Journal articles on the topic 'Proterozoic sedimentary basins'
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Sønderholm, M., and H. F. Jepsen. "Proterozoic basins of North Greenland." Bulletin Grønlands Geologiske Undersøgelse 160 (January 1, 1991): 49–69. http://dx.doi.org/10.34194/bullggu.v160.6713.
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Proterozoic sedimentary and associated igneous rocks along the margin of the Precambrian crystalline shield in North Greenland have been studied by several geological field-teams since 1912 when they were first investigated during the First Thule Expedition. More recently, the Proterozoic strata of North Greenland have been studied in greater detail by the Geological Survey of Greenland (GGU) during the North Greenland Project of 1978-80 and 1983-85. The present paper reviews these studies in an attempt to elucidate the development of the sedimentary basins in North Greenland during the Proterozoic.
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Zamil, M. Sh. "A possible model of the Paleozoic sedimentary basins evolution at the North African platform." Proceedings of higher educational establishments. Geology and Exploration, no. 6 (December 28, 2017): 68–73. http://dx.doi.org/10.32454/0016-7762-2017-6-68-73.
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A dual model of the Paleozoic basins development, disposing on the Late Proterozoic (Pan-African) and the Early Proterozoic (Eburnean) crust, has been proposed. The formation of the first group basins is connected with the subsiding of the sections of the cooling gneissic-domes of«rejuvenated» (Early Precambrian but tectonically reworked at the end of the Proterozoic) Pan-African crust. Accordingly, the development of the second group basins is a result of the Precambrian deep sited (mantle) magmatic chambers cooling and subsiding together with the sites of the old lithosphere, covering them. The manifestation of the Vendian volcanic units on Anti-Atlas, Ugarta, Regibat-Eglab uplifts is the most possible evidence of the mantle magmatic activity, which could create those chambers.
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Hopkins, Roy M. "THE CENTRAL AUSTRALIAN BASINS." APPEA Journal 29, no. 1 (1989): 347. http://dx.doi.org/10.1071/aj88030.
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The Amadeus and Ngalia Basins are two of several intracratonic basins situated in the central region of the Australian Continent and underlain by Upper Proterozoic and Lower Palaeozoic sedimentary rocks.In the Amadeus Basin, the preserved sedimentary section has been deformed by several orogenic events through geological history, with salt tectonics playing an important role in the structural evolution. The Ordovician System is the primary exploration objective. The Cambrian and Proterozoic sequences, which also carry rock strata having source, reservoir and sealing properties, are secondary targets. However, these latter units are sparsely explored, and only limited information is available on their petroleum prospectiveness. Three of the four petroleum accumulations found to date are in Ordovician sandstones, with the fourth accumulation contained in Cambrian sandstones.The initial drilling phase in the Amadeus Basin in the early 1960s was concentrated on geologically defined surface antic :nes, with seismic surveying becoming the principal technique employed in subsequent exploration phases. The ongoing work has demonstrated a major untested structural play associated with a regional thrust fault system — in particular, combination dip and fault closures developed on the underthrust blocks. Stratigraphic prospects also are present in the Amadeus Basin, but none of these yet has been drilled.The Ngalia Basin is similar stratigraphically and structurally to the Amadeus Basin and is considered prospective for oil and gas. Much less work has been done in the Ngalia than in the Amadeus, with only one well drilled in the entire basin. The well yielded a gas snow from a Proterozoic formation, and other direct hydrocarbon indications have been recorded elsewhere in the basin. Rock units having source, reservoir and sealing parameters are present, as are structures capable of forming traps. Again, these are associated largely with a complex regional thrust fault system.
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Gorton, Justin, and Alison Troup. "Petroleum systems of the Proterozoic in northwest Queensland and a description of various play types." APPEA Journal 58, no. 1 (2018): 311. http://dx.doi.org/10.1071/aj17115.
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As part of Queensland Government’s Strategic Resources Exploration Program, in conjunction with the Australian Government’s Exploring for the Future program, a study to improve the subsurface knowledge of Proterozoic basins in northwest Queensland (NWQ) is underway. Proterozoic sedimentary basins are prevalent across central and western Australia. Several of these basins have proven petroleum systems, with the best discoveries to date being in the Greater McArthur Basin, Northern Territory. Recent exploration and appraisal in the Beetaloo Sub-basin of the Greater McArthur Basin has identified large volumes of gas resources contained within unconventional shale reservoirs. In NWQ, the Isa Superbasin and overlying South Nicholson Basin are related in both age and likely deposition to the Greater McArthur Basin. The thick, extensive shale units of the Isa Superbasin are excellent source rocks, while the Mullera Formation in the South Nicholson Basin also has potential but has not been investigated in detail. There are several potential reservoirs within the Proterozoic section and younger units of the overlying Georgina and Carpentaria basins, including clastic and carbonate types. Exploration in the Isa Superbasin identified an estimated 22.1 trillion cubic feet of prospective resources (Armour Energy 2015) in unconventional shale reservoirs of the Lawn Hill Formation and Riversleigh Siltstone. This paper will discuss the stratigraphy, depositional and structural history of these Proterozoic basins and characterise their source and reservoir units using existing and recently acquired geophysical, geochemical, petrographic and petrophysical datasets. From this, several plays or play concepts will be identified and described to help understand the region’s potential for both conventional and unconventional petroleum resources.
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Troup, Alison, and Sally Edwards. "Old basins, new seismic data – architecture of Proterozoic basins in Northwest Queensland." APPEA Journal 62, no. 2 (May 13, 2022): S502—S507. http://dx.doi.org/10.1071/aj21167.
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As part of the Strategic Resources Exploration Program and to complement surveys acquired under Geoscience Australia’s Exploring for the Future (EFTF) initiative, the Geological Survey of Queensland acquired the Camooweal 2D seismic survey in 2019. This survey was designed to support exploration for hydrocarbons in the Georgina and South Nicholson Basins and Isa Superbasin in Northwest Queensland (NWQ) by providing precompetitive sub-surface data to enable interpretation of basin and basement architecture and to examine structures interpreted in the 2018 North West Queensland SEEBASE Study. The Camooweal 2D seismic survey extends Geoscience Australia’s L210 South Nicholson Seismic Survey into an underexplored region of NWQ. It also ties into and complements the 1994 and 2004 Mount Isa seismic surveys, and the 2019 L212 Barkly Seismic Survey in the Northern Territory. The South Nicholson survey highlighted a significant thickness of sedimentary strata and identified a new depocenter of probable Proterozoic age, now referred to as the Carrara Sub-basin. The Camooweal and Barkly surveys extended the seismic coverage in this region and possibly increase the Carrara Sub-basin’s extent underneath the Georgina Basin. This work will present an interpretation of the basin architecture of the Camooweal 2D seismic in light of the recent drilling at NDI Cararra 1 and tie into interpretation of the Barkly Seismic Survey to provide a regional interpretation of NWQ’s Proterozoic basins in the region.
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George, Bivin G., Jyotiranjan S. Ray, and Sanjeev Kumar. "Geochemistry of carbonate formations of the Chhattisgarh Supergroup, central India: implications for Mesoproterozoic global events." Canadian Journal of Earth Sciences 56, no. 3 (March 2019): 335–46. http://dx.doi.org/10.1139/cjes-2018-0144.
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The Chhattisgarh Supergroup is one of the major Proterozoic marine sedimentary sequences of India. It consists of largely undeformed and unmetamorphosed siliciclastic, volcaniclastic, and carbonate formations deposited in two sub-basins, Hirri and Bharadwar, separated by an Archean greenstone belt. In spite of its apparent importance for Mesoproterozoic oceanic records, very few geochemical studies have been carried in the basin. Here, we present results of our high resolution geochemical and C–O–Sr isotopic studies in two carbonate formations of the supergroup: the Charmuria and the Chandi. We observe elevated δ13C values increasing from 2.6‰ to 3.6‰ in these formations, which is consistent with the globally reported late Mesoproterozoic values. Such consistently positive δ13C values are attributed to increased organic carbon burial in the basin margins during the deposition of these carbonates. Based on the principles of δ13C isotope stratigraphy, we suggest a depositional age between 1.0 and 1.2 Ga for these carbonates which form the upper part of the supergroup. The lowest 87Sr/86Sr ratios obtained from the Charmuria and Chandi formations, 0.70723 and 0.70816, respectively, are more radiogenic than the contemporaneous seawater, suggesting that the Sr isotopic system of the formations are altered. Based on the similarity in the δ13C values, we stratigraphically correlate the carbonate formations of the Raipur Group in both the Hirri and Bharadwar sub-basins. We also present a compilation of available δ13C and 87Sr/86Sr records from all the Proterozoic sedimentary successions of India and compare it with the global datasets. We find that while the Indian basins possess records of the Bitter Springs and Shuram δ13C anomalies, they lack evidence for the other major global events of the Proterozoic.
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Rainbird, R. "Some Advances in the Study of Proterozoic Sedimentary Basins of North America." Precambrian Research 129, no. 3-4 (March 10, 2004): 199–201. http://dx.doi.org/10.1016/j.precamres.2003.10.001.
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SARKAR, A., P. P. CHAKRABORTY, B. MISHRA, M. K. BERA, P. SANYAL, and S. PAUL. "Mesoproterozoic sulphidic ocean, delayed oxygenation and evolution of early life: sulphur isotope clues from Indian Proterozoic basins." Geological Magazine 147, no. 2 (September 9, 2009): 206–18. http://dx.doi.org/10.1017/s0016756809990380.
