surface sediments in Tokyo Bay are dominated by marine derived organic matter, which accounts for about 69 ± 5% of TOC sed . - Highlights: • High values of sedimentary organic carbon and nitrogen were observed in summer. • Surface sediments in Tokyo Bay were dominated by marine derived organic matter which was estimated by Bayesian mixing model. • The most amount of terrestrial POC was deposited and degraded in Tokyo Bay before being discharged to the open ocean.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-01

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

  7. Comparing orbiter and rover image-based mapping of an ancient sedimentary environment, Aeolis Palus, Gale crater, Mars

    Science.gov (United States)

    Stack, Kathryn M.; Edwards, Christopher; Grotzinger, J. P.; Gupta, S.; Sumner, D.; Edgar, Lauren; Fraeman, A.; Jacob, S.; LeDeit, L.; Lewis, K.W.; Rice, M.S.; Rubin, D.; Calef, F.; Edgett, K.; Williams, R.M.E.; Williford, K.H.

    2016-01-01

    This study provides the first systematic comparison of orbital facies maps with detailed ground-based geology observations from the Mars Science Laboratory (MSL) Curiosity rover to examine the validity of geologic interpretations derived from orbital image data. Orbital facies maps were constructed for the Darwin, Cooperstown, and Kimberley waypoints visited by the Curiosity rover using High Resolution Imaging Science Experiment (HiRISE) images. These maps, which represent the most detailed orbital analysis of these areas to date, were compared with rover image-based geologic maps and stratigraphic columns derived from Curiosity’s Mast Camera (Mastcam) and Mars Hand Lens Imager (MAHLI). Results show that bedrock outcrops can generally be distinguished from unconsolidated surficial deposits in high-resolution orbital images and that orbital facies mapping can be used to recognize geologic contacts between well-exposed bedrock units. However, process-based interpretations derived from orbital image mapping are difficult to infer without known regional context or observable paleogeomorphic indicators, and layer-cake models of stratigraphy derived from orbital maps oversimplify depositional relationships as revealed from a rover perspective. This study also shows that fine-scale orbital image-based mapping of current and future Mars landing sites is essential for optimizing the efficiency and science return of rover surface operations.

  8. Petrogenesis of the crater-facies Tokapal kimberlite pipe, Indrāvati Basin, Central India

    Directory of Open Access Journals (Sweden)

    N.V. Chalapathi Rao

    2014-11-01

    Full Text Available New geochemical data of the crater-facies Tokapal kimberlite system sandwiched between the lower and upper stratigraphic horizons of the Mesoproterozoic Indrāvati Basin are presented. The kimberlite has been subjected to extensive and pervasive low-temperature alteration. Spinel is the only primary phase identifiable, while olivine macrocrysts and juvenile lapilli are largely pseudomorphed (talc-serpentine-carbonate alteration. However, with the exception of the alkalies, major element oxides display systematic fractionation trends; likewise, HFSE patterns are well correlated and allow petrogenetic interpretation. Various crustal contamination indices such as (SiO2 + Al2O3 + Na2O/(MgO + K2O and Si/Mg are close to those of uncontaminated kimberlites. Similar La/Yb (79–109 of the Tokapal samples with those from the kimberlites of Wajrakarur (73–145 and Narayanpet (72–156, Eastern Dharwar craton, southern India implies a similarity in their genesis. In the discriminant plots involving HFSE the Tokapal samples display strong affinities to Group II kimberlites from southern Africa and central India as well as to ‘transitional kimberlites’ from the Eastern Dharwar craton, southern India, and those from the Prieska and Kuruman provinces of southern Africa. There is a striking similarity in the depleted-mantle (TDM Nd model ages of the Tokapal kimberlite system, Bastar craton, the kimberlites from NKF and WKF, Eastern Dharwar craton, and the Majhgawan diatreme, Bundelkhand craton, with the emplacement age of some of the lamproites from within and around the Palaeo-Mesoproterozoic Cuddapah basin, southern India. These similar ages imply a major tectonomagmatic event, possibly related to the break-up of the supercontinent of Columbia, at 1.3–1.5 Ga across the three cratons. The ‘transitional’ geochemical features displayed by many of the Mesoproterozoic potassic-ultrapotassic rocks, across these Indian cratons are inferred to be

  9. Isotopic and elemental chemistry of sedimentary pyrite: A combined analytical and statistical approach to a novel planetary biosignature

    Science.gov (United States)

    Figueroa, M. C.; Gregory, D. D.; Lyons, T. W.; Williford, K. H.

    2017-12-01

    Life processes affect trace element abundances in pyrite such that sedimentary and hydrothermal pyrite have significantly different trace element signatures. Thus, we propose that these biogeochemical data could be used to identify pyrite that formed biogenetically either early in our planet's history or on other planets, particularly Mars. The potential for this approach is elevated because pyrite is common in diverse sedimentary settings, and its trace element content can be preserved despite secondary overprints up to greenschist facies, thus minimizing the concerns about remobilization that can plague traditional whole rock studies. We are also including in-situ sulfur isotope analysis to further refine our understanding of the complex signatures of ancient pyrite. Sulfur isotope data can point straightforwardly to the involvement of life, because pyrite in sediments is inextricably linked to bacterial sulfate reduction and its diagnostic isotopic expressions. In addition to analyzing pyrite of known biological origin formed in the modern and ancient oceans under a range of conditions, we are building a data set for pyrite formed by hydrothermal and metamorphic processes to minimize the risk of false positives in life detection. We have used Random Forests (RF), a machine learning statistical technique with proven efficiency for classifying large geological datasets, to classify pyrite into biotic and abiotic end members. Coupling the trace element and sulfur isotope data from our analyses with a large existing dataset from diverse settings has yielded 4500 analyses with 18 different variables. Our initial results reveal the promise of the RF approach, correctly identifying biogenic pyrite 97 percent of the time. We will continue to couple new in-situ S-isotope and trace element analyses of biogenic pyrite grains from modern and ancient environments, using cutting-edge microanalytical techniques, with new data from high temperature settings. Our ultimately goal

  10. Classification and sedimentary characteristics of lacustrine hyperpycnal channels: Triassic outcrops in the south Ordos Basin, central China

    Science.gov (United States)

    Xian, Benzhong; Wang, Junhui; Gong, Chenglin; Yin, Yu; Chao, Chuzhi; Liu, Jianping; Zhang, Guodong; Yan, Qi

    2018-06-01

    Subaquatic channels are known as active conduits for the delivery of terrigenous sediments into related marine and lacustrine basins, as well as important targets for hydrocarbon exploration. Compared to submarine channels, lacustrine subaqueous channels created by hyperpycnal flows are understudied. Using well-exposed outcrops collected from three different locations in the southern Ordos Basin, central China, morphologies and architecture of a channelized hyperpycnal system were studied and classified. Six facies associations represent sedimentary processes from strong erosion by bedload dominated hyperpycnal flows, to transitional deposition jointly controlled by bedload and suspended-load dominated hyperpycnal flows, finally to deposition from suspended-load dominated hyperpycnal flows. On the basis of channel morphologies, infilling sediments and sedimentary processes, the documented channels can be classified into four main categories, which are erosional, bedload dominated, suspended-load dominated, and depositional channels. In very proximal and very distal locations, erosional channels and depositional channels serve as two end-members, while in middle areas, bedload-dominated channels and suspended-load dominated channels are transitional types. Erosional channels, as a response to strong erosion from bedload dominated hyperpycnal flows on upper slope, were mainly filled by mud interbedded with thin sand beds. As flow energy decreases, bedload dominated channels develop on middle slopes, which are characterized mainly by under- to balanced sediment infillings with cross-bedded sandstones and/or minor massive sandstones. Compared to bedload dominated channels, suspended-load dominated channels mainly develop in deeper water, and were filled mainly by massive or planar-laminated sandstones. Depositional channels, as a response to suspended-load dominated hyperpycnal flows in deep-water areas, are characterized by thin-medium bed classical turbidites with

  11. The identification of provenance-controlled facies by geochemical methods on a portion of the Vaal Reef, Klerksdorp Goldfield

    International Nuclear Information System (INIS)

    Henckel, J.; Schweitzer, J.K.; Horsch, H.

    1990-01-01

    The use of geochemical methods for identifying provenance controlled facies in Witwatersrand reefs is considered. Three methods - whole rock geochemistry, zircon analysis, and chromite analysis - have been evaluated in order to establish the feasibility of using these geochemical techniques. An area of Vaal Reef where two sedimentological facies with distinct gold distributions had previously been identified was investigated. The studies reported here gave evidence of differences in the source areas for these two facies. Accordingly, it is concluded that the application of geochemistry to identify provenance-controlled facies is a useful technique which can help geologists arrive at a better interpretation of depositional systems within Witwatersrand reefs and thereby assist in the understanding of gold distribution patterns. 26 refs., 11 figs., 4 tabs

  12. Clay mineral facies and lateritization in basalts of the southeastern Parana Basin, Brazil

    International Nuclear Information System (INIS)

    Oliveira, M.T.G. de; Formoso, M.L.L.; Trescases, J.J.; Meunier, A.

