Articles de revues : « Continental margins and sedimentary basin »

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Khabanets, I., et I. Karpenko. « TECTONIC MODEL OF JUNCTION ZONE BETWEEN DNIEPER AND DONETS SEDIMENTARY BASINS AS PROSPECTIVE TERRITORY FOR UNCONVENTIONAL HYDROCARBON ». Ukrainian Geologist, n^o 3(43) (10 octobre 2013) : 112–15. http://dx.doi.org/10.53087/ug.2013.3(43).245571.

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We give and analyze geological data that substantiate the validity division of Dnieper-Donets basin into two separate basins: Donets marginal-continental part that was opening from 793.00–590.75 Ma and Dnieper innerplatform with the disclosure in late Paleozoic – early Mesozoic (385.75–178.00 Ma). Territorially boundary between those margins passes between regional seismic profiles Lozovaja-Shebelinka-Staropokrivka and Mechebylovo-Bryhadyrivka. Donets Basin (Central Donbass) is a remnant continental margin of paleoocean Prototetis II, and north side of Donets basin up to the border of the Dnieper deflection – the remnant of the continental margin Prototetis I.

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McDermott, Kenneth, Paul Bellingham, Rod Graham, James Pindell, Lynn Pryer, Donna Cathro et Brian Horn. « Continental extension and break-up—using the Australian margins as a case study ». APPEA Journal 55, n^o 2 (2015) : 399. http://dx.doi.org/10.1071/aj14034.

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The continental margins of Australia provide an excellent natural laboratory for investigations of continental extension and break-up, with examples of failed rifts, multi-phase extensional systems, and volcanic and non-volcanic margins. The thick sedimentary cover across large parts, however, has hindered understanding of the deep crustal and lithospheric structure due to poor imaging. ION Geophysical has acquired deep, long offset seismic data across Australia’s North West Shelf, as well as the Bight Basin on Australia’s southern margin. These programs provide unique imaging of the deep basement structures and the complete overlying sedimentary section, and across all of the terrains from continental crust to oceanic crust. The authors’ interpretation of these data will be discussed in the context of existing models for continental extension and break-up and the resulting implications for the petroleum system: Models of hyper-extension and possible mantle exhumation will be discussed with regards to the Bonaparte, Browse and Bight basins. Multi-phase extension and the development of intra-sedimentary detachment horizons will be reviewed across many areas. Development of volcanic margins, including the effects of dynamic uplift and magmatic intrusions, will be investigated in the Exmouth Plateau. Creation of enough accommodation space to allow the deposition of the observed (~20 km) sedimentary sections in the Carnarvon and Bonaparte basins.

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Holford, Simon, Nick Schofield, Justin MacDonald, Ian Duddy et Paul Green. « Seismic analysis of igneous systems in sedimentary basins and their impacts on hydrocarbon prospectivity : examples from the southern Australian margin ». APPEA Journal 52, n^o 1 (2012) : 229. http://dx.doi.org/10.1071/aj11017.

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The increasing availability of 3D seismic data from sedimentary basins at volcanic and non-volcanic continental margins has provided fundamental new insights into both the storage and transport of magma in the continental crust. As global hydrocarbon exploration increasingly focuses on passive margin basins with evidence for past intrusive and extrusive igneous activity, constraining the distribution, timing and pathways of magmatism in these basins is essential to reduce exploration risk. Producing and prospective Australian passive margin basins where igneous systems have been identified include the Bight, Otway, Bass, Gippsland and Sorell basins of the southern margin. This paper reviews both the impacts of volcanic activity on sedimentary basin hydrocarbon prospectivity (e.g. advective heating, reservoir compartmentalisation and diagenesis), and the styles, distribution and timing of late Cretaceous–Recent extrusive and intrusive igneous activity along basins of the southern Australian margin, providing illustrative examples based on 2D and 3D seismic reflection data.

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Bell, C. M., et M. Suarez. « The depositional environments and tectonic development of a Mesozoic intra-arc basin, Atacama Region, Chile ». Geological Magazine 130, n^o 4 (juillet 1993) : 417–30. http://dx.doi.org/10.1017/s0016756800020501.

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AbstractA thick succession of continental redbeds was deposited in a 50 km wide intra-arc basin on the Andean active continental margin in the Atacama region of northern Chile during early Cretaceous times. Upper Jurassic to early Cretaceous marine limestones were buried by the seaward progradation of a succession of coastal dunes, saline lakes and sandflats. Aeolian dune fields migrating towards the east across these coastal plains became stabilized by the growth of vegetation. Interdune alluvial areas between the sand dunes and dune fields developed into extensive alluvial braid plains which were in turn superimposed by alluvial fans. These fans were inundated by a regionally extensive saline lake produced by tectonic or volcanic damming of the sedimentary basin. This lake dried up leaving a large area of playa-lake mudflats. The climate was warm and semi-arid with a low and seasonal rainfall. Parts of the area supported a substantial vegetation of woody plants, together with a vertebrate fauna of dinosaurs, pterosaurs and crocodiles. The continental redbeds were derived from a volcanic source and were deposited on continental crust in a deep but narrow, north-south elongated, fault-bounded graben. This extensional basin formed in an intra-arc setting within an active andesitic volcanic chain. Upwards-coarsening sedimentary successions were the product of uplift of the fault-bounded margins of the basin.

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Hoang, Tien Dinh, et Luan Thi Bui. « The mechanism of formation, development and deformation of sedimentary basins in Viet Nam continental shelf ». Science and Technology Development Journal - Natural Sciences 1, T5 (29 novembre 2018) : 278–89. http://dx.doi.org/10.32508/stdjns.v1it5.561.

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The sedimentary basins in area of Việt Nam continental shelf are located along the deep fault systems between the folded Indochinese block and Việt Băc-Hoa Nam platform and with the transitional zone. Is means that the zone attenuated continental crust. Due to that extruction of the Indochinese block toward the SoustEast which wrenched in right, in addition, due to the appearance of the thermal anomaly, producing the activity of Bien Dong seafloor spreading axis and drift of Australian–New Guinea plate toward Nord-East, induced some geodinamic factors to form many sedimentary basins in margins of Biển Dong Sea, such as: rift, pressure, extension, vertical slide cliff, horizontal displacement and wrench. These geodinamic factors created favourable conditions to form, develop and deform the sedimentary basins in Việt Nam continental shelf, followed the pull- apart type mechanism. But each sedimentary basin had its type of mechanism which depended on the concrete place of its basin from the Indochinese block and the thermal anomaly in Bien Dong Sea. Beside, itsformed condition for gas hydrate accumulations in some basins.

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Motoki, Akihisa, Luiz Carlos Chaves Novais, Kenji Freire Motoki, Leonardo Costa de Oliveira, Ricardo De Souza Fasolo et Adrienne Brito Lima. « SATELLITE-DERIVED GRAVIMETRY FOR ABROLHOS CONTINENTAL SHELF, STATES OF ESPÍRITO SANTO AND BAHIA, BRAZIL, AND ITS RELATION TO TECTONIC GENESIS OF SEDIMENTARY BASINS ». Revista Brasileira de Geofísica 32, n^o 4 (1 décembre 2014) : 735. http://dx.doi.org/10.22564/rbgf.v32i4.554.

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ABSTRACT. This paper presents the results of satellite-derived gravimetry for Abrolhos Continental Shelf and the adjacent areas, States of Esp´ırito Santo and Bahia,Brazil, and discusses tectonic genesis of the sedimentary basins. The free-air and Bouguer anomalies on the continental shelf show a gradual increase from coast tocontinental shelf break. The total difference of 135 mGal indicates crust thinning of 4.5 km. The Bouguer anomaly increases beyond the shelf break and continues upto the abyssal plane. The total difference of 260 mGal suggests crustal thinning of 9.0 km. The studied area has two types of passive continental margin: 1) ES-typewith high continental slope, low and narrow continental rise, and high free-air and Bouguer anomalies; 2) SP-type with low continental slope, high and wide continentalrise, and low gravity anomalies. There are three types of sedimentary basins with different geologic structure and tectonic genesis: 1) Basins on the continental shelf,CSH-type; 2) Basin on the continental rise, CRS-type; 3) Continental rift basin, CRF-type. The CSH-type, as Esp´ırito Santo basin, has coherent free-air and Bougueranomalies 40 to 50 mGal lower than the adjacent areas. The sedimentary deposits are 2.0 to 2.5 km thick. The basement depression is sustained by mechanical strengthwithout isostatic compensation. The normal faults of basin border are limited within upper crust. The CRS-type, as Pedro Can´ario basin, has low local residual Bougueranomaly with difference of 40 mGal. The sedimentary deposits are more than 2.7 km thick. The continental side basin border is under isostatic compensation due todeep normal fault between continental slope and continental rise. The oceanic side border is sustained by mechanical strength of the basement. The CRF-type, BesnardPassage, is a continental rift basin originated from mantle pull-apart tectonism. The rift bottom is under complete isostatic compensation. The normal faults of the grabenborder continue to the mantle. The Moho depth along the rift is at least 6.5 km shallower than the adjacent areas.Keywords: satellite-derived gravimetry, Abrolhos Continental Shelf, sedimentary basin, crustal thinning, isostatic compensation. RESUMO. Este artigo apresenta os resultados da gravimetria por satélite para a Plataforma Continental de Abrolhos e as áreas adjacentes, ES-BA, e discute as gêneses tectônicas das bacias sedimentares. As anomalias ar-livre e Bouguer na plataforma continental mostram um aumento gradativo a partir da costa até a quebra da plataforma continental. A diferença total de 135mGal indica afinamento da crosta continental de 4,5 km. A anomalia Bouguer se apresenta além da quebra da plataformae continua até o assoalho abissal. A diferença total de 260 mGal sugere afinamento crustal de 9,0 km. Na área estudada, observam-se dois tipos de margem continental passiva: 1) Tipo ES com talude continental alto, elevação continental baixa e curta e anomalias ar-livre e Bouguer altos; 2) Tipo SP com talude continental baixo, elevação continental alta e extensa e anomalias gravimétricas baixas. Existem três tipos de bacias sedimentares com estrutura geológica e gênesis tectônicas diferentes: 1) Bacias na plataforma continental, Tipo CSH; 2) Bacias na elevação continental, Tipo CRS; 3) Bacia de rifte continental, Tipo CRF. O Tipo CSH, como a bacia do Espírito Santo, possui anomalias ar-livre e Bouguer coerentes 40 a 50 mGal mais baixas do que as áreas adjacentes. Os depósitos sedimentares são de 2,0 a 2,5 km de espessura. A depressão do embasamento é sustentada pela rigidez mecânica sem compensação isostática. As falhas normais das bordas de bacias são limitadas dentro da crosta superior. O Tipo CRS, como a bacia Pedro Canário, tem baixa anomalia Bouguer local com diferença de 40 mGal. Os depósitos sedimentares têm mais de 2,7 km de espessura. A borda da bacia do lado continental está sob compensação isostática devido à falha normal profunda entre talude continental e elevação continental. Aborda do lado oceânico é sustentada pela rigidez mecânica do embasamento. O Tipo CRF, Passagem Besnard, é uma bacia do rifte continental originada do tectonis mode distensão do manto. O fundo da bacia está sob compensação isostática completa. As falhas normais da borda do graben continuam até o manto. A profundidade da Moho ao longo do rifte é pelo menos 6,5 km mais rasa do que as áreas adjacentes.Palavras-chave: gravimetria por satélite, Plataforma Continental de Abrolhos, bacia sedimentar, afinamento crustal, compensação isostática.

