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1
Sissingh, W. "Palaeozoic and Mesozoic igneous activity in the Netherlands: a tectonomagmatic review." Netherlands Journal of Geosciences - Geologie en Mijnbouw 83, no. 2 (2004): 113–34. http://dx.doi.org/10.1017/s0016774600020084.
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AbstractTo date, igneous rocks, either intrusive or extrusive, have been encountered in the Palaeozoic-Mesozoic sedimentary series of the Netherlands in some 65 exploration and production wells. Following 17 new isotopic K/Ar age determinations of the recovered rock material (amounting to a total of 28 isotopic ages from 21 different wells), analysis of the stratigraphic distribution of the penetrated igneous rock bodies showed that the timing of their emplacement was importantly controlled by orogenic phases involving intra-plate wrench and rift tectonics. Magmatism coincided with the Acadian (Late Devonian), Sudetian (early Late Carboniferous), Saalian (Early Permian), Early Kimmerian (late Late Triassic), Mid-Kimmerian (Late Jurassic), Late Kimmerian (earliest Cretaceous) and Austrian (latest Early Cretaceous) tectonic phases. This synchroneity presumably reflects (broadly) coeval structural reorganizations of respectively the Baltica/Fennoscandinavia-Laurentia/Greenland, Laurussia-Gondwana, African-Eurasia and Greenland/Rockall-Eurasia plate assemblies. Through their concomitant changes of the intra-plate tectonic stress regime, inter-plate motions induced intra-plate tectonism and magmatism. These plate-tectonics related events determined the tectonomagmatic history of the Dutch realm by inducing the formation of localized centres, as well as isolated spot occurrences, of igneous activity. Some of these centres were active at (about) the same time. At a number of centres igneous activity re-occurred after a long period of time.
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Sissingh, W. "Syn-kinematic palaeogeographic evolution of the West European Platform: correlation with Alpine plate collision and foreland deformation." Netherlands Journal of Geosciences 85, no. 2 (2006): 131–80. http://dx.doi.org/10.1017/s0016774600077933.
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AbstractSequence stratigraphic correlations indicate that intermittent changes of the kinematic far-field stress-field regimes, and the associated geodynamic re-organisations at the plate-tectonic contacts of the African, Apulian, Iberian and European plates, affected the Tertiary palaeogeographic evolution of the West European Platform through a combination of intra-plate tectonics and fluctuations of relative sea level. A temporal sequence of first-order stages in structural, palaeotopographic and palaeohydrographic development of the platform can be distinguished from the Paleocene onwards. These formative stages are closely linked to major plate-boundary events involving the development of the Pyrenean and Alpine orogens, and can be traced throughout the West European Platform.
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Almeida, Renato P., Maurício G. M. Santos, Antonio R. S. Fragoso-Cesar, Liliane Janikian, and Gelson L. Fambrini. "Recurring extensional and strike-slip tectonics after the Neoproterozoic collisional events in the southern Mantiqueira province." Anais da Academia Brasileira de Ciências 84, no. 2 (2012): 347–76. http://dx.doi.org/10.1590/s0001-37652012005000034.
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In Eastern South America, a series of fault-bounded sedimentary basins that crop out from Southern Uruguay to Southeastern Brazil were formed after the main collisional deformation of the Brasiliano Orogeny and record the tectonic events that affected the region from the Middle Ediacaran onwards. We address the problem of discerning the basin-forming tectonics from the later deformational events through paleostress analysis of more than 600 fault-slip data, mainly from the Camaquã Basin (Southern Brazil), sorted by stratigraphic level and cross-cutting relationships of superposed striations, and integrated with available stratigraphic and geochronological data. Our results show that the Camaquã Basin was formed by at least two distinct extensional events, and that rapid paleostress changes took place in the region a few tens of million years after the major collision (c.a. 630 Ma), probably due to the interplay between local active extensional tectonics and the distal effects of the continued amalgamation of plates and terranes at the margins of the still-forming Gondwana Plate. Preliminary paleostress data from the Castro Basin and published data from the Itajaí Basin suggest that these events had a regional nature.
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Strogen, Dominic P., Karen E. Higgs, Angela G. Griffin, and Hugh E. G. Morgans. "Late Eocene – Early Miocene facies and stratigraphic development, Taranaki Basin, New Zealand: the transition to plate boundary tectonics during regional transgression." Geological Magazine 156, no. 10 (2019): 1751–70. http://dx.doi.org/10.1017/s0016756818000997.
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AbstractEight latest Eocene to earliest Miocene stratigraphic surfaces have been identified in petroleum well data from the Taranaki Basin, New Zealand. These surfaces define seven regional sedimentary packages, of variable thickness and lithofacies, forming a mixed siliciclastic–carbonate system. The evolving tectonic setting, particularly the initial development of the Australian–Pacific convergent margin, controlled geographic, stratigraphic and facies variability. This tectonic signal overprinted a regional transgressive trend that culminated in latest Oligocene times. The earliest influence of active compressional tectonics is reflected in the preservation of latest Eocene – Early Oligocene deepwater sediments in the northern Taranaki Basin. Thickness patterns for all mid Oligocene units onwards show a shift in sedimentation to the eastern Taranaki Basin, controlled by reverse movement on the Taranaki Fault System. This resulted in the deposition of a thick sedimentary wedge, initially of coarse clastic sediments, later carbonate dominated, in the foredeep close to the fault. In contrast, Oligocene active normal faulting in a small sub-basin in the south may represent the most northerly evidence for rifting in southern Zealandia, related to Emerald Basin formation. The Early Miocene period saw a return to clastic-dominated deposition, the onset of regional regression and the southward propagation of compressional tectonics.