    1998-01-01

    Seventeen samples from two lateritic profiles, each with five facies, were studied. These profiles occur on the old planation surface of the plateau basalts of the southern part of ParanáBasin, Brazil. Optical microscopy, X-ray diffraction, electron microprobe, Mössbauer spectroscopy and Fourier Transform Infrared Spectra were used to obtain information about the nature and chemical composition of each weathering facies. In addition, scanning electron microscopy and analyses of clay minerals were performed to detect microcrystalline environmental changes. Both profiles have two major parts: a loose red-clay latosol separated from an underlying mottled clay and an alterite facies; a stone line may or may not be present between the latosol and the underlying units. In both profiles the latosol consists principally of kaolinite, hematite and goethite. Two alterite facies, shaped by differential weathering, are also present in the lower profile: a halloysite–nontronite clayey matrix with a well developed fissure system occurs in the argillaceous alterite and a network of Al–goethite aggregates is typical of the highly porous cortex of the boulder alterite that is found in the stone line and below it. Gibbsite has crystallized in the large pores of porphyritic boulder alterite but is absent in the small pores of the subaphyric boulder alterite. Clay minerals observed in fissures include halloysite associated with goethite and manganese oxides. The basalt has hydrothermal green-clays (mixed layers and trioctahedral smectites) that formed between primary plagioclase, pyroxene and Ti–magnetite crystals while fresh corestones of the boulder alterite have cryptocrystalline iron-rich material. The study of these profiles shows one principal evolutionary trend for clay minerals. This trend is from smectite and mixed layers that form green clays in altered bedrock at the base of the profile to an intermediate association of nontronite and halloysite in the argillaceous

  13. The potential role of fluids during regional granulite-facies dehydration in the lower crust

    Directory of Open Access Journals (Sweden)

    Daniel E. Harlov

    2012-11-01

    Full Text Available High-grade dehydration of amphibolite-facies rocks to granulite-facies is a process that can involve partial melting, fluid-aided solid-state dehydration, or varying degrees of both. On the localized meter scale, solid-state dehydration, due to CO2-rich fluids traveling along some fissure or crack and subsequently outwards along the mineral grain boundaries of the surrounding rock, normally is the means by which the breakdown of biotite and amphibole to orthopyroxene and clinopyroxene occur. Various mineral textures and changes in mineral chemistry seen in these rocks are also seen in more regional orthopyroxene-clinopyroxene-bearing rocks which, along with accompanying amphibolite-facies rocks, form traverses of lower crust. This suggests that solid-state dehydration during high-grade metamorphism could occur on a more regional scale. The more prominent of these fluid-induced textures in the granulite-facies portion of the traverse take the form of micro-veins of K-feldspar along quartz grain boundaries and the formation of monazite inclusions in fluorapatite. The fluids believed responsible take the form of concentrated NaCl- and KCl- brines from a basement ultramafic magma heat source traveling upwards along grain boundaries. Additional experimental work involving CaSO4 dissolution in NaCl-brines, coupled with natural observation of oxide and sulfide mineral associations in granulite-facies rocks, have demonstrated the possibility that NaCl-brines, with a CaSO4 component, could impose the oxygen fugacity on these rocks as opposed to the oxygen fugacity being inherent in their protoliths. These results, taken together, lend credence to the idea that regional chemical modification of the lower crust is an evolutionary process controlled by fluids migrating upwards from the lithospheric mantle along grain boundaries into and through the lower crust where they both modify the rock and are modified by it. Their presence allows for rapid mass and

  14. To what extent can intracrater layered deposits that lack clear sedimentary textures be used to infer depositional environments?

    Science.gov (United States)

    Cadieux, Sarah B.; Kah, Linda C.

    2015-03-01

    Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or similar lithologies that experienced differential cementation. On Earth, rhythmically deposited strata can be examined in terms of stratal packaging, wherein the interplay of tectonics, sediment deposition, and base level (i.e., the position above which sediment accumulation is expected to be temporary) result in changes in the amount of space available for sediment accumulation. These predictable patterns of sediment deposition can be used to infer changes in basin accommodation regardless of the mechanism of deposition (e.g. fluvial, lacustrine, or aeolian). Here, we analyze sedimentary deposits from three craters (Becquerel Crater, Danielson Crater, Crater A) in Arabia Terra. Each crater contains layered deposits that are clearly observed in orbital images. Although orbital images are insufficient to specifically determine the origin of sedimentary deposits, depositional couplets can be interpreted in terms of potential accommodation space available for deposition, and changes in the distribution of couplet thickness through stratigraphy can be interpreted in terms of changing base level and the production of new accommodation space. Differences in stratal packaging in these three craters suggest varying relationships between sedimentary influx, sedimentary base level, and concomitant changes in accommodation space. Previous groundwater upwelling models hypothesize that layered sedimentary deposits were deposited under warm climate conditions of early Mars. Here, we use observed stacking patterns to propose a model for deposition under cold climate conditions, wherein episodic melting of ground ice could raise local base level, stabilize sediment deposition, and result in differential cementation of accumulated strata. Such analysis demonstrates that

  15. Sulfur speciation and isotope analysis of the 2.7 Ga shallow- and deep-facies black shales from Pilbara, Western Australia

    Science.gov (United States)

    Minami, H.; Yamaguchi, K. E.; Naraoka, H.

    2014-12-01

    It has been widely believed that Great Oxidation Event (GOE: Holland, 1994) occurred at ~2.4-2.2 Ga ago. However, some previous studies have found evidence for oxic ocean and atmosphere from earlier rock records (e.g., Hoashi et al., 2009). In order to explore if such oxic environment was local or global and if there was redox heterogeneity in a sedimentary basin before the inferred GOE, using the 2.7 Ga pyrite-bearing drillcore black shales (deep-facies WRL1 and shallow-facies RHDH2A drillcores) from Pilbara, Western Australia, we separately quantified abundance of S-bearing species (SAVS (acid-volatile sulfide), Spy (pyrite), SSO4 (sulfate), Sorg (organic-S), and S0 (elemental S) and Fe-bearing species (Fecarb, Feox, and Femag) by using sequential extraction methods. These samples were previously used by Brocks et al. (1999), Yamaguchi (2002), Yamaguchi et al. (2005), and Eigenbrode and Freeman (2006). The shallow samples have high S contents and are interpreted to have deposited in relatively anoxic environment, but most of deep samples with elevated Fe contents deposited in relatively oxic environment. The DOP values and δ34Spy values are relatively higher in shallow samples, suggesting active bacterial sulfate reduction in reducing environment created due to near-complete consumption of dissolved O2by decomposition of organic matter produced by photosynthesizers living in the surface ocean. All of these observations consistently suggest that the shallower part was anoxic and deeper part was oxic in the 2.7 Ga ocean. The surface ocean would have been oxygenated due to activity of oxygenic photosynthesis. Such redox stratification of the ocean, i.e., development of mid-depth (shallow) OMZ in an essentially oxic ocean, is typically seen in highly productive regions in the modern ocean. Modern-style oceanic redox structure could have existed as far back as 2.7 Ga ago, much earlier than the inferred GOE at ~2.4-2.2 Ga. Brocks et al. (1999) Science 285, 1033

  16. Sedimentary structure and tectonic setting of the abyssal basins adjoining the southeast part of the Ontong Java Plateau, western Pacific Ocean

    Science.gov (United States)

    Shimizu, S.; Masato, N.; Miura, S.; Suetsugu, D.

    2017-12-01

    Ontong Java Plateau(OJP) in the western Pacific Ocean is one of the largest oceanic plateau in the world. Radioactive ages of drilling samples indicate that the most part of the OJP was emplaced about 122 Ma (Mahoney et al., 1993). Taylor (2006) proposed that the OJP formed as a single large volcanic province together with the Manihiki and Hikurangi plateaus. OJP is surrounding by East Mariana, Pigafetta, Nauru, Ellice, Stewart, and Lyra basins. The East Mariana and Pigafetta basins were formed at the Pacific-Izanagi ridge and the Nauru basin was formed at Pacific-Phoenix ridges (Nakanishi et al., 1992). The tectonic history of the Ellice, Stewart, and Lyra basins is still unknown because of lack of magnetic anomaly lineations. Tectonic setting during the OJP formation is thus a matter of controversy. To expose the tectonic setting of the Ellice, Stewart, and Lyra basins, we conducted the Multi-Channel Seismic (MCS) survey in the basins during the research cruise by R/V Mirai of JAMSTEC in 2014. We present our preliminary results of the MCS survey in the Stewart basin(SB) and Ellice Basin(EB). After the regular data processing, we compared the seismic facies of MCS profile with DSDP Site 288 and ODP Site 1184 to assign ages to seismic reflectors. Our processing exposed several remarkable structures in the basins. The graben structures deformed only the igneous basement in the northwestern and northeastern and southwestern margins of the SB. This suggests the graben structures were formed before sedimentary layer deposited. Taylor (2006) proposed that the basin was formed by the NW-SE rifting during the separation of OJP and Manihiki Plateau around 120 Ma. Neal (1997) proposed that the NE-SW rifting formed the basin around 80 Ma. Our study supports the rifting model proposed by Neal et al. (1997) because the displacement of graben in northeastern and southwestern margins of the SB is larger than that in northwestern of the SB. We found several igneous diapirs in the

  17. The predictable nature of the Paleozoic sedimentary sequence beneath the Bruce nuclear site in Southern Ontario, Canada

    International Nuclear Information System (INIS)

    Parmenter, Andrew; Jensen, Mark; Crowe, Richard

    2012-01-01

    Document available in extended abstract form only. A key aspect of a Deep Geologic Repository (DGR) safety case is the ability to develop and communicate an understanding of the geologic stability and resilience to change at time frames relevant to demonstrating repository performance. As part of an on-going Environmental Assessment, Ontario Power Generation (OPG) recently completed site-specific investigations within an 850 m thick Paleozoic sedimentary sequence beneath the Bruce nuclear site for the proposed development of a DGR for Low and Intermediate Level Waste (L and ILW). As envisioned, the shaft-accessed DGR would be excavated at a nominal depth of 680 m within the low permeability Ordovician argillaceous limestone of the Cobourg Formation, which is overlain by more than 200 m of low permeability Ordovician shale. The geo-scientific investigations revealed a relatively undeformed and laterally continuous architecture within the sedimentary sequence at the repository scale (1.5 km 2 ) and beyond. This paper explores the predictable nature of the sedimentary sequence that has contributed to increasing confidence in an understanding of the spatial distribution of groundwater system properties, deep groundwater system evolution and natural barrier performance. Multi-disciplinary geo-scientific investigations of the Bruce nuclear site were completed in 3 phases between 2006 and 2010. The sub-surface investigations included a deep drilling, coring and in-situ testing program and, the completion of a 19.7 km (9 lines) 2-D seismic reflection survey. The drilling program involved 6 (150 mm dia.) deep boreholes (4-vertical; 2 inclined) that were extended through the sedimentary sequence from 4 drill sites, arranged around the 0.3 km 2 footprint of the proposed repository. The more than 3.8 km of rock core (77 mm dia.) retrieved have provided, in part, a strong basis to understand bedrock lithology and mineralogy, facies assemblages, structure, and oil and gas