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Zabanbark, A., et L. I. Lobkovsky. « Geology and prospects of oil and gas bearing of east — Canadian continental margins ». Океанология 59, n^o 4 (17 septembre 2019) : 656–69. http://dx.doi.org/10.31857/s0030-1574594656-669.

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At the limit of the East-Canadian continental margin there are three oil and gas regions from north to south: Labrador Sea shelves, margins of the Great Newfoundland Bank and the continental margin of Nova Scotia. In each of these distinguishing regions are a number of sedimentary basins completely plunging under the water. At the shelf of Labrador Sea distinguishing the following large sedimentary basins: Saglek, Hopdale and Havke, at the margin of Newfoundland Bank it is known the basins: Jeanne d’Arc, Flemish Pass and Orphan. At the Nova Scotia shelf there are Nova Scotian and Sable basins. It is remarkable at the lofty latitude like of Labrador Sea region the age of the productive sediments beginning from more ancient rocks (Paleozoic), than in basins situated in law latitude (Mesozoic). In consequence of this the stratigraphy diapason of oil and gas bearing of the north latitude is considerably wide. The prospect of oil and gas bearing in all region is related principally with continental slopes and turbidites sediments in its. Late Jurassic and early Cretaceous reservoirs would be the aim for deep drilling sediments. Wide distribution of late Cretaceous and early Tertiary prospects reservoirs of oil and gas is quite really so far as they are bedded in the shallow horizons. Also the prospect of oil and gas bearing at the margin of the basin is related to late Cretaceous and Tertiary sediments, to deposits of fan and diapirs salt.

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Zhong, Guang Jian, Da Meng Liu et Guang Hong Tu. « Petroleum Exploration Potential of Xisha Trough Basin in SCS ». Advanced Materials Research 734-737 (août 2013) : 1230–34. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.1230.

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Nowadays oil-gas exploration make a great contribution to the world oil-gas reserve increase. A series of deepwater passive continental margin basins are found in Northern Continental Slope of South China Sea. These basins consisted of thick Mesozoic and Cenozoic sedimentary strata with the characteristics of the major world deepwater oil-gas basins. As one of Cenozoic sedimentary basins in deepwater area of Northern Slope of South China Sea, Xisha Trough Basin developed 1500-8000m thick sedimentary strata, which are north-south zoning characteristics of thicker in the center and thinner both in the north and south sides of basin. In its evolutionary history there are two stages: One is Paleocene-Oligocene Rift with Continental River-Lake Facies sedimentary and the other is Miocene-Quaternary Depression with shallow sea-hemiplegic sedimentary. It has good petroleum geological conditions that source rocks consist of lacustrine mudstones, paralic mudstone, and marine mudstone, Tertiary high porosity and permeability deepwater fan reservoirs are the main reservoir, and structural traps and lithologic traps developed. In a word, it has good oil-gas exploration potential.

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He, Song, Hong Cheng, Shuangqing Li, Cong Cao, Jun He et Fukun Chen. « Spatio-Temporal Evolution of the Crustal Uplift in Eastern NE China : Constraint from Detrital Zircon Ages of Late Mesozoic Clastic Rocks in the Boli Basin ». Minerals 12, n^o 9 (15 septembre 2022) : 1166. http://dx.doi.org/10.3390/min12091166.

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Detrital zircon of clastic rocks has been widely recognized as a powerful tool for the study of crustal uplift, which is of great significance for understanding multi-sphere interaction. However, young detrital zircons can only roughly constrain the depositional time of the strata, and commonly used zircon age probability density and kernel density estimations cannot provide sufficient evidence to reveal spatio-temporal differences in tectonic uplift. The basins developed in active continental margins usually contain abundant magmatic rocks, which can provide insights into basin evolution and crustal deformation when combined with sedimentary characteristics. In this study, we report detrital zircon ages of Late Mesozoic clastic rocks from the Boli Basin, being part of the Great Sanjiang Basin Group in eastern NE China, which is strongly affected by the Paleo-Pacific subduction. In conjunction with the age data of coeval magmatic rocks and potential sedimentary sources of basement rocks adjacent to the basin, the geochronologic results of this study provide solid evidence for the formation of the Boli Basin and the spatio-temporal evolution of the crustal uplift in northeastern China. The Boli Basin went through multi-phase tectonic evolution of syn-rift and post-rift stages, based on the zircon age data of clastic and igneous rocks. When the geographical distribution characteristics of potential sedimentary sources and their percentages of contribution are taken into account, two stages of eastward migration of the crustal uplift and two episodes of basin destruction caused by the tectonic extension and subsequent compression can be proposed for the Boli Basin. These processes were caused successively by the rolling back of the subducted Paleo-Pacific slab, the docking of the Okhotomorsk block along the eastern continental margin of East Asia, and the transition of the subduction zone by the collision of the Okhotomorsk block.

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Honegger, Belén Viera, Ethel Morales, Matias Soto et Bruno Conti. « SEISMIC STRATIGRAPHY OF THE EOCENE–LOWER OLIGOCENE IN THE URUGUAYAN CONTINENTAL MARGIN / ESTRATIGRAFIA SÍSMICA DO EOCENO AO OLIGOCENO INFERIOR NA MARGEM CONTINENTAL URUGUAIA ». Journal of Sedimentary Environments 3, n^o 4 (31 décembre 2018) : 290–306. http://dx.doi.org/10.12957/jse.2018.39248.

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The Uruguayan continental margin was generated following the fragmentation of the Gondwana supercontinent and the subsequent opening of South Atlantic Ocean. It constitutes an extensive sedimentation area in which three sedimentary basins can be found: the Punta del Este Basin, the southernmost portion of the Pelotas Basin, and the poorly defined Oriental del Plata Basin. The aim of this work was the identification and characterization of the different seismic units (seismic facies, systems tracts, depositional sequences) for the sedimentary interval assigned to the Eocene in the Uruguayan continental margin. Sequence stratigraphy was used as a basin analysis method for this purpose, using a database that consisted of approximately 10,000 kilometers of 2D seismic sections, acquired in exploratory surveys in 2007 and 2008. The workflow included the recognition of stacking patterns and/or stratal terminations, the definition of genetically significant stratigraphic surfaces and, based on these, the identification of systems tracts and depositional sequences. Three depositional sequences were identified in the studied sedimentary interval. The basal sequence is composed of four depositional systems tracts, including falling stage, normal regression (lowstand and highstand) and transgressive deposits. The intermediate sequence only preserves lowstand normal regression deposits. The third sequence is composed by three depositional systems tracts, including lowstand, transgressive and falling stage deposits. ResumoA margem continental uruguaia foi gerada após a fragmentação do supercontinente Gondwana e a subsequente abertura do Oceano Atlântico Sul. Constitui uma extensa área de sedimentação em três bacias sedimentares: a bacia de Punta del Este, a porção mais ao sul da Bacia de Pelotas e a Bacia Oriental del Plata, pouco definida. O objetivo deste trabalho foi a identificação e caracterização das diferentes unidades sísmicas (fácies sísmicas, tratos de sistemas, seqüências deposicionais) para o intervalo sedimentar atribuído ao Eoceno na margem continental uruguaia. Com este objetivo, utilizou-se a estratigrafia de seqüencias como método de análise de bacias, tendo-se utilizado um banco de dados constituído por aproximadamente 10.000 km de seções sísmicas 2D, adquiridas em pesquisas exploratórias em 2007 e 2008. O trabalho incluiu o reconhecimento de padrões de empilhamento e/ou terminações estratais, a definição de superfícies estratigráficas geneticamente significativas, tendo-se efetuado com base nelas, a identificação de tratos de sistemas e seqüências deposicionais. Três seqüências deposicionais foram identificadas no intervalo sedimentar estudado. A seqüência basal é composta por quatro tratos de sistemas deposicionais, incluindo a fase de abaixamento do nível do mar, a regressão normal e depósitos transgressivos. A sequência intermediária apenas preserva os depósitos de regressão normais de nível de mar baixo. A terceira seqüência é composta por três tratos de sistemas deposicionais, incluindo depósitos de nível de mar baixo, transgressivos e de abaixamento do nível do mar.

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Zhang, Jinyu, Zoltán Sylvester et Jacob Covault. « How do basin margins record long-term tectonic and climatic changes ? » Geology 48, n^o 9 (29 mai 2020) : 893–97. http://dx.doi.org/10.1130/g47498.1.

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Abstract A long-standing goal of sedimentary geoscience is to understand how tectonic and climatic changes are reflected in basin fill. Here, we use 14 numerical models of continental-scale sediment-routing systems spanning millions of years to investigate the responses of sediment supply and basin sedimentation to changes in uplift and precipitation in the source area. We also investigate the extent to which these signals can be altered by relative sea level (the sum of subsidence and eustasy). In cases of constant relative sea level, sediment supply and margin progradation have similar responses because nearly all of the sediment is transported beyond the coastal plain and continental shelf to the basin margin. Thus, margin progradation can be used as a proxy for sediment supply. However, changes in uplift and precipitation result in different erosional patterns in the source area and different basin-margin depositional patterns. Changes in uplift result in gradual (over several million years) adjustment to new steady states of source-area erosion and margin progradation, whereas changes in precipitation result in abrupt changes in erosion and progradation followed by a return to the initial steady states. In cases of changing relative sea level, sediment storage on the shelf attenuates signals of uplift, but signals of precipitation change can be interpreted in the basin-margin record because climate-induced sediment supply changes are large enough to influence margin progradation. Understanding the relationship between sediment supply and basin-margin progradation, and their linked responses to forcings, improves our ability to interpret signals of environmental change in the stratigraphic record.

