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1
Scharf, Andreas, Frank Mattern, Mohammed Al-Wardi, et al. "Chapter 2 Tectonostratigraphy of the eastern part of the Oman Mountains." Geological Society, London, Memoirs 54, no. 1 (2021): 11–47. http://dx.doi.org/10.1144/m54.2.
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AbstractThis chapter provides comprehensive descriptions of 52 numbered formations/rock units of the Southeastern Oman Mountains, based on available literature. The oldest eight siliciclastic and carbonate formations are positioned below the ‘Hercynian’ Unconformity. The overlying formation (9–16) mostly represent carbonates which accumulated in a passive margin platform setting during or after the opening of the Neo-Tethys Ocean. The passive margin slope and platform collapsed during the late Cretaceous because of the obduction of the Semail Ophiolite along with the deep marine Hawasina sedimentary rocks. The collapsing passive margin interval was recorded within the syn-obductional Aruma Group (17; Muti Formation). Above this formation are the allochthonous units (18–42) of the tectonically lower Hawasina deep-sea basin and the structurally overlying Semail Ophiolite. The former contains Permian to Upper Cretaceous formations, while the latter is Cenomanian in age. Above the allochthonous rocks, the Neo-autochthonous formations were deposited, starting with the post-obductional uppermost Cretaceous Aruma Group (43; Al-Khod Formation) until the Quaternary deposits (52). All these formations/rock units are depicted on an accompanying map and stratigraphic chart.
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Peace, Alexander L., and J. Kim Welford. "Conjugate margins — An oversimplification of the complex southern North Atlantic rift and spreading system?" Interpretation 8, no. 2 (2020): SH33—SH49. http://dx.doi.org/10.1190/int-2019-0087.1.
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The prevalence of conjugate margin terminology and studies in the scientific literature is testimony to the contribution that this concept and approach has made to the study of passive margins, and more broadly extensional tectonics. However, when applied to the complex rift, transform, and spreading system of the southern North Atlantic (i.e., the passive margins of Newfoundland, Labrador, Ireland, Iberia, and southern Greenland), it becomes obvious that at these passive continental margin settings, additional geologic phenomena complicate this convenient description. These aspects include (1) the preservation of relatively undeformed continental fragments, (2) formation of transform systems and oblique rifts, (3) triple junctions (with rift and spreading axes), (4) multiple failed rift axes, (5) postbreakup processes such as magmatism, (6) localized subduction, and (7) ambiguity in identification of oceanic isochrons. Comparison of two different published reconstructions of the region indicates the ambiguity in conducting conjugate margin studies. This demonstrates the need for a more pragmatic approach to the study of continental passive margin settings where a greater emphasis is placed on the inclusion of these possibly complicating features in palinspastic reconstructions, plate tectonics, and evolutionary models.
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Tuitt, Adrian, Simon Holford, Richard Hillis, et al. "Continental margin compression: a comparison between compression in the Otway Basin of the southern Australian margin and the Rockall-Faroe area in the northeast Atlantic margin." APPEA Journal 51, no. 1 (2011): 241. http://dx.doi.org/10.1071/aj10017.
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There is growing recognition that many passive margins have undergone compressional deformation subsequent to continental breakup, including the southern Australian margin. This deformation commonly results in formation of domal anticlines with four-way dip closures that are attractive targets for hydrocarbon exploration, and many such structures host major hydrocarbon accumulations in the Otway and Gippsland basins; however, the driving mechanisms behind formation of these structures are not completely understood. We compare the history of post-breakup compression in the Otway Basin of the southern Australian margin, with that of the Rockall-Faroe area of the northeast Atlantic margin, which has been far more extensively studied with the aim of establishing a better understanding of the genesis and prospectivity of such structures. Both margins have experienced protracted Mesozoic rifting histories culminating in final continental separation in the Eocene, followed by distinct phases of compressional deformation and trap formation. Whilst the structural style of the anticlines in both margins is similar (mainly fault-propagation folds formed during tectonic inversion), the number, amplitude, and length of the structures in the northeast Atlantic margin are much higher than the southern Australian margin. We propose that compressional structures at both margins formed due to far-field stresses related to plate boundaries, but the magnitude of these stresses in the northeast Atlantic margin is likely to have been higher, and the strength of the lithosphere lower. In the northeast Atlantic margin, the presence of Early Cenozoic basalt lava flows may have also contributed to an increase in pore-fluid pressure in the underlying sediment making pre-existing faults more prone to reactivation.
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Archer, D. E., and B. A. Buffett. "A two-dimensional model of the methane cycle in a sedimentary accretionary wedge." Biogeosciences Discussions 9, no. 3 (2012): 2967–3002. http://dx.doi.org/10.5194/bgd-9-2967-2012.
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Abstract. A two-dimensional model of sediment column geophysics and geochemistry has been adapted to the problem of an accretionary wedge formation, patterned after the margin of the Juan de Fuca plate as it subducts under the North American plate. Much of the model description was given in a companion paper about application of the model to a passive margin setting; here we build on that formulation to simulate the deformation of the sediment wedge as it approaches the subduction zone. The active margin configuration of the model shares sensitivities with the passive margin configuration, in that sensitivities to organic carbon deposition and respiration kinetics, and to vertical bubble transport and redissolution in the sediment, are stronger than the sensitivity to ocean temperature. The active margin simulation also shows a sensitivity to plate subduction velocity, with higher plate velocities producing less hydrate per meter of coastline than slower velocities or the passive margin configuration. However, the local hydrate concentrations, as pore volume saturation, are higher in the active setting than the passive, as generally observed in the field.
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Archer, D. E., and B. A. Buffett. "A two-dimensional model of the methane cycle in a sedimentary accretionary wedge." Biogeosciences 9, no. 8 (2012): 3323–36. http://dx.doi.org/10.5194/bg-9-3323-2012.
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Abstract. A two-dimensional model of sediment column geophysics and geochemistry has been adapted to the problem of an accretionary wedge formation, patterned after the margin of the Juan de Fuca plate as it subducts under the North American plate. Much of the model description is given in a companion paper about the application of the model to an idealized passive margin setting; here we build on that formulation to simulate the impact of the sediment deformation, as it approaches the subduction zone, on the methane cycle. The active margin configuration of the model shares sensitivities with the passive margin configuration, in that sensitivities to organic carbon deposition and respiration kinetics, and to vertical bubble transport and redissolution in the sediment, are stronger than the sensitivity to ocean temperature. The active margin simulation shows a complex sensitivity of hydrate inventory to plate subduction velocity, with results depending strongly on the geothermal heat flux. In low heat-flux conditions, the model produces a larger inventory of hydrate per meter of coastline in the passive margin than active margin configurations. However, the local hydrate concentrations, as pore volume saturation, are higher in the active setting than in the passive, as generally observed in the field.
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Galyamov, A. L., A. V. Volkov, K. V. Lobanov, and K. Y. Murashov. "Prospects for identifying strategic metals deposits in the Russian Arctic." Arctic: Ecology and Economy, no. 1(25) (March 2017): 59–74. http://dx.doi.org/10.25283/2223-4594-2017-1-59-74.
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Mineral deposits are important in the economy of the Russian Arctic. In addition to the petroleum and gas, the resources of PGE minerals and gold, nickel and titanium are more than 10% of global significance. Meanwhile, the most arctic territory is out of availability of detailed geological and geophysical data due to severe climatic situation. The spatial relations of ore deposits and ore-bearing sequences of different geodynamic settings at Russia territory show that the geological sequences of three basic types of geodynamic environment contain an overwhelming number (over 70%) deposits: archaean-proterozoic basement, passive continental margin, volcanic arcs of active margins. There are two groups of ore types. The first are the types (i.e. BIF) are specific to definite sedimentary or igneous rocks, the second (i.e. gold veins etc.) are due to superimposed geotectonic processes. The complex metallogeny may be found in the subductional and accretional terrains, where the blocks of different geodynamic formation are combined. In these areas ores, previously deposited, might been transformed under the later processes until the regeneration and development of new type ores. The convergence of passive margins also might had caused the changes of geodynamic environments and led to form the vertical and lateral facies with metallogenic features combined. In Arctic regions, despite the similar ratio formation areas, the relative number of discovered and evaluated ore deposits is low in areas of active margin, including volcanic arcs and collision. This is especially true for deposits of lead and zinc, ferrous and rare metals. The significant lack of gold deposits is evident. In the areas of passive margin facies the most hidden deposits are of rare and ferrous metals, as well as lead, zinc and gold.
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Beranek, Luke P., Victoria Pease, Robert A. Scott, and Tonny B. Thomsen. "Detrital zircon geochronology of Ediacaran to Cambrian deep-water strata of the Franklinian basin, northern Ellesmere Island, Nunavut: implications for regional stratigraphic correlations." Canadian Journal of Earth Sciences 50, no. 10 (2013): 1007–18. http://dx.doi.org/10.1139/cjes-2013-0026.