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AbstractAnalyses of sulphur isotope compositions in sedimentary pyrites from the Vindhyan, Chattisgarh and Cuddapah basins show heavy δ34S (> +25 ‰) values during the Mesoproterozoic. The data provide evidence in support of a hypothesized global Proterozoic sulphidic anoxic ocean where very low concentrations of marine sulphate, bacterially reduced in closed systems, produced δ34S values in pyrites similar to or even heavier than marine sulphate. The extreme environmental conditions induced by these anoxic oceans could have been responsible for the delayed oxygenation of the biosphere and retarded evolution of multicellular life.
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Holk, Gregory J., T. Kurtis Kyser, Don Chipley, Eric E. Hiatt, and Jim Marlatt. "Mobile Pb-isotopes in Proterozoic sedimentary basins as guides for exploration of uranium deposits." Journal of Geochemical Exploration 80, no. 2-3 (September 2003): 297–320. http://dx.doi.org/10.1016/s0375-6742(03)00196-1.
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Whitford, D. J., P. J. Hamilton, and J. Scott. "SEDIMENTARY PROVENANCE STUDIES IN AUSTRALIAN BASINS USING NEODYMIUM MODEL AGES." APPEA Journal 34, no. 1 (1994): 320. http://dx.doi.org/10.1071/aj93029.
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An understanding of the tinting of basin evolution is fundamental to the development of successful play concepts. The Sm-Nd geochronometer can be used to determine quantitatively the `average' age at which segments of continental crust have been extracted from the earth's mantle. Variations in Nd model ages within sedimentary rock sequences indicate changes in sedimentary provenance over time and provide a potential correlation tool.In the Eromanga Basin, there is a distinct lithological contrast between the main reservoir unit, the Jurassic Hutton Sandstone, and the overlying Birkhead Formation. The quartz-rich Hutton Sandstone is characterised by relatively old Nd model ages, generally within the range 1.3–1.5 Ga. In contrast the lithic-rich Birkhead Formation has much younger model ages, generally Neodymium model ages measured in mudstones within the Flag Sandstone from the Harriet Field in the Barrow Sub-basin of the North West Shelf, range from 2.1–2.5 Ga. The old ages are consistent with the sediments being derived from the Archaean shield areas and the younger Proterozoic complexes of Western Australia. Tentative correlations based on model ages between mudstone units from two wells are consistent with correlations based on heavy mineral suites.Neodymium model ages have application to correlation at both regional and local scales within basins. Reliable information can be obtained on both sandstones and mudstones on samples as small 50 g. Potentially they can provide important quantitative information complementary to that derived from more conventional approaches.
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Cosgrove, G. I. E., L. Colombera, and N. P. Mountney. "Eolian stratigraphic record of environmental change through geological time." Geology 50, no. 3 (November 22, 2021): 289–94. http://dx.doi.org/10.1130/g49474.1.
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Abstract The terrestrial sedimentary record provides a valuable archive of how ancient depositional systems responded to and recorded changes in Earth's atmosphere, biosphere, and geosphere. However, the record of these environmental changes in eolian sedimentary successions is poorly constrained and largely unquantified. Our study presents the first global-scale, quantitative investigation of the architecture of eolian systems through geological time via analysis of 55 case studies of eolian successions. Eolian deposits accumulating (1) under greenhouse conditions, (2) in the presence of vascular plants and grasses, and (3) in rapidly subsiding basins associated with the rifting of supercontinents are represented by significantly thicker eolian dune-set, sand-sheet, and interdune architectural elements. Pre-vegetation eolian systems are also associated with more frequent interactions with non-eolian environments. The interplay of these forcings has resulted in dune-set thicknesses that tend to be smallest and largest in Proterozoic and Mesozoic successions, respectively. In the Proterozoic, the absence of sediment-binding plant roots rendered eolian deposits susceptible to post-depositional wind deflation and reworking by fluvial systems, whereby highly mobile channels reworked contiguous eolian deposits. During the Mesozoic, humid greenhouse conditions (associated with relatively elevated water tables) and high rates of basin subsidence (associated with the breakup of Pangea) favored the rapid transfer of eolian sediment beneath the erosional baseline. The common presence of vegetation promoted accumulation of stabilizing eolian systems. These factors acted to limit post-depositional reworking. Eolian sedimentary deposits record a fingerprint of major environmental changes in Earth history: climate, continental configuration, tectonics, and land-plant evolution.
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McLaren, Sandra, Mike Sandiford, and Roger Powell. "Contrasting styles of Proterozoic crustal evolution: A hot-plate tectonic model for Australian terranes." Geology 33, no. 8 (August 1, 2005): 673–76. http://dx.doi.org/10.1130/g21544ar.1.
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Abstract Proterozoic terranes in Australia record complex tectonic histories in the interval 1900– 1400 Ma that have previously been interpreted by means of simple intracratonic or plate-tectonic models. However, these models do not fully account for (1) repeated tectonic reactivation (both orogenesis and rifting), (2) mainly high-temperature–low-pressure metamorphism, (3) rifting and sag creating thick sedimentary basins, (4) the nature and timing of voluminous felsic magmatism, (5) relatively large aspect ratio orogenic belts, and (6) a general paucity of diagnostic plate-boundary features. A key to understanding these histories is the observation that Australian Proterozoic terranes are characterized by an extraordinary, but heterogeneous, enrichment of the heat-producing elements. This enrichment must contribute to long-term lithospheric weakening, and thus we advocate a hybrid lithospheric evolution model with two tectonic switches: plate-boundary–derived stresses and heat-producing-element–related lithospheric weakening. The Australian Proterozoic crustal growth record is therefore a function of the magnitude of these stresses, the way in which the heat-producing elements are distributed, and how both of these change with time.
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Neogi, Susobhan, Apoorve Bhardwaj, and Amitava Kundu. "Evolution of Neoproterozoic Shillong Basin, Meghalaya, NE India: implications of supercontinent break-up and amalgamation." Geological Magazine 159, no. 4 (December 9, 2021): 628–44. http://dx.doi.org/10.1017/s0016756821001230.
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AbstractFragmentation and amalgamation of supercontinents play an important role in shaping our planet. The break-up of such a widely studied supercontinent, Rodinia, has been well documented from several parts of India, especially the northwestern and eastern sector. Interestingly, being located very close to the Proterozoic tectonic margin, northeastern India is expected to have had a significant role in Neoproterozoic geodynamics, but this aspect has still not been thoroughly studied. We therefore investigate a poorly studied NE–SW-trending Shillong Basin of Meghalaya from NE India, which preserves the stratigraphic record and structural evolution spanning the Neoproterozoic Era. The low-grade metasedimentary rocks of Shillong Basin unconformably overlie the high-grade Archean–Proterozoic basement and comprise a c. 4000-m-thick platform sedimentary rock succession. In this study, we divide this succession into three formations: lower Tarso, middle Ingsaw and upper Umlapher. A NW–SE-aligned compression event later caused the thrusting of these sedimentary rocks over the basement with a tectonic contact in the western margin, resulting in NE–SW-trending fold belts. The rift-controlled Shillong Basin shows a comparable Neoproterozoic evolution with the equivalent basins of peninsular India and eastern Gondwana. The recorded Neoproterozoic rift tectonics are likely associated with Rodinia’s break-up and continent dispersion, which finally ended with the oblique collision of India with Australia and the intrusion of Cambrian granitoids during the Pan-African Orogeny, contributing to the assembly of Gondwana. This contribution is the first to present a complete litho-structural evolution of the Shillong Basin in relation to regional and global geodynamic settings.
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Zepeda-Martínez, Mildred, Michelangelo Martini, Luigi A. Solari, and Claudia C. Mendoza-Rosales. "Reconstructing the tectono-sedimentary evolution of the Early–Middle Jurassic Tlaxiaco Basin in southern Mexico: New insights into the crustal attenuation history of southern North America during Pangea breakup." Geosphere 17, no. 4 (June 21, 2021): 1294–317. http://dx.doi.org/10.1130/ges02309.1.
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Abstract During Pangea breakup, several Jurassic extensional to transtensional basins were developed all around the world. The boundaries of these basins are major structures that accommodated continental extension during Jurassic time. Therefore, reconstructing the geometry of Jurassic basins is a key factor in identifying the major faults that produced continental attenuation during Pangea breakup. We reconstruct the tectono-sedimentary evolution of the Jurassic Tlaxiaco Basin in southern Mexico using sedimentologic, petrographic, and U-Pb geochronologic data. We show that the northern boundary of the Tlaxiaco Basin was an area of high relief composed of the Paleozoic Acatlán Complex, which was drained to the south by a set of alluvial fans. The WNW-trending Salado River–Axutla fault is exposed directly to the north of the northernmost fan exposures, and it is interpreted as the Jurassic structure that controlled the tectono-sedimentary evolution of the Tlaxiaco Basin at its northern boundary. The eastern boundary is represented by a topographic high composed of the Proterozoic Oaxacan Complex, which was exhumed along the NNW-trending Caltepec fault and was drained to the west by a major meandering river called the Tlaxiaco River. Data presented in this work suggest that continental extension during Pangea breakup was accommodated in Mexico not only by NNW-trending faults associated with the development of the Tamaulipas–Chiapas transform and the opening of the Gulf of Mexico, but also by WNW-trending structures. Our work offers a new perspective for future studies that aim to reconstruct the breakup evolution of western equatorial Pangea.
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Skulski, Thomas, Robert P. Wares, and Alan D. Smith. "Early Proterozoic (1.88–1.87 Ga) tholeiitic magmatism in the New Québec orogen." Canadian Journal of Earth Sciences 30, no. 7 (July 1, 1993): 1505–20. http://dx.doi.org/10.1139/e93-129.