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Larsen, Michael, Christian Knudsen, Dirk Frei, Martina Frei, Thomas Rasmussen et Andrew G. Whitham. « East Greenland and Faroe–Shetland sediment provenance and Palaeogene sand dispersal systems ». Geological Survey of Denmark and Greenland (GEUS) Bulletin 10 (29 novembre 2006) : 29–32. http://dx.doi.org/10.34194/geusb.v10.4899.

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The sedimentation and basin evolution of the Kangerlussuaq Basin, southern East Greenland has gained renewed interest with the licensing rounds offshore the Faroe Islands in 2000 and 2005, as it forms an important analogy to the Faroese geological setting. The Faroes frontier area is in part covered by basalts and is a high-risk area with poorly known plays and sedimentary basins. It is therefore essential to obtain as much information as possible on the evolution of sedimentary basins on the rifted volcanic margins closest to the Faroese Islands margin. Plate reconstructions of the North Atlantic region indicate the former close proximity of East Greenland to the Faroe Islands region (Fig. 1), and the Kangerlussuaq Basin thus constitutes the most important field analogue with respect to stratigraphy, major unconformities and basin evolution. The study of the sedimentary succession in the Kangerlussuaq Basin, and the provenance of the sandstones in particular, will provide constraints on exploration models and may help to predict the distribution of potential reservoir sandstones in the Faroese offshore basins, and eventually lead to development of play types that are new to this frontier region.This paper presents the main conclusions from two research projects: Stratigraphy of the pre-basaltic sedimentary succession of the Kangerlussuaq Basin -Volcanic basin of the North Atlantic and An innovative sedimentary provenance analysis, jointly undertaken by the Geological Survey of Denmark and Greenland (GEUS) and CASP (formerly Cambridge Arctic Shelf Programme). Both projects were initiated in October 2002 and concluded in September 2005. They form part of Future Exploration Issues Programme of the Faroese Continental Shelf (SINDRI programme), established by the Faroese Ministry of Petroleum and financed by the partners of the Sindri Group (see Acknowledgements).

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Fekkak, Abdelilah, André Pouclet et Lakhlifi Badra. « The Pre-Pan-African rifting of Saghro (Anti-Atlas, Morocco) : example of the middle Neoproterozoic Basin of Boumalne ». Bulletin de la Société Géologique de France 173, n^o 1 (1 janvier 2002) : 25–35. http://dx.doi.org/10.2113/173.1.25.

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Abstract In the Anti-Atlas, the Boumalne basin includes 3,000 m of Middle Neoproterozoic sediments. It consists of turbiditic deposits folded during the major Pan-African event ca 685 Ma. A syn-sedimentary basaltic pile of lava flows is interbedded in the upper part of the lower formation. These lavas show an initial rift tholeiite (IRT) chemical signature. Petrographical analysis of sediments and typology of detrital zircons indicate a continental margin sedimentation, without any volcano-sedimentary supply from a close volcanic arc. It is concluded that the Boumalne Basin formed in a continental passive margin evolving from an intracontinental rift. This interpretation differs clearly from that of a back-arc basin which is commonly accepted. Hence, the opening of this basin is related to the pre-Pan-African Saghro rift synchronous to the Central Anti-Atlas oceanization, and not to the demise of this oceanic domain along an active margin.

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Tang, Xin, Yuanchen Guo, Tingqiang Zhou et Sen Guo. « Distribution Characteristics of Nanopores and Discriminant Characteristics of Sedimentary Environment of the Longmaxi Formation in the Southern Sichuan Basin ». Journal of Nanoscience and Nanotechnology 21, n^o 1 (1 janvier 2021) : 431–37. http://dx.doi.org/10.1166/jnn.2021.18741.

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Shale contains a large number of nanopores. The nanopores control the reservoir structure. The formation of nanopores in shale is closely related to the sedimentary environment. The palaeosedimentary structural background determines the provenance and sedimentary diagenesis of mud shale during shale deposition, refines the palaeo-shale and palaeo-sedimentary-tectonic environments of the Longmaxi Formation in the southern Sichuan Basin by elemental geochemical means, and determines the palaeo-deposition of the Longmaxi Formation. The tectonic setting and a numerical simulation method are used to explore the sedimentary tectonic evolution characteristics of the Longmaxi Formation. The results show that the parent rock of the Longmaxi Formation is relatively enriched with light rare earth elements, and the distribution of heavy rare earth elements is relatively stable. The vertical direction shows a trend of increasing from the bottom of the formation to the top of the formation, showing a mixed genesis; the tectonic setting is a passive continental margin, and the active continental margin is the main margin.

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Carrera, Marcelo G., et Colin D. Sumrall. « Ordovician sponges from the Lenoir Limestone, Tennessee : new evidence for a differential sponge distribution along the margins of Laurentia ». Journal of Paleontology 94, n^o 1 (13 septembre 2019) : 34–44. http://dx.doi.org/10.1017/jpa.2019.67.

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AbstractFive genera of anthaspidellid and streptosollenid demosponges are described from the Ordovician Lenoir Limestone near Lenoir City, Loudon County, Tennessee, USA including: Rhopalocoelia regularis Raymond and Okulitch, Rugocoelia loudonensis n. sp., Psarodictyum sp. (Anthaspidellidae), Allosacus pedunculatus n. sp., and Zitelella varians Raymond and Okulitch (Streptosolenidae). These findings confirm the major paleobiogeographic picture for Laurentian sponges (i.e., the differential distribution of sponge faunas along both North American margins), because none of these eastern margin species has been reported from western margin faunas. Only one genus typical of the Great Basin fauna, Rugocoelia Johns, 1994, is reported from Tennessee, but as a new species. Possible explanations are discussed for this differential distribution, mainly related to climatic constraints or sedimentary differences, preventing the free distribution of sponge species between Laurentian continental margins.UUID: http://zoobank.org/2b990a4c-7bc8-4eb6-b8a9-fe4ecf7bdbf9

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Kessler, Franz L., John Jong et Mazlan Madon. « The Sedimentary Record of Paleogene Sequences in Sarawak, Malaysia ». Berita Sedimentologi 47, n^o 1 (15 août 2021) : 33–56. http://dx.doi.org/10.51835/bsed.2021.47.1.52.

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In this paper, we compare the oldest Tertiary sedimentary sequences in the south ern margin of the South China Sea based on outcrop and well data along the Sarawak margin, northern Borneo. Paleogene rocks in Sarawak are present in three tectono stratigraphic zones and represent three depositional settings. Outcrops and deep exploration wells in the Miri Zone indicate shelfal clastics, carbonates, and clay dominated neritic sediments. In the Sibu Zone (Rajang Fold Thrust Belt), Late Cretaceous to Late Eocene deep marine clastic sediments indicate a shallowing upward of the depositional basin, which was later buried to great depths (?) and metamorphosed. In the Kuching Zone, the Kayan and Plat eau sandstones represent a fluvial dominated non marine depositional setting. There are two major unconformities within the Paleogene of Sarawak: the Rajang Unconformity, dated as approximatively 37 Ma, and the younger near Top Eocene (a.k.a. Base Oligocen e) unconformity of 33.7 Ma. The likely presence of Eocene strata in the margins of Sundaland is associated with an early phase of regional extensional tectonism, which was also observed in the Penyu and Malay basins, offshore Peninsular Malaysia, and is probably related to the onset of rifting of the South China Sea continental crust.

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Zhukov, N. N., A. M. Nikishin, E. I. Petrov et S. I. Freiman. « Rift systems of the East Siberian continental margin ». Moscow University Bulletin. Series 4. Geology, n^o 5 (28 octobre 2020) : 3–16. http://dx.doi.org/10.33623/0579-9406-2020-5-3-16.

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This paper presents an analysis of the structure and geological history of the shelf of the East Siberian continental margin, based on the interpretation of seismic data in conjunction with geological information. The article describes the main structural elements of the East Siberian Sea which formed as a result of rifting processes (barremian–aptian) — the Novosibirsky, the Mansky, North Melvillsky and Dremheadsky rifts in the northern part of the East Siberian basin, and the Mellvillsky rift in the southern part. Rifts are considered together with volcanic zones and the main relative elevations — De-Long, Wrangel, Kotelnichesky and Baranovsky elevations. It is assumed that the process of rifting thinned out the crust of the Podvodnikov basin. The sedimentary basin was formed by rifting.

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Shipilov, E. V., L. I. Lobkovsky et T. A. Kirillova. « On tectonic-geodynamic relationships of the Eurasian basin and the Lomonosov Ridge with the continental margin of Siberia according to new seismic data ». Arctic : Ecology and Economy, n^o 4(40) (décembre 2020) : 34–42. http://dx.doi.org/10.25283/2223-4594-2020-4-34-42.

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Basing on the results of the interpretation of new seismic materials, the authors consider the structural features of the southern segments of the Eurasian Basin and the Lomonosov Ridge in the zone of junction with the continental margin of Siberia (the Laptev and East Siberian Seas). Interpretative analysis of the materials shows that the base of the sedimentary cover of the southern segment of the Eurasian Basin, where there are no regular linear magnetic anomalies, is predominantly represented by strongly stretched blocks of the continental basement. The formation the axial zone of spreading of the Gakkel Ridge here took place according to a three-stage development scheme: rifting in the Aptian-Alba and its telescoping development in the Late Cretaceous — Paleocene-Eocene, inherited valley formation in late neotectonic time. The development of the Severny Basin located in the zone of junction of the Lomonosov Ridge with the continental margin is similar to the scenario for the formation of pull-apart basins. Its formation was interconnected with the simultaneously opening adjacent extreme southeastern segment of the Amundsen Basin of the Eurasian Basin.

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Bai, Yongliang, Simon E. Williams, R. Dietmar Müller, Zhan Liu et Maral Hosseinpour. « Mapping crustal thickness using marine gravity data : Methods and uncertainties ». GEOPHYSICS 79, n^o 2 (1 mars 2014) : G27—G36. http://dx.doi.org/10.1190/geo2013-0270.1.

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Crustal thickness is a critical parameter for understanding the processes of continental rifting and breakup and the evolution of petroleum systems within passive margins. However, direct measurements of crustal thickness are sparse and expensive, highlighting the need for methodologies using gravity anomaly data, jointly with other geophysical data, to estimate crustal thickness. We evaluated alternative gravity inversion methodologies to map crustal thickness variations at rifted continental margins and adjacent oceanic basins, and we tested our methodology in the South China Sea (SCS). Different strategies were investigated to estimate and remove the gravity effect of density variations of sediments and the temperature and pressure variations of the lithospheric mantle from the observed free air gravity anomaly data. Sediment density was calculated using a relationship between sediment thickness, porosity, and density. We found that this method is essential for crustal thickness inversion in the presence of a thick sedimentary cover by comparing the Moho depths obtained from gravity inversion and seismic interpretation in the Yinggehai Basin where sediments are up to 13 km thick; the inversion accuracy depended on the parameters of the exponential equation between porosity and the buried depth. We modeled the lithospheric mantle temperature field based on oceanic crustal age, continental crustal stretching factors, and other boundary conditions. We tested three different methods to calculate the thermal expansion coefficient, which is either held constant or is a linear/polynomial function of temperature, for applying a thermal correction and found that the inversion results were relatively insensitive to alternative methods. We compared inversion results with two recent deep seismic profiles that image the rifted continental edge at the northern margin of the SCS and the continental Liyue Bank (Reed Bank) at the southern margin, and we found that the inversion accuracy was improved considerably by removing sediment, thermal, and pressure gravity effects.