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Rollinson, Hugh. "When did plate tectonics begin?" Geology Today 23, no. 5 (2007): 186–91. http://dx.doi.org/10.1111/j.1365-2451.2007.00631.x.
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Young, Grant M. "Proterozoic plate tectonics, glaciation and iron-formations." Sedimentary Geology 58, no. 2-4 (1988): 127–44. http://dx.doi.org/10.1016/0037-0738(88)90066-8.
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Hao, Wenxing, Rixiang Zhu, and Guang Zhu. "Jurassic tectonics of the eastern North China Craton: Response to initial subduction of the Paleo-Pacific Plate." GSA Bulletin 133, no. 1-2 (2020): 19–36. http://dx.doi.org/10.1130/b35585.1.
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Abstract The Yanshan fold-and-thrust belt (YFTB) on the northern margin of the eastern North China Craton (NCC) contains a succession of Jurassic volcano-sedimentary rocks that record the response of the NCC to the initial stages of subduction of the Paleo-Pacific Plate. We present stratigraphic profiles and new zircon U-Pb data from four basins in the YFTB to constrain the ages of the Jurassic lithological units and tectonic events related to the initial subduction. Following uplift at 200–190 Ma, protracted eruption of basalt at 188–167 Ma reflects the earliest tectonic activity in the YFTB. The eruption occurred in a backarc extensional setting, and migrated toward the west, consistent with WNW-directed subduction of the Paleo-Pacific Plate. The measured profiles and geochronological data demonstrate that the earliest phase of shortening in the YFTB during the Jurassic (event A of the Yanshan Movement in the Chinese literature) took place at 167 Ma. This compression terminated the magmatism and extension of the Early–Middle Jurassic, and resulted in the development of local thrusts, regional uplift, and a disconformity, without involvement of intense folding or the development of an angular unconformity. These observations are consistent with a weak to moderate intensity of deformation. The Jurassic rocks in the YFTB record the response of a backarc to the initial stages of subduction of the Paleo-Pacific Plate. Jurassic tectonics in the YFTB and the entire eastern China continent suggests that initial subduction of the Paleo-Pacific Plate began at ca. 190 Ma, and is consistent with the passive margin collapse model.
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McGrew, Allen J., and Joshua J. Schwartz. "Introduction: Active Margins in Transition—Magmatism and Tectonics through Time: An Issue in Honor of Arthur W. Snoke." Geosphere 17, no. 4 (2021): 981–86. http://dx.doi.org/10.1130/ges02422.1.
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Abstract The evolution of active margins through time is the record of plate tectonics as inscribed on the continents. This themed issue honors the eclectic contributions of Arthur W. Snoke (Fig. 1) to the study of active margins with a series of papers that amply demonstrate the broad scope of active margin tectonics and the diverse methods that tectonic geologists employ to decipher their histories. Taken together, this set of papers illustrates the diversity of boundary conditions that guide the development of active margins and the key parameters that regulate their evolution in time and space.
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Russell, M. J. "Metal deposits in relation to plate tectonics." Marine and Petroleum Geology 2, no. 3 (1985): 286. http://dx.doi.org/10.1016/0264-8172(85)90023-6.
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Zhou, Zhonghe, Qingren Meng, Rixiang Zhu, and Min Wang. "Spatiotemporal evolution of the Jehol Biota: Responses to the North China craton destruction in the Early Cretaceous." Proceedings of the National Academy of Sciences 118, no. 34 (2021): e2107859118. http://dx.doi.org/10.1073/pnas.2107859118.
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The Early Cretaceous Jehol Biota is a terrestrial lagerstätte that contains exceptionally well-preserved fossils indicating the origin and early evolution of Mesozoic life, such as birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. New geochronologic studies have further constrained the ages of the fossil-bearing beds, and recent investigations on Early Cretaceous tectonic settings have provided much new information for understanding the spatiotemporal distribution of the biota and dispersal pattern of its members. Notably, the occurrence of the Jehol Biota coincides with the initial and peak stages of the North China craton destruction in the Early Cretaceous, and thus the biotic evolution is related to the North China craton destruction. However, it remains largely unknown how the tectonic activities impacted the development of the Jehol Biota in northeast China and other contemporaneous biotas in neighboring areas in East and Central Asia. It is proposed that the Early Cretaceous rift basins migrated eastward in the northern margin of the North China craton and the Great Xing’an Range, and the migration is regarded to have resulted from eastward retreat of the subducting paleo-Pacific plate. The diachronous development of the rift basins led to the lateral variations of stratigraphic sequences and depositional environments, which in turn influenced the spatiotemporal evolution of the Jehol Biota. This study represents an effort to explore the linkage between terrestrial biota evolution and regional tectonics and how plate tectonics constrained the evolution of a terrestrial biota through various surface geological processes.
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Bowin, C. O., W. Yi, R. D. Rosson, and S. T. Bolmer. "Phase change in subducted lithosphere, impulse, and quantizing Earth surface deformations." Solid Earth 6, no. 3 (2015): 1075–85. http://dx.doi.org/10.5194/se-6-1075-2015.