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The New Québec orogen contains two volcano-sedimentary sequences bounded by unconformities. Each sequence records a change from continental sedimentation and alkaline volcanism to marine sedimentation and tholeiitic volcanism. The first sequence records 2.17 Ga rifting and the development, by 2.14 Ga, of a passive margin along the eastern part of the Superior craton. The second sequence developed between 1.88 and 1.87 Ga in pull-apart basins that reflect precollisional dextral transtension along the continental margin. Second-sequence magmatism comprises (i) carbonatitic and lamprophyric intrusions and mildly alkaline mafic to felsic volcanic rocks; (ii) widespread intrusion of tholeiitic gabbro sills, and submarine extrusion of plagioclase glomeroporphyritic basalts and younger aphyric basalts and picrites; and (iii) late-stage, mafic to felsic volcanism and intrusion of carbonatites. Crustal thinning allowed primitive tholeiitic magmas to equilibrate at progressively lower pressures before more buoyant derivative liquids could erupt. Early primitive melts were trapped at the base of the crust and crystallized olivine and orthopyroxene with minor crustal contamination. Derivative melts, similar to transitional mid-ocean-ridge basalts, migrated upward into mid-crustal magma chambers where they became saturated in calcic plagioclase. Subsequent tapping of these magma chambers allowed plagioclase ultraphyric magmas to intrude the sedimentary pile and erupt on the sea floor. Prolonged lithospheric extension resulted in more voluminous mantle melting and eruption of picrites and basalts in the south. Primitive magmas in the north were trapped beneath thicker crust and crystallized wehrlite cumulates. Resulting basaltic melts intruded the volcano-sedimentary pile, or erupted as aphyric basalts.
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Henriksen, Niels, A. K. Higgins, Feiko Kalsbeek, and T. Christopher R. Pulvertaft. "Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. 2nd edition." GEUS Bulletin 18 (November 27, 2009): 1–126. http://dx.doi.org/10.34194/geusb.v18.4993.
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The geological development of Greenland spans a period of nearly 4 Ga, from Eoarchaean to the Quaternary. Greenland is the largest island on Earth with a total area of 2 166 000 km2, but only c. 410 000 km2 are exposed bedrock, the remaining part being covered by a major ice sheet (the Inland Ice) reaching over 3 km in thickness. The adjacent offshore areas underlain by continental crust have an area of c. 825 000 km2.
Greenland is dominated by crystalline rocks of the Precambrian shield, which formed during a succession of Archaean and Palaeoproterozoic orogenic events and stabilised as a part of the Laurentian shield about 1600 Ma ago. The shield area can be divided into three distinct types of basement provinces: (1) Archaean rocks (3200–2600 Ma old, with local older units up to> 3800 Ma) that were almost unaffected by Proterozoic or later orogenic activity; (2) Archaean terrains reworked during the Palaeoproterozoic around 1900–1750 Ma ago; and (3) terrains mainly composed of juvenile Palaeoproterozoic rocks (2000–1750 Ma in age). Subsequent geological developments mainly took place along the margins of the shield. During the Proterozoic and throughout the Phanerozoic major sedimentary basins formed, notably in North and North-East Greenland, in which sedimentary successions locally reaching 18 km in thickness were deposited. Palaeozoic orogenic activity affected parts of these successions in the Ellesmerian fold belt of North Greenland and the East Greenland Caledonides; the latter also incorporates reworked Precambrian crystalline basement complexes.
Late Palaeozoic and Mesozoic sedimentary basins developed along the continent–ocean margins in North, East and West Greenland and are now preserved both onshore and offshore. Their development was closely related to continental break-up with formation of rift basins. Initial rifting in East Greenland in latest Devonian to earliest Carboniferous time and succeeding phases culminated with the opening of the North Atlantic Ocean in the late Paleocene. Sea-floor spreading was accompanied by extrusion of Palaeogene (early Tertiary) plateau basalts in both central West and central–southern East Greenland.
During the Quaternary Greenland was almost completely covered by ice, and the present day Inland Ice is a relic from the Pleistocene ice ages. Vast amounts of glacially eroded detritus were deposited on the continental shelves around Greenland.
Mineral exploitation in Greenland has so far encompassed cryolite, lead-zinc, gold, olivine and coal. Current prospecting activities in Greenland are concentrated on gold, base metals, platinum group elements, molybdenum, iron ore, diamonds and lead-zinc. Hydrocarbon potential is confined to the major Phanerozoic sedimentary basins, notably the large basins offshore North-East and West Greenland. While reserves of oil or gas have yet to be found, geophysical data combined with discoveries of oil seeps onshore have revealed a considerable potential for offshore oil and gas.
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Hiatt, Eric E., T. Kurtis Kyser, Paul A. Polito, Jim Marlatt, and Peir Pufahl. "The Paleoproterozoic Kombolgie Subgroup (1.8 Ga), McArthur Basin, Australia: Sequence stratigraphy, basin evolution, and unconformity-related uranium deposits following the Great Oxidation Event." Canadian Mineralogist 59, no. 5 (September 1, 2021): 1049–83. http://dx.doi.org/10.3749/canmin.2000102.
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ABSTRACT Proterozoic continental sedimentary basins contain a unique record of the evolving Earth in their sedimentology and stratigraphy and in the large-scale, redox-sensitive mineral deposits they host. The Paleoproterozoic (Stratherian) Kombolgie Basin, located on the Arnhem Land Plateau, Northern Territory, is an exceptionally well preserved, early part of the larger McArthur Basin in northern Australia. This intracratonic basin is filled with 1 to 2 km-thick, relatively undeformed, nearly flat-lying, siliciclastic rocks of the Kombolgie Subgroup. Numerous drill cores and outcrop exposures from across the basin allow sedimentary fabrics, structures, and stratigraphic relationships to be studied in great detail, providing an extensive stratigraphic framework and record of basin development and evolution. Tectonic events controlled the internal stratigraphic architecture of the basin and led to the formation of three unconformity-bounded sequences that are punctuated by volcanic events. The first sequence records the onset of basin formation and is comprised of coarse-grained sandstone and polymict lithic conglomerate deposited in proximal braided rivers that transported sediment away from basin margins and intra-basin paleohighs associated with major uranium mineralization. Paleo-currents in the upper half of this lower sequence, as well as those of overlying sequences, are directed southward and indicate that the major intra-basin topographic highs no longer existed. The middle sequence has a similar pattern of coarse-grained fluvial facies, followed by distal fluvial facies, and finally interbedded marine and eolian facies. An interval marked by mud-rich, fine-grained sandstones and mud-cracked siltstones representing tidal deposition tops this sequence. The uppermost sequence is dominated by distal fluvial and marine facies that contain halite casts, gypsum nodules, stromatolites, phosphate, and “glauconite” (a blue-green mica group mineral), indicating a marine transgression. The repeating pattern of stratigraphic sequences initiated by regional tectonic events produced well-defined coarse-grained diagenetic aquifers capped by intensely cemented distal fluvial, shoreface, eolian, and even volcanic units, and led to a well-defined heterogenous hydrostratigraphy. Basinal brines migrated within this hydrostratigraphy and, combined with paleotopography, dolerite intrusion, faulting, and intense burial diagenesis, led to the economically important uranium deposits the Kombolgie Basin hosts. Proterozoic sedimentary basins host many of Earth's largest high-grade iron and uranium deposits that formed in response to the initial oxygenation of the hydrosphere and atmosphere following the Great Oxygenation Event. Unconformity-related uranium mineralization like that found in the Kombolgie Basin highlights the interconnected role that oxygenation of the Earth, sedimentology, stratigraphy, and diagenesis played in creating these deposits.
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Li, Shuang-Qing, Song He, and Fukun Chen. "Provenance changes across the mid-Cretaceous unconformity in basins of northeastern China: Evidence for an integrated paleolake system and tectonic transformation." GSA Bulletin 133, no. 1-2 (June 1, 2020): 185–98. http://dx.doi.org/10.1130/b35660.1.
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Abstract Detrital zircon U-Pb dating and whole-rock Nd isotopic analyses were carried out on selected stratigraphic horizons across a major unconformity between synrift and postrift stages in the Songliao Basin and Dasanjiang basin group of NE China to constrain the crustal evolution of the source area providing detritus into these basins. The strata underlying the mid-Cretaceous unconformity in the Songliao Basin show regionally distinct detrital zircon age populations and Nd isotopic compositions, which generally are characterized by Phanerozoic age peaks and relatively depleted Nd isotopic compositions, indicating derivation from nearby highlands. In contrast, the overlying strata are dominated by Proterozoic zircon ages and enriched Nd isotopic compositions, which imply that the provenance source region shifted to the northern part of the North China craton. A coeval provenance change also affected the sedimentary architecture in the eastern Dasanjiang basin group, marking the migration of erosion centers from west to east. The contribution from Lesser Xing’an–Zhangguangcai ranges was pronounced during deposition of synrift strata but became negligible afterward in the Songliao and Dasanjiang areas, which is consistent with both basin complexes temporarily forming an extensive lake system during the early Late Cretaceous. This paleolake was likely responsible for transgressive events recorded in the Late Cretaceous strata of basins in NE China. Combining observations from seismic reflection profiles and the stratigraphic record of neighboring intracontinental sedimentary basins as well as widespread contemporaneous exhumation and denudation events, we suggest that the provenance variation in basin strata was controlled by large-scale tectonic transitions in East Asia. The switch from extension to contraction during the mid-Cretaceous is attributed to the docking of the Okhotomorsk block along the East Asian continental margin. The resulting lithospheric buckling might have been responsible for reshaping the basin-and-range configuration in NE Asia.
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NEUMANN, N., P. SOUTHGATE, and G. GIBSON. "Defining unconformities in Proterozoic sedimentary basins using detrital geochronology and basin analysis—An example from the Mount Isa Inlier, Australia." Precambrian Research 168, no. 3-4 (February 2009): 149–66. http://dx.doi.org/10.1016/j.precamres.2008.09.012.