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Andrieu, Simon, Nicolas Saspiturry, Marine Lartigau, Benoit Issautier, Paul Angrand et Eric Lasseur. « Large-scale vertical movements in Cenomanian to Santonian carbonate platform in Iberia : indicators of a Coniacian pre-orogenic compressive stress ». BSGF - Earth Sciences Bulletin 192 (2021) : 19. http://dx.doi.org/10.1051/bsgf/2021011.

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The Cenomanian to early Santonian interval is usually considered a time of postrifting tectonic quiescence around the northern margins of Iberia that preceded the onset of the Pyrenean convergence by crustal thrusting in the latest Santonian. However, plate kinematic models of the Mesozoic evolution of Iberia poorly constrain the Turonian-Santonian position of Iberia relative to Eurasia. This study reconstructs changes in the sedimentary facies and architecture of the Iberian carbonate platform throughout the Late Cretaceous and sheds new light on the geodynamic evolution of the Iberia-Eurasia relationship at that time. Sixteen outcrop sections were described and 24 sedimentary facies identified that define 5 depositional environments ranging from the deep marine basin to the continental setting. From these and previously published field data we reconstruct the evolution of the Pyrenean carbonate platform, on an east-west transect nearly 400 km long, on the basis of 11 short-term depositional sequences and 5 long-term hemicycles. In our interpretation, the Cenomanian and Turonian correspond to a postrift stage during which the European and Iberian margins, together with the deep basin between them, subside gently, as shown by accommodation rates varying from ∼15 to 30 m/My in the margins and ∼100 to 150 m/My in the basin. The Coniacian and early Santonian are characterized by a large-scale flexural response consisting of (1) uplift of the southern Iberian margin, with negative accommodation rates, karstified surfaces and paleosols, and (2) increasing subsidence rates in the basin and its edges (the northern Iberian margin and eastern Aquitaine platform), with accommodation rates several times greater than during the Turonian. We propose that far-field stress possibly related to the northeastward motion of Africa, and/or onset of shortening at the Iberia-Europe boundary in the central and eastern Pyrenees led to the incipient large-scale flexural deformation in the Pyrenean domain. The late Santonian and Campanian are an early orogenic stage marked by rapid subsidence throughout the Pyrenean domain, except at its western end. We evidence for the first time a pre-orogenic flexure at the Iberia-Europe plate boundary induced by regional plate reorganisation between Africa and Europe during the Coniacian and the early Santonian.

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Khan, Majid, et Ahmed Abdelmaksoud. « Unfolding impacts of freaky tectonics on sedimentary sequences along passive margins : Pioneer findings from western Indian continental margin (Offshore Indus Basin) ». Marine and Petroleum Geology 119 (septembre 2020) : 104499. http://dx.doi.org/10.1016/j.marpetgeo.2020.104499.

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Gregersen, Ulrik, Paul C. Knutz, Henrik Nøhr-Hansen, Emma Sheldon et John R. Hopper. « Tectonostratigraphy and evolution of the West Greenland continental margin ». Bulletin of the Geological Society of Denmark 67 (27 juillet 2020) : 1–21. http://dx.doi.org/10.37570/bgsd-2019-67-01.

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Large structural highs and sedimentary basins are identified from mapping of the West Greenland continental margin from the Labrador Sea to the Baffin Bay. We present a new tectonic elements map and a map of thickness from the seabed to the basement of the entire West Greenland margin. In addition, a new stratigraphic scheme of the main lithologies and tectonostratigraphy based on ties to all offshore exploration wells is presented together with seven interpreted seismic sections. The work is based on interpretation of more than 135 000 km of 2D seismic reflection data supported by other geophysical data, including gravity- and magnetic data and selected 3D seismic data, and is constrained by correlation to wells and seabed samples. Eight seismic mega-units (A–H) from the seabed to the basement, related to distinct tectonostratigraphic phases, were mapped. The oldest units include pre-rift basins that contain Proterozoic and Palaeozoic successions. Cretaceous syn-rift phases are characterised by development of large extensional fault blocks and basins with wedge-shaped units. The basin strata include Cretaceous and Palaeogene claystones, sandstones and conglomerates. During the latest Cretaceous, Paleocene and Eocene, crustal extension followed by oceanic crust formation took place, causing separation of the continental margins of Greenland and Canada with north-east to northward movement of Greenland. From Paleocene to Eocene, volcanic rocks dominated the central West Greenland continental margin and covered the Cretaceous basins. Development of the oceanic crust is associated with compressional tectonics and the development of strike-slip and thrust faults, pull-apart basins and inversion structures, most pronounced in the Davis Strait and Baffin Bay regions. During the late Cenozoic, tectonism diminished, though some intra-plate vertical adjustments occurred. The latest basin development was characterised by formation of thick Neogene to Quaternary marine successions including contourite drifts and glacial related shelf progradation towards the west and south-west.

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Martini, Ivan, Elisa Ambrosetti, Andrea Brogi, Mauro Aldinucci, Frank Zwaan et Fabio Sandrelli. « Polyphase extensional basins : interplay between tectonics and sedimentation in the Neogene Siena-Radicofani Basin (Northern Apennines, Italy) ». International Journal of Earth Sciences 110, n^o 5 (28 avril 2021) : 1729–51. http://dx.doi.org/10.1007/s00531-021-02038-4.

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AbstractRift-basins are the shallow effects of lithosphere-scale extensional processes often producing polyphase faulting. Their sedimentary evolution depends on the mutual interplay between tectonics, climate, and eustasy. Estimating the role of each factor is generally a challenging issue. This paper is focused on the tectono-sedimentary evolution of the Neogene Siena-Radicofani Basin, a polyphase structural depression located in the inner Northern Apennines. Since Miocene, this basin developed after prolonged extensional tectonics, first as a bowl-shaped structural depression, later reorganized into a half-graben structure due to the activation of high-angle normal faults in the Zanclean. At that time the basin contained coeval continental and marine settings controlled by the normal faulting that caused the development of local coarse-grained depositional systems. These were investigated to: (i) discriminate between the influences of tectonics and climate on sedimentation patterns, and (ii) provide detailed time constraints on fault activity. The analysed successions were deposited in an interval between 5.08 and 4.52 Ma, when a climate-induced highstand phase occurred throughout the Mediterranean. However, evidence of local relative sea-level drops is registered in the sedimentary record, often associated with increased accommodation space and sediment supply. Such base-level fluctuations are not connected to climate changes, suggesting that the faults generally control sedimentation along the basin margins.

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Radkovets, Natalia, et Yuriy Koltun. « GEODYNAMICS ». GEODYNAMICS 1(32)2022, n^o 1(32) (28 juin 2022) : 36–48. http://dx.doi.org/10.23939/jgd2022.02.036.

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Purpose. The objective of this study is the investigation of the Silurian-Lower Devonian (Lochkovian) carbonate-clay sedimentary complex of the southwestern slope of the East-European platform. Its formation was the result of a single cycle of geodynamic and sedimentary events in the lithological record of the southern continental margin of Baltica. Methodology. The study is based on well-logs correlation, lithological and geochemical investigations of core samples, and petrographic thin sections analysis. The obtained results were used to establish patterns of changes in the material composition of the studied strata in time and space in order to determine the basin development dynamics of the continental margin of the Eastern European platform southwestern slope in the Silurian-Early Devonian. Results. It is established that the formation of the carbonate-clay sequence represents a single sedimentary cycle and was the result of a complex of geodynamic, depositional and paleoclimatic events that took place on the Baltica southern continental margin. The Silurian period was characterized by intensive development of benthic organisms and reef structure formation in the proximal part of the basin and clay-carbonate muds enriched with dispersed organic matter in its distal part. In the Early Devonian, carbonate biogenic sedimentation continued throughout the basin. The carbonate maximum content (80–98%) proves the existence of the reef constructions in the basin sedimentary record. Lower values of carbonate content are characteristic of marls (40–55%) and biodetritic limestones (56–75%), which make up the main part of the Silurian sequence. There are no reef constructions in the section of the Lochkovian stage of Devonian, and the calcium carbonate content in the rocks varies from 45 to 83%. The content of CaCO3 in mudstones and calcareous mudstones of the Silurian varies from 5 to 15%. Originality. The applied complex of lithological, geochemical, geological-geophysical and paleogeographic investigations allowed studying the sedimentary basin dynamics in the Silurian-Early Devonian with the assessment of the possibility of participation of these strata in oil and gas hydrocarbons generation. Practical significance. The obtained results show that the carbonate-clay complex of sedimentary rocks of the Silurian and Lower Devonian (Lochkovian) of the studied region can be considered as a separate petroleum system, including source rocks, reservoir rocks and possible conventional and unconventional oil and gas accumulations.

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Magalhães, José Ricardo, José Antonio Barbosa, Jefferson Tavares C. Oliveira et Mário F. de Lima Filho. « CHARACTERIZATION OF THE OCEAN-CONTINENT TRANSITION IN THE PARAÍBA BASIN AND NATAL PLATFORM REGION, NE BRAZIL ». Revista Brasileira de Geofísica 32, n^o 3 (1 septembre 2014) : 481. http://dx.doi.org/10.22564/rbgf.v32i3.504.