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Abstract. The new paradigm of plate tectonics began in 1960 with Harry H. Hess's 1960 realization that new ocean floor was being created today and is not everywhere of Precambrian age as previously thought. In the following decades an unprecedented coming together of bathymetric, topographic, magnetic, gravity, seismicity, seismic profiling data occurred, all supporting and building upon the concept of plate tectonics. Most investigators accepted the premise that there was no net torque amongst the plates. Bowin (2010) demonstrated that plates accelerated and decelerated at rates 10−8 times smaller than plate velocities, and that globally angular momentum is conserved by plate tectonic motions, but few appeared to note its existence. Here we first summarize how we separate where different mass sources may lie within the Earth and how we can estimate their mass. The Earth's greatest mass anomalies arise from topography of the boundary between the metallic nickel–iron core and the silicate mantle that dominate the Earth's spherical harmonic degree 2 and 3 potential field coefficients, and overwhelm all other internal mass anomalies. The mass anomalies due to phase changes in olivine and pyroxene in subducted lithosphere are hidden within the spherical harmonic degree 4–10 packet, and are an order of magnitude smaller than those from the core–mantle boundary. Then we explore the geometry of the Emperor and Hawaiian seamount chains and the 60° bend between them that aids in documenting the slow acceleration during both the Pacific Plate's northward motion that formed the Emperor seamount chain and its westward motion that formed the Hawaiian seamount chain, but it decelerated at the time of the bend (46 Myr). Although the 60° change in direction of the Pacific Plate at of the bend, there appears to have been nary a pause in a passive spreading history for the North Atlantic Plate, for example. This, too, supports phase change being the single driver for plate tectonics and conservation of angular momentum. Since mountain building we now know results from changes in momentum, we have calculated an experimental deformation index value (1–1000) based on a world topographic grid at 5 arcmin spacing and displayed those results for viewing.
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Goodwin, A. M., M. B. Lambert, and O. Ujike. "Geochemical and metallogenic relations in volcanic rocks of the southern Slave Province: implications for late Neoarchean tectonics." Canadian Journal of Earth Sciences 43, no. 12 (2006): 1835–57. http://dx.doi.org/10.1139/e06-074.
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Late Neoarchean volcanic belts in the southern Slave Province include (1) in the east, the Cameron River – Beaulieu River belts, which are characterized by stratigraphically thin, flow-rich, classic calc-alkaline, arc-type sequences with accompanying syngenetic volcanogenic massive sulphide deposits; and (2) in the west, the Yellowknife belt, which is characterized by stratigraphically thick, structurally complex, pyroclastic-rich, adakitic, back-arc basin-type sequences, with accompanying epigenetic lode-gold deposits. The volcanic belt association bears persuasive chemical evidence of subduction-initiated magma generation. However, the greenstone belts, together with coeval matching patterned belts in Superior Province of the southern Canadian Shield, bear equally persuasive evidence of prevailing autochthonous–parautochthonous relations with respect to component stratigraphic parts and to older gneissic basement. The eastern and western volcanic belts in question are petrogenetically ascribed to a "westerly inclined" (present geography) subduction zone(s) that produced shallower (east) to deeper (west), slab-initiated, mantle wedge-generated, parent magmas. This early stage microplate tectonic process involved modest mantle subduction depths, small tectonic plates, and small sialic cratons. In the larger context of Earth's progressively cooling, hence subduction-deepening mantle, this late Neoarchean greenstone belt development (2.73–2.66 Ga) merged with the massive end-Archean tonalite–trondhjemite–granodiorite–granite (TTGG) "bloom" (2.65–2.55 Ga), resulting in greatly enhanced craton stability. Successive subduction-deepening, plate-craton-enlarging stages, with appropriate metallotectonic response across succeeding Proterozoic time and beyond, led to modern-mode plate tectonics.
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Afzal, Jawad, Mark Williams, and Richard J. Aldridge. "Revised stratigraphy of the lower Cenozoic succession of the Greater Indus Basin in Pakistan." Journal of Micropalaeontology 28, no. 1 (2009): 7–23. http://dx.doi.org/10.1144/jm.28.1.7.
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Abstract. A refined stratigraphy for the lower Cenozoic succession of the Greater Indus Basin in Pakistan is presented. This region preserves an important East Tethyan marine succession through the Paleocene–Eocene, but its interpretation in terms of regional (tectonic) and global (climatic) effects has been inhibited by poor stratigraphy. Established dinoflagellate, nannofossil, planktonic foraminiferal and shallow benthonic foraminiferal biostratigraphical data for the Greater Indus Basin in Pakistan are collated, reinterpreted (where necessary) and correlated with the global standard chronostratigraphy and biostratigraphy of the early Palaeogene. Inter-regional stratigraphical correlations for the Upper Indus Basin and Lower Indus Basin are resolved. Age-diagnostic larger benthonic foraminifera from the Late Paleocene Lockhart Formation are illustrated. These collective biostratigraphical data provide a means of interpreting the lithostratigraphy and physical stratigraphical relationships of the Palaeogene succession in terms of the interplay between local tectonics (India–Asia collision) and global sea-level change. The timing of the Tethys closure, initial and final contact of the Indian–Asian plates, and dispersal of land mammals on the Indian Plate are discussed and correlated in the stratigraphical record of the basin.
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Soták, Ján, Zuzana Pulišová, Dušan Plašienka, and Viera Šimonová. "Stratigraphic and tectonic control of deep-water scarp accumulation in Paleogene synorogenic basins: a case study of the Súľov Conglomerates (Middle Váh Valley, Western Carpathians)." Geologica Carpathica 68, no. 5 (2017): 403–18. http://dx.doi.org/10.1515/geoca-2017-0027.