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Love, G. D., C. Stalvies, E. Grosjean, W. Meredith, and C. E. Snape. "Analysis of Molecular Biomarkers Covalently Bound Within Neoproterozoic Sedimentary Kerogen." Paleontological Society Papers 14 (October 2008): 67–83. http://dx.doi.org/10.1017/s1089332600001613.
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Catalytic hydropyrolysis (HyPy) is a powerful analytical technique for fragmenting macromolecular organic matter, such as kerogen (insoluble sedimentary organic matter), and releasing covalently-bound molecular constituents including branched and cyclic biomarker hydrocarbons. Here we illustrate our molecular approach to paleobiology with lipid biomarker data collected from rock bitumens and kerogens hosted within sedimentary units of the Neoproterozoic Huqf Supergroup, South Oman Salt Basin, Sultanate of Oman. We emphasize that parallel analyses of free and bound biomarker pools affords more confidence that we have correctly identified syngenetic compounds. One enigmatic class of compounds that is prominent in many late Proterozoic and Cambrian sedimentary rocks and oils, including from the Huqf Supergroup, is a series of C14-C30 mid-chain methylalkanes which were originally denoted X-peaks. Despite their abundance in the Precambrian rock record, little is known about the organisms responsible for their biosynthesis. Here we propose a possible origin of X-peak methylalkanes from colorless sulfur bacteria (a very heterogeneous group of chemolithotrophic γ-proteobacteria). In modern marine settings, these bacteria are abundant mat formers wherever a sedimentary sulfide-rich horizon intersects the seafloor producing a steep geochemical redox gradient. This condition may have been met more commonly on shallow marine shelves in late Neoproterozoic basins and these benthic mats may have acted as environmental buffers consuming hydrogen sulfide. If our hypothesis is correct, proliferation of sulfide-oxidizing benthic microbial mats, commencing in the late Cryogenian in South Oman Salt Basin, implies unique and specific benthic conditions during the evolution of the earliest metazoans.
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Farhoud, Khamis. "Accommodation zones and tectono-stratigraphy of the Gulf of Suez, Egypt: A contribution from aeromagnetic analysis." GeoArabia 14, no. 4 (October 1, 2009): 139–62. http://dx.doi.org/10.2113/geoarabia1404139.
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ABSTRACT This paper starts with an up-to-date literature review of the pre-rift, syn-rift and post-rift stratigraphy of the Gulf of Suez. The geometry and depth of the Proterozoic basement is not generally known due to poor seismic images below the Upper Miocene evaporites (including massive rock salt) and clastics. The pre-rift Paleozoic to Early Oligocene succession shows that several local basins (c. 10s of km in extent) occur in the Gulf, with thick sedimentary sections (e.g. c. 3,000 m for Paleozoic and 1,000 m for Jurassic and Lower Cretaceous). The origin and distribution of these basins is not well understood and the presence of similar pre-rift basins in the southern Gulf is not known to occur. The syn-rift Late Oligocene to Middle Miocene and post-rift Late Miocene – Pliocene successions are widely distributed within the rift basin and reach a thickness in excess of 5,000 m. In order to visualize the grain and relative relief of the Proterozoic basement, a series of aeromagnetic images are shown in this paper. The images include Total Magnetic Intensity (TMI), Reduced-to-Pole (RTP), filtered regional and structural RTP, and Second Vertical Derivative (SVD). The paper also shows a three-dimensional visualization image of the magnetic basement that highlights the distribution of the basins in the Gulf. The magnetic lows do not generally trend along the Suez (NNW-trending Clysmic) Fault, but instead show highly variable orientations attributed to a complex pattern of criss-crossing faults. In particular, two areas were selected to interpret the geometry and depth of the basement. The first area covered the northern Zaafarana Accommodation Zone and involved modeling five aeromagnetic profiles. The Zone was interpreted as an EW-trending basement plateau bounded by basins that are c. 8,000 m deep. The second modeled area (four profiles) covered the southern Morgan Accommodation Zone. This zone was interpreted as an ENE-trending plateau of similar relief to the Zaafarana Zone. The Morgan Zone is terminated in the eastern Gulf by the 8,000-m-deep Morgan Basin. The very deep basins surrounding the two plateaus may contain both pre-rift and syn-rift source rocks, from which the numerous surrounding petroleum fields were sourced.
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Lambeck, Alexis, David Huston, and Karin Barovich. "Typecasting prospective Au-bearing sedimentary lithologies using sedimentary geochemistry and Nd isotopes in poorly exposed Proterozoic basins of the Tanami region, Northern Australia." Mineralium Deposita 45, no. 5 (March 25, 2010): 497–515. http://dx.doi.org/10.1007/s00126-010-0281-z.
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Uysal, I. Tonguç, Claudio Delle Piane, Andrew James Todd, and Horst Zwingmann. "Precambrian faulting episodes and insights into the tectonothermal history of north Australia: microstructural evidence and K–Ar, <sup>40</sup>Ar–<sup>39</sup>Ar, and Rb–Sr dating of syntectonic illite from the intracratonic Millungera Basin." Solid Earth 11, no. 5 (September 4, 2020): 1653–79. http://dx.doi.org/10.5194/se-11-1653-2020.
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Abstract. Australian terranes concealed beneath Mesozoic cover record complex Precambrian tectonic histories involving a successive development of several Proterozoic to Palaeozoic orogenic systems. This study presents an integrated approach combining K–Ar, 40Ar–39Ar, and Rb–Sr geochronologies of Precambrian authigenic illites from the recently discovered Millungera Basin in north-central Australia. Brittle deformation and repeated fault activity are evident from the sampled cores and their microstructures, probably associated with the large-scale faults inferred from interpretations of seismic surveys. Rb–Sr isochron, 40Ar–39Ar total gas, and K–Ar ages are largely consistent in indicating late Mesoproterozoic and early Proterozoic episodes (∼1115±26, ∼ 1070±25, ∼1040±24, ∼1000±23, and ∼905±21 Ma) of active tectonics in north-central Australia. K–Ar results show that illites from fault gouges and authigenic matrix illites in undeformed adjacent sandstones precipitated contemporaneously, indicating that advection of tectonically mobilized fluids extended into the undeformed wall rocks above or below the fracture and shear (fault gouge) zones. Isotopic age data clearly indicate a Mesoproterozoic minimum age for the Millungera Basin and thus previously unrecorded late Mesoproterozoic–early Neoproterozoic tectonic events in north-central Australia. This study provides insight into the enigmatic time–space distribution of Precambrian tectonic zones in central Australia, which are responsible for the formation of a number of sedimentary basins with significant energy and mineral resources.
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Gayer, Rodney A., and Reinhard O. Greiling. "Caledonian nappe geometry in north-central Sweden and basin evolution on the Baltoscandian margin." Geological Magazine 126, no. 5 (September 1989): 499–513. http://dx.doi.org/10.1017/s0016756800022822.
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AbstractStructural analysis of the Lower Allochthon in the north-central Scandinavian Caledonides has allowed the construction of restorable cross-sections consistent with the development of a foreland-propagating linked thrust system. The internal geometry of an antiformal stack, the Njakafjäll duplex, within the Lower Allochthon demonstrates tectonic shortening of c. 50% and suggests an overall predeformational width for the Lower Allochthon in this area of at least c. 130 km, and possibly considerably greater if the buried trailing edge of the Lower Allochthon lies in a comparable position to that farther south in Tröndelag. These results, combined with a stratigraphic analysis of the imbricates within the Lower Allochthon and of the adjoining Autochthon and Middle Allochthon, indicate the development, from Proterozoic through Cambrian times, of two sedimentary basins on the c. 200 km wide continental margin of Baltica bordering the Iapetus Ocean. The basins were separated by a region of basement relief, the Børgefjell domain, above which a reduced sequence of Vendian to Cambrian rocks accumulated. This Børgefjell basement high, and the similar Njakafjäll basement high to the east, subsequently became the sites of antiformal stack development. It is argued that the frequent incorporation of basement into the thrust sheets, together with the thin sedimentary fill of these basins, compared with the much greater fill in basins to the south in Jämtland and to the north of Finnmark, implies major palaeogeographic changes along the Baltoscandian margin, possibly related to early rift geometries. The apparent lack of subsequent foreland basin development in north-central Scandinavia compared with areas to the south may indicate a deeper level of thrust detachment beneath the Middle Allochthon to the north, such that any foreland basin sediments have been removed in the hangingwall and subsequently eroded. An alternative possibility is a primary absence of foreland basin development that may relate to a differing response to thrust loading by continental lithosphere which had been variably thinned during the earlier rift regime.
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Meert, Joseph G., and Manoj K. Pandit. "Chapter 3 The Archaean and Proterozoic history of Peninsular India: tectonic framework for Precambrian sedimentary basins in India." Geological Society, London, Memoirs 43, no. 1 (2015): 29–54. http://dx.doi.org/10.1144/m43.3.
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MADISHEVA, R. K., and V. S. PORTNOV. "ABOUT OIL AND GAS POTENTIAL OF THE ARYSKUM DEPRESSION OF THE SOUTH TORGAI SEDIMENTARY BASIN." Neft i Gaz 131, no. 5 (October 30, 2022): 65–76. http://dx.doi.org/10.37878/2708-0080/2022-5.04.