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ABSTRACT. Several studies have tried to address the evolution of the Atlantic conjugate margins, including Brazil and West Africa. However, past researchadvances has been hindered by a lack of data for the marginal region in the eastern portion of northeastern Brazil, extending from the Pernambuco Shear Zone tothe Touros High. This situation has imposed serious limitations on the development of a regional view of the paleotectonic and paleogeographic evolution of the marginin this area and on correlations with regional counterparts in Africa. Here, we present an investigation using regional seismic and potential field data. The results showthat this region represents a basement high forming a narrow platform with a thin sedimentary cover (0.8-2.5 km) and an abrupt shelf break, which created a large bypasszone towards the slope. The analysis of a deep seismic section revealed that thinned continental crust (transitional crust) occupies a narrow zone and that the continentaloceanicboundary (COB) is located approximately 100 km to the east of the present coastline. Geophysical modeling integrated with interpretation of the seismic datasuggests that this region is characterized by an abrupt thinning of continental crust, with an accompanying sudden rise of the Moho. There are also indications for theexistence of a zone of extremely thinned continental crust, which was interpreted as proto-oceanic crust. Our findings suggest that the study area shows strong similaritiesto non-volcanic rifted margins.Keywords: Paraíba and Natal Platform Basins, continental-oceanic transition, northeastern Brazilian continental margin, Atlantic rift. RESUMO. Vários trabalhos têm tentado abordar a evolução das margens conjugadas do Atlântico, incluindo o nordeste do Brasil e o oeste da África. Entretanto,o avanço de pesquisas anteriores tem sido dificultado em razão da falta de dados na região marginal da porção oriental do nordeste do Brasil, a área entre a Zonade Cisalhamento de Pernambuco e o Alto de Touros. Este fato tem imposto limitações ao desenvolvimento de modelos regionais sobre a evolução paleotectônica e paleogeográfica desta região, assim como na correlação com sua contraparte na África. Aqui é apresentada uma investigação realizada com base em dados sísmicos e de métodos potenciais regionais. Os resultados mostraram que esta região representa um alto do embasamento que forma uma plataforma estreita com uma coberturasedimentar pouco espessa (0,8-2,5 km) e uma quebra abrupta da plataforma, o que criou uma grande zona de by pass através do talude. A análise de uma seçao sísmica profunda revelou que a crosta continental afinada (crosta transicional) representa uma estreita zona, e que o limite crosta continental-oceânica (COB) está localizadoa aproximadamente 100 km a leste da atual linha de costa. A modelagem geofísica, integrada com a interpretação sísmica, indica que esta região é caracterizada porum afinamento abrupto da crosta continental, com a consequente ascensão súbita da Moho. Também há evidências da existência de uma zona de crosta continental extremamente afinada, a qual foi interpretada como crosta proto-oceânica. Estes novos dados demonstram que esta área apresenta fortes similaridades com margens rifteadas não vulcânicas.Palavras-chave: bacias da Paraíba e da Plataforma de Natal, transição crosta continental-oceânica, margem continental do nordeste Brasileiro, rifte Atlântico.

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Hou, Pengfei, Lesli J. Wood et Zane R. Jobe. « Tectonic–sedimentary interplay of a confined deepwater system in a foreland basin setting : the Pennsylvanian lower Atoka Formation, Ouachita Mountains, U.S.A. » Journal of Sedimentary Research 91, n^o 7 (15 juillet 2021) : 683–709. http://dx.doi.org/10.2110/jsr.2020.064.

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ABSTRACT Submarine fans deposited in structurally complex settings record important information on basin evolution and tectonic–sedimentary relationships but are often poorly preserved in outcrops due to syndepositional and post depositional deformation. This study aims to understand the influence of tectonics on the deposition of the synorogenic Pennsylvanian lower Atoka submarine fan system deposited in a structurally complex foreland basin during the Ouachita orogeny. This study is a synthesis of new outcrop stratigraphic data as well as published stratigraphic and structural data. The lower Atoka crops out in the Ouachita Mountains and the southern Arkoma Basin and is divided into three structural–depositional zones: the foredeep, the wedge top, and the continental foreland. The mean paleoflow is axial, and each zone exhibits unique patterns in facies distribution. The foredeep consists of two fan systems, a large westward-prograding fan that exhibits significant longitudinal and lateral facies changes, and a small eastward-prograding fan on the western part. The wedge top consists of a westward-prograding fan that exhibits subtle longitudinal facies change. The continental foreland consists of small slope fan systems along the northern and western margins. By comparing to basin morphology and structural styles, we interpret the facies distribution patterns in the three zones as the result of different combinations of lateral structural confinement, axial and lateral sediment supply, and paleogeography. This study provides an improved and comprehensive understanding of the lower Atoka deepwater system and has implications for deciphering the tectonic–sedimentary relationships in laterally confined submarine fan systems.

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O'Brien, G. W., et D. T. Heggie. « HYDROCARBON GASES IN SEAFLOOR SEDIMENTS, OTWAY AND GIPPSLAND BASINS : IMPLICATIONS FOR PETROLEUM EXPLORATION ». APPEA Journal 29, n^o 1 (1989) : 96. http://dx.doi.org/10.1071/aj88014.

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During April- May 1988, the BMR research vessel Rig Seismic carried out a 21- day geochemical and sedimento- logical research program in the Otway (17 days) and Gippsland (4 days) Basins. The concentrations and molecular compositions of light hydrocarbon gases (C1- C4) were measured in sediments at 203 locations on the continental shelf and upper continental slope: the presence of thermogenic hydrocarbons was inferred from the molecular compositions of the gas mixtures. Thermogenic hydrocarbons were identified in near- surface sediments at 32 locations in the Otway Basin; 6 of these locations were on the Crayfish Platform, 7 were on the Mussel Platform and 17 were in the Voluta Trough. Thermogenic hydrocarbons were identified at 10 locations in the Gippsland Basin. Data from the Otway Basin indicated that total C1- C4 gas concentrations were higher in the Voluta Trough than on the basin margins, probably because intense faulting in the trough facilitates gas migration from deeply buried source rocks and/or reservoirs to the seafloor. However, anomalies were detected where the Tertiary sequence was thick and relatively unfaulted. The wet gas contents of the anomalies were highest on the basin margins, lower in the Voluta Trough and co- varied with the depth of burial of the basal Early Cretaceous sedimentary sequence. These data, when integrated with geohistory, thermal maturation modelling and well data, suggest that the areas with the best potential for liquid hydrocarbon entrapment and preservation are the Crayfish Platform and the inshore part of the Mussel Platform. In contrast, the Late Cretaceous Sherbrook Group and much of the Voluta Trough appear to be gas prone.Thermogenic anomalies in the Gippsland Basin were concentrated within and along the margins of the Central Deep where mature Latrobe Group source rocks are present. The wet gas content of these anomalies was variable, which is consistent with the spatial heterogeneity of hydrocarbon accumulations in the Gippsland Basin.

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Buslov, Mikhail M., et Anna V. Kulikova. « RELATIONSHIP OF THE FORMATION OF OROGENS AND SEDIMENTARY BASINS OF ASIA IN THE MESOZOIC-CENOZOIC ». Interexpo GEO-Siberia 2, n^o 1 (21 mai 2021) : 25–31. http://dx.doi.org/10.33764/2618-981x-2021-2-1-25-31.

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The stages of the formation of mountain systems (orogens) and sedimentary basins of Asia are highlighted and an analogy is given. The stages are manifested in the Jurassic, Cretaceous, and Cenozoic as a result of collisions to the southern active margin of the Asian continent, respectively, of the Quingtang, North China, and Indian continental blocks, which led to the formation of large intracontinental orogenic belts that are the source of sedimentary basin demolition.

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Papadopoulou, S., E. Aravadinou, C. Karavoulia et P. Xypolias. « THE TECTONOSTRATIGRAPHY OF CYCLADIC BLUESCHIST UNIT ON SIKINOS AND SIFNOS : IMPLICATION FOR THE MESOZOIC TECTONIC SETTING ». Bulletin of the Geological Society of Greece 50, n^o 1 (27 juillet 2017) : 114. http://dx.doi.org/10.12681/bgsg.11707.

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This study presents new results for the tectonostratigraphic configuration of the Cycladic Blueschist unit (CBU) in the islands of Sikinos and Sifnos. These results show that the observed tectonostratigraphy in CBU results from tectonic repetitions of a thinner sequence. Tectonic repetitions have been achieved by a series of largescale ductile thrusts that operated during burial and exhumation of CBU. Restoration of the tectonostratigraphy in both islands implies an original, pre-metamorphic sequence, which was made up by a volcano sedimentary complex at the base and an overlying carbonate-rich sedimentary succession. This Mesozoic protolithic sequence was possibly formed in a continental terrane or in a transitional domain between a continental terrane and an oceanic basin. We suggest that the Mesozoic protolith of the CBU was formed in an incipient oceanic basin rather than a mature ocean like Pindos Ocean. This incipient oceanic basin was developed either along south part or along the north margin of Pelagonian microcontinent.

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Zhang, Qian, Bin Zhang, Qian Yu, Yupeng Men, Haiquan Zhang, Jianwei Kang, Junfeng Cao, Ankun Zhao, Yexin Zhou et Xintao Feng. « Study on the Provenance and Tectonic Setting of Mudstone in the Lower Silurian Longmaxi Formation of the Yanyuan Basin on the Western Margin of the Yangtze Platform ». Minerals 13, n^o 2 (29 janvier 2023) : 194. http://dx.doi.org/10.3390/min13020194.

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This study investigates the provenance and tectonic background of the lower Silurian Longmaxi Formation black shale of the Yanyuan Basin in the western Kangdian ancient land and provides guidance for shale gas exploration and development in the area. The mineral petrological and geochemical characteristics of the Longmaxi Formation black shale in this area have been studied in detail. The study area is mainly a passive continental margin environment, but also has the attributes of an active continental margin and island arc environment due to the collision between the western oceanic crust and the Yangtze continental crust. The source rocks are mainly felsic igneous rocks, with a small contribution of intermediate–basic rocks. It is inferred that the Kangdian ancient land in the eastern part of the area could be the main provenance area, but with the contribution of sediments derived from oceanic island arc located in the west. During the whole Longmaxi period, the tectonic movement was intense, the climate was cold, the degree of chemical weathering was low, and it was a highly volatile geological sedimentary basin. Therefore, the highly siliceous organic-rich mudstone, which was different from the Sichuan Basin, was deposited.

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Sokolov, S. D., L. I. Lobkovsky, V. A. Vernikovsky, M. I. Tuchkova, N. O. Sorokhtin et M. V. Kononov. « Late Mesozoic–Cenozoic Tectonics and Geodynamics of the East Arctic Region ». Russian Geology and Geophysics 63, n^o 4 (1 avril 2022) : 324–41. http://dx.doi.org/10.2113/rgg20214435.