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Abstract The Súľov Conglomerates represent mass-transport deposits of the Súľov-Domaniža Basin. Their lithosomes are intercalated by claystones of late Thanetian (Zones P3 - P4), early Ypresian (Zones P5 - E2) and late Ypresian to early Lutetian (Zones E5 - E9) age. Claystone interbeds contain rich planktonic and agglutinated microfauna, implying deep-water environments of gravity-flow deposition. The basin was supplied by continental margin deposystems, and filled with submarine landslides, fault-scarp breccias, base-of-slope aprons, debris-flow lobes and distal fans of debrite and turbidite deposits. Synsedimentary tectonics of the Súľov-Domaniža Basin started in the late Thanetian - early Ypresian by normal faulting and disintegration of the orogenic wedge margin. Fault-related fissures were filled by carbonate bedrock breccias and banded crystalline calcite veins (onyxites). The subsidence accelerated during the Ypresian and early Lutetian by gravitational collapse and subcrustal tectonic erosion of the CWC plate. The basin subsided to lower bathyal up to abyssal depth along with downslope accumulation of mass-flow deposits. Tectonic inversion of the basin resulted from the Oligocene - early Miocene transpression (σ1 rotated from NW-SE to NNW-SSE), which changed to a transpressional regime during the Middle Miocene (σ1 rotated from NNE-SSW to NE-SW). Late Miocene tectonics were dominated by an extensional regime with σ3 axis in NNW-SSE orientation.
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Roberts, D. G. "The Caribbean-South America plate boundary and regional tectonics." Marine and Petroleum Geology 2, no. 1 (1985): 91–92. http://dx.doi.org/10.1016/0264-8172(85)90053-4.
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Sissingh, W. "Punctuated Neogene tectonics and stratigraphy of the African-Iberian plate-boundary zone: concurrent development of Betic-Rif basins (southern Spain, northern Morocco)." Netherlands Journal of Geosciences - Geologie en Mijnbouw 87, no. 4 (2008): 241–89. http://dx.doi.org/10.1017/s0016774600023350.
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AbstractThis paper integrates the sequence stratigraphic and tectonic data related to the Neogene geodynamic and palaeogeographic development of the African-Iberian plate boundary zone between Spain and Morocco. Though the dating of individual tectonostratigraphic sequences and their delimiting sequence boundaries varies in accuracy and precision, their apparent correlation strongly suggests contemporaneous development of the Betic and Rif basins. This may likely be attributed to regional changes of the overall compressional intra-plate stress field. This, in turn, was governed by coeval plate-kinematic changes related to the ongoing collisional convergence of Africa and Iberia. The Neogene succession is characterised by brief tectonic pulses that governed the sequence stratigraphic development of the Betic-Rif basins (NBR phases). It broadly correlates with the coeval sequences in the compressional foreland basins and extensional rift basins in front of the collisional Alpine and Pyrenean orogens (CRF phases). These regionally correlatable basinal deformation events indicate that stress-related episodic changes at the African-Iberian plate-boundary zone resulted in an essentially direct cause-and-effect relationship between the tectonostratigraphic evolution of Neogene basins in northern African (Morocco), southern Europe (Spain) and western Europe (France, Switzerland, Germany).
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Dickinson, J. A., M. W. Wallace, G. R. Holdgate, J. Daniels, S. J. Gallagher, and L. Thomas. "NEOGENE TECTONICS IN SE AUSTRALIA: IMPLICATIONS FOR PETROLEUM SYSTEMS." APPEA Journal 41, no. 1 (2001): 37. http://dx.doi.org/10.1071/aj00002.
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The influence of Neogene tectonics in the SE Australian basins has generally been underestimated in the petroleum exploration literature. However, onshore stratigraphic and offshore seismic data indicates that significant deformation and exhumation (up to one km or more) has occurred during the late Tertiary-Quaternary. This tectonism coincides with a change in the dynamics of the Australian plate, beginning at around 12 Ma, resulting in a WNW–ESE compressional regime which has continued to the present day.Significant late Miocene tectonism is indicated by a regional angular unconformity at around the Mio-Pliocene boundary in the onshore and nearshore successions of the SE Australian basins.Evidence of on going Pliocene- Quaternary tectonism is widespread in all of the SE Australian basins. Late Tertiary tectonism has produced structures in the offshore SE Australian basins which have been favourable targets for petroleum accumulation (e.g. Nerita structure, Torquay Sub-basin; Cormorant structure, Bass Basin). In the offshore Gippsland Basin, most of the oil- and gas-bearing structures have grown during Oligocene-Recent time. Some Gippsland Basin structures were largely produced prior to the mid- Miocene, while others have a younger structural history. In areas of intense late Tertiary exhumation and uplift (e.g. proximal to the Otway and Strzelecki Ranges), burial/maturation models of petroleum generation may be significantly affected by Neogene uplift.Many structures produced by late Miocene-Pliocene deformation are dry. These relatively young structures may post-date the major maturation episodes, with the post-structure history of the basins dominated by exhumation and cooling.
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Amanipoor, Hakimeh. "ACTIVE DEFORMATION DELINEATED BY GEOMORPHIC AND SEDIMENTARY RESPONSE OF RIVERS, CENTRAL ZAGROS FOLD – THRUST BELT, SW IRAN." Geodesy and Cartography 41, no. 3 (2015): 137–44. http://dx.doi.org/10.3846/20296991.2015.1086143.