  18. Ambient Temperature Flotation of Sedimentary Phosphate Ore Using Cottonseed Oil as a Collector

    Directory of Open Access Journals (Sweden)

    Yaoyang Ruan

    2017-04-01

    Full Text Available The mid-low grade sedimentary phosphate ore, abundant in silicate and carbonate gangue minerals, exhibits a poor processability. It is conventionally enriched using high temperature flotation to remove silicate gangues with fatty acid as a collector. Cottonseed oil has been proved to be an efficient collector for achieving ambient temperature flotation of the sedimentary phosphate ore used in this study. Flotation kinetics was investigated to ascertain the excellent collecting performance of cottonseed oil, as compared with oleic acid, and the phosphate flotation fitted well with the first-order flotation model. Based on the analysis of flotation reagent effect on the direct flotation process using the response surface methodology (RSM, a closed circuit of direct-reverse flotation for stepwise removing silicate and carbonate gangues from the sedimentary phosphate ore was established. Consequently, a required high quality of phosphate concentrate containing 30.16% P2O5 was obtained, with a recovery of 90.90%. Scanning electron microscopy (SEM and X-ray diffraction analysis (XRD of the flotation products confirmed that the majority of silicate and carbonate gangues were effectively removed from the concentrate products.

  19. Integrated techniques to evaluate the features of sedimentary rocks of archaeological areas of Sicily

    Directory of Open Access Journals (Sweden)

    Maria Brai

    2004-02-01

    Full Text Available Sicily includes a great variety of lithologies, giving a high complexity to the geologic landscape. Their prevalent lithology is sedimentary. It is well known that rocks of sedimentary origin, compared with metamorphic and volcanic deposits, can be relatively soft and hence fairly easy to model. Nevertheless, this workability advantage is a drawback for Cultural Heritage applications. In fact, these materials show a high porosity, with pore-size distributions that lead to deterioration through absorption of water. In this paper, several sedimentary rocks used in historical Cultural Heritage items of Sicily, from "Magna Graecia" to nowadays, are classified for mineralogical features, chemical composition, and for porosity. Particularly, some samples collected in quarries relevant to the archaeological sites of 41 Agrigento, Segesta and Selinunte will be considered and characterized using integrated techniques (XRD, XRF, NMR and CT. Data on samples obtained in laboratory will be compared with the relevant values measured in situ on monuments of historical-cultural interest of the quoted archaeological places.

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

    International Nuclear Information System (INIS)

    Beauchamp, B.

    1997-01-01

    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

  1. The role of deep-water sedimentary processes in shaping a continental margin: The Northwest Atlantic

    Science.gov (United States)

    Mosher, David C.; Campbell, D.C.; Gardner, J.V.; Piper, D.J.W.; Chaytor, Jason; Rebesco, M.

    2017-01-01

    The tectonic history of a margin dictates its general shape; however, its geomorphology is generally transformed by deep-sea sedimentary processes. The objective of this study is to show the influences of turbidity currents, contour currents and sediment mass failures on the geomorphology of the deep-water northwestern Atlantic margin (NWAM) between Blake Ridge and Hudson Trough, spanning about 32° of latitude and the shelf edge to the abyssal plain. This assessment is based on new multibeam echosounder data, global bathymetric models and sub-surface geophysical information.The deep-water NWAM is divided into four broad geomorphologic classifications based on their bathymetric shape: graded, above-grade, stepped and out-of-grade. These shapes were created as a function of the balance between sediment accumulation and removal that in turn were related to sedimentary processes and slope-accommodation. This descriptive method of classifying continental margins, while being non-interpretative, is more informative than the conventional continental shelf, slope and rise classification, and better facilitates interpretation concerning dominant sedimentary processes.Areas of the margin dominated by turbidity currents and slope by-pass developed graded slopes. If sediments did not by-pass the slope due to accommodation then an above grade or stepped slope resulted. Geostrophic currents created sedimentary bodies of a variety of forms and positions along the NWAM. Detached drifts form linear, above-grade slopes along their crests from the shelf edge to the deep basin. Plastered drifts formed stepped slope profiles. Sediment mass failure has had a variety of consequences on the margin morphology; large mass-failures created out-of-grade profiles, whereas smaller mass failures tended to remain on the slope and formed above-grade profiles at trough-mouth fans, or nearly graded profiles, such as offshore Cape Fear.

  2. Excess europium content in Precambrian sedimentary rocks and continental evolution

    Science.gov (United States)

    Jakes, P.; Taylor, S. R.

    1974-01-01

    It is proposed that the europium excess in Precambrian sedimentary rocks, relative to those of younger age, is derived from volcanic rocks of ancient island arcs, which were the source materials for the sediments. Precambrian sedimentary rocks and present-day volcanic rocks of island arcs have similar REE patterns, total REE abundances, and excess Eu, relative to the North American shale composite. The present upper crustal REE pattern, as exemplified by that of sediments, is depleted in Eu, relative to chondrites. This depletion is considered to be a consequence of development of a granodioritic upper crust by partial melting in the lower crust, which selectively retains europium.

  3. Characteristics and model of sandstone type uranium deposit in south of Songliao basin

    International Nuclear Information System (INIS)

    Yu Wenbin; Yu Zhenqing

    2010-01-01

    Through analyzing the uranium deposit tectonic environment, upper cretaceous sequence stratigraphy, depositional system, evolutionary characteristics of sand bodies, the effect of subsequent transformation and the characteristic of uranium deposit, the sandstone type uranium deposit in southern basin is different from typical interlayer oxidation zone sandstone type uranium deposit. The formation and evolution of sandstone-type uranium deposit are controlled by structure fensters; the favorable sedimentary facies type is braided river facies, and the ore body is braided river sand body. The size of uranium deposits is controlled by the local oxidation zone with the characteristics of sandstone type uranium deposit in partial oxidation zone. Uranium ore bodies which distribute in the roof wings of structure fenstes, and occur in gray layers between the upper and lower oxidation zone, showing tabular, and the plate of uranium ore body is controlled by the local oxidation zone. Based on the geological features of sandstone-type uranium deposits, the metallogenic model of local oxidation zones sandstone-type uranium deposits has been set up in the south of Songliao Baisn. (authors)

  4. Simulación de Facies mediante un Modelo Geoestadístico integrado para el desarrollo de un campo petrolero ecuatoriano.

    Directory of Open Access Journals (Sweden)

    Carlos Portilla

    2017-05-01

    Full Text Available La construcción de un modelo geoestadístico a partir de la integración de datos geofísicos, registros de pozos, información litológica, facies interpretadas, topes estratigráficos, coordenadas de pozos, surveys, wellheaders,los cuales son esenciales para determinar la ubicación de potenciales yacimientos de hidrocarburos y poder determinar el volumen de petróleo original en el sitio (POES. Para lo cual se recopilará información de campo para crear una base de datos la misma que se ingresará a la plataforma de trabajo Openworks, que a su vez, serán cargados a sesiones individuales en el Software Decision Space Geoscience (DSG, lo cual permitirá crear modelos de las diferentes realizaciones geoestadísticas que consisten en modelos de facies utilizando los algoritmos de Simulación Secuencial Indicadora y Simulación Plurigaussiana, además tomando en cuenta las propiedades petrofísicas nos permitirá seleccionar la que más se asemeje a la realidad geológica del campo y de esta manera realizar la estimación de reservas. Los métodos de simulación numérica de yacimientos que se aplican en el software DSG permiten generar datos en las zonas que no cuentan con información, a partir de técnicas o algoritmos de interpolación para cada modelo que se generará, los cuales serán estudiados en el presente proyecto.   Abstract   The objective of this research is to build a geostatistical model from the integration of geophysical data, logging wells and lithology information to determine the location of potential hydrocarbon deposits and know the POES of field. For which we have to collect information about field according to coordinates of wells, surveys, wellheaders, logging wells, facies interpreted stratigraphic tops and a database to be input in the platform OpenWorks, those data will be charged in individual sessions in the Software Decision Space Geoscience (DSG, which will create models of different Geostatistical

  5. Long-term sedimentary recycling of rare sulphur isotope anomalies.

    Science.gov (United States)

    Reinhard, Christopher T; Planavsky, Noah J; Lyons, Timothy W

    2013-05-02

    The accumulation of substantial quantities of O2 in the atmosphere has come to control the chemistry and ecological structure of Earth's surface. Non-mass-dependent (NMD) sulphur isotope anomalies in the rock record are the central tool used to reconstruct the redox history of the early atmosphere. The generation and initial delivery of these anomalies to marine sediments requires low partial pressures of atmospheric O2 (p(O2); refs 2, 3), and the disappearance of NMD anomalies from the rock record 2.32 billion years ago is thought to have signalled a departure from persistently low atmospheric oxygen levels (less than about 10(-5) times the present atmospheric level) during approximately the first two billion years of Earth's history. Here we present a model study designed to describe the long-term surface recycling of crustal NMD anomalies, and show that the record of this geochemical signal is likely to display a 'crustal memory effect' following increases in atmospheric p(O2) above this threshold. Once NMD anomalies have been buried in the upper crust they are extremely resistant to removal, and can be erased only through successive cycles of weathering, dilution and burial on an oxygenated Earth surface. This recycling results in the residual incorporation of NMD anomalies into the sedimentary record long after synchronous atmospheric generation of the isotopic signal has ceased, with dynamic and measurable signals probably surviving for as long as 10-100 million years subsequent to an increase in atmospheric p(O2) to more than 10(-5) times the present atmospheric level. Our results can reconcile geochemical evidence for oxygen production and transient accumulation with the maintenance of NMD anomalies on the early Earth, and suggest that future work should investigate the notion that temporally continuous generation of new NMD sulphur isotope anomalies in the atmosphere was likely to have ceased long before their ultimate disappearance from the rock record.