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Abstract Tectonic and geodynamic models of the formation of the Amerasian Basin are discussed. The Arctic margins of the Chukchi region and Northern Alaska have much in common in their Late Jurassic–Early Cretaceous tectonic evolution: (1) Both have a Neoproterozoic basement and a complexly deformed sedimentary cover, with the stage of Elsmere deformations recorded in their tectonic history; (2) the South Anyui and Angayucham ocean basins have a common geologic history from the beginning of formation in the late Paleozoic to the closure at the end of the Early Cretaceous, which allows us to consider them branches of the single Proto-Arctic Ocean, the northern margin of which was passive and the southern margin was active; (3) the dipping of the oceanic and, then, continental lithosphere took place in subduction zones southerly; (4) the collision of the passive and active margins of both basins occurred at the end of the Early Cretaceous and ended in Hauterivian–Barremian time; (5) the collision resulted in thrust–fold structures of northern vergence in the Chukchi fold belt and in the orogen of the Brooks Ridge. A subduction-convective geodynamic model of the formation of the Amerasian Basin is proposed, which is based on seismic-tomography data on the existence of a circulation of matter in the upper mantle beneath the Arctic and East Asia in a horizontally elongated convective cell with a length of several thousand kilometers. This circulation involves the subducted Pacific lithosphere, the material of which moves along the bottom of the upper mantle from the subduction zone toward the continent, forming the lower branch of the cell, and the closing upper branch of the cell forms a reverse flow of matter beneath the lithosphere toward the subduction zone, which is the driving force determining the surface kinematics of crustal blocks and the deformation of the lithosphere. The viscous dragging of the Amerasian lithosphere by the horizontal flow of the upper mantle matter toward the Pacific leads to the separation of the system of blocks of Alaska and the Chukchi region from the Canadian Arctic margin. The resulting scattered deformations can cause a different-scale thinning of the continental crust with the formation of a region of Central Arctic elevation and troughs or with a breakup of the continental crust with subsequent rifting and spreading in the Canadian Basin.

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Huang, Guangwen, Dehai Wu, Guangnan Huang, Wanwen Xue, Zhuang Min et Pengfei Fan. « Provenance of Jurassic Sediments from Yuqia Sandstone-Type Uranium Deposits in the Northern Margin of Qaidam Basin, China and Its Implications for Uranium Mineralization ». Minerals 12, n^o 1 (11 janvier 2022) : 82. http://dx.doi.org/10.3390/min12010082.

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The Yuqia uranium deposit is a newly discovered sandstone-type uranium deposit in the northern margin of the Qaidam Basin. Concerning the sources of sediment in the basin, most scholars have focused on the study of Cenozoic sediment sources in the northern part of the basin, rather than on the study of Jurassic provenance and its implications for uranium mineralization. In this paper, the Jurassic sandstones in the area were selected for petrography, petrogeochemistry and electron microprobe analysis (EPMA), and the significance of sedimentary provenance and uranium metallogeny were further discussed, based on the previous data of detrital zircon chronology. It is reported here for the first time that coffinite and pitchblende are the main contributors. Independent uranium minerals in the region mainly occur in strawberry pyrite, xenotime, and margins or of quartz. The rocks in the source area, Jurassic sandstones, were mainly formed under the tectonic setting of the active continental margin; however, the sediments are mainly derived from the Indosinian and Paleozoic granitoids exposed in the northern margin of the Qaidam Basin. The uranium-rich granites in the source area led to the preconcentration of uranium in the sandstone of the target layer, and the uranium was brought into the ore-bearing target layer through uranium-bearing oxygenated water. The reduction reaction occurred under the action of reducing matter, and finally, the U6+ was reduced to U4+ in the formation of coffinite and pitchblende.

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Løtveit, Ingrid F., Willy Fjeldskaar et Magnhild Sydnes. « Tilting and Flexural Stresses in Basins Due to Glaciations—An Example from the Barents Sea ». Geosciences 9, n^o 11 (11 novembre 2019) : 474. http://dx.doi.org/10.3390/geosciences9110474.

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Many of the Earth’s sedimentary basins are affected by glaciations. Repeated glaciations over millions of years may have had a significant effect on the physical conditions in sedimentary basins and on basin structuring. This paper presents some of the major effects that ice sheets might have on sedimentary basins, and includes examples of quantifications of their significance. Among the most important effects are movements of the solid Earth caused by glacial loading and unloading, and the related flexural stresses. The driving factor of these movements is isostasy. Most of the production licenses on the Norwegian Continental Shelf are located inside the margin of the former Last Glacial Maximum (LGM) ice sheet. Isostatic modeling shows that sedimentary basins near the former ice margin can be tilted as much as 3 m/km which might significantly alter pathways of hydrocarbon migration. In an example from the SW Barents Sea we show that flexural stresses related to the isostatic uplift after LGM deglaciation can produce stress changes large enough to result in increased fracture-related permeability in the sedimentary basin, and lead to potential spillage of hydrocarbons out of potential reservoirs. The results demonstrate that future basin modeling should consider including the loading effect of glaciations when dealing with petroleum potential in former glaciated areas.

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Somoza, Luis, Teresa Medialdea et Francisco J. González. « Giant mass-transport deposits in the southern Scotia Sea (Antarctica) ». Geological Society, London, Special Publications 477, n^o 1 (6 mars 2018) : 195–205. http://dx.doi.org/10.1144/sp477.2.

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AbstractOn the basis of 2D multichannel and very-high-resolution seismic data and swath bathymetry, we report a sequence of giant mass-transport deposits (MTDs) in the Scan Basin (southern Scotia Sea, Antarctica). MTDs with a maximum thickness of c. 300 m extend up to 50 km from the Discovery and Bruce banks towards the Scan Basin. The headwall area consists of multiple U-shaped scars intercalated between volcanic edifices, up to 250 m high and 7 km wide, extending c. 14 km downslope from 1750 to 2900 m water depth. Seismic sections show that these giant MTDs are triggered by the intersection between diagenetic fronts related to silica transformation and vertical fluid-flow pipes linked to magmatic sills emplaced within the sedimentary sequence of the Scan Basin. This work supports that the diagenetic alteration of siliceous sediments is a possible cause of slope instability along world continental margins where bottom-simulating reflectors related to silica diagenesis are present at a regional scale.

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Pysklywec, R. N., et J. X. Mitrovica. « Mantle flow mechanisms of epeirogeny and their possible role in the evolution of the Western Canada Sedimentary Basin ». Canadian Journal of Earth Sciences 37, n^o 11 (1 novembre 2000) : 1535–48. http://dx.doi.org/10.1139/e00-057.

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Otherwise stable cratons periodically experience enigmatic episodes of large-scale uplift and subsidence that may result in widespread marine transgressions and the subsequent formation of sedimentary basins. Strata in the Western Canada Sedimentary Basin, for example, record flooding events that reached deep into the interior of the continent during the Devonian to Carboniferous. The epeirogenic motion which caused this deposition was contemporaneous with compressive tectonic events along the western plate margin of Laurussia. We propose that the long-wavelength component of inferred subsidence and uplift across the basin was the result of mantle flow-induced dynamic topography. In particular, we investigate the epeirogenic signals associated with the coupled mantle processes of near-surface subduction and later stage penetration of accumulated slab material through the endothermic phase change at 660 km depth. Numerical simulations of convection are presented to model the thermo-mechanical evolution of subduction in the mantle. The associated dynamic topography is initially characterized by tilting of the continental margin and submergence approximately 1000 km from the trench due to viscous effects associated with the subduction. A more extensive transgression onto the continental platform follows as accumulating slab material penetrates through the endothermic phase change. We argue that the predicted subsidence and uplift is broadly consistent with the inferred record of DevonianCarboniferous epeirogeny across western Canada, and thus that the evolution of the Western Canada Sedimentary Basin may be intimately connected to mantle flow processes occurring contemporaneously beneath the craton.

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Moghadam, Behnaz Rafiei, Khalil Rezaei, Ali Solgi, Pantea Ghiahchi et Mohsen AleAli. « Gradation and geochemistry of the Fenced Lagoon sediments (Bandar Anzali) with regard to source rock and tectonic location ». Journal of Geology, Geography and Geoecology 29, n^o 1 (10 avril 2020) : 154–65. http://dx.doi.org/10.15421/112014.

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The location of the Fenced Lagoon in the urban basin of Bandar Anzali, which should be considered due to its impact on the lives of the people of the region in terms of the conservation of the wetland and its environmental issues, and, on the other hand, the potential of this area to be introduced as a geotourism center determine the need to investigate the area’s sedimentology and geochemistry. Therefore, to study sedimentary and geochemical properties of the Fenced Lagoon sediments located in Bandar Anzali, 33 samples were taken in the form of 6 cores and 12 grabs, and basic sedimentation tests and heavy metals measurement were carried out on them .Studies show that the sediments range from sand to clay in terms of gradation and have mainly coastal-river origin. The sediments of this lake are classified into four sedimentary types: Muddy Sand, Slightly Gravelly Muddy Sand, Sand and Slightly Gravelly Sand, and sand is the main component of all of these sediments. The most abundant sedimentary types belong to Muddy Sand and Sand and the least abundant sedimentary types belong to Slightly Gravelly Muddy Sand and Slightly Gravely Sand. The nature of the source rock is derived from acidic to intermediate combination and in general, sedimentary rocks of the area under study are within the continental arch islands and, to a lesser extent, the active continental margin.

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Zhang, Li, Changmin Zhang et Luxing Dou. « Paleoenvironment Implication of Red Paleosols in a Late Cretaceous Continental Succession, Songliao Basin, NE China ». Minerals 11, n^o 9 (10 septembre 2021) : 993. http://dx.doi.org/10.3390/min11090993.

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The limited knowledge of Late Cretaceous terrestrial environments and their response to tectonic events in mid-latitudes can be addressed through continental basin deposits such as paleosols. Paleosols have been discovered in the Late Cretaceous Yaojia Formation in the southern Songlaio Basin and are recognized by evidence of soil structures controlled by pedogenesis. Sedimentary facies research on red paleosols was conducted on the Late Cretaceous Yaojia Formation in the outcrop of the southern Songliao Basin to interpret the depositional environments and tectonic significance of red paleosols during the greenhouse period. Mudflat, lake margin, and shallow lake depositional environments in a semi-arid climate are interpreted from the outcrops based on sedimentary descriptions and interpretation as well as geochemical and micromorphological analyses of paleosols in outcrops. We reconstructed the paleoenvironmental and paleoclimatic conditions through the paleosols in the mudflats and lake margin. The red paleosols in the mudflats and lake margin deposits formed in a stable landscape influenced by the tectonic uplift of the Songliao Basin, which is considered as new important evidence for tectonic uplift influenced by the collision of the Okhotomorsk Block with East Asia. The tectonic uplift process in East Asia is identified from the evolution of the depositional environments and drainage conditions inferred from different types of paleosols. Thus, the paleosols-bearing red bed deposits in outcrops provide an important contribution of the Late Cretaceous terrestrial paleoclimate and the tectonic setting research.