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The article discusses laboratory studies carried out to compare the composition of oils from Mesozoic and pre-Mesozoic formations: a comprehensive analysis of the molecular composition of oils by chromatography-mass spectrometry; separation and identification of the composition of alkanes by gas-liquid chromatography; NMR-spectroscopic determination of the fragment composition of oils; mass spectrometry was used to determine the isotopic composition of carbon, which identifies the genesis of hydrocarbons in relation to the zones of oil and gas formation. As a result of the study, the laboratory data were obtained, which made it possible to reveal the similarity between oils from deposits of different ages within the graben-synclines, namely, close values of geochemical parameters and the relative content of individual classes of biomarkers made it possible to assume the genetic unity of oils from the Lower Cretaceous and Proterozoic of the Akshabulak graben-syncline and genetic unity of oils from the Lower Cretaceous and Paleozoic of the Aksai horst anticline. The value of the pristane/ phytane ratios indicates a common environment for the formation of the initial organic matter within the structures - suboxidizing conditions in the Akshabulak graben syncline and oxidizing conditions in the Aksai horst anticline, and the existence of a higher redox potential in the Bosingen graben-syncline. Gas- liquid chromatography data showed a slight difference in the thermal transformation of the studied oils, which were classified as "mature". The results of NMR spectrometry in combination with other methods indicate the genetic unity of oils from the Lower Cretaceous and Proterozoic of the Akshabulak graben- syncline and the genetic unity of oils from the Lower Cretaceous and Paleozoic of the Aksai horst anticline. A comparative analysis of the carbon isotopic composition of oils from the Jurassic and Cretaceous deposits of the Aryskum depression and oils from various basins of the world showed a similar range of their variations and a possible genetic relationship of these oils with organic matter of the sapropel type.
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Lockwood, A. M., and C. D’Ercole. "THE EVOLUTION OF THE BERNIER RIDGE, SOUTHERN CARNARVON BASIN, WESTERN AUSTRALIA:IMPLICATIONS FOR PETROLEUM PROSPECTIVITY." APPEA Journal 44, no. 1 (2004): 241. http://dx.doi.org/10.1071/aj03009.
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The basement topography of the Gascoyne Platform and adjoining areas in the Southern Carnarvon Basin was investigated using satellite gravity and seismic data, assisted by a depth to crystalline basement map derived from modelling the isostatic residual gravity anomaly. The resulting enhanced view of the basement topography reveals that the Gascoyne Platform extends further westward than previously indicated, and is bounded by a northerly trending ridge of shallow basement, named the Bernier Ridge.The Bernier Ridge is a product of rift-flank uplift prior to the Valanginian breakup of Gondwana, and lies east of a series of small Mesozoic syn-rift sedimentary basins. Extensive magmatic underplating of the continental margin associated with this event, and a large igneous province is inferred west of the ridge from potential field and seismic data. Significant tectonic events that contributed to the present form of the Bernier Ridge include the creation of the basement material during the Proterozoic assembly of Rodinia, large-scale faulting during the ?Cambrian, uplift and associated glaciation during the early Carboniferous, and rifting of Gondwana during the Late Jurassic. The depositional history and maturity of the Gascoyne Platform and Bernier Ridge show that these terrains have been structurally elevated since the mid-Carboniferous.No wells have been drilled on the Bernier Ridge. The main source rocks within the sedimentary basins west of the Bernier Ridge are probably Jurassic, similar to those in the better-known Abrolhos–Houtman and Exmouth Sub-basins, where they are mostly early mature to mature and within the oil window respectively. Within the Bernier Ridge area, prospective plays for petroleum exploration in the Jurassic succession include truncation at the breakup unconformity sealed by post-breakup shale, and tilted fault blocks sealed by intraformational shale. Plays in the post-breakup succession include stratigraphic traps and minor rollover structures.
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Russell, Michael J. "Comment and Reply on “Ore genesis by episodic dewatering of sedimentary basins: Application to giant Proterozoic lead-zinc deposits”." Geology 13, no. 4 (1985): 318. http://dx.doi.org/10.1130/0091-7613(1985)13<318a:caroog>2.0.co;2.
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Sawkins, Frederick J. "Comment and Reply on “Ore genesis by episodic dewatering of sedimentary basins: Application to giant Proterozoic lead-zinc deposits”." Geology 13, no. 4 (1985): 318. http://dx.doi.org/10.1130/0091-7613(1985)13<318b:caroog>2.0.co;2.
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Gregersen, Ulrik, Paul C. Knutz, Henrik Nøhr-Hansen, Emma Sheldon, and John R. Hopper. "Tectonostratigraphy and evolution of the West Greenland continental margin." Bulletin of the Geological Society of Denmark 67 (July 27, 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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SAHOO, DEBIDARSANI, KAMAL LOCHAN PRUSETH, DEWASHISH UPADHYAY, SAMEER RANJAN, DIPAK C. PAL, RAHUL BANERJEE, and SHEKHAR GUPTA. "New constraints from zircon, monazite and uraninite dating on the commencement of sedimentation in the Cuddapah basin, India." Geological Magazine 155, no. 6 (April 4, 2017): 1230–46. http://dx.doi.org/10.1017/s0016756817000140.
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AbstractThe Cuddapah basin in southern India, consisting of the Palnad, Srisailam, Kurnool and Papaghni sub-basins, contains unmetamorphosed and undeformed sediments deposited during a long span of time in the Proterozoic. In the absence of robust age constraints, there is considerable confusion regarding the relative timing of sedimentation in these sub-basins. In this study, U–Pb isotopic dating of zircon and U–Th–Pbtotaldating of monazite and uraninite from the gritty quartzite that supposedly belongs to the formation Banganapalle Quartzite have been used to constrain the beginning of sedimentation in the Palnad sub-basin. Magmatic and detrital zircons recording an age of 2.53 Ga indicate that the sediments were derived from the granitic basement or similar sources and were deposited after 2.53 Ga. Hydrothermally altered zircons both in the basement and the cover provide concordant ages of 2.32 and 2.12 Ga and date two major hydrothermal events. Thus, the gritty quartzite must have been deposited sometime between 2.53 and 2.12 Ga and represents the earliest sediments in the Cuddapah basin. Monazite and uraninite give a wide spectrum of ages between 2.5 Ga and 150 Ma, which indicates several pulses of hydrothermal activity over a considerable time span, both in the basement granite and the overlying quartzite. The new age constraints suggest that the gritty quartzite may be stratigraphically equivalent to the Gulcheru Quartzite that is the oldest unit in the Cuddapah basin, and that a sedimentary/erosional hiatus exists above it.
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Hughes, G. Wyn, David J. Grainger, Abdul-Jaleel Abu-Bshait, and M. Jarad Abdul-Rahman. "Lithostratigraphy and Depositional History of Part of the Midyan Region, Northwestern Saudi Arabia." GeoArabia 4, no. 4 (October 1, 1999): 503–42. http://dx.doi.org/10.2113/geoarabia0404503.
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ABSTRACT The Midyan region provides a unique opportunity in which to examine exposures of the Upper Cretaceous and Neogene sedimentary succession. Recent investigations have yielded new interpretations of its depositional environments, stratigraphic relationships, and structure. In this paper, all the lithostratigraphic units of the Midyan succession are considered to be informal in advance of an on-going process of formalization. The region is bounded to the north and northeast by mountains of Proterozoic rocks and to the west and south by the Gulf of Aqaba and the Red Sea, respectively. The Wadi Ifal plain occupies most of the eastern half of the region, beneath which is a thick sedimentary succession within the Ifal basin. The oldest sedimentary rocks are the fluviatile Upper Cretaceous Adaffa formation and marine siliciclastics and carbonates of the lower Miocene Tayran group, unconformable on the Proterozoic basement. The Tayran group is unconformably overlain by the deep-marine lower Miocene Burqan formation that, in turn, is overlain by marine mudstones, carbonates, and evaporites of the middle Miocene Maqna group. The poorly exposed middle Miocene Mansiyah and middle to upper Miocene Ghawwas formations consist of marine evaporites and shallow to marginal marine sediments, respectively. The youngest rocks are alluvial sands and gravels of the Pliocene Lisan formation. A complex structural history is due to Red Sea Oligocene-Miocene extension tectonics, and Pliocene-Recent anti-clockwise rotation of the Arabian Plate relative to Africa on the Dead Sea Transform Fault. The Upper Cretaceous succession is a probable pre-rift unit. The Oligocene?-Miocene syn-rift 1 phase of continental extension caused slow subsidence (Tayran group). Syn-rift 2 was an early Miocene phase of rapid subsidence (Burqan formation) whereas syn-rift 3 (early to middle Miocene) was another phase of slow deposition (Maqna group). The middle to late Miocene syn-rift 4 phase coincided with the deposition of the Mansiyah and Ghawwas formations. The Lower Pliocene to Recent succession is related to the drift (post-rift) phase during which about 45 kilometers of sinistral movement occurred on the Dead Sea Fault. The structural control on sedimentation is evident: the Ifal basin was formed by east-west lithospheric extension; pull-apart basins occur along major left-lateral faults on the eastern coast of the Gulf of Aqaba; and basin-bounding faults controlled deposition of the Burqan, Ghawwas, and Lisan formations. Pliocene to Recent earth movements may be responsible for activating salt diapirism in the Ifal basin. Extensive Quaternary faulting and regional uplift caused the uplift of coral reefs to at least 6 to 8 meters above sea level.
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Klitzke, P., J. I. Faleide, M. Scheck-Wenderoth, and J. Sippel. "A lithosphere-scale structural model of the Barents Sea and Kara Sea region." Solid Earth Discussions 6, no. 2 (July 10, 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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Pryer, L. L., K. K. Romine, T. S. Loutit, and R. G. Barnes. "CARNARVON BASIN ARCHITECTURE AND STRUCTURE DEFINED BY THE INTEGRATION OF MINERAL AND PETROLEUM EXPLORATION TOOLS AND TECHNIQUES." APPEA Journal 42, no. 1 (2002): 287. http://dx.doi.org/10.1071/aj01016.