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Enigmatic successions of deep-water strata referred to as the Nesmith beds and Grant Land Formation comprise the exposed base of the Franklinian passive margin sequence in northern Ellesmere Island, Nunavut. To test stratigraphic correlations with Ediacaran to Cambrian shallow-water strata of the Franklinian platform that are inferred by regional basin models, >500 detrital zircons from the Nesmith beds and Grant Land Formation were analyzed for sediment provenance analysis using laser ablation (LA–ICP–MS) and ion-microprobe (SIMS) methods. Samples of the Nesmith beds and Grant Land Formation are characterized by 1000–1300, 1600–2000, and 2500–2800 Ma detrital zircon age distributions and indicate provenance from rock assemblages of the Laurentian craton. In combination with regional stratigraphic constraints, these data support an Ediacaran to Cambrian paleodrainage model that features the Nesmith beds and Grant Land Formation as the offshore marine parts of a north- to northeast-directed depositional network. Proposed stratigraphic correlations between the Nesmith beds and Ediacaran platformal units of northern Greenland are consistent with the new detrital zircon results. Cambrian stratigraphic correlations within northern Ellesmere Island are permissive, but require further investigation because the Grant Land Formation provenance signatures agree with a third-order sedimentary system that has been homogenized by longshore current or gravity-flow processes, whereas coeval shallow-water strata yield a restricted range of detrital zircon ages and imply sources from local drainage areas or underlying rock units. The detrital zircon signatures of the Franklinian passive margin resemble those for the Cordilleran and Appalachian passive margins of Laurentia, which demonstrates the widespread recycling of North American rock assemblages after late Neoproterozoic continental rifting and breakup of supercontinent Rodinia.
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Spahic, Darko, Bojan Glavas-Trbic, Slavica Djajic, and Tivadar Gaudenyi. "Neoproterozoic-paleozoic evolution of the Drina formation (Drina-Ivanjica entity)." Annales g?ologiques de la Peninsule balkanique 79, no. 2 (2018): 57–68. http://dx.doi.org/10.2298/gabp1802057s.
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This paper addresses a Drina-Ivanjica basement member, Drina Formation, characterized by ? controversial Neoproterozoic to Carboniferous age. The Drina Formation is also informally referred to as the ?Lower Drina Formation? and the ?Upper Drina Formation? including the Golija Formation as a conditional analog unit of the latter. A review of the biostratigraphic, sedimentary and paleogeographic constraints identified Drina Formation (Inner Dinarides) as a migrated crustal segment derived from a marginal section of northern Gondwana, being, however, of Neoproterozoic-Early Paleozoic age. The presence of arenites, pelites, conglomerates, scarce limestones, basic (sub)volcanics and tuffs of the volcano-sedimentary Drina Formation metamorphosed up to greenschist and locally up to amphibolite facies, coupled with the absence of felsic volcanism implies a passive margin setting. Considering the age, such environment was probably associated with the perplexed Lower Paleozoic Avalonian-Cadomian arc, situated along the former north Gondwanan active margin. More precisely, the Drina Formation originated from a depositional junction between the Gondwana sediment supplier (Sahara metacraton) and Cadomian arc. A comparison with the regional Early Paleozoic succession of the ?Kucaj Unit? (eastern Serbia) yields the absence of typical anchimetamorphic Silurian to Lower Devonian deep-marine fossil-bearing succession. The volcano-sedimentary passive margin system of Drina Formation is overlain by a late Variscan convergencerelated voluminous clastic sequence allocated as the Golija Formation.
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Anjerdi, Javad, Mahdi Jafarzadeh, Adel Najafzadeh, and Rahim Mahari. "Provenance of Upper Devonian Ilanqareh Formation (NW Iran), assessed using petrography and major element geochemistry." Boletín de la Sociedad Geológica Mexicana 74, no. 3 (2022): A160722. http://dx.doi.org/10.18268/bsgm2022v74n3a160722.
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In this study, a combination of petrographic and major element geochemical methods was employed on sandstones and shales of Upper Devonian Ilanqareh Formation, northwest of Iran, aimed at investigating the tectonic setting and the weathering degree of rocks in the source area. The index of compositional variability (ICV below 1) indicated that the studied quartzarenite and subarkose sandstones were not in the first cycle. Petrographic studies showed the existence of a craton interior provenance for these sandstones and geochemical studies identified recycling of older formations as an important source of these deposits. The chemical index of alteration (CIA values of 78.18 to 90.42 for sandstones and 91.55 to 91.93 for shale samples) indicated that the samples were affected by the high degree of weathering due to the humid climate in the source areas. Geochemical discrimination diagrams revealed that the samples were deposited in a passive margin. According to the paleogeography, this passive margin was the margin of a rift basin in the northwest of Gondwana, and the Ilanqareh deposits were derived from the Arabian-Nubian shield and the recycling of the Lower Palaeozoic sandstones in the region.
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Iqbal, Shahid, Michael Wagreich, Mehwish Bibi, Irfan U. Jan, and Susanne Gier. "Multi-Proxy Provenance Analyses of the Kingriali and Datta Formations (Triassic–Jurassic Transition): Evidence for Westward Extension of the Neo-Tethys Passive Margin from the Salt Range (Pakistan)." Minerals 11, no. 6 (2021): 573. http://dx.doi.org/10.3390/min11060573.
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The Salt Range, in Pakistan, preserves an insightful sedimentary record of passive margin dynamics along the NW margin of the Indian Plate during the Mesozoic. This study develops provenance analyses of the Upper Triassic (Kingriali Formation) to Lower Jurassic (Datta Formation) siliciclastics from the Salt and Trans Indus ranges based on outcrop analysis, petrography, bulk sediment elemental geochemistry, and heavy-mineral data. The sandstones are texturally and compositionally mature quartz arenites and the conglomerates are quartz rich oligomictic conglomerates. Geochemical proxies support sediment derivation from acidic sources and deposition under a passive margin setting. The transparent heavy mineral suite consists of zircon, tourmaline, and rutile (ZTR) with minor staurolite in the Triassic strata that diminishes in the Jurassic strata. Together, these data indicate that the sediments were supplied by erosion of the older siliciclastics of the eastern Salt Range and adjoining areas of the Indian Plate. The proportion of recycled component exceeds the previous literature estimates for direct sediment derivation from the Indian Shield. A possible increase in detritus supply from the Salt Range itself indicates notably different conditions of sediment generation, during the Triassic–Jurassic transition. The present results suggest that, during the Triassic–Jurassic transition in the Salt Range, direct sediment supply from the Indian Shield was probably reduced and the Triassic and older siliciclastics were exhumed on an elevated passive margin and reworked by a locally established fluvio-deltaic system. The sediment transport had a north-northwestward trend parallel to the northwestern Tethyan margin of the Indian Plate and normal to its opening axis. During the Late Triassic, hot and arid hot-house palaeoclimate prevailed in the area that gave way to a hot and humid greenhouse palaeoclimate across the Triassic–Jurassic Boundary. Sedimentological similarity between the Salt Range succession and the Neo-Tethyan succession exposed to the east on the northern Indian passive Neo-Tethyan margin suggests a possible westward extension of this margin.
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Spikings, Richard, and Roelant Van der Lelij. "The Geochemical and Isotopic Record of Wilson Cycles in Northwestern South America: From the Iapetus to the Caribbean." Geosciences 12, no. 1 (2021): 5. http://dx.doi.org/10.3390/geosciences12010005.
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Isotopic and geochemical data delineate passive margin, rift and active margin cycles in northwestern South America since ~623 Ma, spanning from the Iapetus Wilson Cycle. Ultramafic and mafic rocks record rifting associated with the formation of the Iapetus Ocean during 623–531 Ma, while the initiation of subduction of the Iapetus and Rheic oceans is recorded by continental arc plutons that formed during 499–414 Ma, with alternating compressive and extensional stages. Muscovite 40Ar/39Ar dates suggest there may have been a phase of Carboniferous metamorphism, although this remains tentative. A Passive margin was modified by active margin magmatism that started at ~294 Ma and culminated with collisional tectonics that signaled the final stages of the amalgamation of western Pangaea. Early Pangaea fragmentation included back-arc rifting during 245–216 Ma, leading to a Pacific active margin that spanned from 213–115 Ma. Trench retreat accelerated during 144–115 Ma, forming a highly attenuated continental margin prior to the collision of the Caribbean Large Igneous Province at ~75 Ma.
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Uhlein, Alexandre, Gabriel Jubé Uhlein, Fabrício de Andrade Caxito, and Samuel Amaral Moura. "Wrapping a Craton: A Review of Neoproterozoic Fold Belts Surrounding the São Francisco Craton, Eastern Brazil." Minerals 14, no. 1 (2023): 43. http://dx.doi.org/10.3390/min14010043.