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The mountain generation in Iran is because of continental collision between the Arabian and Eur-asia plate. Southwestern Iran shows active shorten that its evidences is deformation of crust and frequent earthquakes. At depth, active basement of the Zagros fold-thrust-belt in southwestern Iran, which are covered by folding of the Phanerozoic sediments, affected by some blind thrusted faults that have seismic nature. The Zagros fold-thrust-belt can be divided into 4 lithotectonic units including Sanandaj-Sirjan Zone (SSZ), Imbricate Zone (IZ), Zagros Fold Belt (ZFB), and Molasse Cover Sequence (MCS); this dividing and classification is based on geomorphology landscape, drainage pattern, rate of tectonics and stratigraphic records. Each tectonic unit characterized by especial abnormal forces in river systems. Active tectonics has the most important role to control the river systems by changing of channels incline. Change in the drainage pattern, channels cut, longitudinal profile, anomalous changes of sinuosity, changing of the side form and forming of terrace, change of river direction, compact meanders, cutting of meanders and geomorphology features of the rivers are responds to the active tectonics of region that are studied using remote sensing, DEM and field observations. These parameters are used to understand the vertical movement in the study area. Existing structures, especially growing anticlines and blind thrusted faults in the Zagros fold-thrust-belt, which cut the river channels and sometimes put them in parallel, are used in the study of their effect on the longitudinal and transverse tilt of morphological changes.
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Puglisi, Diego. "Tectonic evolution of the Sicilian Maghrebian Chain inferred from stratigraphic and petrographic evidences of Lower Cretaceous and Oligocene flysch." Geologica Carpathica 65, no. 4 (2014): 293–305. http://dx.doi.org/10.2478/geoca-2014-0020.
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Abstract The occurrence of a Lower Cretaceous flysch group, cropping out from the Gibraltar Arc to the Balkans with a very similar structural setting and sedimentary provenance always linked to the dismantling of internal areas, suggests the existence of only one sedimentary basin (Alpine Tethys s.s.), subdivided into many other minor oceanic areas. The Maghrebian Basin, mainly developed on thinned continental crust, was probably located in the westernmost sector of the Alpine Tethys. Cretaceous re-organization of the plates triggered one (or more) tectonic phases, well recorded in almost all the sectors of the Alpine Tethys. However, the Maghrebian Basin seems to have been deformed by Late- or post-Cretaceous tectonics, connected with a “meso-Alpine” phase (pre-Oligocene), already hypothesized since the beginning of the nineties. Field geological evidence and recent biostratigraphic data also support this important meso- Alpine tectonic phase in the Sicilian segment of the Maghrebian Chain, indicated by the deformations of a Lower Cretaceous flysch sealed by Lower Oligocene turbidite deposits. This tectonic development is emphasized here because it was probably connected with the onset of rifting in the southern paleomargin of the European plate, the detaching of the so-called AlKaPeCa block (Auct.; i.e. Alboran + Kabylian + Calabria and Peloritani terranes) and its fragmentation into several microplates. The subsequent early Oligocene drifting of these microplates led to the progressive closure of the Maghrebian Basin and the opening of new back-arc oceanic basins, strongly controlled by extensional processes, in the western Mediterranean (i.e. Gulf of Lion, Valencia Trough, Provençal Basin and Alboran Sea).
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Garefalakis, Philippos, and Fritz Schlunegger. "Tectonic processes, variations in sediment flux, and eustatic sea level recorded by the 20 Myr old Burdigalian transgression in the Swiss Molasse basin." Solid Earth 10, no. 6 (2019): 2045–72. http://dx.doi.org/10.5194/se-10-2045-2019.
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Abstract. The stratigraphic architecture of the Swiss Molasse basin, situated on the northern side of the evolving Alps, reveals crucial information about the basin's geometry, its evolution, and the processes leading to the deposition of the siliciclastic sediments. Nevertheless, the formation of the Upper Marine Molasse (OMM) and the controls on the related Burdigalian transgression have still been a matter of scientific debate. During the time period from ca. 20 to 17 Ma, the Swiss Molasse basin was partly flooded by a shallow marine sea striking SW–NE. Previous studies have proposed that the transgression occurred in response to a rise in global sea level, a reduction of sediment flux, or an increase in tectonically controlled accommodation space. Here, we readdress this problem and extract stratigraphic signals from the Burdigalian molasse deposits that can be related to changes in sediment supply rate, variations in the eustatic sea level, and subduction tectonics. To achieve this goal, we conducted sedimentological and stratigraphic analyses of several sites across the entire Swiss Molasse basin. Field investigations show that the transgression and the subsequent evolution of the Burdigalian seaway was characterized by (i) a deepening and widening of the basin, (ii) phases of erosion and non-deposition during Lower Freshwater Molasse (USM), OMM, and Upper Freshwater Molasse (OSM) times, and (iii) changes in along-strike drainage reversals. We use these changes in the stratigraphic record to disentangle tectonic and surface controls on the facies evolution at various scales. As the most important mechanism, rollback subduction of the European mantle lithosphere most likely caused a further downwarping of the foreland plate, which we use to explain the deepening and widening of the Molasse basin, particularly at distal sites. In addition, subduction tectonics also caused the uplift of the Aar massif. This process was likely to have shifted the patterns of surface loads, thereby resulting in a buckling of the foreland plate and influencing the water depths in the basin. We use this mechanism to explain the establishment of distinct depositional settings, particularly the formation of subtidal shoals wherein a bulge in relation to this buckling is expected. The rise of the Aar massif also resulted in a reorganization of the drainage network in the Alpine hinterland, with the consequence that the sediment flux to the basin decreased. We consider this reduction in sediment supply to have amplified the tectonically controlled deepening of the Molasse basin. Because the marine conditions were generally very shallow, subtle changes in eustatic sea level contributed to the formation of several hiatuses that chronicle periods of erosion and non-sedimentation. These processes also amplified the tectonically induced increase in accommodation space during times of global sea level highstands. Whereas these mechanisms are capable of explaining the establishment of the Burdigalian seaway and the formation of distinct sedimentological niches in the Swiss Molasse basin, the drainage reversal during OMM times possibly requires a change in tectonic processes at the slab scale, most likely including the entire Alpine range between the Eastern and Central Alps. In conclusion, we consider rollback tectonics to be the main driving force controlling the transgression of the OMM in Switzerland, with contributions by the uplift of individual crustal blocks (here the Aar massif) and by a reduction of sediment supply. This reduction of sediment flux was likely to have been controlled by tectonic processes as well when basement blocks became uplifted, thereby modifying the catchment geometries. Eustatic changes in sea level explain the various hiatuses and amplified the deepening of the basin during eustatic highstand conditions.