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Goričan, Špela, Josip Halamić, Tonći Grgasović et Tea Kolar-Jurkovšek. « Stratigraphic evolution of Triassic arc-backarc system in northwestern Croatia ». Bulletin de la Société Géologique de France 176, n^o 1 (1 janvier 2005) : 3–22. http://dx.doi.org/10.2113/176.1.3.

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Abstract Middle Triassic arc-related extensional tectonics in the western Tethys generated a complex pattern of intra-and backarc basins. We studied volcano-sedimentary successions of subsided continental-margin blocks (Mts. Žumberak and Ivanščica) and of dismembered incomplete ophiolite sequences interpreted as remnants of a backarc basin (Mts. Medvednica and Kalnik) in northwestern Croatia. We dated the successions with radiolarians, conodonts, foraminifers, algae, and sponges. The continental margin experienced a phase of accelerated subsidence in the late Anisian that was approximately coincident with the onset of intermediate and acidic volcanism; pelagic sediments with volcaniclastics accumulated atop subsided carbonate platforms. These relatively shallow basins were later infilled completely by prograding platforms in the late Ladinian-Carnian. In the backarc basin, sea-floor spreading initiated near the Anisian-Ladinian boundary and continued into the late Carnian. Pillow basalts were erupted and interlayered with radiolarian cherts and shales. The studied area was a part of a larger Triassic arc-backarc system preserved in the southern Alps, Alpine-Carpathian Belt, Dinarides, and Hellenides. Volcano-sedimentary successions of Mts. Medvednica and Kalnik are relics of the Meliata-Maliak backarc basin. In comparison to other previously dated oceanic remnants of this system, the longest continuous sea-floor spreading is now documented in one restricted tectonic unit.

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Tran, Huy Nhu, Xuan Van Tran, San Thuong Ngo et Huong Thi Mai Tran. « The tectonic evolution and new exploration results onhydrocarbon potential, cased study in the NE-Eastern part, Cuu Long basin,Vietnam continental shelf ». Science and Technology Development Journal 19, n^o 1 (31 mars 2016) : 180–89. http://dx.doi.org/10.32508/stdj.v19i1.517.

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New exploration results proved the presence of Tertiary sedimentary basins with hydrocarbon potential in the boundaries of Vietnam continental shelf. These basins were perhaps formed in the Early Oligocene on the Mesozoic basement of continental crust and were filled with mainly deltaic clastic sediments. Since very early Miocene these basins have linked together and extended wider. Sediments of marine and prograding delta facies accumulated and widespreaded on the whole continental shelf. At the Middle Miocene to present-day the opening of the Bien Dong Sea (Vietnam East Sea), the regional tectonic subsidence and the eustatic fluctuation had created sedimentary formations of open and deep marine facies with turbidite shale, platform carbonate including reef build-up. Andesite and basalt extrusion occurred in form of dykes resulting from tectonic inversions in Late Oligocene, in the beginning of Middle Miocene, particularly in Late Miocene-Pliocene. These Tertiary sedimentary basins are expected to have hydrocarbon potential and need to be investigated and explored adequately. The main risk is the drilling technology, the exploitation in the deep sea and high investment cost. The recently exploration results in illustrated a better potential in Lower Oligocene reservoir in South East margin of Cuu Long basin and many new signs. These signs need to be highlight researched for predicting accumulation distribution in study area, in purpose of oil and gas exploration for next stages.

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Ziska, Heri, Uni Árting et Morten S. Riishuus. « Interaction between volcanic and non-volcanic systems and its implication for prospectivity in the Faroe–Shetland Basin, NE Atlantic continental margin ». Petroleum Geoscience 28, n^o 2 (17 février 2022) : petgeo2021–058. http://dx.doi.org/10.1144/petgeo2021-058.

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Exploration in the Faroe–Shetland Basin on the Faroese Continental Shelf has revealed thick and complex volcanic successions and discovery of inter-volcanic oil-bearing siliciclastic sandstone fan deposits in the central parts of the basin. The possibility for such play types at the fringe of the North Atlantic Igneous Province requires a better understanding of the interaction between competing sedimentary and volcanic depositional transport systems. We have re-examined volcanic units in cuttings from exploration wells in the greater Judd Sub-basin area for evaluation of facies and geochemical affinity. This allows for chemostratigraphical correlation of wells to the absolute radiometrically age-constrained Faroe Islands Basalt Group. The collective well data were subsequently tied to a regional interpretation of 2D seismic data which facilitated a detailed interpretation of temporal development of the volcanic successions in the Judd Sub-basin area in terms of geometry, volcanic facies, depositional environment, and interdigitation with non-volcanic sedimentary units.The Judd Sub-basin was influenced by major volcanic phases during pre-breakup and syn-breakup. The influence was both direct, in the form of volcanic deposits, and indirect, in the form of obstructing established sedimentary transport systems and creating new provenance areas. The volcanic transport systems reached different areas of the Judd Sub-basin at different times during pre-breakup volcanism. The earliest incursion in the west was during late Mid Paleocene (T-sequence T31/T32). With at least three stratigraphically discrete incursions of volcanic material into the Judd Sub-basin, possibilities arise for sub- and inter-volcanic stratigraphic and structural traps for each incursion.

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Soper, N. J. « Neoproterozoic sedimentation on the northeast margin of Laurentia and the opening of Iapetus ». Geological Magazine 131, n^o 3 (mai 1994) : 291–99. http://dx.doi.org/10.1017/s0016756800011067.

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AbstractVery thick shallow water sedimentary sequences were deposited in Neoproterozoic time along the future margins of Laurentia. On the eastern margin these include the Eleonore Bay and Hecla Hoek sequences of Greenland and Svalbard; these are described and their geotectonic context briefly reviewed. They present both geotectonic and geodynamic problems: why did subsidence continue for some 300 Ma prior to the opening of Iapetus, and how could 15–20 km of sediment be accommodated in an ensialic environment?Prolonged slow stretching appears to have affected the eastern margin of Laurentia while the western (Cordilleran) margin progressed through the rift-drift transition as the Pacific opened. It is proposed that expansion of the Pacific was associated with both the convergence of Proto-Gondwanan continental terranes during the Pan-African orogeny (the extended SWEAT hypothesis) and also the maintenance of very slow extension rates on the future Iapetus margin. The strain-hardening effect of slow stretching may have been inhibited by a continuous basin-fill of juvenile heat-producing Grenville detritus. The onset of subduction in the Pacific freed up this margin; major rifting took place between East Greenland and possibly the Tornquist margin of Baltica in Vendian time, followed by the opening of northern Iapetus.

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Le Roy, P., F. Guillocheau, A. Piqué et A. M. Morabet. « Subsidence of the Atlantic Moroccan margin during the Mesozoic ». Canadian Journal of Earth Sciences 35, n^o 4 (1 avril 1998) : 476–93. http://dx.doi.org/10.1139/e97-111.

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This paper presents a combined study based on seismic interpretation, sequence stratigraphy, and the evaluation of subsidence that aims to characterize the structure and development of the Essaouira Basin in Morocco. Located in the coastal Meseta adjoining the continental margin, this basin records an initial Carnian-Hettangian deformation phase during rifting in the central part of the North Atlantic region. The geometry of the basin as a function of time shows a succession of half-grabens and horsts that developed westwards from reactivated Hercynian structures. The postrift stage is characterized by an aggrading sedimentary sequence, as shown by concordant seismic sequences stacking over the onshore part of the basin. The Upper Cretaceous coincides with a sequence showing a transition towards a prograding regime that leads to the topography of the present-day margin. Using the high-resolution analysis provided by sequence stratigraphy, it is possible to recognize fine-scale stratigraphic variations in the sedimentary succession. The well-to-well correlation of sedimentary cycles forms a dataset for evaluating subsidence. Residual subsidence curves reveal a differential behaviour between the present onshore and offshore areas. Although the computed subsidence rates are low across the onshore zone, curves for the western offshore part of the basin follow theoretical lithospheric cooling curves that are compatible with a stretch factor ( beta ) of nearly 1.4. Steep temporary gradients on the computed curves may be correlated with tectonic phases documented across the North Atlantic region that exerted a tight control on the development of the Essaouira Basin from Triassic rifting until the uplift of the Atlas Mountains during the Cenozoic.

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Larsen, Michael, Brian Bell, Pierpaolo Guarnieri, Henrik Vosgerau et Rikke Weibel. « Exploration challenges along the North Atlantic volcanic margins : the intra-volcanic sandstone play in subsurface and outcrop ». Geological Society, London, Petroleum Geology Conference series 8, n^o 1 (27 octobre 2016) : 231–45. http://dx.doi.org/10.1144/pgc8.13.

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AbstractThe margins of the North Atlantic rift are covered by an extensive succession of volcanic rocks, with up to 5 km of continental flood basalts, hyaloclastites and interbedded sedimentary rocks. The volcanic succession deteriorates seismic imaging and has hampered petroleum exploration in these areas. Focused research and pioneering exploration activity, however, has improved the understanding and development of new play models in volcanic-influenced basins. In 2004, the Rosebank discovery finally proved that intra-volcanic siliciclastic sandstones of the Flett Formation may form attractive hydrocarbon reservoirs in the Faroe–Shetland Basin.The Kangerlussuaq Basin in southern East Greenland offers a unique opportunity to study the interaction of siliciclastic sediments with lavas and various volcaniclastic units. It is demonstrated that: (1) laterally extensive siliciclastic sedimentary units are present in the lower part of the volcanic succession; (2) the morphology of the lavas controlled variations in sandstone geometry and thickness; and (3) deposition of the interbedded sediments and lavas occurred in a low-relief environment close to sea level. The mineralogical composition of the intra-volcanic sediments is highly variable, ranging from siliciclastic to purely volcaniclastic. Diagenetic studies suggest that the nature of the volcanic component in volcaniclastic sandstones is more important to reservoir properties than the relative concentration.

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Parson, L. M., D. G. Masson, C. D. Pelton et A. C. Grant. « Seismic stratigraphy and structure of the east Canadian continental margin between 41 and 52°N ». Canadian Journal of Earth Sciences 22, n^o 5 (1 mai 1985) : 686–703. http://dx.doi.org/10.1139/e85-075.

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The seismic stratigraphy of the eastern Grand Banks continental margin is examined, and a five-fold division of the sedimentary sequence overlying basement is proposed. Oceanic basement of Cretaceous age underlies the eastern part of the study area; to the west, continental basement ranging in age from Late Precambrian to ?Jurassic underlies the Grand Banks. The sediment units, ranging in age from Early Cretaceous to Recent, have been dated by extrapolation of both commercial and DSDP drilling results from the Grand Banks and from the formerly conjugate Iberian margin. Identification of oceanic magnetic anomalies in the Newfoundland Basin agrees with the proposed age of the two oldest, Early Cretaceous units.