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A synthesis of the evolution of the Neoproterozoic belts or orogens surrounding the São Francisco craton (SFC) in northeastern and southeastern Brazil is presented. Emphasis is placed on recognizing the superposition of sedimentary basins, from rift to passive margin to retroarc and foreland, as well as identifying three diachronic continental collisions in the formation of the SFC. The Tonian passive margin occurs in the southern Brasília Belt with the Vazante, Canastra, and Araxá Groups. During the Tonian, island magmatic arcs and basins developed in front and behind these arcs (fore- and back-arcs). Subsequently, in the Cryogenian–Ediacaran, a retroarc foreland basin developed with part of the Araxá Group and the Ibiá Group, and finally, a foreland basin developed, which was filled by the Bambuí Group. A tectonic structure of superimposed nappes, with subhorizontal S1–2 foliation, formed between 650 and 610 Ma, is striking. In the northern Brasília Belt, there is the Stenian passive margin of the Paranoá Group, the Tonian intrusion of the Mafic–Ultramafic Complexes, and the Mara Rosa Island magmatic arc, active since the Tonian, with limited volcanic–sedimentary basins associated with the arc. A thrust–fold belt structure is prominent, with S1 foliation and late transcurrent, transpressive tectonics characterized by the Transbrasiliano (TB) lineament. The Cryogenian–Ediacaran collision between the Paranapanema and São Francisco cratons is the first collisional orogenic event to the west. In the Rio Preto belt, on the northwestern margin of the São Francisco craton, the Cryogenian–Ediacaran Canabravinha rift basin is prominent, with gravitational sediments that represent the intracontinental termination of the passive margin that occurs further northeast. The rift basin was intensely deformed at the Ediacaran–Cambrian boundary, as was the Bambuí Group. On the northern and northeastern margins of the São Francisco craton, the Riacho do Pontal and Sergipano orogens stand out, showing a comparable evolution with Tonian and Cryogenian rifts (Brejo Seco, Miaba, and Canindé); Cryogenian–Ediacaran passive margin, where the Monte Orebe ophiolite is located; and Cordilleran magmatic arcs, which developed between 620 and 610 Ma. In the Sergipano fold belt, with a better-preserved outer domain, gravitational sedimentation occurs with glacial influence. A continental collision between the SFC and the PEAL (Pernambuco-Alagoas Massif) occurred between 610 and 540 Ma, with intense deformation of nappes and thrusts, with vergence to the south and accommodation by dextral transcurrent shear zones, such as the Pernambuco Lineament (PE). The Araçuaí belt or orogen was formed at the southeastern limit of the SFC by a Tonian intracontinental rift, later superimposed by a Cryogenian–Ediacaran rift–passive margin of the Macaúbas Group, with gravitational sedimentation and glacial influence, and distally by oceanic crust. It is overlain by a retroarc basin with syn-orogenic sedimentation of the Salinas Formation, partly derived from the Rio Doce cordilleran magmatic arc and associated basins, such as the Rio Doce and Nova Venécia Groups. A third continental collision event (SF and Congo cratons), at the end of the Ediacaran (580–530 Ma), developed a thrust–fold belt that deforms the sediments of the Araçuaí Belt and penetrates the Paramirim Corridor, transitioning to the south to a dextral strike-slip shear zone that characterizes the Ribeira Belt.
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Le Pichon, X., and F. Barbier. "Passive margin formation by low-angle faulting within the upper crust: The Northern Bay of Biscay Margin." Tectonics 6, no. 2 (1987): 133–50. http://dx.doi.org/10.1029/tc006i002p00133.
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White, Susan, and John A. Webb. "The influence of tectonics on flank margin cave formation on a passive continental margin: Naracoorte, Southeastern Australia." Geomorphology 229 (January 2015): 58–72. http://dx.doi.org/10.1016/j.geomorph.2014.09.003.
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Radhakrishna, T., B. K. Bansal, and Ch Ramakrishna. "Geodynamic events leading to formation of passive western continental margin of India." Journal of Geodynamics 148 (November 2021): 101878. http://dx.doi.org/10.1016/j.jog.2021.101878.
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Tang, Xin, Yuanchen Guo, Tingqiang Zhou, and Sen Guo. "Distribution Characteristics of Nanopores and Discriminant Characteristics of Sedimentary Environment of the Longmaxi Formation in the Southern Sichuan Basin." Journal of Nanoscience and Nanotechnology 21, no. 1 (2021): 431–37. http://dx.doi.org/10.1166/jnn.2021.18741.
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Shale contains a large number of nanopores. The nanopores control the reservoir structure. The formation of nanopores in shale is closely related to the sedimentary environment. The palaeosedimentary structural background determines the provenance and sedimentary diagenesis of mud shale during shale deposition, refines the palaeo-shale and palaeo-sedimentary-tectonic environments of the Longmaxi Formation in the southern Sichuan Basin by elemental geochemical means, and determines the palaeo-deposition of the Longmaxi Formation. The tectonic setting and a numerical simulation method are used to explore the sedimentary tectonic evolution characteristics of the Longmaxi Formation. The results show that the parent rock of the Longmaxi Formation is relatively enriched with light rare earth elements, and the distribution of heavy rare earth elements is relatively stable. The vertical direction shows a trend of increasing from the bottom of the formation to the top of the formation, showing a mixed genesis; the tectonic setting is a passive continental margin, and the active continental margin is the main margin.
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Aizberg, R. E., Ya G. Gribik, and R. G. Garetsky. "Tectonic features of different types of oil and gas bearing basins in the west of the East European platform." Doklady of the National Academy of Sciences of Belarus 66, no. 1 (2022): 104–8. http://dx.doi.org/10.29235/1561-8323-2022-66-1-104-108.
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In the Neoproterozoic and Paleozoic, different-type sedimentary basins, some of which are oil-and-gas bearing, were formed in the western East European Platform (EEP). These basins are confined to two types of regional structures – rift intracontinental and passive-coastal. Their tectonic features determined the geological conditions of oil and gas formation and oil and gas accumulation. The Pripyat paleorift oil and gas bearing basin, which is the closing western segment of the Hercynian Pripyat-Dneprov-Donetsk avalacogenes, has the largest hydrocarbon reserves in the region and a complex structure. High density of block and plicate-block divisions of oil-and-gas bearing complexes is connected with syngenetic faults and salt tectonics. The oil-and-gas content of the sedimentary basins of the Caledonian passive margin of the West WEP – Baltica, Podlaska-Brest, Lublin, Volyn-Podolsk, is caused by the extended areal of the oil-and-gas formation in the sub- and near-thrust deep-submerged sedimentary complexes in the Teisser-Tornquist zone. It was the main source of hydrocarbon-fluid migration eastward into the sedimentary basins of the WEP passive margin.
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Spooner, Cameron, Randell Stephenson, and Robert W. H. Butler. "Pooled subsidence records from numerous wells reveal variations in pre-break-up rifting along the proximal domains of the Iberia–Newfoundland continental margins." Geological Magazine 156, no. 08 (2018): 1323–33. http://dx.doi.org/10.1017/s0016756818000651.
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AbstractThe Iberia–Newfoundland continental margin is one of the most-studied conjugate margins in the world. However, many unknowns remain regarding the nature of rifting preceding its break-up. We analyse a large dataset of tectonic subsidence curves, created from publicly available well data, to show spatial and temporal trends of rifting in the proximal domains of the margin. We develop a novel methodology of bulk averaging tectonic subsidence curves that can be applied on any conjugate margin with a similar spread of well data. The method does not rely on the existence of conjugate, deep seismic profiles and, specifically, attempts to forego the risk of quantitative bias derived from localized anomalies and uncertain stratigraphic dating and correlation. Results for the Iberia–Newfoundland margin show that active rift-driven tectonic subsidence occurred in the Central segment of the conjugate margin from c. 227 Ma (early Norian) to c. 152.1 Ma (early Tithonian), in the southern segment from c. 208.5 Ma (early Rhaetian) to c. 152.1 Ma (early Tithonian) and in the northern segment from c. 201.3 Ma (early Hettangian) to c. 132.9 Ma (early Hauterivian). This indicates that rifting in the stretching phase of the proximal domain of the Iberia–Newfoundland margin does not mirror hyperextended domain rifting trends (south to north) that ultimately led to break-up. The insights into broad-scale three-dimensional spatial and temporal trends, produced using the novel methodology presented in this paper, provide added value for interpretation of the development of passive margins, and new constraints for modelling of the formation of conjugate margins.
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Dewing, Keith, J. C. Harrison, Brian R. Pratt, and Ulrich Mayr. "A probable late Neoproterozoic age for the Kennedy Channel and Ella Bay formations, northeastern Ellesmere Island and its implications for passive margin history of the Canadian Arctic." Canadian Journal of Earth Sciences 41, no. 9 (2004): 1013–25. http://dx.doi.org/10.1139/e04-044.