  6. Characteristics of depositional environment and evolution of Upper Cretaceous Mishrif Formation, Halfaya Oil field, Iraq based on sedimentary microfacies analysis

    Science.gov (United States)

    Zhong, Yuan; Zhou, Lu; Tan, Xiucheng; Guo, Rui; Zhao, Limin; Li, Fei; Jin, Zhimin; Chen, Yantao

    2018-04-01

    As one of the most important carbonate targets in the Middle East, Upper Cretaceous Mishrif Formation has been highlighted for a long time. Although consensus has been reached on the overall sedimentary background, disputes still exist in understanding the sedimentary environment changes among sub-regions due to relatively limited research, rare outcrop, and incomplete drilled core, which hinders the analysis on sedimentary environment and thus the horizontal and vertical correlation. In this study, taking the Halfaya Oil Field as an example, the sedimentary microfacies analysis method was introduced to comprehensively characterize the cored interval of Mishrif Formation, including Single Layers MC1-1 to MA2. A total of 11 sedimentary microfacies are identified through system identification of sedimentary microfacies and environmental analysis, with reference to the standard microfacies classification in the rimmed carbonate platform. Then three kinds of environments are identified through microfacies assemblage analysis, namely restricted platform, open platform, and platform margin. Systematic analyses indicate that the deposits are mainly developed in the open platform and platform margin. Meanwhile, rock-electricity interpretation model is established according to the electricity response to cored intervals, and is then employed to interpret the uncored intervals, which finally helps build the sedimentary evolution pattern through horizontal and vertical correlation. It is proposed that the Single Layers MC1-1 to MB2-3 were deposited in the open platform featured by low water level, including sub-environments of low-energy shoal within platform and inter-shoal sea; Single Layers MB2-2 to MB1-2B were deposited in the open platform and platform margin, including sub-environments of high-energy shoal on the platform margin, low-energy shoal within platform, inter-shoal sea, and open sea; and Single Layers MB1-2A to MA2 were again deposited in the open platform

  7. Sedimentary characteristics of samples collected from some submarine canyons

    NARCIS (Netherlands)

    Bouma, Arnold H.

    Oriented rectangular cores of 20.3 × 30.5 cm and 45.7 cm high have been collected in a number of submarine canyons off southern California (U.S.A.) and off the southern tip of Baja California (Mexico) for a detailed study of their sedimentary structures. By applying several methods, mainly X-ray

  8. An Overview of the Soutpansberg Sedimentary and Volcanic Rocks

    Directory of Open Access Journals (Sweden)

    J.W. Bristow

    1986-11-01

    Full Text Available Volcanic and sedimentary rocks occupy a faulted graben within the previously uplifted and eroded high-grade gneiss terrain of the Limpopo Mobile Belt. The rocks comprise the Soutpansberg Group and represent an important sequence of Proterozoic rocks. Their general geology and volcanology is summarised in this paper.

  9. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    acids in the coastal Arabian Sea sediments: whereas amino acids content of fulvic acids was lower than that of humic acids in the coastal sediments of Bay of Bengal. Slope sedimentary humic acids were relatively enriched in amino acids as compared...

  10. FEATURES OF GEODEFORMATION CHANGES OF NEAR SURFACE SEDIMENTARY ROCKS

    Directory of Open Access Journals (Sweden)

    I. A. Larionov

    2016-11-01

    Full Text Available The results of investigations of the deformation process in the near surface sedimentary rocks, which has been carried out in a seismically active region of Kamchatka peninsular since 2007,are presented. The peculiarity of the experiments on the registration of geodeformations is the application of a laser deformograph-interferometer constructed according to the Michelson interferometer scheme.

  11. Coralgal facies of the Upper Eocene-Lower Oligocene limestones in Letca-Rastoci area

    Directory of Open Access Journals (Sweden)

    Ioana Prica

    2001-09-01

    Full Text Available In this paper are described the coralgal facies identified in the Upper Eocene-Lower Oligocene limestone succession (Cozla Formation outcropping in two quarries at Letca and Rastoci (Sălaj district, Romania. In the studied profiles the coral and algae limestones are interlayered with bioclastic limestones with foraminifera. On the top of relatively deep water deposits, coral and algae crusts and dendritic corals coated by algae were deposited. The environment registered a gradual deepening, the deposits being completely immersed, while bioclastic limestones with foraminifera were recurrently formed. This cycle is repeated, the whole succession being caracterized by several such “parasequences”.

  12. Fluid heterogeneity during granulite facies metamorphism in the Adirondacks: stable isotope evidence

    Science.gov (United States)

    Valley, J.W.; O'Neil, J.R.

    1984-01-01

    The preservation of premetamorphic, whole-rock oxygen isotope ratios in Adirondack metasediments shows that neither these rocks nor adjacent anorthosites and gneisses have been penetrated by large amounts of externally derived, hot CO2-H2O fluids during granulite facies metamorphism. This conclusion is supported by calculations of the effect of fluid volatilization and exchange and is also independently supported by petrologic and phase equilibria considerations. The data suggest that these rocks were not an open system during metamorphism; that fluid/rock ratios were in many instances between 0.0 and 0.1; that externally derived fluids, as well as fluids derived by metamorphic volatilization, rose along localized channels and were not pervasive; and thus that no single generalization can be applied to metamorphic fluid conditions in the Adirondacks. Analyses of 3 to 4 coexisting minerals from Adirondack marbles show that isotopic equilibrium was attained at the peak of granulite and upper amphibolite facies metamorphism. Thus the isotopic compositions of metamorphic fluids can be inferred from analyses of carbonates and fluid budgets can be constructed. Carbonates from the granulite facies are on average, isotopically similar to those from lower grade or unmetamorphosed limestones of the same age showing that no large isotopic shifts accompanied high grade metamorphism. Equilibrium calculations indicate that small decreases in ??18O, averaging 1 permil, result from volatilization reactions for Adirondack rock compositions. Additional small differences between amphibolite and granulite facies marbles are due to systematic lithologie differences. The range of Adirondack carbonate ??18O values (12.3 to 27.2) can be explained by the highly variable isotopic compositions of unmetamorphosed limestones in conjunction with minor 18O and 13C depletions caused by metamorphic volatilization suggesting that many (and possibly most) marbles have closely preserved their

  13. Verdine and glaucony facies from surficial sediments of the eastern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Thamban, M.; Lamboy, M.

    -trioctahedral Fe-rich 1:l clay mineral. Clay Miner., 23: 237-247. Murthy, K.S.R., 1989. Seismic stratigraphy of Ongole-Paradip continental shelf East coast of India. Indian J. Mar. Sci., 16: 47-58. Murthy, K.S.R., Rao, T.C.S., Subramanyam, AS., Rao, M... at the continent- ocean boundary: the verdine facies. Clay Miner. 25: 477-483. Rao, K.M. and Rao, T.C.S., 1994. Holocene sea levels of Visakhapatnam shelf, East Coast of India. J. Geol. Sot. India, 44: 685-689. Rao, V.P., 1991. Clay mineral distribution...

  14. LA VALIDEZ PRIMA FACIE Y EL PRINCIPIO DE DERROTABILIDAD DE LAS NORMAS JURÍDICAS

    OpenAIRE

    GARCÍA-YZAGUIRRE, JOSÉ VÍCTOR

    2012-01-01

    El presente artículo pretende explorar las implicancias teóricas del concepto prima facie y como este se relaciona con el principio de derrotabilidad, el cual es aplicable para justificar el incumplimiento de un deber jurídico a causa del acatamiento de otro en un contexto en el que ambos son incompatibles entre sí. Partiremos desde su sustento conceptual analizando cuál es el rol y la importancia del contexto en el razonamiento jurídico hasta arribar a pautas concretas de cómo opera en la pr...

  15. Fluoride characterization by principal component analysis in the hydrochemical facies of Serra Geral Aquifer System in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Arthur Nanni

    2008-12-01

    Full Text Available Principal component analysis is applied to 309 groundwater chemical data information from wells in the Serra Geral Aquifer System. Correlations among seven hydrochemical parameters are statistically examined. A four-component model is suggested and explains 81% of total variance. Component 1 represents calcium-magnesium bicarbonated groundwaters with long time of residence. Component 2 represents sulfated and chlorinated calcium and sodium groundwaters; Component 3 represents sodium bicarbonated groundwaters; and Component 4 is characterized by sodium sulfated with high fluoride facies. The components' spatial distribution shows high fluoride concentration along analyzed tectonic fault system and aligned on northeast direction in other areas, suggesting other hydrogeological fault systems. High fluoride concentration increases according to groundwater pumping depth. The Principal Component Analysis reveals features of the groundwater mixture and individualizes water facies. In this scenery, it can be determined hydrogeological blocks associated with tectonic fault system here introduced.A Análise de Componentes Principais foi aplicada em 309 dados químicos de águas subterrâneas de poços do Sistema Aqüífero Serra Geral. Correlações entre sete parâmetros hidroquímicos foram examinadas através da estatística. O modelo de quatro componentes foi utilizado por explicar 81% da variância total. A Componente 1 é representada por águas cálcio-magnesianas com longo tempo de residência, a Componente 2 representa águas bicarbonatadas sulfatadas e cloretadas, a Componente 3 representa águas bicarbonatadas sódicas e a Componente 4 é caracterizada por águas de fácies sódica e sulfatada com alto fluoreto. A distribuição espacial das componentes mostra águas com concentrações anômalas ao longo dos sistemas tectônicos de falhas, analisados e alinhados a NE em algumas áreas, sugerindo outros sistemas de falhas hidrogeológicos. As