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Moore, A. M. G., J. B. Willcox, N. F. Exon et G. W. O'Brien. « CONTINENTAL SHELF BASINS ON THE WEST TASMANIA MARGIN ». APPEA Journal 32, n^o 1 (1992) : 231. http://dx.doi.org/10.1071/aj91018.

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The continental margin of western Tasmania is underlain by the southern Otway Basin and the Sorell Basin. The latter lies mainly under the continental slope, but it includes four sub-basins (the King Island, Sandy Cape, Strahan and Port Davey sub-basins) underlying the continental shelf. In general, these depocentres are interpreted to have formed at the 'relieving bends' of a major left-lateral strike-slip fault system, associated with 'southern margin' extension and breakup (seafloor spreading). The sedimentary fill could have commenced in the Jurassic; however, the southernmost sub-basins (Strahan and Port Davey) may be Late Cretaceous and Paleocene, respectively.Maximum sediment thickness is about 4300 m in the southern Otway Basin, 3600 m in the King Island Sub-basin, 5100 m in the Sandy Cape Basin, 6500 m in the Strahan Sub-basin, and 3000 m in the Port Davey Sub-basin. Megasequences in the shelf basins are similar to those in the Otway Basin, and are generally separated by unconformities. There are Lower Cretaceous non-marine conglomerates, sandstones and mudstones, which probably include the undated red beds recovered in two wells, and Upper Cretaceous shallow marine to non-marine conglomerates, sandstones and mudstones. The Cainozoic sequence often commences with a basal conglomerate, and includes Paleocene to Lower Eocene shallow marine sandstones, mudstones and marl, Eocene shallow marine limestones, marls and sandstones, and Oligocene and younger shallow marine marls and limestones.The presence of active source rocks has been demonstrated by the occurrence of free oil near TD in the Cape Sorell-1 well (Strahan Sub-basin), and thermogenic gas from surficial sediments recovered from the upper continental slope and the Sandy Cape Sub-basin. Geohistory maturation modelling of wells and source rock 'kitchens' has shown that the best locations for liquid hydrocarbon entrapment in the southern Otway Basin are in structural positions marginward of the Prawn-1 well location. In such positions, basal Lower Cretaceous source rocks could charge overlying Pretty Hill Sandstone reservoirs. In the King Island Sub-Basin, the sediments encountered by the Clam-1 well are thermally immature, though hydrocarbons generated from within mature Lower Cretaceous rocks in adjacent depocentres could charge traps, providing that suitable migration pathways are present. Whilst no wells have been drilled in the Sandy Cape Sub-basin, basal Cretaceous potential source rocks are considered to have entered the oil window in the early Late Cretaceous, and are now capable of generating gas/condensate. Upper Cretaceous rocks appear to have entered the oil window in the Paleocene. In the Strahan Sub-Basin, mature Cretaceous sediments in the depocentres are available to traps, though considerable migration distances would be required.It is concluded that the west Tasmania margin, which has five strike-slip related depocentres and the potential to have generated and entrapped hydrocarbons, is worthy of further consideration by the exploration industry. The more prospective areas are the southern Otway Basin, and the Sandy Cape and Strahan sub-basins of the Sorell Basin.

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Parson, Lindsay M., et Alan J. Evans. « Seafloor topography and tectonic elements of the Western Indian Ocean ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 363, n^o 1826 (15 janvier 2005) : 15–24. http://dx.doi.org/10.1098/rsta.2004.1472.

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The break–up of Gondwanaland and dispersal of several of its component continental fragments, which eventually formed the margins of the Indian Ocean, have produced an ocean basin of enormous variety, both in relief and in origin of seafloor features. The western half of the Indian Ocean alone contains every type of tectonic plate boundary, both active and fossil, and, along with some of the deepest fracture zones, the most complex mid–ocean ridge configurations and some of the thickest sedimentary sequences in the world's ocean basins. This ocean is one of the most diverse on the face of the globe. We explore the evolution of the morphology of the Indian Ocean floor, and discuss the effect of its variations, maxima and minima, on the interconnectivity of the ocean's water masses.

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Klitzke, P., J. I. Faleide, M. Scheck-Wenderoth et J. Sippel. « A lithosphere-scale structural model of the Barents Sea and Kara Sea region ». Solid Earth Discussions 6, n^o 2 (10 juillet 2014) : 1579–624. http://dx.doi.org/10.5194/sed-6-1579-2014.

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Abstract. The Barents Sea and Kara Sea region as part of the European Arctic shelf, is geologically situated between the Proterozoic East-European Craton in the south and early Cenozoic passive margins in the north and the west. Proven and inferred hydrocarbon resources encouraged numerous industrial and academic studies in the last decades which brought along a wide spectrum of geological and geophysical data. By evaluating all available interpreted seismic refraction and reflection data, geological maps and previously published 3-D-models, we were able to develop a new lithosphere-scale 3-D-structural model for the greater Barents Sea and Kara Sea region. The sedimentary part of the model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian). Downwards, the 3-D-structural model is complemented by the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distribution of the main megasequences delineates five major subdomains differentiating the region (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). The vertical resolution of five sedimentary megasequences allows comparing for the first time the subsidence history of these domains directly. Relating the sedimentary structures with the deeper crustal/lithospheric configuration sheds some light on possible causative basin forming mechanisms that we discuss. The newly calculated LAB deepens from the typically shallow oceanic domain in three major steps beneath the Barents and Kara shelves towards the West-Siberian Basin in the east. Thereby, we relate the shallow continental LAB and slow/hot mantle beneath the southwestern Barents Sea with the formation of deep Paleozoic/Mesozoic rift basins. Thinnest continental lithosphere is observed beneath Svalbard and the NW Barents Sea where no Mesozoic/early Cenozoic rifting has occurred but strongest Cenozoic uplift and volcanism since Miocene times. The East Barents Sea Basin is underlain by a LAB at moderate depths and a high-density anomaly in the lithospheric mantle which follows the basin geometry and a domain where the least amount of late Cenozoic uplift/erosion is observed. Strikingly, this high-density anomaly is not present beneath the adjacent southern Kara Sea. Both basins share a strong Mesozoic subsidence phase whereby the main subsidence phase is younger in the South Kara Sea Basin.

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Mustaev, R. N., E. A. Lavrenova, V. Yu Kerimov et R. A. Mamedov. « Peculiarities of Tertiary petroleum systems evolution under prograding shelf environment on the continental margin of the East Siberian Sea ». Journal of Petroleum Exploration and Production Technology 11, n^o 10 (4 septembre 2021) : 3617–26. http://dx.doi.org/10.1007/s13202-021-01280-5.

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AbstractThe upper part of the sedimentary cover within the East Siberian Sea shelf comprises Cenozoic clinoform deposits, which accumulated in passive continental margin settings. In the Eastern Arctic, the productivity of clinoform deposits has been proved on the Alaska North Slope and in the Beaufort–Mackenzie Basin. Considering that Cenozoic clinoform deposits are widely represented in the Russian part of the Eastern Arctic, they undoubtedly attract considerable interest from the standpoint of hydrocarbons prospecting. However, despite increasingly closer attention to this interval of the sedimentary section, it is still poorly understood due to its complicated geology. The lack of drilled wells in the region imposes a considerable limitation on an understanding of sedimentary basins development. In this situation, geophysical data become the primary source of information for building geologic models in the Russian sector of the Eastern Arctic. An assessment of hypothetical Cenozoic petroleum systems of the East Siberian Sea is the main objective of this paper. It is to be said research performed under high uncertainty of input data. The results obtained from basin analysis and numerical modeling indicate the possibility that an active petroleum system may exist in the Cenozoic sedimentary wedge of the East Siberian Sea. The outlook for the clinoform complex largely depends on the source rock maturity, i.e., higher prospects should be expected in areas where the prograding wedge has maximum thickness. Considering all factors (reservoir quality prediction, proximity to a hydrocarbon kitchen, timing), the Eocene–Oligocene part of the sedimentary section appears to offer the greatest promise within the study area. Here, predominantly oil accumulations may be expected at a depth of 2.5–3.5 km below sea bottom.

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Ghods, A., et J. Arkani-Hamed. « Interpretation of the satellite magnetic anomaly of the Nova Scotia marginal basin ». Canadian Journal of Earth Sciences 35, n^o 2 (1 février 1998) : 162–74. http://dx.doi.org/10.1139/e97-095.

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Satellite magnetic anomaly maps show well-defined negative anomalies over some deep sedimentary marginal basins, such as the Nova Scotia marginal basin. A possible explanation would be the thermal demagnetization of the oceanic upper crust due to thermal blanketing by the sediments and the oceanic lower crust and uppermost mantle due to subsidence into hotter regions beneath. We examine this possibility by computing the thermoviscous remanent magnetization of the oceanic lithosphere beneath the Nova Scotia basin using a detailed thermal evolution model which takes into account the continental rifting, sea-floor spreading, and subsequent subsidence. It is concluded that the thermal demagnetization is not sufficient to explain the entire observed negative magnetic anomaly over the basin; it contributes ~40% to the anomaly. We suggest that a major part, ~60%, of the anomaly arises from the particular location of the early Mesozoic oceanic lithosphere beneath the basin, which has a relatively weaker bulk remanent magnetization compared with a highly magnetic continental crust in the west and north and the strong magnetic oceanic lithosphere of the Cretaceous Quiet Zone in the east.

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Chupakhina, Anastasia, Yevgeny Dubinin et Andrey Grokholsky. « CONDITIONS FOR THE FORMATION OF THE STRUCTURES OF THE MOZAMBIQUE BASIN (PHYSICAL MODELING) ». LIFE OF THE EARTH 44, n^o 2 (11 mai 2022) : 136–49. http://dx.doi.org/10.29003/m3023.0514-7468.2022_44_2/136-149.

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Based on the results of physical modeling, the conditions of formation of the Mozambique Ridge and the Beira High, formed during the opening of the Mozambique Basin, are considered. The Mozambique Ridge is a series of blocky uplifts rising up to 3500 m above the seafloor. One of the most probable hypotheses of the ridge origin suggests its partial separation from the margin of the African continent as a result of plume activity. Modern studies show that the northeastern part of the ridge is composed of thinned continental crust overlain by sedimentary cover, while its southern part is characterized by a large number of extrusive centers, indicating increased magmatic activity. Experimental studies have shown that the formation of the Mozambique Ridge occurred under the conditions of the African-Antarctic continental rift with the presence of structural heterogeneities in the lithosphere of the African continent and the influence of a hot spot. The Beira High is a continental block that was separated from Antarctica during the split of Gondwana.

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