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Dieni, Iginio, Francesco Massari, and Jacques Médus. "Age, depositional environment and stratigraphic value of the Cuccuru ’e Flores Conglomerate: insight into the Palaeogene to Early Miocene geodynamic evolution of Sardinia." Bulletin de la Société Géologique de France 179, no. 1 (2008): 51–72. http://dx.doi.org/10.2113/gssgfbull.179.1.51.
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Abstract The Cuccuru ’e Flores Conglomerate of eastern Sardinia, a syntectonic unit lining major Cenozoic faults, has been dated by means of palynology at the early middle Lutetian. The deposits were mainly laid down by sediment gravity flows in a subaqueous setting and formed aprons of laterally interfingering debris cones at the toe of active tectonic scarps. Most clasts of rudites are of local provenance. Interestingly, the rudites include minor amounts of clasts of formations which no longer crop out in the area, providing important information on the reconstruction of the original stratigraphic succession and palaeogeography, especially during late Cretaceous and early Palaeogene times. During the Eocene, i.e. in a pre-rotation stage, Sardinia was subjected to the influence of both Alpine and Pyrenean orogenic belts. In eastern Sardinia, the compressional stress field was consistent with that existing in the foreland of the Alpine chain in Corsica, and was expressed by significant wrench tectonics affecting the Variscan basement and the pre-Oligocene sedimentary cover. Deformations associated with major strike-slip faults, such as enéchelon folds and positive flower structures occurring in fault-restraining bends, suggest a shortening direction around N105° (in present-day coordinates). A subsequent wrenching phase of Late Oligocene-Early Miocene age involved reactivation of former “Alpine” faults in a sharply different stress field. This tectonics reflects the intermediate position of the eastern Sardinia belt between the area affected by back-arc stretching (the Sardinian rift and the Liguro-Provençal basin) and the arcuate Apenninic subduction front active in a framework of left-lateral oblique plate convergence.
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Jablonski, D., and A. J. Saitta. "PERMIAN TO LOWER CRETACEOUS PLATE TECTONICS AND ITS IMPACT ON THE TECTONO-STRATIGRAPHIC DEVELOPMENT OF THE WESTERN AUSTRALIAN MARGIN." APPEA Journal 44, no. 1 (2004): 287. http://dx.doi.org/10.1071/aj03011.
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The post-Lower Permian succession of the Perth Basin and Westralian Superbasin can be directly related to the plate tectonic evolution of the Gondwanan Super-continent. In the Late Permian to Albian the northern edge of Gondwana continued to break into microplates that migrated to the north and were accreted into what is today the southeastern Asia (Burma–China) region. These separation events are recorded as a series of stratigraphically distinct transgressions (corresponding to the initial stretching of the asthenosphere and acceleration of subsidence rates) followed by rapid regressions (when new oceanic crust was emplaced in thinned continental crust causing uplifts of large continental masses). Because the events are synchronous across large regions, and may be identified from specific log and seismic signatures, the intensity of stratigraphically related transgressive/regressive cycles varies, depending on the distance from the break-up centres and these cycles allow the identification of regionally significant megasequences even in undrilled areas. The tectonic evolution and resulting stratigraphy can be described by eight plate tectonic events:Visean (Carboniferous) break-up of the southeastern Asia (Simao, Indochina and South China);Kungurian (uppermost Early Permian) break-up of Qiangtang and Sibumasu;Lowermost Norian uplift due to Bowen Orogeny in eastern Australia;Hettangian break-up of Mangkalihat (northeastern Borneo);Oxfordian break-up of Argo/West Burma, and Sikuleh (Western Sumatra);Kimmeridgian break-up of the West Sulawesi microplate;Tithonian break-up of Paternoster-Meratus (central Borneo); andValanginian break-up of Greater India/India.These events should be identifiable in all Australian Phanerozoic basins and beyond, potentially providing a template for a synchronisation of the Permian to Early Cretaceous stratigraphy.
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Hindle, David, Boris Sedov, Susanne Lindauer, and Kevin Mackey. "The Ulakhan fault surface rupture and the seismicity of the Okhotsk–North America plate boundary." Solid Earth 10, no. 2 (2019): 561–80. http://dx.doi.org/10.5194/se-10-561-2019.
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Abstract. New field work, combined with analysis of high-resolution aerial photographs, digital elevation models, and satellite imagery, has identified an active fault that is traceable for ∼90 km across the Seymchan Basin and is part of the Ulakhan fault system, which is believed to form the Okhotsk–North America plate boundary. Age dating of alluvial fan sediments in a channel system that is disturbed by fault activity suggests the current scarp is a result of a series of large earthquakes (≥Mw 7.5) that have occurred since 11.6±2.7 ka. A possible channel feature offset by 62±4 m associated with these sediments yields a slip rate of 5.3±1.3 mm yr−1, in broad agreement with rates suggested from global plate tectonics. Our results clearly identify the Ulakhan fault as the Okhotsk–North America plate boundary and show that tectonic strain release is strongly concentrated on the boundaries of Okhotsk. In light of our results, the likelihood of recurrence of Mw 7.5 earthquakes is high, suggesting a previously underestimated seismic hazard across the region.