  16. Influence of pre-tectonic carbonate facies architecture on deformation patterns of syntectonic turbidites, an example from the central Mexican fold-thrust belt

    Science.gov (United States)

    Vásquez Serrano, Alberto; Tolson, Gustavo; Fitz Diaz, Elisa; Chávez Cabello, Gabriel

    2018-04-01

    The Mexican fold-thrust belt in central México excellently exposes relatively well preserved syntectonic deposits that overlay rocks with lateral lithostratigraphic changes across the belt. We consider the deformational effects of these changes by investigating the geometry, kinematics and strain distribution within syntectonic turbidites, which are deposited on top of Albian-Cenomanian shallow and deep water carbonate layers. Field observations and detailed structural analysis at different stratigraphic and structural levels of the Late Cretaceous syntectonic formation are compared with the deformation as a function of lithological and structural variations in the underlying carbonate units, to better understand the effect of these lithostratigraphic variations on deformation, kinematics, strain distribution and propagation of deformation. From our kinematic analyses, we conclude that the syntectonic strata are pervasively affected by folding in all areas and that deformation partitioning localized shear zones at the boundaries of this unit, particularly along the contact with massive carbonates. At the boundaries with massive platformal carbonates, the turbidites are strongly deformed by isoclinal folding with a pervasive sub-horizontal axial plane cleavage and 70-60% shortening. In contrast, contacts with thinly-bedded carbonate layers (basinal facies), do not show strain localization, and have horizontal shortening of 50-40% that is accommodated by buckle folds with a less pervasive, steeply dipping cleavage. The mechanical properties variations in the underlying pre-tectonic units as a function of changes in lithostratigraphy fundamentally control the deformation in the overlying syntectonic strata, which is an effect that could be expected to occur in any deformed sedimentary sequence with such variations.

  17. Contribution of seismic processing to put up the scaffolding for the 3-dimensional study of deep sedimentary basins: the fundaments of trans-national 3D modelling in the project GeoMol

    Science.gov (United States)

    Capar, Laure

    2013-04-01

    Within the framework of the transnational project GeoMol geophysical and geological information on the entire Molasse Basin and on the Po Basin are gathered to build consistent cross-border 3D geological models based on borehole evidence and seismic data. Benefiting from important progress in seismic processing, these new models will provide some answers to various questions regarding the usage of subsurface resources, as there are geothermal energy, CO2 and gas storage, oil and gas production, and support decisions-making to national and local administrations as well as to industries. More than 28 000 km of 2D seismic lines are compiled reprocessed and harmonized. This work faces various problems like the vertical drop of more than 700 meters between West and East of the Molasse Basin and to al lesser extent in the Po Plain, the heterogeneities of the substratum, the large disparities between the period and parameters of seismic acquisition, and depending of their availability, the use of two types of seismic data, raw and processed seismic data. The main challenge is to harmonize all lines at the same reference level, amplitude and step of signal processing from France to Austria, spanning more than 1000 km, to avoid misfits at crossing points between seismic lines and artifacts at the country borders, facilitating the interpretation of the various geological layers in the Molasse Basin and Po Basin. A generalized stratigraphic column for the two basins is set up, representing all geological layers relevant to subsurface usage. This stratigraphy constitutes the harmonized framework for seismic reprocessing. In general, processed seismic data is available on paper at stack stage and the mandatory information to take these seismic lines to the final stage of processing, the migration step, are datum plane and replacement velocity. However several datum planes and replacement velocities were used during previous processing projects. Our processing sequence is to

  18. Use of structural geology in exploration for and mining of sedimentary rock-hosted Au deposits

    Science.gov (United States)

    Peters, Stephen G.

    2001-01-01

    Structural geology is an important component in regional-, district- and orebody-scale exploration and development of sedimentary rock-hosted Au deposits.Identification of timing of important structural events in an ore district allows analysis and classification of fluid conduits and construction of genetic models for ore formation.The most practical uses of structural geology deal with measurement and definition of various elements that comprise orebodies, which can then be directly applied to ore-reserve estimation,ground control,grade control, safety issues,and mine planning.District- and regional-scale structural studies are directly applicable to long-term strategic planning,economic analysis,and land ownership. Orebodies in sedimentary rock-hosted Au deposits are discrete, hypogene, epigenetic masses usually hosted in a fault zone,breccia mass, or lithologic bed or unit. These attributes allow structural geology to be directly applied to the mining and exploration of sedimentary rock-hosted Au deposits. Internal constituents in orebodies reflect unique episodes relating to ore formation.The main internal constituents in orebodies are ore minerals, gangue, and alteration minerals that usually are mixed with one another in complex patterns, the relations among which may be used to interpret the processes of orebody formation and control.Controls of orebody location and shape usually are due to structural dilatant zones caused by changes in attitude, splays, lithologic contacts,and intersections of the host conduit or unit.In addition,conceptual parameters such as district fabric,predictable distances, and stacking also are used to understand the geometry of orebodies.Controls in ore districts and location and geometry of orebodies in ore districts can be predicted to various degrees by using a number of qualitative concepts such as internal and external orebody plunges,district plunge, district stacking, conduit classification, geochemical, geobarometric and

  19. Tectonostratigraphic reconstruction Cretaceous volcano-sedimentary in the northwestern Andes: from extensional tectonics to arc accretion.

    Science.gov (United States)

    Zapata, S.; Patino, A. M.; Cardona, A.; Mejia, D.; Leon, S.; Jaramillo, J. S.; Valencia, V.; Parra, M.; Hincapie, S.

    2014-12-01

    Active continental margins characterized by continuous convergence experienced overimposed tectonic configurations that allowed the formation of volcanic arcs, back arc basins, transtensional divergent tectonics or the accretion of exotic volcanic terranes. Such record, particularly the extensional phases, can be partially destroyed and obscure by multiple deformational events, the accretion of exotic terranes and strike slip fragmentation along the margin. The tectonic evolution of the northern Andes during the Mesozoic is the result of post Pangea extension followed by the installation of a long-lived Jurassic volcanic arc (209 - 136 ma) that apparently stops between 136 Ma and 110 Ma. The Quebradagrande Complex has been define as a single Lower Cretaceous volcano-sedimentary unit exposed in the western flank of the Central Cordillera of the Colombian Andes that growth after the Late Jurassic to Early Cretaceous magmatic hiatus. The origin of this unit have been related either to an oceanic volcanic arc or a marginal basin environment. The existence of such contrasting models reflect the regional perspective followed in published studies and the paucity of detail analysis of the volcano-sedimentary sequences.We integrate multiple approaches including structural mapping, stratigraphy, geochemistry, U-Pb provenance and geochronology to improve the understanding of this unit and track the earlier phases of accumulation that are mask on the overimposed tectonic history. Our preliminary results suggest the existence of different volcano-sedimentary units that accumulated between 100 Ma and 82 Ma.The older Lower Cretaceous sequences was deposited over Triassic metamorphic continental crust and include a upward basin deepening record characterized by thick fan delta conglomerates, followed by distal turbidites and a syn-sedimentary volcanic record at 100 ma. The other sequence include a 85 - 82 Ma fringing arc that was also formed close to the continental margin or

  20. Direct stable isotope porewater equilibration and identification of groundwater processes in heterogeneous sedimentary rock

    Energy Technology Data Exchange (ETDEWEB)

    David, Katarina, E-mail: k.david@student.unsw.edu.au [School of Mining Engineering, UNSW Australia, NSW 2052 (Australia); Connected Waters Initiative Research Centre, UNSW Australia, NSW 2052 (Australia); Timms, Wendy [School of Mining Engineering, UNSW Australia, NSW 2052 (Australia); Connected Waters Initiative Research Centre, UNSW Australia, NSW 2052 (Australia); Baker, Andy [Connected Waters Initiative Research Centre, UNSW Australia, NSW 2052 (Australia)

    2015-12-15

    The off-axis integrated cavity output spectrometry (ICOS) method to analyse porewater isotopic composition has been successfully applied over the last decade in groundwater studies. This paper applies the off-axis ICOS method to analyse the porewater isotopic composition, attempts to use the isotopic shift in groundwater values along with simple geochemical mixing model to define the groundwater processes in the Sydney Basin, Australia. Complementary data included geophysical, hydrogeological, geochemical, and mineralogical investigations. Porewater from core samples were analysed for δ{sup 18}O and δ{sup 2}H from various sedimentary units in the Basin and compared to endpoint water members. Stable δ{sup 18}O and δ{sup 2}H values of porewaters in the Basin (− 9.5 to 2.8‰ for δ{sup 18}O and − 41.9 to 7.9‰ for δ{sup 2}H) covered a relatively narrow range in values. The variability in water isotopes reflects the variability of the input signal, which is the synoptic variability in isotopic composition of rainfall, and to a minor extent the subsequent evaporation. The porosity, bulk density and mineralogy data demonstrate the heterogeneity that adds the complexity to variations in the isotope profile with depth. The source of chloride in the sedimentary sequence was related to rock–water and cement/matrix–water interaction rather than to evaporation. The heterogeneous character of the sedimentary rock strata was supported by a change in pore pressures between units, density and variability in rock geochemical analyses obtained by using X-ray fluorescence (XRF) and X-ray power diffraction analyses. This research identified distinct hydrogeological zones in the Basin that were not previously defined by classic hydrogeological investigations. Isotopic signature of porewaters along the detailed vertical profile in combination with mineralogical, geochemical, geophysical and hydrogeological methods can provide useful information on groundwater movement in

  1. Sedimentary dykes in the Oskarshamn-Vaestervik area. A study of the mechanism of formation

    Energy Technology Data Exchange (ETDEWEB)

    Roeshoff, Kennert [BBK AB, Solna (Sweden); Cosgrove, John [Imperial College, London (United Kingdom). Dept. of Earth Sciences and Engineering