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The Kennedy Channel and Ella Bay formations are the two oldest stratigraphic units exposed in the Franklinian margin sedimentary sequence in the Canadian Arctic Islands. An Early Cambrian age had previously been accepted by the occurrence of trilobites and small shelly fossils in the type section of the Kennedy Channel Formation. Reinvestigation of the area around the type section shows that several large strike-slip faults cut the succession and that the olenelloid trilobites are from an infaulted slice of a younger unit, the Lower Cambrian Kane Basin Formation. Thus, there is no unambiguous paleontological evidence for the age of either the Kennedy Channel or Ella Bay formations. However, the abundance of stromatolites, absence of trace fossils, and separation from overlying Lower Cambrian clastics by a regional angular unconformity indicate a probable late Neoproterozoic age for these two formations. The Ella Bay Formation likely correlates with the Portfjeld Formation in North Greenland, the Spiral Creek Formation in East Greenland, and the Risky Formation of the Mackenzie Mountains in northwestern Canada. The passive margin that existed in northern Laurentia during the early Paleozoic was, therefore, established in the late Neoproterozoic, and the onset of rifting must have preceded this, rather than occurring in the Early Cambrian as some authors have suggested.
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Schiffer, Christian, Alexander Peace, Jordan Phethean, et al. "The Jan Mayen microplate complex and the Wilson cycle." Geological Society, London, Special Publications 470, no. 1 (2018): 393–414. http://dx.doi.org/10.1144/sp470.2.
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AbstractThe opening of the North Atlantic region was one of the most important geodynamic events that shaped the present day passive margins of Europe, Greenland and North America. Although well-studied, much remains to be understood about the evolution of the North Atlantic, including the role of the Jan Mayen microplate complex. Geophysical data provide an image of the crustal structure of this microplate and enable a detailed reconstruction of the rifting and spreading history. However, the mechanisms that cause the separation of microplates between conjugate margins are still poorly understood. We assemble recent models of rifting and passive margin formation in the North Atlantic and discuss possible scenarios that may have led to the formation of the Jan Mayen microplate complex. This event was probably triggered by regional plate tectonic reorganizations rejuvenating inherited structures. The axis of rifting and continental break-up and the width of the Jan Mayen microplate complex were controlled by old Caledonian fossil subduction/suture zones. Its length is related to east–west-oriented deformation and fracture zones, possibly linked to rheological heterogeneities inherited from the pre-existing Precambrian terrane boundaries.
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Boillot, G., M. O. Beslier, C. M. Krawczyk, D. Rappin, and T. J. Reston. "The formation of passive margins: constraints from the crustal structure and segmentation of the deep Galicia margin, Spain." Geological Society, London, Special Publications 90, no. 1 (1995): 71–91. http://dx.doi.org/10.1144/gsl.sp.1995.090.01.04.
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Dunster, J. N., and B. A. Mcconachie. "Tectono‐sedimentary setting of the Lady Loretta Formation: Synrift, sag or passive margin?" Australian Journal of Earth Sciences 45, no. 1 (1998): 89–92. http://dx.doi.org/10.1080/08120099808728369.
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Hopper, John R., and W. Roger Buck. "The effect of lower crustal flow on continental extension and passive margin formation." Journal of Geophysical Research: Solid Earth 101, B9 (1996): 20175–94. http://dx.doi.org/10.1029/96jb01644.
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Cooper, D. J. W. "Hamrat Duru Group: revised stratigraphy of a Mesozoic deep-water passive margin in the Oman Mountains." Geological Magazine 124, no. 2 (1987): 157–64. http://dx.doi.org/10.1017/s0016756800015971.
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AbstractThe stratigraphy of the Hawasina Complex is redefined and rationalized to conform with standard stratigraphical nomenclature. Previously proposed tectono-stratigraphical units are abandoned in favour of a system that relies on the lateral correlation of lithofacies between structural units. To this end, the Dibba, Dhera, Wahrah and Al Ayn Formations are incorporated into an expanded Hamrat Duru Group. This group is divided into five formations, the Zulla, Guweyza Sandstone, Guweyza Limestone, Sid'r and Nayid and spans Triassic to Mid Cretaceous (Cenomanian) time. It locally passes up into the syn-orogenic sediments of the Riyamah Member of the Muti Formation. The nomenclature of the deeper-water, chert-dominated formations is left unaltered.
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Hersi, O. Salad, D. Lavoie, and G. S. Nowlan. "Reappraisal of the Beekmantown Group sedimentology and stratigraphy, Montréal area, southwestern Quebec: implications for understanding the depositional evolution of the Lower-Middle Ordovician Laurentian passive margin of eastern Canada." Canadian Journal of Earth Sciences 40, no. 2 (2003): 149–76. http://dx.doi.org/10.1139/e02-077.
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Detailed lithostratigraphic mapping of the Beekmantown Group of southwestern Quebec has refined the field application of the previously proposed tripartite division of the group (i.e., Theresa, Beauharnois, and Carillon formations). The group is a peritidal-dominated succession that accumulated on the epicontinental Laurentian passive margin. Biostratigraphic data based on conodonts from this group indicate an Early to early Middle Ordovician age and are partially time-correlative with the Wallace Creek to Naylor Ledge strata of the Philipsburg Group, southern Quebec. This conodont biostratigraphy sheds new light on the temporal evolution and depositional framework of the Beekmantown platform. The platform evolved as a distally steepened ramp during deposition of the Theresa Formation and the Ogdensburg Member of the Beauharnois Formation (early to middle Ibexian). Correlative strata of the Philipsburg Group include the Wallace Creek and Morgan Corner formations, which represent outer platform sediments. The coarse-grained sandstone of the Theresa Formation accumulated in the innermost platform, whereas coarse-grained carbonates of the Ogdensburg Member indicate open-marine, subtidal to intertidal carbonate sand shoals. By late Ibexian, the platform developed a pronounced margin where thrombolites flourished under high-energy conditions. These are represented by the thrombolite-rich Hasting Creek and Naylor Ledge formations of the Philipsburg Group. Consequently, a broad lagoon formed on the lee side of the platform margin, where low-energy conditions prevailed and accumulation of burrow-mottled dolostones of the Huntingdon Member of the upper Beauharnois Formation took place. The lagoon became more restricted during the latest stages of the basin fill (Whiterockian), and high intertidal to supratidal sediments of the Carillon Formation were deposited.
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Znad, Rabeea, and Ibrahim Aljumaily. "Article Review/ The Tectonic Evolution of Erbil Area (Ne Iraq) as a Part of the Northeastern Margin of the Arabian-Nubian Plate Throughout Albian-Early Eocene." IRAQI BULLETIN OF GEOLOGY AND MINING 19, no. 2 (2023): 105–23. http://dx.doi.org/10.59150/ibgm1902a08.
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The Albian-Early Eocene tectonic evolution of the Zagros Foreland Basin of the High Folded Zone in the Iraqi Kurdistan region has been studied based on the recent foreland basin system concept. This study showed that during the cretaceous (Albian – Cenomanian) there was a geodynamic shift from a passive margin to a foreland basin system phase, not to an active margin phase as mentioned in the previous studies. The advance of the continental margin of the Arabian-Nubian Plate (ANP) toward the subduction zone imposed a tectonic load leading to the form of a flexural wave. The consequences of the last tectonic event were reflected by the continuous deposition of the Balambo Formation. in a foredeep depozone. This happened concomitantly with a flexural emergence of the continental shelf further to the west forming a forebulge depozone represented by the deposition of reefal facies of the Qamchuqa Formation. These geodynamic changes are considered here to represent the Megasequence boundary between the Tectonic Megasequence (TMS) of AP8 and AP9. The last sequence of the passive margin was the Qamchuqa Formation Which is called the Pre-Orogenic Carbonate Platform and was separated from the Bekhme Formation by regional unconformity (Megasequence boundary). The latter is represented by the Lower Sequence of the foreland basin system, which is called the Syn-Orogenic Carbonate Platform (SCP). During the Middle Campanian, the Zagros foreland basin started with the underfilled stage, and it was entirely clear by the end of the Cretaceous comprising a broad threefold subdivision of depositional realms that translated into three stratigraphic units known as trinity underfilled units of foreland basin system. The lower carbonate unit, the pelagic and hemipelagic unit, and the upper flysch clastic unit are represented by Bekhme, Shiranish, and Tanjero Formations respectively. All of these units were superimposed during basin depocenter migration and became younger toward the southwest in front of progressing the orogenic wedge toward the Arabian Craton. During the late Maastrichtian to Paleocene – Early Eocene, the Zagros foreland basin underwent a transition from underfill to fill the stage. Deep exhumation of the orogenic wedge and ophiolite assemblage had supplied the clastic sediment of the Kolosh Formation into the basin covering the foredeep and most of the forebulge and backbulge depozones.
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Franz, Gesa, Marion Jegen, Max Moorkamp, Christian Berndt, and Wolfgang Rabbel. "Formation and geophysical character of transitional crust at the passive continental margin around Walvis Ridge, Namibia." Solid Earth 14, no. 3 (2023): 237–59. http://dx.doi.org/10.5194/se-14-237-2023.