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Zwaan, Frank, Guido Schreurs, and Susanne J. H. Buiter. "A systematic comparison of experimental set-ups for modelling extensional tectonics." Solid Earth 10, no. 4 (2019): 1063–97. http://dx.doi.org/10.5194/se-10-1063-2019.
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Abstract. Analogue modellers investigating extensional tectonics often use different machines, set-ups and model materials, implying that direct comparisons of results from different studies can be challenging. Here we present a systematic comparison of crustal-scale analogue experiments using simple set-ups simulating extensional tectonics, involving either a foam base, a rubber base, rigid basal plates or a conveyor base system to deform overlying brittle-only or brittle-viscous models. We use X-ray computed tomography (CT) techniques for a detailed 3-D analysis of internal and external model evolution. We find that our brittle-only experiments are strongly affected by their specific set-up, as the materials are directly coupled to the model base. Experiments with a foam or rubber base undergo distributed faulting, whereas experiments with a rigid plate or conveyor base experience localized deformation and the development of discrete rift basins. Pervasive boundary effects may occur due to extension-perpendicular contraction of a rubber base. Brittle-viscous experiments are less affected by the experimental set-up than their brittle-only equivalents since the viscous layer acts as a buffer that decouples the brittle layer from the base. Under reference conditions, a structural weakness at the base of the brittle layer is required to localize deformation into a rift basin. Brittle-viscous plate and conveyor base experiments better localize deformation for high brittle-to-viscous thickness ratios since the thin viscous layers in these experiments allow deformation to transfer from the experimental base to the brittle cover. Brittle-viscous-base coupling is further influenced by changes in strain rate, which affects viscous strength. We find, however, that the brittle-to-viscous strength ratios alone do not suffice to predict the type of deformation in a rift system and that the localized or distributed character of the experimental set-up needs to be taken into account as well. Our set-ups are most appropriate for investigating crustal-scale extension in continental and selected oceanic settings. Specific combinations of set-up and model materials may be used for studying various tectonic settings or lithospheric conditions. Here, natural factors such as temperature variations, extension rate, water content and lithology should be carefully considered. We hope that our experimental overview may serve as a guide for future experimental studies of extensional tectonics.
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Ali, Syed Haroon, Osman M. Abdullatif, Lamidi O. Babalola, et al. "Sedimentary facies, depositional environments and conceptual outcrop analogue (Dam Formation, early Miocene) Eastern Arabian Platform, Saudi Arabia: a new high-resolution approach." Journal of Petroleum Exploration and Production Technology 11, no. 6 (2021): 2497–518. http://dx.doi.org/10.1007/s13202-021-01181-7.
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AbstractThis paper presents the facies and depositional environment of the early Miocene Dam Formation, Eastern Arabian platform, Saudi Arabia. Deposition of Dam Formation (Fm.) was considered as a restricted shallow marine deposition. Few studies suggest the role of sea-level change in its deposition but were without decisive substantiation. Here, we describe the facies and high-resolution model of Dam Fm. under varying depositional conditions. The depositional conditions were subjected to changing relative sea level and tectonics. High-resolution outcrop photographs, sedimentological logs, and thin sections present that the mixed carbonate–siliciclastic sequence was affected by a regional tectonics. The lower part of Dam Fm. presents the development of carbonate ramp conditions that are represented by limestones and marl. The depositional conditions fluctuated with the fall of sea level, and uplift in the region pushed the siliciclastic down-dip and covered the whole platform. The subsequent rise in sea level was not as pronounced and thus allowed the deposition of microbial laminites and stromatolitic facies. The southeast outcrops, down-dip, are more carbonate prone as compared to the northwest outcrop, which allowed the deposition of siliciclastic-prone sedimentation up-dip. All facies, architecture, heterogeneity, and deposition were controlled by tectonic events including uplift, subsidence, tilting, and syn-sedimentary faulting, consequently affecting relative sea level. The resulting conceptual outcrop model would help to improve our understanding of mixed carbonate–siliciclastic systems and serve as an analogue for other stratigraphic units in the Arabian plate and region. Our results show that Dam Fm. can be a good target for exploration in the Northern Arabian Gulf.
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Boutelier, D., and O. Oncken. "3-D thermo-mechanical laboratory modeling of plate-tectonics: modeling scheme, technique and first experiments." Solid Earth 2, no. 1 (2011): 35–51. http://dx.doi.org/10.5194/se-2-35-2011.
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Abstract. We present an experimental apparatus for 3-D thermo-mechanical analogue modeling of plate tectonic processes such as oceanic and continental subductions, arc-continent or continental collisions. The model lithosphere, made of temperature-sensitive elasto-plastic analogue materials with strain softening, is submitted to a constant temperature gradient causing a strength reduction with depth in each layer. The surface temperature is imposed using infrared emitters, which allows maintaining an unobstructed view of the model surface and the use of a high resolution optical strain monitoring technique (Particle Imaging Velocimetry). Subduction experiments illustrate how the stress conditions on the interplate zone can be estimated using a force sensor attached to the back of the upper plate and adjusted via the density and strength of the subducting lithosphere or the lubrication of the plate boundary. The first experimental results reveal the potential of the experimental set-up to investigate the three-dimensional solid-mechanics interactions of lithospheric plates in multiple natural situations.