    2002-07-01

    This study of the sedimentary dykes from the Oskarshamn-Vaestervik area, near Aespoe and surrounding region, is aimed at understanding the mechanism of their formation. In particular it is important to establish whether or not they formed by the injection of high pressure fluidized sediments and if so what the likely effect of any future over pressured sediments will be on the stability of the fracture network in the basement rocks at Aespoe. This report is made up of a review of the literature on sedimentary dykes, a discussion of the various mechanical models for hydraulic fracturing and a description of the field and laboratory study carried out on the sedimentary dykes. The literature review indicates a remarkable consensus on the mode of formation of these structures based on their fabric (particularly layering generated in part by variation in clast size) and the composition of the infilling material. Two modes of origin have been recognised. These are the passive infilling of dykes where the dyke material has entered an open fracture under the influence of gravity, and active, i.e. forceful injection of a fluidized sediment under high pressure into a pre-existing fracture or into a fracture generated by the high pressure fluid. The discussion of the theory of fluid induced fracturing leads to the recognition of three systems which are the two end members and an intermediate form of a complete spectrum of materials ranging from unconsolidated and incohesive sediments, through cemented but porous rocks to crystalline rocks with no intrinsic porosity and whose only porosity relates to that imparted by the fracture network that the rock contains. The theory best suited to analyses this latter system is one based on fracture mechanics and is known as the theory of external hydraulic fracturing. From the point of view of the sedimentary dykes in the study area around the Aespoe Hard Rock Laboratory, where the dykes occur in the fractured granitic basement, this is

  2. Sedimentary dykes in the Oskarshamn-Vaestervik area. A study of the mechanism of formation

    International Nuclear Information System (INIS)

    Roeshoff, Kennert; Cosgrove, John

    2002-07-01

    This study of the sedimentary dykes from the Oskarshamn-Vaestervik area, near Aespoe and surrounding region, is aimed at understanding the mechanism of their formation. In particular it is important to establish whether or not they formed by the injection of high pressure fluidized sediments and if so what the likely effect of any future over pressured sediments will be on the stability of the fracture network in the basement rocks at Aespoe. This report is made up of a review of the literature on sedimentary dykes, a discussion of the various mechanical models for hydraulic fracturing and a description of the field and laboratory study carried out on the sedimentary dykes. The literature review indicates a remarkable consensus on the mode of formation of these structures based on their fabric (particularly layering generated in part by variation in clast size) and the composition of the infilling material. Two modes of origin have been recognised. These are the passive infilling of dykes where the dyke material has entered an open fracture under the influence of gravity, and active, i.e. forceful injection of a fluidized sediment under high pressure into a pre-existing fracture or into a fracture generated by the high pressure fluid. The discussion of the theory of fluid induced fracturing leads to the recognition of three systems which are the two end members and an intermediate form of a complete spectrum of materials ranging from unconsolidated and incohesive sediments, through cemented but porous rocks to crystalline rocks with no intrinsic porosity and whose only porosity relates to that imparted by the fracture network that the rock contains. The theory best suited to analyses this latter system is one based on fracture mechanics and is known as the theory of external hydraulic fracturing. From the point of view of the sedimentary dykes in the study area around the Aespoe Hard Rock Laboratory, where the dykes occur in the fractured granitic basement, this is

  3. Reactive solute transport in physically and chemically heterogeneous porous media with multimodal reactive mineral facies: the Lagrangian approach.

    Science.gov (United States)

    Soltanian, Mohamad Reza; Ritzi, Robert W; Dai, Zhenxue; Huang, Chao Cheng

    2015-03-01

    Physical and chemical heterogeneities have a large impact on reactive transport in porous media. Examples of heterogeneous attributes affecting reactive mass transport are the hydraulic conductivity (K), and the equilibrium sorption distribution coefficient (Kd). This paper uses the Deng et al. (2013) conceptual model for multimodal reactive mineral facies and a Lagrangian-based stochastic theory in order to analyze the reactive solute dispersion in three-dimensional anisotropic heterogeneous porous media with hierarchical organization of reactive minerals. An example based on real field data is used to illustrate the time evolution trends of reactive solute dispersion. The results show that the correlation between the hydraulic conductivity and the equilibrium sorption distribution coefficient does have a significant effect on reactive solute dispersion. The anisotropy ratio does not have a significant effect on reactive solute dispersion. Furthermore, through a sensitivity analysis we investigate the impact of changing the mean, variance, and integral scale of K and Kd on reactive solute dispersion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Application of probabilistic facies prediction and estimation of rock physics parameters in a carbonate reservoir from Iran

    International Nuclear Information System (INIS)

    Karimpouli, Sadegh; Hassani, Hossein; Nabi-Bidhendi, Majid; Khoshdel, Hossein; Malehmir, Alireza

    2013-01-01

    In this study, a carbonate field from Iran was studied. Estimation of rock properties such as porosity and permeability is much more challenging in carbonate rocks than sandstone rocks because of their strong heterogeneity. The frame flexibility factor (γ) is a rock physics parameter which is related not only to pore structure variation but also to solid/pore connectivity and rock texture in carbonate reservoirs. We used porosity, frame flexibility factor and bulk modulus of fluid as the proper parameters to study this gas carbonate reservoir. According to rock physics parameters, three facies were defined: favourable and unfavourable facies and then a transition facies located between these two end members. To capture both the inversion solution and associated uncertainty, a complete implementation of the Bayesian inversion of the facies from pre-stack seismic data was applied to well data and validated with data from another well. Finally, this method was applied on a 2D seismic section and, in addition to inversion of petrophysical parameters, the high probability distribution of favorable facies was also obtained. (paper)

  5. Stratigraphy and facies development of the marine Late Devonian near the Boulongour Reservoir, northwest Xinjiang, China

    Science.gov (United States)

    Suttner, Thomas J.; Kido, Erika; Chen, Xiuqin; Mawson, Ruth; Waters, Johnny A.; Frýda, Jiří; Mathieson, David; Molloy, Peter D.; Pickett, John; Webster, Gary D.; Frýdová, Barbora

    2014-02-01

    Late Devonian to Early Carboniferous stratigraphic units within the 'Zhulumute' Formation, Hongguleleng Formation (stratotype), 'Hebukehe' Formation and the Heishantou Formation near the Boulongour Reservoir in northwestern Xinjiang are fossil-rich. The Hongguleleng and 'Hebukehe' formations are biostratigraphically well constrained by microfossils from the latest Frasnian linguiformis to mid-Famennian trachytera conodont biozones. The Hongguleleng Formation (96.8 m) is characterized by bioclastic argillaceous limestones and marls (the dominant facies) intercalated with green spiculitic calcareous shales. It yields abundant and highly diverse faunas of bryozoans, brachiopods and crinoids with subordinate solitary rugose corals, ostracods, trilobites, conodonts and other fish teeth. The succeeding 'Hebukehe' Formation (95.7 m) consists of siltstones, mudstones, arenites and intervals of bioclastic limestone (e.g. 'Blastoid Hill') and cherts with radiolarians. A diverse ichnofauna, phacopid trilobites, echinoderms (crinoids and blastoids) together with brachiopods, ostracods, bryozoans and rare cephalopods have been collected from this interval. Analysis of geochemical data, microfacies and especially the distribution of marine organisms, which are not described in detail here, but used for facies analysis, indicate a deepening of the depositional environment at the Boulongour Reservoir section. Results presented here concern mainly the sedimentological and stratigraphical context of the investigated section. Additionally, one Late Devonian palaeo-oceanic and biotic event, the Upper Kellwasser Event is recognized near the section base.

  6. Seismic facies analysis from pre-stack data using self-organizing maps

    International Nuclear Information System (INIS)

    Kourki, Meysam; Ali Riahi, Mohammad

    2014-01-01

    In facies analysis, seismic data are clustered in different groups. Each group represents subsurface points with similar physical properties. Different groups can be related to differences in lithology, physical properties of rocks and fluid changes in the rocks. The supervised and unsupervised data clustering are known as two types of clustering architecture. In supervised clustering, the number of clusters is predefined, while in unsupervised clustering, a collection of patterns partitions into groups without predefined clusters. In this study, the pre-stack data clustering is used for seismic facies analysis. In this way, a horizon was selected from pre-stack data, followed by sorting of data using offset. A trace associated with each CDP is constructed, for which the first and second samples are related to the first and second offsets, respectively. The created trace is called consolidated trace which is characteristic of subsurface points. These consolidated traces are clustered by using self-organizing maps (SOM). In proposed pre-stack seismic data clustering, points with similar physical properties are placed in one cluster. Seismic data associated with hydrocarbon reservoirs have very different characteristics that are easily recognized. The efficiency of the proposed method was tested on both synthetic and real seismic data. The results showed that the algorithm improves the data classification and the points of different properties are noticeable in final maps. (paper)

  7. [First trimester screening for Down syndrome at Prima facie. A 6-year survey].

    Science.gov (United States)

    Roth, P; Bernard, J-P; Meyer, V; Beaujard, M-P; Salomon, L-J; Ville, Y

    2016-02-01

    To evaluate the results of screening for trisomy 21 by the combined risk of first trimester (as defined by the decree of June 23, 2009) in the Prima facie structure. Single center study involving all patients that were seen for first trimester screening at Prima facie with singleton living pregnancy, not obtained by embryo donation, between 1 January 2009 and 31 December 2014. Eighteen thousand two hundred and fifty-one patients were included, of which underwent screening for trisomy 21 by the combined risk. One thousand and forty-six (6.1%) had a calculated risk higher than 1/250. Seventy-five were affected by trisomy 21, of whom 65 in the high risk group. The sensitivity and specificity of screening are 86.7% and 94.4%. The median nuchal translucency was 0.98 MoM. Screening for trisomy 21 by calculating the combined risk of first trimester enabled to detect 86.7% of trisomy 21 with a false positive rate of 5.6%. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. HIV status: the prima facie right not to know the result.