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Abstract. When interpreting geophysical models, we need to establish a link between the models' physical parameters and geological units. To define these connections, it is crucial to consider and compare geophysical models with multiple, independent parameters. Particularly in complex geological scenarios, such as the rifted passive margin offshore Namibia, multi-parameter analysis and joint inversion are key techniques for comprehensive geological inferences. The models resulting from joint inversion enable the definition of specific parameter combinations, which can then be ascribed to geological units. Here we perform a user-unbiased clustering analysis of the two parameters electrical resistivity and density from two models derived in a joint inversion along the Namibian passive margin. We link the resulting parameter combinations to breakup-related lithology and infer the history of margin formation. This analysis enables us to clearly differentiate two types of sediment cover. The first type of sediment cover occurs near the shore and consists of thick, clastic sediments, while the second type of sediment cover occurs further offshore and consists of more biogenic, marine sediments. Furthermore, we clearly identify areas of interlayered massive, and weathered volcanic flows, which are usually only identified in reflection seismic studies as seaward-dipping reflectors. Lastly, we find a distinct difference in the signature of the transitional crust south of and along the supposed hotspot track Walvis Ridge. We ascribe this contrast to an increase in magmatic activity above the volcanic centre along Walvis Ridge and potentially a change in the melt sources or depth of melting. This change of the predominant volcanic signature characterizes a rift-related southern complex and a plume-driven Walvis Ridge regime. All of these observations demonstrate the importance of multi-parameter geophysical analysis for large-scale geological interpretations. Additionally, our results may improve future joint inversions using direct parameter coupling, by providing a guideline for the complex passive margin's parameter correlations.
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Lickorish, W. Henry, and Philip S. Simony. "Evidence for late rifting of the Cordilleran margin outlined by stratigraphic division of the Lower Cambrian Gog Group, Rocky Mountain Main Ranges, British Columbia and Alberta." Canadian Journal of Earth Sciences 32, no. 7 (1995): 860–74. http://dx.doi.org/10.1139/e95-072.
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The Lower Cambrian McNaughton Formation of the Gog Group occupies a stratigraphic position transitional between the rift-related rocks of the underlying Upper Proterozoic Miette Group, and the overlying Paleozoic passive margin succession. A major regional unconformity, overlain by a distinctive orthoquartzite marker, has been traced within the McNaughton Formation. This unconformity has been shown to truncate normal faults active during the deposition of the lower McNaughton Formation. The lower McNaughton Formation consists of mature, coarse-grained fluvial sediments accumulated in hanging-wall half-grabens of active normal faults. These faults represent the final stage of rifting on the continental margin. The unconformity on the footwall blocks of these faults can be traced into the hanging wall, and is overlain by the shoreface sediments of the transgressive upper McNaughton Formation. Formal subdivision of the McNaughton Formation into four lithostratigraphic members is proposed, in order to describe this geometry.
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Singtuen, Vimoltip, Burapha Phajuy, Apussorn Anumart, Punya Charusiri, Natnicha Chawthai, and Heiner Heggemann. "Geochemistry and provenance of Mesozoic sandstones in Khon Kaen Geopark: Implication for tectonics of the western Khorat Plateau of Thailand." PLOS ONE 18, no. 4 (2023): e0284974. http://dx.doi.org/10.1371/journal.pone.0284974.
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Khon Kaen Geopark, representing an area of dinosaur fossil diversity, was selected for investigations to reveal the origin and tectonic setting of the Khorat Group. The area occupied by Mesozoic sedimentary rocks of four formal formations of the Khorat Group, namely the Phra Wihan Formation (PWF), Sao Khua Formation (SKF), Phu Phan Formation (PPF), and Khok Kruat Formation (KKF). A field investigation and macroscopic observations suggested that the immature sedimentary rocks of the study area are mainly clast-supported, pebbly sandstone and siltstone with few calcretes. The 50 rock samples that were selected for petrographical and geochemical investigations revealed that the sandstones of the PWF and PPF are quartz arenite and sublitharenite, with some subarkose, whereas those of the SKF are mainly subarkose and sublitharenite. In addition, the KKF dominantly presents sublitharenite with pebbles and calcretes. Mesozoic sandstones contain quartz, feldspars, various types of rock fragments, and accessory minerals (biotite, muscovite, zircon, and tourmaline), with siliceous, ferrous, and calcareous cement. Petrographic (Q–F–L) and geochemical (major and trace element) data suggested that the sources of sediments are mostly quartzose sedimentary rocks and some felsic-intermediate igneous rocks. Chondrite-normalized rare earth element patterns indicated that the origins of the studied sandstones are quartzose sedimentary rocks deposited in a passive continental margin or an upper continental crust. Geochemical traits of the sedimentary successions demonstrated that the provenance of the Khorat Basin prior to reworking by fluvial processes was situated in the passive continental margin or recycled orogen of the paleo-volcanic arc during the Mesozoic period.
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MacNaughton, Robert B., Guy M. Narbonne, and Robert W. Dalrymple. "Neoproterozoic slope deposits, Mackenzie Mountains, northwestern Canada: implications for passive-margin development and Ediacaran faunal ecology." Canadian Journal of Earth Sciences 37, no. 7 (2000): 997–1020. http://dx.doi.org/10.1139/e00-012.
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The youngest formations of the Neoproterozoic Windermere Supergroup in northwestern Canada (Gametrail, Blueflower, and Risky formations) record the transition from slope to shelf deposition on a prograding passive margin. Eleven facies associations are recognized, representing environments ranging from carbonate- and siliciclastic-dominated continental slope to open carbonate shelf and siliciclastic shoreface. Seven simple sequences are recognized, which can be grouped into three composite sequences. Combination of the data presented here with previous work on underlying and overlying formations indicates that the sequence-stratigraphic record is least detailed in the deepest-water facies and most detailed in shelf facies, reflecting the relative inability of high-frequency relative sea-level oscillations to affect deposition in deep-water settings. Falling-stage deposits are especially common in the upper slope region. Several major sequence boundaries (unconformities) are clustered in the interval a short distance below the Precambrian-Cambrian boundary. The most significant of these occurs high in the Blueflower Formation, not at the top of the Risky Formation as commonly inferred. This interval containing several surfaces may reflect thermal uplift related to the rifting recorded in rocks of this age in the southern Canadian Cordillera. Renewed subsidence (thermal relaxation) commenced just prior to the Neoproterozoic-Cambrian boundary, giving rise to a thick succession of shelf to nonmarine basal-Cambrian deposits. Ediacaran body fossils previously reported from the studied units occur in a range of slope to shoreface environments, including some facies that were deposited below the photic zone. The most common taxa occur across a spectrum of facies and were apparently ecological generalists.
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Mclntyre, C. L., and P. J. Stickland. "SEQUENCE STRATIGRAPHY AND HYDROCARBON PROSPECTIVITY OF THE CAMPANIAN TO EOCENE SUCCESSION, NORTHERN BONAPARTE BASIN, AUSTRALIA." APPEA Journal 38, no. 1 (1998): 313. http://dx.doi.org/10.1071/aj97015.
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The Campanian to Eocene succession of the Northern Bonaparte Basin contains a number of siliciclastic reservoirs which provide alternative targets to the Callovian structural plays that have dominated exploration to date. The succession is part of the Passive Margin Megasequence which extends from the Aptian to the Pliocene, and is traditionally subdivided into the Turnstone, Johnson and Grebe Formations.Prograding deltaics of the Turnstone Formation swamped an incipient Early-Campanian carbonate ramp following a second-order sequence-boundary. Five third-order sequences are recognised within the Turnstone Formation, each dominated by Lowstand (shelf-margin wedge) and Highstand Systems Tract components. A coeval basinal carbonate system resulted in the deposition of marls and lutites distal of the clastic deltaics. In the Early Paleocene, drowning of the clastic system led to the establishment of a productive carbonate ramp. Rare lowstand siliciclastic reservoirs are developed within carbonate-dominated prograding complexes, as incised valley-fill, and possibly within prominent slope canyons. In the Late Paleocene, a third-order transgression drowned the carbonate system. The Early Eocene Grebe sandstones were then deposited as a second-order lowstand package upon a prominent sequence-boundary. Subsequent flooding of the siliciclastic system resulted in the re-establishment of the prograding carbonate ramp system.The morphology of the passive-margin was strongly influenced by the interplay between sediment-supply and subsidence. The predominantly ramp-like geometry of the margin promoted the development of numerous shallow-marine lowstand reservoirs. The hydrocarbon prospectivity of each of these reservoirs is primarily controlled by the magnitude of the subsequent flooding events: Only the largest transgressions resulted in sufficient reduction of depositional energy to isolate the lowstand siliciclastics.Vertical migration remains the critical risk for all passive margin plays, as the reservoirs are separated from the Late Jurassic and Early Cretaceous source kitchens by up to one kilometre of claystone dominated sequences. None-the-less, the widespread occurrence of shallow hydrocarbon shows in the greater Bonaparte Basin indicates that Neogene faulting does provide locally valid migration pathways into post-rift reservoirs.