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The Barrow and Dampier Sub-basins of the Northern Carnarvon Basin developed by repeated reactivation of long-lived basement structures during Palaeozoic and Mesozoic tectonism. Inherited basement fabric specific to the terranes and mobile belts in the region comprise northwest, northeast, and north–south-trending Archaean and Proterozoic structures. Reactivation of these structures controlled the shape of the sub-basin depocentres and basement topography, and determined the orientation and style of structures in the sediments.The Lewis Trough is localised over a reactivated NEtrending former strike-slip zone, the North West Shelf (NWS) Megashear. The inboard Dampier Sub-basin reflects the influence of the fabric of the underlying Pilbara Craton. Proterozoic mobile belts underlie the Barrow Sub-basin where basement fabric is dominated by two structural trends, NE-trending Megashear structures offset sinistrally by NS-trending Pinjarra structures.The present-day geometry and basement topography of the basins is the result of accumulated deformation produced by three main tectonic phases. Regional NESW extension in the Devonian produced sinistral strikeslip on NE-trending Megashear structures. Large Devonian-Carboniferous pull-apart basins were introduced in the Barrow Sub-basin where Megashear structures stepped to the left and are responsible for the major structural differences between the Barrow and Dampier Sub-basins. Northwest extension in the Late Carboniferous to Early Permian marks the main extensional phase with extreme crustal attenuation. The majority of the Northern Carnarvon basin sediments were deposited during this extensional basin phase and the subsequent Triassic sag phase. Jurassic extension reactivated Permian faults during renewed NW extension. A change in extension direction occurred prior to Cretaceous sea floor spreading, manifest in basement block rotation concentrated in the Tithonian. This event changed the shape and size of basin compartments and altered fluid migration pathways.The currently mapped structural trends, compartment size and shape of the Barrow and Dampier Sub-basins of the Northern Carnarvon Basin reflect the “character” of the basement beneath and surrounding each of the subbasins.Basement character is defined by the composition, lithology, structure, grain, fabric, rheology and regolith of each basement terrane beneath or surrounding the target basins. Basement character can be discriminated and mapped with mineral exploration methods that use non-seismic data such as gravity, magnetics and bathymetry, and then calibrated with available seismic and well datasets. A range of remote sensing and geophysical datasets were systematically calibrated, integrated and interpreted starting at a scale of about 1:1.5 million (covering much of Western Australia) and progressing to scales of about 1:250,000 in the sub-basins. The interpretation produced a new view of the basement geology of the region and its influence on basin architecture and fill history. The bottom-up or basement-first interpretation process complements the more traditional top-down seismic and well-driven exploration methods, providing a consistent map-based regional structural model that constrains structural interpretation of seismic data.The combination of non-seismic and seismic data provides a powerful tool for mapping basement architecture (SEEBASE™: Structurally Enhanced view of Economic Basement); basement-involved faults (trap type and size); intra-sedimentary geology (igneous bodies, basement-detached faults, basin floor fans); primary fluid focussing and migration pathways and paleo-river drainage patterns, sediment composition and lithology.
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Zhirnov, A. M. "On the vertical growth of continents in deep depressions of the Earth’s peridotite mantle." LITHOSPHERE (Russia) 20, no. 5 (October 30, 2020): 727–45. http://dx.doi.org/10.24930/1681-9004-2020-20-5-727-745.
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Research subject. The geological structure and evolution of the Earth’s continents.Methods. This article is based on a long-term study and review of geological, geophysical and bathymetric published data, as well as on an analysis of the major geological discoveries of the 20th century.Results and conclusions. It is established that all the continents on the Earth, except for Antarctica, constitute a single Northen megamaterik, which was being formed during a prolonged period of time (4.4 billion years) in a deep three-beam cavity on the surface of the peridotite mantle. The ancient Hadean– Archean basement of the megacontinent was being formed during the period of 3 billion years, which comprises about 70% of the Earth’s geological history. In the Late Proterozoic and Phanerozoic, periodically formed local depressions were flooded with sedimentary material leading to the formation of sedimentary basins and folded rock structures. As a result, the thickness of the megacontinent’s crust steadily increased reaching a large size of 15–40 or 60–70 km. During this period, the primary oceanic (peridotite) crust with a thickness of 3–5 km remained unchanged until the Mesozoic–Cenozoic, when it was covered with a layer of younger basalts and loose rock sediments with a thickness of 1–2 km.
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Burrett, M. R. Bendall C. F., and H. J. Askin. "PETROLEUM SYSTEMS IN TASMANIA'S FRONTIER ONSHORE BASINS." APPEA Journal 40, no. 1 (2000): 26. http://dx.doi.org/10.1071/aj99002.
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Sedimentary successions belonging to three petroleum su persy stems can be recognised in and below the Late Carboniferous to Late Triassic onshore Tasmania Basin. These are the Centralian, Larapintine and Gondwanan. The oldest (Centralian) is poorly known and contains possible mature source rocks in Upper Proterozoic dolomites. The Larapintine 2 system is represented by rocks of the Devonian fold and thrust belt beneath the Tasmania Basin. Potential source rocks are micrites and shales within the 1.8 km-thick tropical Ordovician Gordon Group carbonates. Conodont CAI plots show that the Gordon Group lies in the oil and gas windows over most of central Tasmania and probably under much of the Tasmania Basin. Potential reservoirs are the upper reefal parts of the Gordon Group, paleokarsted surfaces within the Gordon Group and the overlying sandstones of the Siluro-Devonian Tiger Range and Eldon Groups. Seal rocks include shales within the Siluro-Devonian and Upper Carboniferous-Permian tillites and shales.The Gondwanan supersystem is the most promising supersystem for petroleum exploration within the onshore Tasmania Basin. It is divided into two petroleum systems— the Early Permian Gondwanan 1 system, and the Late Permian to Triassic Gondwanan 2 system. Excellent source rocks occur in the marine Tasmanite Oil Shale and other sections within the Lower Permian Woody Island and Quamby Formations of the Gondwanan 1 system and within coals and freshwater oil shales of the Gondwanan 2 system. These sources are within the oil and gas windows across most of the basin and probably reached peak oil generation at about 100 Ma. An oil seep, sourced from a Tasmanites-rich, anoxic shale, is found within Jurassic dolerite 40 km WSW of Hobart. Potential Gondwanan 1 reservoirs are the glaciofluvial Faulkner Group sandstones and sandstones and limestones within the overlying parts of the glaciomarine Permian sequence. The Upper Permian Ferntree Mudstone Formation provides an effective regional seal. Potential Gondwanan 2 reservoirs are the sandstones of the Upper Permian to Norian Upper Parmeener Supergroup. Traps consisting of domes, anticlines and faults were formed probably during the Early Cretaceous. Preliminary interpretation of a short AGSO seismic profile in the Tasmania Basin shows that, contrary to earlier belief, structures can be mapped beneath extensive and thick (300 m) sills of Jurassic dolerite. In addition, the total section of Gondwana to Upper Proterozoic to Triassic sediments appears to be in excess of 8,500 m. These recent studies, analysis of the oil seep and drilling results show that the Tasmanian source rocks have generated both oil and gas. The Tasmania Basin is considered prospective for both petroleum and helium and is comparable in size and stratigraphy to other glaciomarine-terrestrial Gondwanan basins such as the South Oman and Cooper Basins.
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Verlekar, Purushottam Anil, and Mahender Kotha. "Provenance, tectonics and palaeo environment of Mesoproterozoic Saundatti Quartzite Member of Kaladgi Basin, India: A petrographic view." Journal of The Indian Association of Sedimentologists 37, no. 2 (December 31, 2020): 91–102. http://dx.doi.org/10.51710/jias.v37i2.101.
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The Kaladgi Basin, one of the important Proterozoic Sedimentary basins of Peninsular India, exposes a thick sequence of Proterozoic succession composed of a variety of lithologies with predominance of arenaceous rocks interrupted with Carbonate sediments at different stratigraphic levels. The present work focuses mainly on understanding the Sedimentological nature and diagenetic character of the Lower part of the Lokapur sub-group rocks that are exposed in and around Savadatti Town, Belagavi District of Karnataka. These rocks are mainly composed of Arenite sequences of varying grain size. The clastic succession comprises lithologies Sandstones with minor conglomeratic facies at the lower regimes. An attempt is made to identify the detailed petrographic character of the sandstones to understand the provenance and depositional environments based on the detailed petrographic observation. The study suggests that the coarse clastic conglomerates are essentially polymictic types and the sandstones are sub-mature to mature (mineralogically), medium to coarse grained and can be categorized mainly into lithic/feldspathic and quartz arenites. Minor occurance of feldspars as the framework constituent also suggests that the rock have undergone considerable transport. However with their variable degree of alteration (from fresh to partially alter to completely altered grains) associated with textural maturity and nature of Quartz point towards the possibility of derivation of these sediments from two different sources. Palaeocurrent data that indicate a NW palaeoslope suggest the derivation of sediments from a variety of granitic and gnesssic crystalline complexes occurring along the basin margin. The maturity of the sandstones (Quartz Arenites) is attributed to the recycling and re-working of the older sediments. Analysis of Textural parameters of these rocks pointed towards deposition under beach environments. The lack in preservation of much amount of feldspar in these sandstones is indicates a remote source and relatively dry-arid climate of the source area.
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ZHANG, J., and D. CUNNINGHAM. "Polyphase transpressional development of a NNE-striking basement-cored anticline in the Xining Basin, northeastern Qinghai–Tibetan Plateau." Geological Magazine 150, no. 4 (January 23, 2013): 626–38. http://dx.doi.org/10.1017/s0016756812000866.