    Science.gov (United States)

    Chan, Tak Kwong

    2016-02-01

    When a patient regains consciousness from Cryptococcus meningitis, the clinician may offer an HIV test (in case it has not already been done) (scenario 1) or offer to tell the patient his HIV status (in case the test has already been performed with a positive result while the patient was unconscious) (scenario 2). Youngs and Simmonds proposed that the patient has the prima facie right to refuse an HIV test in scenario 1 but not the prima facie right not to be told the HIV status in scenario 2. I submit that the claims to the right of refusal in both scenarios are similarly strong as they should both be grounded in privacy, self determination or dignity. But a conscientious agent should bear in mind that members of the public also have the right not to be harmed. When the circumstance allows, a proper balance of the potential benefits and harm for all the competing parties should guide the clinical decision as to whose right should finally prevail. Where a full ethical analysis is not possible, the presumption should favour respecting the patient's right of refusal in both scenarios. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

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

    International Nuclear Information System (INIS)

    Lloyd, J.W.

    1980-01-01

    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 14 C ages. The decay hypothesis is found to be plausible with realistic aquifer characteristics but a non-homogeneous flow is indicated from the 14 C data. (author)

  10. The Upper Permian sandstones of Mountains Mecsek: form elements of uranium ore mineralization and facies relations Pt. 2

    International Nuclear Information System (INIS)

    Vincze, Janos; Somogyi, Janos

    1984-01-01

    The ore mineralization in the Upper Permian sandstones of Mountais Mecsek, Hungary, was brought about at the oxidation-reduction front between the grey and red sandstones; the predominant rock colour here is green. The sandstones of different colour are oxidation-reduction species. The formation is a megacycle containing in its core grey sandstones of reduced state with coalified plant remains and in its mantle oxidized red sandstones. Uranium accumulates mainly in the transitional green facies. Uranium content gets enriched to a commercial concentration only if the difference in potential of neighbouring beds is in the range of 400-480 mV. The relationship between organic matter and uranium content in the individual facies is shown. The principles of oxidation-reduction processes in the formation of boundary facies are discussed. (V.N.)

  11. Subsurface temperature maps in French sedimentary basins: new data compilation and interpolation

    International Nuclear Information System (INIS)

    Bonte, D.; Guillou-Frottier, L.; Garibaldi, C.; Bourgine, B.; Lopez, S.; Bouchot, V.; Garibaldi, C.; Lucazeau, F.

    2010-01-01

    Assessment of the underground geothermal potential requires the knowledge of deep temperatures (1-5 km). Here, we present new temperature maps obtained from oil boreholes in the French sedimentary basins. Because of their origin, the data need to be corrected, and their local character necessitates spatial interpolation. Previous maps were obtained in the 1970's using empirical corrections and manual interpolation. In this study, we update the number of measurements by using values collected during the last thirty years, correct the temperatures for transient perturbations and carry out statistical analyses before modelling the 3D distribution of temperatures. This dataset provides 977 temperatures corrected for transient perturbations in 593 boreholes located in the French sedimentary basins. An average temperature gradient of 30.6 deg. C/km is obtained for a representative surface temperature of 10 deg. C. When surface temperature is not accounted for, deep measurements are best fitted with a temperature gradient of 25.7 deg. C/km. We perform a geostatistical analysis on a residual temperature dataset (using a drift of 25.7 deg. C/km) to constrain the 3D interpolation kriging procedure with horizontal and vertical models of variograms. The interpolated residual temperatures are added to the country-scale averaged drift in order to get a three dimensional thermal structure of the French sedimentary basins. The 3D thermal block enables us to extract isothermal surfaces and 2D sections (iso-depth maps and iso-longitude cross-sections). A number of anomalies with a limited depth and spatial extension have been identified, from shallow in the Rhine graben and Aquitanian basin, to deep in the Provence basin. Some of these anomalies (Paris basin, Alsace, south of the Provence basin) may be partly related to thick insulating sediments, while for some others (southwestern Aquitanian basin, part of the Provence basin) large-scale fluid circulation may explain superimposed

  12. 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

  13. The Use of Ground Penetrating Radar to Exploring Sedimentary Ore In North-Central Saudi Arabia

    Science.gov (United States)

    Almutairi, Yasir; Almutair, Muteb

    2015-04-01

    Ground Penetrating Radar (GPR) is a non-destructive geophysical method that provides a continuous subsurface profile, without drilling. This geophysical technique has great potential in delineating the extension of bauxites ore in north-central Saudi Arabia. Bauxite is from types sedimentary ores. This study aim to evaluate the effectiveness of Ground Penetrating Radar (GPR) to illustrate the subsurface feature of the Bauxite deposits at some selected mining areas north-central Saudi Arabia. Bauxite is a heterogeneous material that consists of complex metals such as alumina and aluminum. An efficient and cost-effect exploration method for bauxite mine in Saudi Arabia is required. Ground penetrating radar (GPR) measurements have been carrying out along outcrop in order to assess the potential of GPR data for imaging and characterising different lithological facies. To do so, we have tested different antenna frequencies to acquire the electromagnetic signals along a 90 m profile using the IDS system. This system equipped with a 25 MHz antenna that allows investigating the Bauxite layer at shallow depths where the clay layers may existed. Therefore, the 25 MHz frequency antenna has been used in this study insure better resolution of the subsurface and to get more penetration to image the Bauxite layer. After the GPR data acquisition, this data must be processed in order to be more easily visualized and interpreted. Data processing was done using Reflex 6.0 software. A series of tests were carried out in frequency filtering on a sample of radar sections, which was considered to better represent the entire set of data. Our results indicated that the GPR profiling has a very good agreement for mapping the bauxite layer depth at range of 7 m to 11 m. This study has emphasized that the high-resolution GPR method is the robust and cost-effect technique to map the Bauxite layer. The exploration of Bauxite resource using the GPR technique could reduce the number of holes to

  14. Tectonics and sedimentary process in the continental talud in Uruguay

    International Nuclear Information System (INIS)

    De Santa Ana, H.; Soto, M.; Morales, E.; Tomasini, J.; Hernandez-Molina, F.; Veroslavsky, G.

    2012-01-01

    The morphology and evolution of the continental margin of Uruguay is due to the interaction of an important set of sedimentary processes. The contourite and turbiditic are the most significant processes which are associated with the development of submarine canyons as well as the gravitational mass respect to major landslides. These processes generate erosional and depositional features with a direct impact on different areas of application, which have potential environmental risks (gravitational landslides, earthquakes, tsunamis) and potential economic resources

  15. Favorability for uranium in tertiary sedimentary rocks, southwestern Montana

    International Nuclear Information System (INIS)

    Wopat, M.A.; Curry, W.E.; Robins, J.W.; Marjaniemi, D.K.

    1977-10-01

    Tertiary sedimentary rocks in the basins of southwestern Montana were studied to determine their favorability for potential uranium resources. Uranium in the Tertiary sedimentary rocks was probably derived from the Boulder batholith and from silicic volcanic material. The batholith contains numerous uranium occurrences and is the most favorable plutonic source for uranium in the study area. Subjective favorability categories of good, moderate, and poor, based on the number and type of favorable criteria present, were used to classify the rock sequences studied. Rocks judged to have good favorability for uranium deposits are (1) Eocene and Oligocene strata and undifferentiated Tertiary rocks in the western Three Forks basin and (2) Oligocene rocks in the Helena basin. Rocks having moderate favorability consist of (1) Eocene and Oligocene strata in the Jefferson River, Beaverhead River, and lower Ruby River basins, (2) Oligocene rocks in the Townsend and Clarkston basins, (3) Miocene and Pliocene rocks in the Upper Ruby River basin, and (4) all Tertiary sedimentary formations in the eastern Three Forks basin, and in the Grasshopper Creek, Horse Prairie, Medicine Lodge Creek, Big Sheep Creek, Deer Lodge, Big Hole River, and Bull Creek basins. The following have poor favorability: (1) the Beaverhead Conglomerate in the Red Rock and Centennial basins, (2) Eocene and Oligocene rocks in the Upper Ruby River basin, (3) Miocene and Pliocene rocks in the Townsend, Clarkston, Smith River, and Divide Creek basins, (4) Miocene through Pleistocene rocks in the Jefferson River, Beaverhead River, and Lower Ruby River basins, and (5) all Tertiary sedimentary rocks in the Boulder River, Sage Creek, Muddy Creek, Madison River, Flint Creek, Gold Creek, and Bitterroot basins

  16. Properties of Pliocene sedimentary geomagnetic reversal records from the Mediterranean

    OpenAIRE

    Linssen, J.H.

    1991-01-01

    In the history of the Earth the dipolar geomagnetic field has frequently reversed polarity. Though this property was already known early this century (Brunhes, 1906), nowadays the characteristics and the origin of polarity transitions are still largely unknown. The geomagnetic field and its variations are recorded in rocks as a natural remanent magnetization (NRM) during the formation of these rocks. The study of the NRM in sedimentary reversal records is the subject of this dissertation.

  17. Sedimentary noise and sea levels linked to land-ocean water exchange and obliquity forcing.

    Science.gov (United States)

    Li, Mingsong; Hinnov, Linda A; Huang, Chunju; Ogg, James G

    2018-03-08

    In ancient hothouses lacking ice sheets, the origins of large, million-year (myr)-scale sea-level oscillations remain a mystery, challenging current models of sea-level change. To address this mystery, we develop a sedimentary noise model for sea-level changes that simultaneously estimates geologic time and sea level from astronomically forced marginal marine stratigraphy. The noise model involves two complementary approaches: dynamic noise after orbital tuning (DYNOT) and lag-1 autocorrelation coefficient (ρ 1 ). Noise modeling of Lower Triassic marine slope stratigraphy in South China reveal evidence for global sea-level variations in the Early Triassic hothouse that are anti-phased with continental water storage variations in the Germanic Basin. This supports the hypothesis that long-period (1-2 myr) astronomically forced water mass exchange between land and ocean reservoirs is a missing link for reconciling geological records and models for sea-level change during non-glacial periods.