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Sokolov, S. D., L. I. Lobkovsky, V. A. Vernikovsky, M. I. Tuchkova, N. O. Sorokhtin, and M. V. Kononov. "Late Mesozoic–Cenozoic Tectonics and Geodynamics of the East Arctic Region." Russian Geology and Geophysics 63, no. 4 (2022): 324–41. http://dx.doi.org/10.2113/rgg20214435.
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Abstract Tectonic and geodynamic models of the formation of the Amerasian Basin are discussed. The Arctic margins of the Chukchi region and Northern Alaska have much in common in their Late Jurassic–Early Cretaceous tectonic evolution: (1) Both have a Neoproterozoic basement and a complexly deformed sedimentary cover, with the stage of Elsmere deformations recorded in their tectonic history; (2) the South Anyui and Angayucham ocean basins have a common geologic history from the beginning of formation in the late Paleozoic to the closure at the end of the Early Cretaceous, which allows us to consider them branches of the single Proto-Arctic Ocean, the northern margin of which was passive and the southern margin was active; (3) the dipping of the oceanic and, then, continental lithosphere took place in subduction zones southerly; (4) the collision of the passive and active margins of both basins occurred at the end of the Early Cretaceous and ended in Hauterivian–Barremian time; (5) the collision resulted in thrust–fold structures of northern vergence in the Chukchi fold belt and in the orogen of the Brooks Ridge. A subduction-convective geodynamic model of the formation of the Amerasian Basin is proposed, which is based on seismic-tomography data on the existence of a circulation of matter in the upper mantle beneath the Arctic and East Asia in a horizontally elongated convective cell with a length of several thousand kilometers. This circulation involves the subducted Pacific lithosphere, the material of which moves along the bottom of the upper mantle from the subduction zone toward the continent, forming the lower branch of the cell, and the closing upper branch of the cell forms a reverse flow of matter beneath the lithosphere toward the subduction zone, which is the driving force determining the surface kinematics of crustal blocks and the deformation of the lithosphere. The viscous dragging of the Amerasian lithosphere by the horizontal flow of the upper mantle matter toward the Pacific leads to the separation of the system of blocks of Alaska and the Chukchi region from the Canadian Arctic margin. The resulting scattered deformations can cause a different-scale thinning of the continental crust with the formation of a region of Central Arctic elevation and troughs or with a breakup of the continental crust with subsequent rifting and spreading in the Canadian Basin.
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Clift, Peter D., and Alastair H. F. Robertson. "A Cretaceous Neo-Tethyan carbonate margin in Argolis, southern Greece." Geological Magazine 127, no. 4 (1990): 299–308. http://dx.doi.org/10.1017/s0016756800014862.
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AbstractThe Argolis Peninsula, southern Greece, is believed to form part of a Pelagonian microcontinent located between two oceanic basins, the Pindos to the west and theVardar to the east, in Triassic to Tertiary time. In eastern Argolis, two important units are exposed: (i) the Ermioni Limestones cropping out in the southwest; (ii) the Poros Formation, observed on an offshore island in the northeast, and on the adjacent mainland. Both these units comprise late Cretaceous (Aptian-Maastrichtian) pelagic limestones, calciturbidites, lenticular matrix- and clast-supported limestone conglomerates and slump sheets. However, the Poros Formation is distinguished from the Ermioni Limestones by the presence of bituminous micritic limestones and an increasing proportion of shale up sequence. These successions are deep-water slope carbonates that once formed the southeast-facing passive margin of the Pelagonian platform (Akros Limestone). Beyond this lay a late Cretaceous ocean basin in the Vardar Zone. This ocean was consumed in an easterly-dipping subduction zone in latest Cretaceous (?) to early Tertiary time, giving rise to an accretionary complex (Ermioni Complex). During early Tertiary (Palaeocene-Eocene) time the passive continental margin (Pelagonian Zone) collided with the trench and accretionary complex to the east. As the suture tightened, former lower-slope carbonates (Ermioni Limestones) were accreted to the base of the over-riding thrust sheets and emplaced onto the platform. Farther west, bituminous upper slope carbonates (Poros Formation) flexurally subsided and passed transitionally upwards into calcareous flysch and olistostromes in a foreland basin. These sediments were then overridden by the emplacing thrust stack and themselves underplated. Late-stage high-angle faulting then disrupted the tectonostratigraphy, in places juxtaposing relatively high and low structural levels of the complex.
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Mazarovich, A. O., A. S. Abramova, K. O. Dobrolyubova, Yu A. Zaraiskaya, E. A. Moroz, and S. Yu Sokolov. "LANDSIDE HAZARD ON THE NORWEGIAN CONTINENTAL MARGIN." Bulletin of Kamchatka Regional Association «Educational-Scientific Center». Earth Sciences, no. 1(61) (2024): 42–56. http://dx.doi.org/10.31431/1816-5524-2024-1-61-42-56.
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Numerous landslides are located on the passive margin of Norway. According to the landslides number and the extent of their detachment zones, the margin can be divided into three segments (from south to north) — Scandinavian, Barents Sea and Svalbard. The fourth segment (Arctic) is the transition area located north of the Spitsbergen archipelago. In the Scandinavian segment, about forty large submarine landslide bodies have been identified on the continental slope and deeper. The Barents Sea segment is dominated by deep-sea fan deposits and relatively small landslides. No large landslides were found in the Svalbard segment. Analysis of published and original geological and geophysical data indicates that the formation of new landslides may occur in the Svalbard segment, as well as on the Vestnesa Ridge.
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Malinovsky, A. I. "RESHETNIKOVKA FORMATION OF SOUTH-WESTERN PRIMORYE — FRAGMENT OF THE LATE PALEOZOIC PASSIVE CONTINENTAL." Bulletin of Kamchatka Regional Association «Educational-Scientific Center». Earth Sciences, no. 1(61) (2024): 5–18. http://dx.doi.org/10.31431/1816-5524-2024-1-61-5-18.
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The results of mineralogical and geochemical studies of terrigenous rocks of the Early-Middle Permian Reshetnikovka formation in the southwestern part of Primorsky Krai are considered. Based on the data obtained, conclusions are drawn about the geodynamic nature of the deposits, and the main sources of clastic matter are determined. It has been found that, in terms of their parameters, the sandstones of the formation correspond to arkoses and are petrogenic rocks that were formed by of geochemically “mature”, largely weathered parent rocks of sources areas. Judging by the mineralogical and geochemical features of sandy rocks, as well as the position of their composition points on discriminant diagrams, in the Early-Middle Permian time sedimentation took place in basins associated with the passive continental margin. These basins were intra- and intercontinental rifts and aulacogens. The sedimentation was mainly influenced by continental sources of supply – cratons and uplifted crystalline basement blocks, which framed rift zones. Acidic igneous rocks were eroded with minor participation of ancient sedimentary formations.
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Zwaan, Frank, Giacomo Corti, Derek Keir, and Federico Sani. "Analogue modelling of marginal flexure in Afar, East Africa: Implications for passive margin formation." Tectonophysics 796 (December 2020): 228595. http://dx.doi.org/10.1016/j.tecto.2020.228595.
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Salazar‐Mora, Claudio A., Ritske S. Huismans, Haakon Fossen, and Marcos Egydio‐Silva. "The Wilson Cycle and Effects of Tectonic Structural Inheritance on Rifted Passive Margin Formation." Tectonics 37, no. 9 (2018): 3085–101. http://dx.doi.org/10.1029/2018tc004962.
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Harahap, Bhakti H. "Tectonostratigraphy of the Southern Part of Papua and Arafura Sea, Eastern Indonesia." Indonesian Journal on Geoscience 7, no. 3 (2012): 167–87. http://dx.doi.org/10.17014/ijog.7.3.167-187.