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AbstractThe Xiaoxia anticline is a basement-cored fold in the northeastern Qinghai–Tibetan Plateau. It formed during the Middle–Late Cenozoic in a NNE-orientation oblique to prevailing WNW-striking thrusts in the surrounding region. The fold lies within the fault-bounded Xining Basin, which has behaved as a clockwise rotating and internally deforming block during the mid–late Tertiary. Proterozoic crystalline basement rocks and Jurassic–Cretaceous–Cenozoic terrestrial sediments exposed within the fold record three separate oblique-slip deformation events as determined by cross-cutting generations of faults and folds. The modern Xiaoxia anticline developed by: (1) outward-directed thrusting on the two fold limbs and, (2) oblique-slip thrusting on closely spaced minor NNE-striking faults that caused distributed uplift and passive shear folding of the sedimentary cover within the fold core. Tilted and thrusted river terraces on the flanks of the Xiaoxia anticline dated by optically stimulated luminescence and electron spin resonance indicate that folding has continued into the Late Quaternary (post-45.5 ± 5.5 ka) and therefore may still be active today. The development of the Xiaoxia anticline appears to be best explained in the context of the kinematic evolution of the Xining Basin's bounding strike-slip faults. Formation of the Xiaoxia anticline demonstrates that partitioned transpression in an evolving transpressional setting can invert intra-montane basins and produce basement-cored folds, thereby contributing to regional plateau uplift.
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Friedmann, S. Julio, and John P. Grotzinger. "Sedimentology, stratigraphy, and tectonic implications of a paleo-Proterozoic continental extensional basin: the El Sherana – Edith River groups, Northern Territory, Australia." Canadian Journal of Earth Sciences 31, no. 4 (April 1, 1994): 748–64. http://dx.doi.org/10.1139/e94-068.
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The ca. 1.83 Ga El Sherana – Edith River basin of Northern Territory, Australia, contains terrestrial sedimentary and volcanic rocks deposited during continental extension or transtension. Braid-plain sandstones and conglomerates, turbiditic sediments, and interbedded mafic and felsic volcanics, including ignimbrites, filled the basin. Alluvial fans and rock avalanche breccias are locally developed. Prebasinal structure controlled antecedent topography and influenced drainage patterns, thickness changes, and facies distribution.Unconformities bound all formations of the El Sherana and Edith River groups, revealed by beveled and incised strata, reversals in paleocurrent trends, sharp discordance in juxtaposed facies, and paleovalleys filled with unique sediments. Scarp-derived sediments are preserved only in a small, transfer-related strike-slip basin within the larger basin environment. Unconformities are regional and are interpreted as time lines throughout the basin. These unconformities developed during regrading of slopes forced by active tectonism, accompanied by syntectonic sedimentation and basin depocenter migration.The El Sherana – Edith River strata overlie older sediments (~2.1–1.88 Ga) of the Pine Creek orogen, which formed during a period of global orogeny related to continental assembly. Development of the El Sherana – Edith River basin began substantially (40–50 Ma) after denudation of the Pine Creek orogen belt, and is related to regional postcollisional extension. This extension is recorded by basin formation, bimodal tholeiitic and alkalic magmatism, and elevated geotherms. Other paleo-Proterozoic basins of northern Australia show a similar history of rift deposition above a fossil compressional belt.
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Botor, Dariusz, Stanisław Mazur, Aneta A. Anczkiewicz, István Dunkl, and Jan Golonka. "Thermal history of the East European Platform margin in Poland based on apatite and zircon low-temperature thermochronology." Solid Earth 12, no. 8 (August 20, 2021): 1899–930. http://dx.doi.org/10.5194/se-12-1899-2021.
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Abstract. The Phanerozoic tectonothermal evolution of the SW slope of the East European Platform (EEP) in Poland is reconstructed by means of thermal maturity, low-temperature thermochronometry, and thermal modelling. We provide a set of new thermochronometric data and integrate stratigraphic and thermal maturity information to constrain the burial and thermal history of sediments. Apatite fission track (AFT) analysis and zircon (U-Th)/He (ZHe) thermochronology have been carried out on samples of sandstones, bentonites, diabase, and crystalline basement rocks collected from 17 boreholes located in central and NE Poland. They penetrated sedimentary cover of the EEP subdivided from the north to south into the Baltic, Podlasie, and Lublin basins. The average ZHe ages from Proterozoic basement rocks as well as Ordovician to Silurian bentonites and Cambrian to lower Carboniferous sandstones range from 848 ± 81 to 255 ± 22 Ma with a single early Permian age of 288 Ma, corresponding to cooling after a thermal event. The remaining ZHe ages represent partial reset or source ages. The AFT ages of samples are dispersed in the range of 235.8 ± 17.3 Ma (Middle Triassic) to 42.1 ± 11.1 Ma (Paleogene) providing a record of Mesozoic and Cenozoic cooling. The highest frequency of the AFT ages is in the Jurassic and Early Cretaceous prior to Alpine basin inversion. Thermal maturity results are consistent with the SW-ward increase of the Paleozoic and Mesozoic sediments thickness. An important break in a thermal maturity profile exists across the base Permian–Mesozoic unconformity. Thermal modelling showed that significant heating of Ediacaran to Carboniferous sedimentary successions occurred before the Permian with maximum paleotemperatures in the earliest and latest Carboniferous for Baltic–Podlasie and Lublin basins, respectively. The results obtained suggest an important role of early Carboniferous uplift and exhumation at the SW margin of the EEP. The SW slope of the latter was afterward overridden in the Lublin Basin by the Variscan orogenic wedge. Its tectonic loading interrupted Carboniferous uplift and caused resumption of sedimentation in the late Viséan. Consequently, a thermal history of the Lublin Basin is different from that in the Podlasie and Baltic basins but similar to other sections of the Variscan foreland, characterized by maximum burial at the end of Carboniferous. The Mesozoic thermal history was characterized by gradual cooling from peak temperatures at the transition from Triassic to Jurassic due to decreasing heat flow. Burial caused maximum paleotemperatures in the SW part of the study area, where the EEP was covered by an extensive sedimentary pile. However, further NE, due to low temperatures caused by shallow burial, the impact of fluids can be detected by vitrinite reflectance, illite/smectite, and thermochronological data. Our new results emphasize the importance of using multiple low-temperature thermochronometers and thermal modelling in connection with thermal maturity analysis to elucidate the near-surface evolution of platform margins.
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Seeley, John M., and G. Randy Keller. "Delineation of subsurface Proterozoic Unkar and Chuar Group sedimentary basins in northern Arizona using gravity and magnetics: Implications for hydrocarbon source potential." AAPG Bulletin 87, no. 8 (August 2003): 1299–321. http://dx.doi.org/10.1306/031903200198.
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Perron, Paul, Michel Guiraud, Emmanuelle Vennin, Isabelle Moretti, Éric Portier, Laetitia Le Pourhiet, and Moussa Konaté. "Influence of basement heterogeneity on the architecture of low subsidence rate Paleozoic intracratonic basins (Reggane, Ahnet, Mouydir and Illizi basins, Hoggar Massif)." Solid Earth 9, no. 6 (November 7, 2018): 1239–75. http://dx.doi.org/10.5194/se-9-1239-2018.
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Abstract. The Paleozoic intracratonic North African Platform is characterized by an association of arches (ridges, domes, swells, or paleo-highs) and low subsidence rate syncline basins of different wavelengths (75–620 km). The Reggane, Ahnet, Mouydir and Illizi basins are successively delimited from east to west by the Amguid El Biod, Arak-Foum Belrem, and Azzel Matti arches. Through the analysis of new unpublished geological data (i.e., satellite images, well logs, seismic lines), the deposits associated with these arches and syncline basins exhibit thickness variations and facies changes ranging from continental to marine environments. The arches are characterized by thin amalgamated deposits with condensed and erosional surfaces, whereas the syncline basins exhibit thicker and well-preserved successions. In addition, the vertical facies succession evolves from thin Silurian to Givetian deposits into thick Upper Devonian sediments. Synsedimentary structures and major unconformities are related to several tectonic events such as the Cambrian–Ordovician extension, the Ordovician–Silurian glacial rebound, the Silurian–Devonian Caledonian extension/compression, the late Devonian extension/compression, and the Hercynian compression. Locally, deformation is characterized by near-vertical planar normal faults responsible for horst and graben structuring associated with folding during the Cambrian–Ordovician–Silurian period. These structures may have been inverted or reactivated during the Devonian (i.e., Caledonian, Mid–Late Devonian) compression and the Carboniferous (i.e., pre-Hercynian to Hercynian). Additionally, basement characterization from geological and geophysics data (aeromagnetic and gravity maps), shows an interesting age-dependent zonation of the terranes which are bounded by mega-shear zones within the arches–basins framework. The old terranes are situated under arches while the young terranes are located under the basins depocenter. This structural framework results from the accretion of Archean and Proterozoic terranes inherited from former orogeny (e.g., Pan-African orogeny 900–520 Ma). Therefore, the sedimentary infilling pattern and the nature of deformation result from the repeated slow Paleozoic reactivation of Precambrian terranes bounded by subvertical lithospheric fault systems. Alternating periods of tectonic quiescence and low-rate subsidence acceleration associated with extension and local inversion tectonics correspond to a succession of Paleozoic geodynamic events (i.e., far-field orogenic belt, glaciation).
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Alexandrino, Carlos, and Valiya Hamza. "Terrestrial Heat Flow in Non-Thermal Ground Water Circulation Settings of Brazil." International Journal of Terrestrial Heat Flow and Applications 1, no. 1 (April 26, 2018): 46–51. http://dx.doi.org/10.31214/ijthfa.v1i1.19.
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Data on Silica content of ground waters have been employed in obtaining estimates of heat flow for more than 500 localities, distributed over six tectonic provinces in Brazil. The procedure adopted is based on the use of an improved geo-thermometry relation for solubility of silica in ground waters. It is coupled with a revised interpretation of the empirical relation between silica content and heat flow, that allows for independent determination of the depth of circulation of ground waters. According to the results obtained mean heat flow values obtained for sedimentary areas of the late Proterozoic Sao Francisco basin and the Paleozoic Amazon basins are in the range of 45 to 47mW/m2. Similar range of heat flow values were found for the Precambrian Borborema province in the northeastern region of Brazil. Higher heat flow values of greater than 50mW/m2 were encountered for the eastern coastal area of Sergipe – Alagoas. On the other hand, Parana basin in southeast Brazil is found to have heat flow values higher than 55mW/m2. Such ranges of mean heat flow values are found to be in reasonably good agreement with those reported in earlier studies, using conventional methods. This trend is considered as indication that silica content of ground waters may be used for obtaining reliable estimates of conductive heat flow in areas where practical limitations impede use of conventional methods.