  18. Modern sedimentary processes along the Doce river adjacent continental shelf

    Directory of Open Access Journals (Sweden)

    Valéria da Silva Quaresma

    Full Text Available In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.

  19. Sedimentology and paleoenvironments of a new fossiliferous late Miocene-Pliocene sedimentary succession in the Rukwa Rift Basin, Tanzania

    Science.gov (United States)

    Mtelela, Cassy; Roberts, Eric M.; Hilbert-Wolf, Hannah L.; Downie, Robert; Hendrix, Marc S.; O'Connor, Patrick M.; Stevens, Nancy J.

    2017-05-01

    This paper presents a detailed sedimentologic investigation of a newly identified, fossiliferous Late Neogene sedimentary succession in the Rukwa Rift Basin, southwestern Tanzania. This synrift deposit is a rare and significant new example of a fossiliferous succession of this age in the Western Branch of East Africa Rift System. The unit, informally termed the lower Lake Beds succession, is late Miocene to Pliocene in age based on cross-cutting relationships, preliminary biostratigraphy, and U-Pb geochronology. An angular unconformity separates the lower Lake Beds from underlying Cretaceous and Oligocene strata. Deposition was controlled by rapid generation of accommodation space and increased sediment supply associated with late Cenozoic tectonic reactivation of the Rukwa Rift and synchronous initiation of the Rungwe Volcanic Centre. The lower Lake Beds, which have thus far only been identified in three localities throughout the Rukwa Rift Basin, are characterized by two discrete lithologic members (herein A and B). The lower Member A is a volcanic-rich succession composed mostly of devitrified volcanic tuffs, and volcaniclastic mudstones and sandstones with minor conglomerates. The upper Member B is a siliciclastic-dominated succession of conglomerates, sandstones, mudstones and minor volcanic tuffs. Detailed facies analysis of the lower Lake Beds reveals various distinctive depositional environments that can be grouped into three categories: 1) alluvial fan; 2) fluvial channel; and 3) flood basin environments, characterized by volcanoclastic-filled lakes and ponds, abandoned channel-fills and pedogenically modified floodplains. Member A represents a shallow lacustrine setting filled by tuffaceous sediments, which grade up into a system of alluvial fans and high-energy, proximal gravel-bed braided rivers. An unconformity marks the contact between the two members. Member B shows an upward transition from a high-energy, gravel-bed braided river system to a sandy

  20. Recirculation System for Geothermal Energy Recovery in Sedimentary Formations: Laboratory Experiments and Numerical Simulations

    Science.gov (United States)

    Elkhoury, J. E.; Detwiler, R. L.; Serajian, V.; Bruno, M. S.

    2012-12-01

    Geothermal energy resources are more widespread than previously thought and have the potential for providing a significant amount of sustainable clean energy worldwide. In particular, hot permeable sedimentary formations provide many advantages over traditional geothermal recovery and enhanced geothermal systems in low permeability crystalline formations. These include: (1) eliminating the need for hydraulic fracturing, (2) significant reduction in risk for induced seismicity, (3) reducing the need for surface wastewater disposal, (4) contributing to decreases in greenhouse gases, and (5) potential use for CO2 sequestration. Advances in horizontal drilling, completion, and production technology from the oil and gas industry can now be applied to unlock these geothermal resources. Here, we present experimental results from a laboratory scale circulation system and numerical simulations aimed at quantifying the heat transfer capacity of sedimentary rocks. Our experiments consist of fluid flow through a saturated and pressurized sedimentary disc of 23-cm diameter and 3.8-cm thickness heated along its circumference at a constant temperature. Injection and production ports are 7.6-cm apart in the center of the disc. We used DI de-aired water and mineral oil as working fluids and explored temperatures from 20 to 150 oC and flow rates from 2 to 30 ml/min. We performed experiments on sandstone samples (Castlegate and Kirby) with different porosity, permeability and thermal conductivity to evaluate the effect of hydraulic and thermal properties on the heat transfer capacity of sediments. The producing fluid temperature followed an exponential form with time scale transients between 15 and 45 min. Steady state outflow temperatures varied between 60% and 95% of the set boundary temperature, higher percentages were observed for lower temperatures and flow rates. We used the flow and heat transport simulator TOUGH2 to develop a numerical model of our laboratory setting. Given

  1. Automatic interpretation of seismic micro facies using the fuzzy mathematics method

    Energy Technology Data Exchange (ETDEWEB)

    Dongrun, G.; Gardner, G.H.F.

    1988-01-01

    The interpretation of seismic micro facies concentrates on changes involving single reflection or several reflections, and endeavors to explain the relations between these changes and stratigraphic variation or hydrocarbon accumulation. In most cases, one can not determine the geological significance of reflection character anomalies on single or several seismic sections. But when one maps them on a plane, their distribution may on the whole indicate the geological significance. It is stated how the fuzzy method is used on a VAX computer to automatically construct a plane map of the reflection character changes in a time window. What an interpreter needs to do for whole interpretation is only to provide some parameters, such as time window, threshold, weight coefficients etc.

  2. La validez prima facie y el principio de derrotabilidad de Las normas jurídicas

    Directory of Open Access Journals (Sweden)

    José Víctor García-Yzaguirre

    2012-01-01

    Full Text Available El presente artículo pretende explorar las implicancias teóricas del concepto prima facie y como este se relaciona con el principio de derrotabilidad, el cual es aplicable para justificar el incumplimiento de un deber jurídico a causa del acatamiento de otro en un contexto en el que ambos son incom- patibles entre sí. Partiremos desde su sustento conceptual analizando cuál es el rol y la importancia del contexto en el razonamiento jurídico hasta arribar a pautas concretas de cómo opera en la práctica judicial ofreciendo algunos ejemplos hipotéticos y jurisprudenciales.

  3. Mineralizations of the Lavalleja Group (Uruguay), a Probable Neoproterozoic Volcano-sedimentary Sequence

    International Nuclear Information System (INIS)

    Sanchez Bettucci, L.; Oyhantcabal, P.; Loureiro, J.; Basei, M.; Ramos, V.; Preciozzi, F.; Basei, M.

    2004-01-01

    The Lavalleja Group is located in the southern extreme of the Dom Feliciano Belt, being tentatively correlated with the Porongos and Brusque Groups of Brazil. The basement of the Lavalleja Group is probably represented by granitic gneissic rocks of the Campanero Unit with ages, in the southern portion, ranging from 1.75 to 2.1 Ga (U-Pb in zircon). The Lavalleja Group is characterized by narrow bands of meta sedimentary and meta volcanic rocks and it is separated in three formations, namely (from base to top): Zanja del Tigre, Fuente del Puma and Minas. Outcrops assigned to the Minas Formation have been recently correlated with the Arroyo del Soldado Group. Only the Fuente del Puma formation hosts base metals, Au and Ag occurrences. The Fuente del Puma formation is divided into three informal units: sedimentary, volcanic and hornblenditic gabbros. The sedimentary unit is characterized by an important amount of carbonates. Syn collisional to pos tectonic granitic bodies (Carapé Complex) intrudes the Lavalleja Group and the Campanero Unit. Several mineralizations are located in the Fuente del Puma Formation, those associated to Arrospide, Ramallo-Reus, Chape, Valencia, La Oriental, Apolonia, Redondo Hill, La China and La Paloma mines are the most important. In addition, many occurrences of Cu-Zn-Pb were recognized in the region. The Cu-Zn-Pb mineralization includes massive sulfides with pyrite-chalcopyrite-sphalerite-galena-pyrrothyte, arsenopyrite-hematite into small bodies with lenticular shape. The host rock shows frequently hydrothermal alteration. The geochemistry and the geological features of the mineralizations suggest Besshi Massive Sulphide Zn-Cu-Pb and SEDEX Zn-Pb as most probably genetic models for the deposits related to the Neoproterozoic orogeny. Early mineralizations are syngenetic and were formed on the sea floor, although the main mineralizations are related to remobilization during syn- to late-metamorphic events and thrusting

  4. Coastal dune facies, Permian Cutler Formation (White Rim Sandstone), Capitol Reef National Park area, southern Utah

    Science.gov (United States)

    Kamola, Diane L.; Chan, Marjorie A.

    1988-04-01

    The Permian Cutler Formation (White Rim Sandstone) in the Capitol Reef National Park area in southern Utah is an excellent example of a coastal dune complex subjected to periodic flooding by marine waters. Wind-ripple, grainfall and grainflow laminae compose the cross-sets deposited by eolian dunes. However, wave-reworked structures such as oscillation ripples, the occurrence of the characteristically marine trace fossils Thalassinoides and Chondrites, and interfingering marine carbonate beds of the Kaibab Formation collectively indicate marine interaction with the eolian environment. Four facies are distinguished: cross-stratified sandstone, burrowed to bioturbated sandstone, brecciated and deformed sandstone, and ripple-laminated sandstone and thin carbonate beds. One unusual aspect of the cross-stratified sandstone facies is the abundance of coarse-grained sand. Coarse-grained sand is atypical in many ancient eolian slipface deposits, but occurs here in large slipface foresets as both grainflow and wind-ripple deposits. No water-laid structures are found in these slipface deposits. Coarse-grained sand was probably transported to the Cutler shoreline by fluvial systems draining the Uncompahgre Uplift to the east, and then concentrated as coarse-grained ripples in interdune areas. Some of these coarse-grained ripples migrated up the stoss side of the dunes and accumulations of coarse-grained sand avalanched down the crest to form grainflow deposits. An extensive amount of soft-sediment deformation is indicated by the presence of convolute bedding and brecciation. These features occur near the zone of interfingering with marine carbonate beds of the Kaibab Formation. The water-saturated and moist conditions required for extensive deformation may have been controlled by the proximity of these sandstones to the shoreline, and fluctuations in the associated groundwater table.

  5. Beaulieu-Boycott-Innes syndrome: an intellectual disability syndrome with characteristic facies.

    <