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DOI: 10.17014/ijog.v7i3.145Sedimentary history and stratigraphy of the Papua and Arafura Sea areas, eastern Indonesia, are gained from surface geological mapping combined with published data from oil companies. Development of some sedimentary units demonstrates that the tectonism have influenced sedimentation of such units comprising a succession of Phanerozoic rocks developing in a stable continental margin. The succession underlain by Cambrian-Silurian-Devonian metamorphic rocks consists of Tuaba, Kariem, Awitagoh, and Kemum Formation, and Modio Dolomite (Pre-Rift Phase). These rocks having been intruded by Late Permian-Middle Triassic granitoids and Carboniferous granite, are unconformably overlain by Late Carboniferous to Cretaceous siliciclastic-rich units comprising Aifam Group and Tipuma Formation (syn-Rift Phase) and Kembelangan Group (Mesozoic Passive Margin Post-Rift). The Aifam Group is separated by a regionally continuous boundary on its top contact from the Triassic-Early Jurassic Tipuma Formation, which filled the block-faulted rift valley subbasins of continentally deposited red beds in the breakup stage. Regionally, developed erosion surfaces of the breakup unconformity have separated these red beds from generally transgressive post-breakup deposits of the Jurassic to Cretaceous marine sediments of the Kembelangan Group. Beach to shallow marine-glauconitic sandstone and shale of the group pass upward into shelf mudstone. Relative sea level fall related to the tectonic stability of the area led to the development of Eocene to Late Miocene platform carbonates of the New Guinea Limestone Supergroup which occurred in the entire island of Papua and the southern of Arafura that overlie these non-carbonate units (Tertiary passive margin). It is separated from the siliciclastic-rich packages by the Tertiary - Pre-Tertiary boundary. The sea level fluctuation within the group was also recorded during the formation of thin, discontinuous sandstone beds/lenses of Sirga Formation and Adi Member of the Oligocene age (Convergence phase). Turbidite sediments of the Miocene Klasafet Formation was deposited in a deep marine environment at the same time as the eruption of magmatic arc (Compressional phase). The mainland area was exposed above sea level at Late Miocene to Pleistocene (Melanesian Orogeny) and terrigenous detritus deposition began to fill in the basin as molasses type deposits with a marine influence in part (Buru and Steenkool Formations).
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Pystin, A. M., O. V. Grakova, Yu I. Pystina, et al. "U-Pb (LA-SF-ICP-MS) dating and probable provenance of detrital zircons from terrigenous deposits of the Upper Precambrian of the Subpolar Urals." LITHOSPHERE (Russia) 22, no. 6 (2023): 741–60. http://dx.doi.org/10.24930/1681-9004-2022-22-6-741-760.
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Research subject. Upper Precambrian metaterrigenous deposits of the northern part of the Lyapinsky anticlinorium in the Subpolar Urals.Material and methods. From the metaterrigenous rocks of the Upper Precambrian section of different stratigraphic levels, monofractions of zircons were isolated and their optical and isotope-geochronological (U-Pb LA-SF-ICPMS) studies were performed.Results. Age boundaries of the formation of the Puivinskaya, Khobeinskaya, and Moroinskaya Formations in the Subpolar Urals were specified. A comparison was carried out of age populations of detrital zircons from metaterrigenous deposits of the Subpolar Urals and terrigenous sequences of adjacent regions similar in age. The age boundaries and the proposed location of crystalline complexes, the probable provenance areas of terrigenous material, were established.Conclusions. The lower age limit of the formation of the basal layers of the Upper Precambrian of the Subpolar Urals does not go beyond the Late Riphean. The north-eastern periphery of the East European Platform, including the Subpolar Urals, in the Late Precambrian belonged to the same continental margin, and the accumulation of the Middle-North Timan and Subpolar Ural Upper Riphean sediments occurred in the common sedimentation basin. The lower age boundary of the formation of the Puivinskaya Formation (about 1000 Ma) determines the probable formation time of the Timan passive margin.
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Pepe, Fabrizio, Giovanni Bertotti, Federico Cella, and Ennio Marsella. "Rifted margin formation in the south Tyrrhenian Sea: A high-resolution seismic profile across the north Sicily passive continental margin." Tectonics 19, no. 2 (2000): 241–57. http://dx.doi.org/10.1029/1999tc900067.
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Zwaan, Frank, Giacomo Corti, Derek Keir, and Federico Sani. "A review of tectonic models for the rifted margin of Afar: Implications for continental break-up and passive margin formation." Journal of African Earth Sciences 164 (April 2020): 103649. http://dx.doi.org/10.1016/j.jafrearsci.2019.103649.
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Anderson, Arlene V., and Kristian E. Meisling. "Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska." Geosphere 17, no. 6 (2021): 1972–96. http://dx.doi.org/10.1130/ges02272.1.
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Abstract The Ulungarat Basin of Arctic Alaska is a unique exposed stratigraphic record of the mid-Paleozoic transition from the Romanzof orogeny to post-orogenic rifting and Ellesmerian passive margin subsidence. The Ulungarat Basin succession is composed of both syn-rift and post-rift deposits recording this mid-Paleozoic transition. The syn-rift deposits unconformably overlie highly deformed Romanzof orogenic basement on the mid-Paleozoic regional angular unconformity and are unconformably overlain by post-rift Endicott Group deposits of the Ellesmerian passive margin. Shallow marine strata of Eifelian age at the base of the Ulungarat Formation record onset of rifting and limit age of the Romanzof orogeny to late Early Devonian. Abrupt thickness and facies changes within the Ulungarat Formation and disconformably overlying syn-rift Mangaqtaaq Formation suggest active normal faulting during deposition. The Mangaqtaaq Formation records lacustrine deposition in a restricted down-faulted structural low. The unconformity between syn-rift deposits and overlying post-rift Endicott Group is interpreted to be the result of sediment bypass during deposition of the outboard allochthonous Endicott Group. Within Ulungarat Basin, transgressive post-rift Lower Mississippian Kekiktuk Conglomerate and Kayak Shale (Endicott Group) are older and thicker than equivalents to the north. North of Ulungarat Basin, deformed pre-Middle Devonian rocks were exposed to erosion at the mid-Paleozoic regional unconformity for ∼50 m.y., supplying sediments to the rift basin and broader Arctic Alaska rifted margin beyond. Although Middle Devonian to Lower Mississippian chert- and quartz-pebble conglomerates and sandstones across Arctic Alaska share a common provenance from the eroding ancestral Romanzof highlands, they were deposited in different tectonic settings.
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Zhang, Feng-Qi, Hong-Xiang Wu, Yildirim Dilek, Wei Zhang, Kong-Yang Zhu, and Han-Lin Chen. "Guadalupian (Permian) onset of subduction zone volcanism and geodynamic turnover from passive- to active-margin tectonics in southeast China." GSA Bulletin 132, no. 1-2 (2019): 130–48. http://dx.doi.org/10.1130/b32014.1.
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Abstract New stratigraphic, geochemical, and geochronological data from the late Paleozoic depositional record in Anhui Province, China, signal the onset of active-margin magmatism in East Asia. Chert-shale sequences of the Gufeng Formation are part of a Carboniferous–Permian carbonate platform that developed along the passive margin of the South China block. Thin tuffaceous interlayers in these sequences represent distal ash deposits, marking discrete volcanic events. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon dating of the stratigraphically bottom and near-top tuffaceous interlayers has revealed crystallization ages of 270 Ma and 264 Ma, respectively, constraining the time span of subaerial eruptions to ∼6 m.y. during the Guadalupian Epoch. High SiO2 and Al2O3 contents, enrichments in large ion lithophile and light rare earth elements, and depletion patterns of high field strength and heavy rare earth elements indicate a calc-alkaline magma source in an arc setting for the origin of these volcanic tuff deposits. Detrital zircon geochronology of sandstones in the overlying Longtan Formation shows two prominent age populations of 290–250 Ma and 1910–1800 Ma. The former age cluster overlaps with the tightly constrained zircon ages obtained from the Gufeng Formation. The latter age group is compatible with the known magmatic-metamorphic ages from Cathaysia in the South China block, and it points to the existence of a NE-SW–trending topographic high as a major sediment source. We interpret this topographic high and silicic volcanism to represent an Andean-type active margin, developed above a north-dipping paleo-Pacific slab. Our tightly constrained Guadalupian eruption ages indicate the inception of magmatic arc construction and mark a major switch from passive- to active-margin tectonics along SE Asia.
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Ahmed, Farooq, Aimal Khan Kasi, M. Mohibullah, and Razzaq Abdul Manan. "PETROLOGY AND GEOCHEMISTRY OF THE LATE CRETACEOUS PAB FORMATION, WESTERN SULAIMAN FOLD- THRUST- BELT, PAKISTAN: IMPLICATIONS FOR PROVENANCE AND PALEO-WEATHERING." Journal of Mountain Area Research 6 (December 25, 2021): 45. http://dx.doi.org/10.53874/jmar.v6i0.98.
Full textAbstract:
Late Cretaceous sandstone succession of the Pab Formation in western Sulaiman Fold Thrust belt Pakistan was investigated for petrology and bulk rock chemistry to determine its source terrain, paleo-weathering and tectonic setting. The formation is mainly comprised of sandstone with reddish to maroon color shale and arenaceous limestone. Texturally, the sandstone is fine to coarse grained, sub-angular to well-rounded and moderately to well sorted. The sandstone is petrologically and geochemically classified as quartz arenite to sub lithic arenite. The detritus was mainly derived from plutonic acidic source. QtFL and QmFLt suggests that recycled orogeny and Craton Interior setting were major sources of sediments. Geochemical models support that the detritus was derived from quartzose sedimentary source terrain, suggest deposition in a passive continental margin setting. Average values of chemical indices are CIA 59% CIW 67% and CIV 12.70%, which suggest moderate to high degree of chemical weathering in source area, that may reflect humid climate condition in the source area. The petrographic study and geochemical models demonstrate that the Pab Formation is mostly composed of mature sandstone from acidic plutonic and low-grade metamorphic rocks terrain in recycled and Craton Interior setting deposited on western passive margin of Indian plate in Tethys Ocean.