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Baludikay, Blaise K., Camille François, Marie Catherine Sforna, Jérémie Beghin, Yohan Cornet, Jean-Yves Storme, Nathalie Fagel, et al. "Raman microspectroscopy, bitumen reflectance and illite crystallinity scale: comparison of different geothermometry methods on fossiliferous Proterozoic sedimentary basins (DR Congo, Mauritania and Australia)." International Journal of Coal Geology 191 (April 2018): 80–94. http://dx.doi.org/10.1016/j.coal.2018.03.007.
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Belgarde, Catherine, Gianreto Manatschal, Nick Kusznir, Sonia Scarselli, and Michal Ruder. "Rift processes in the Westralian Superbasin, North West Shelf, Australia: insights from 2D deep reflection seismic interpretation and potential fields modelling." APPEA Journal 55, no. 2 (2015): 400. http://dx.doi.org/10.1071/aj14035.
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Acquisition of long-offset (8–10 km), long-record length (12–18 sec), 2D reflection seismic and ship-borne potential fields data (WestraliaSpan by Ion/GXT and New Dawn by PGS) on the North West Shelf of Australia provide the opportunity to study rift processes in the context of modern models for rifted margins (Manatschal, 2004). Basement and Moho surfaces were interpreted on seismic reflection data. Refraction models from Geoscience Australia constrain Moho depth and initial densities for gravity modelling through standard velocity-density transformation. 2D joint inversion of seismic reflection and gravity data for Moho depth and basement density constrain depth to basement on seismic. 2D gravity and magnetic intensity forward modelling of key seismic lines constrain basement thickness, type and density. Late Permian and Jurassic-Early Cretaceous rift zones were mapped on seismic reflection data and constrained further by inversion and forward modelling of potential fields data. The Westralian Superbasin formed as a marginal basin in Eastern Gondwana during the Late Permian rifting of the Sibumasu terrane. Crustal necking was localised along mechanically-weak Proterozoic suture belts or Early Paleozoic sedimentary basins (such as Paterson and Canning). Mechanically-strong cratons (such as Pilbara and Kimberley) remained intact, resulting in necking and hyper-extension at their edges. Late Permian hyper-extended areas (such as Exmouth Plateau) behaved as mechanically-strong blocks during the Jurassic to Early Cretaceous continental break-up. Late Permian necking zones were reactivated as failed-rift basins and localised the deposition of the Jurassic oil-prone source rocks that have generated much of the oil discovered on the North West Shelf.
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Andrejewskis, A. J. "ONSHORE ACREAGE RELEASE 2001." APPEA Journal 41, no. 2 (2001): 86. http://dx.doi.org/10.1071/aj00056.
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It is my privilege to present the onshore acreage release for the year 2001 on behalf of the States and Territories.I will be presenting the information as supplied to me by each department of the States and Territories.Before doing so, I would like to make a few remarks. Many of these will be familiar to you, but I believe bear repeating to remind ourselves.While there appears to be a resurgence of onshore interest and activity, last year saw the lowest level of onshore exploration activity in many years.At the risk of being emotive, Australia does not deserve this poor level of exploration activity.Australia has vast sedimentary basins, and these are under-explored by any world standards. Targets range from Palaeogoics (even neo-Proterozoic) to Tertiary.Australia needs:To have innovative concepts.The drive to carry out these concepts.Support of the governments and community.Financial backing of good ideas and good people.Land access.While this list is not exhaustive, it does encapsulate the key issues.The opportunities for onshore oil and gas successes are vast so I urge all in the industry to pursue these opportunities.And now, I turn to each state, starting with Queensland.
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Hassler, Scott W., and Bruce M. Simonson. "Deposition and alteration of volcaniclastic strata in two large, early Proterozoic iron-formations in Canada." Canadian Journal of Earth Sciences 26, no. 8 (August 1, 1989): 1574–85. http://dx.doi.org/10.1139/e89-134.
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The Gunflint Iron-formation of western Ontario and the Sokoman Iron-formation of the Labrador–Quebec geosyncline both contain interbeds of coarse-grained volcaniclastic detritus. Volcaniclastic beds in the Gunflint are typically less than a metre thick and display normal grading and other physical structures typical of high- and low-density turbidites. Similar volcaniclastic beds are present in the Sokoman, as well as thicker accumulations with structures indicative of deposition from high-density turbidity currents. The volcaniclastic detritus in both iron-formations consists largely of well-sorted vitric ash and lapilli with accessory holocrystalline grains and solitary feldspar crystals. Internal textures of the vitric grains, plus the presence of armored lapilli in the Gunflint, suggest they are products of hydroclastic eruptions. However the clasts in most beds are heterogeneous and well-rounded, indicating they are sedimentary rather than eruptive deposits. Quench textures, coalesced vesicles, and diabasic textures indicate that the volcaniclastics were originally basaltic in composition, but the rocks have been pervasively altered to iron-rich chlorite, calcite, and K-feldspar (Or98 Ab2 An0) with minor quartz and illite. In addition to being pseudomorphs after the original volcaniclastic textures within grains, these minerals also occur as interstitial and vesicle-filling cements. Fibrous rims of chlorite and poikilotopic to blocky calcite are the most abundant cement types. Cementation commenced early, inasmuch as some zones show little evidence of compaction. Patterns of cementation and alteration may indicate that geothermal gradients in such iron-formation basins were steeper than they are in the most closely comparable modern settings, namely passive margins.
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Wang, Yumeng, Guoxiang Chi, Zenghua Li, and Sean Bosman. "Large-scale thermal convection in sedimentary basins revealed by coupled quartz cementation-dissolution distribution pattern and reactive transport modeling – a case study of the Proterozoic Athabasca Basin (Canada)." Earth and Planetary Science Letters 574 (November 2021): 117168. http://dx.doi.org/10.1016/j.epsl.2021.117168.
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Nelson, R. G., T. N. Crabb, and R. A. Gerdes. "A REVIEW OF GEOPHYSICAL EXPLORATION IN THE POLDA BASIN, SOUTH AUSTRALIA." APPEA Journal 26, no. 1 (1986): 319. http://dx.doi.org/10.1071/aj85028.
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The Polda Basin is an intracratonic basin, at least 5000 m in depth, extending from the edge of the Great Australian Bight nearly 400 km east to the centre of Eyre Peninsula in southern South Australia, it can now be recognised as a structural feature of some antiquity, originating possibly as a crustal downwarp in Proterozoic time during the same orogenic regime that gave rise to the Officer and Amadeus basins of central Australia, with which it has strong affinities. Its internal structure indicates that it has been subject to the same orogenic episodes that have affected southern and central Australia, culminating in rotational block faulting associated with the final pull-apart of Gondwanaland. Extensive salt mobilisation observed on seismic sections, confirmed by the drilling of the Mercury 1 and Columbia 1 wells, supports the concept of the basin's Cambrian or Precam-brian origins.The exploration history of the basin is a useful example of the application of a number of geophysical disciplines to arrive at a satisfactory interpretation. A reappraisal of geophysical data was undertaken after Outback Oil N.L. drillhole Gemini 1 penetrated 'uneconomic' basement at 856 m, far short of the anticipated sedimentary section of 1830-2440 m. Interpretation of shipborne magnetic data, not previously considered, indicated that a seismic horizon close to where Gemini 1 penetrated igneous rock was related to a thin layer of magnetic material which did not correspond to deep magnetic basement. Further detailed aeromagnetic and seismic studies confirmed this interpretation, which was tested by the drilling of two exploration wells. Mercury 1 and Columbia 1. Although unsuccessful as hydrocarbon discovery wells, these two wells confirmed the overall validity of the interpretation. Stratigraphic information derived from these wells and from further geophysical studies and drilling onshore have led to a new assessment of the basin and its potential.
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Cathles, Lawrence, and Alain Prinzhofer. "What Pulsating H2 Emissions Suggest about the H2 Resource in the Sao Francisco Basin of Brazil." Geosciences 10, no. 4 (April 17, 2020): 149. http://dx.doi.org/10.3390/geosciences10040149.
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Proterozoic sedimentary basins very often emit natural hydrogen gas that may be a valuable part of a non-carbon energy infrastructure. Vents in the Sao Francisco Basin in Brazil release hydrogen to the atmosphere mainly during the daylight half of the day. Daily temperature and the regular daily tidal atmospheric pressure variations have been suggested as possible causes of the pulsing of H2 venting. Here, we analyze a ~550 m-diameter depression that is barren of vegetation and venting hydrogen mainly at its periphery. We show that daily temperature changes propagated only ~1/2 m into the subsurface and are thus too shallow to explain the H2 variations measured at 1-m depth. Pressure changes could propagate deeply enough, and at the depth at which the cyclic variations are measured hydrogen concentration will have the observed phase relationship to atmospheric pressure changes provided: (1) the pressure wave is terminated by geologic barriers at about 25% of its full potential penetration distance, and (2) the volume of gas in the vents is very small compared to the volume of gas tapped by the venting. These constraints suggest that there is a shallow gas reservoir above the water table under the ~550 m-diameter barren-of-vegetation depression. The 1D-analytical and finite-element calculations presented in this paper help define the hydrogen system and suggest the further steps needed to characterize its volume, hydrogen flux and resource potential.