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Larsen, H. C., A. Saunders, L. M. Larsen, et al. "ODP activities on the South-East Greenland margin: Leg 152 drilling and continued site surveying." Rapport Grønlands Geologiske Undersøgelse 160 (January 1, 1994): 73–79. http://dx.doi.org/10.34194/rapggu.v160.8235.
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Two main types of passive margins known as volcanic and non-volcanic rifted margins, based on the extent of volcanic activity associated with their formation, are widely recognised. Volcanic rifted margins have now been identified along the edges of many continents (Coffin & Eldholm, 1992) and cannot any longer be considered as rare exceptions to 'normal' (non-volcanic) continental break-up.
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McMechan, Margot, Lisel Currie, Filippo Ferri, William Matthews, and Paul O’Sullivan. "Cambrian detrital zircon signatures of the northern Cordilleran passive margin, Liard area, Canada: evidence of sediment recycling, non-Laurentian ultimate sources, and basement denudation." Canadian Journal of Earth Sciences 54, no. 6 (2017): 609–21. http://dx.doi.org/10.1139/cjes-2016-0127.
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Detrital zircon U–Pb age probability distributions for the Cambrian Vizer formation (informal) and Mount Roosevelt Formation (middle member) of the northern Canadian Cordilleran passive margin indicate extensive recycling from ∼1.7 to 1.6 Ga Paleoproterozoic sandstones and Proterozoic and Lower Cambrian strata, respectively. The units have minor or no first cycle input from Laurentian basement. The lower part of the Vizer formation contains North American magmatic gap (1610–1490 Ma) detrital zircons and lacks ultimate Grenvillian sourced grains, indicating that the grains were likely sourced from a nearby Mesoproterozoic basin and have an ultimate non-Laurentian source. Detrital zircon U–Pb ages of 670–640 Ma from the middle member of the Mount Roosevelt Formation indicate associated volcanic clasts were locally sourced, and are not of syn-sedimentary Middle Cambrian age. Provenance of these units was indirectly impacted by the Liard Line basement feature. Detrital zircon U–Pb age probability distributions from the northern Canadian Cordilleran passive margin indicate sediments were sourced from the east in the Early Cambrian (Terreneuvian; Vizer formation and correlatives) and the northeast during Early Cambrian (Series 2) deposition of Sekwi Formation and correlative strata. In the early Middle Cambrian, the middle member of the Mount Roosevelt Formation was primarily locally sourced, whereas the upper member was derived from Laurentian basement to the east and southeast. The change from reworked Paleoproterozoic cover in the Terrenuvian to primary basement sources in the Middle Cambrian suggests significant denudation of the basement occurred southeast of the Liard Line.
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González-Bonorino, Gustavo. "Early development and flysch sedimentation in Ordovician Taconic foreland basin, west-central Newfoundland." Canadian Journal of Earth Sciences 27, no. 9 (1990): 1247–57. http://dx.doi.org/10.1139/e90-133.
Full textAbstract:
During the Early to Late Ordovician the Taconic foredeep in west-central Newfoundland evolved from an underfilled to an overfilled state in response to cratonward advance, thickening, and erosion of the Taconic Orogen. Early orogen-derived sediment in the foreland basin consisted of middle(?) to lake Arenigian deep-water mudstones that accumulated on an inner (craton-facing) slope prism (uppermost parts of Shallow Bay and Green Point formations and correlative units). These deposits are interbedded with and overlie passive-margin slope sediments. In the middle Arenigian to early Llanvirnian, sand from the orogen formed several small, sand-rich submarine fans (Lower Head Formation and correlative units) on the lower reaches of the inner slope and basin plain. The fans may have been fed by closely spaced rivers draining the orogen, as presently occurs in western South America. Only proximal portions of these fans are now exposed. The flysch basin was narrow, constricted by the inner slope and the passive-margin slope, and located a short distance seaward from the buried hingeline of the proto-North American craton. As the orogen thickened sufficiently to override the crustal ramp, the carbonate shelf on the craton drowned, clastic depocentres migrated onto the foundered craton, and a thicker flysch (Mainland Sandstone) accumulated in Llanvirnian-Llandeilian time. In the Caradocian the foreland basin was overfilled with shallow-marine terrigenous sediments (Long Point Formation). Regional flysch dispersal was from a St. Lawrence promontory to a Quebec reentrant.
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Afreen, Noori, and Rais Sarwar. "Provenance, Tectonic Setting and Climatic Conditions during Lower Permian Barakar Sedimentation in the Mand Gondwana Basin, India - A Petrographic Approach." International Journal of Geology and Earth Sciences 2, no. 1 (2016): 1–18. https://doi.org/10.5281/zenodo.1494795.
Full textAbstract:
The present study is an attempt to determine the provenance characteristics, tectonic setting and climatic conditions prevailing at time of sedimentation of Barakar Formation (Lower Permian). The Barakar Formation is chiefly composed of sandstones with subordinate amount of shales, carbonaceous shales and coal seams. The average composition of Barakar sandstones is quartz 57.93 to 82.42% (42.35 to 75.45% monocrystalline and 2.99 to 37.16% polycrystalline quartz), feldspar 3.0 to 15.16% and rock fragments upto 4.95%. These sandstones have been classified as sub-arkose and sub-litharenites types. The modal composition indicates that component minerals of these sandstones have been derived from craton interior and recycled orogenic belt, where different types of granitic, gneissic, sedimentary and metasedimentary rocks were exposed. The dominance of K-feldspar over plagioclase in these rock samples suggests that the source rocks were exposed for long duration of time and subjected to intense weathering under humid climatic conditions.
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ŽÁČKOVÁ, ELIŠKA, JIŘÍ KONOPÁSEK, JAN KOŠLER, and PETR JEŘÁBEK. "Detrital zircon populations in quartzites of the Krkonoše–Jizera Massif: implications for pre-collisional history of the Saxothuringian Domain in the Bohemian Massif." Geological Magazine 149, no. 3 (2011): 443–58. http://dx.doi.org/10.1017/s0016756811000744.
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AbstractAge spectra of detrital zircons from metamorphosed quartzites of the Krkonoše–Jizera Massif in the northeastern part of the Saxothuringian Domain were obtained by U–Pb laser ablation inductively coupled plasma mass spectrometry dating. The zircon ages cluster in the intervals of 450–530 Ma and 550–670 Ma, and show individual data between 1.6 and 3.1 Ga. Zircons in the analysed samples are predominantly of Cambrian–Ordovician and Neoproterozoic age, and the marked peak at c. 525–500 Ma suggests a late Cambrian maximum age for the sedimentary protolith. Detritus of the quartzites probably originated from the erosion of Cambrian–Ordovician granitoids and their Neoproterozoic (meta)sedimentary or magmatic country rocks. The lack of Neoproterozoic (meta)sedimentary rocks in the central and eastern part of the Krkonoše–Jizera Massif suggests that the country rocks to voluminous Cambrian–Ordovician magmatic bodies were largely eroded during the formation of early Palaeozoic rift basins along the southeast passive margin of the Saxothuringian Domain. The detrital zircon age spectra confirm the previous interpretation that the exposed basement, dominated by Neoproterozoic to Cambrian–Ordovician granitoids, was overthrust during Devonian–Carboniferous subduction–collision processes by nappes composed of metamorphosed equivalents of the uppermost Cambrian–Devonian passive margin sedimentary formations. Only a negligible number of Mesoproterozoic ages, typically from the Grenvillian event, supports the interpretation that the Saxothuringian Neoproterozoic basement has an affinity to the West African Craton of the northwestern margin of Gondwana.
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Ivanov, V. L. "Evolution of Antarctic prospective sedimentary basins." Antarctic Science 1, no. 1 (1989): 51–56. http://dx.doi.org/10.1017/s095410208900009x.
Full textAbstract:
No less than 15–20 sedimentary basins are now known on the Antarctic continental landmass and surrounding continental shelves. Reconstruction of their tectonic and stratigraphic evolution is a specialized task. Owing to the polar position of the continent, the Pacific and Atlantic global geostructures are closely spaced there and the interplay between them is strong enough to result in hybridization of the characteristic tectonic features of the various basins. The present morphostructure of the southern polar region of the Earth is characterized by a prominent circumpolar zoning. Therefore, the sedimentary basins form a gigantic ring along the continental margin, including both the shelf proper and the edge of the continent. Within the ring, the basins are associated with different types of margins successively replacing each other, from the Mesozoic magmatic are in the Pacific segment to the classic passive margin off East Antarctica. The formation of the sedimentary basins in the Antarctic segment of the Pacific mobile belt was a part of a single process of geosynclinal development, whereas on the craton flank the process was superposed on the continental structures by rifting during Gondwana fragmentation. During post-break-up tectonism, continental glaciation played an important part in the formation of the sedimentary basins.