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Hornung, Thomas, and Rainer Brandner. "Biochronostratigraphy of the Reingraben Turnover (Hallstatt Facies Belt): Local black shale events controlled by regional tectonics, climatic change and plate tectonics." Facies 51, no. 1-4 (2005): 460–79. http://dx.doi.org/10.1007/s10347-005-0061-x.
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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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Friend, C. R. L., and A. P. Nutman. "Tectono-stratigraphic terranes in Archaean gneiss complexes as evidence for plate tectonics: The Nuuk region, southern West Greenland." Gondwana Research 72 (August 2019): 213–37. http://dx.doi.org/10.1016/j.gr.2019.03.004.
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De Pascale, Gregory P. "Comment on “Crustal faults in the Chilean Andes: geological constraints and seismic potential” by Santibáñez et al. (2019), Andean Geology 46 (1): 32-65." Andean Geology 48, no. 1 (2021): 175. http://dx.doi.org/10.5027/andgeov48n1-3310.
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Understanding the location and nature of Quaternary active crustal faults is critical to reduce both the impact of fault rupture and strong ground motions hazards (when these faults rupture causing earthquakes). It is also important for understanding how and where deformation related to plate tectonics is accommodated along geological structures (oftentimes faults and folds). In Chile, work on active tectonics in the upper crust (neotectonics or earthquake geology) is relatively new, in particular regarding fault-focused studies. Therefore, any effort to further progress in our understanding of active fault systems for the benefit of the public, and for aiding local and regional governments and the earthquake engineering and scientific community with mitigation strategies should be applauded. Demonstrating where active faults are located through careful mapping, and to determine how fast they accommodate tectonic deformation and their seismic and fault rupture hazards are key questions in neotectonics. Recently Santibáñez et al. (2019) explore active fault systems in the Chilean Andes. In their paper they outline active and potentially seismogenic (i.e., earthquake producing) fault systems in the Chilean Andes through a review of the literature, seismicity, case studies (earthquakes), and modeling data and then they define potential tectonic domains for subdivision of Chile. These domains were suggested to allow “a first-order approach for seismic potential assessment” (Santibáñez et al., 2019). The three subdivisions they suggest, i.e., domains are the External Forearc, Inner Forearc and Volcanic Arc, were proposed based on several fault parameters (e.g., fault length), case studies, the morphotectonic setting and seismicity. Their paper generates a great foundation to build upon for both the active tectonics and geological hazards community, in addition to being useful for potential end users such as the Chilean local and national government from a planning perspective. Although the Santibáñez et al. (2019) paper takes steps in the right direction, and should be considered an important contribution to the scientific community, this comment addresses three potential issues with their analysis and conclusions that should be reflected upon by the seismic hazard and active tectonics community. These ideas are summarized below and expanded on in detail thereafter.
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Khan, Majid, Yike Liu, Asam Farid, and Muhammad Owais. "Characterizing Seismo-stratigraphic and Structural Framework of Late Cretaceous-Recent succession of offshore Indus Pakistan." Open Geosciences 10, no. 1 (2018): 174–91. http://dx.doi.org/10.1515/geo-2018-0014.
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Abstract Regional seismic reflection profiles and deep exploratory wells have been used to characterize the subsurface structural trends and seismo-stratigraphic architecture of the sedimentary successions in offshore Indus Pakistan. To improve the data quality, we have reprocessed the seismic data by applying signal processing scheme to enhance the reflection continuity for obtaining better results. Synthetic seismograms have been used to identify and tie the seismic reflections to the well data. The seismic data revealed tectonically controlled, distinct episodes of normal faulting representing rifting during Mesozoic and transpression at Late Eocene time. A SW-NE oriented anticlinal type push up structure is observed resulted from the basement reactivation and recent transpression along Indian Plate margin. The structural growth of this particular pushup geometry was computed. Six mappable seismic sequences have been identified on seismic records. In general, geological formations are at shallow depths towards northwest due to basement blocks uplift. A paleoshelf is also identified on seismic records overlain by Cretaceous sediments, which is indicative of Indian-African Plates rifting at Jurassic time. The seismic interpretation reveals that the structural styles and stratigraphy of the region were significantly affected by the northward drift of the Indian Plate, post-rifting, and sedimentation along its western margin during Middle Cenozoic. A considerable structural growth along the push up geometry indicates present day transpression in the margin sediments. The present comprehensive interpretation can help in understanding the complex structures in passive continental margins worldwide that display similar characteristics but are considered to be dominated by rifting and drifting tectonics.
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Escalona, Alejandro, and Paul Mann. "Tectonics, basin subsidence mechanisms, and paleogeography of the Caribbean-South American plate boundary zone." Marine and Petroleum Geology 28, no. 1 (2011): 8–39. http://dx.doi.org/10.1016/j.marpetgeo.2010.01.016.
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Barr, Sandra M., and Rebecca A. Jamieson. "Tectonic setting and regional correlation of Ordovician–Silurian rocks of the Aspy terrane, Cape Breton Island, Nova Scotia." Canadian Journal of Earth Sciences 28, no. 11 (1991): 1769–79. http://dx.doi.org/10.1139/e91-158.
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Interlayered mafic and felsic metavolcanic rocks and metasedimentary rocks of Ordovician to Silurian age are characteristic of the Aspy terrane of northwestern Cape Breton Island. These rocks were affected by medium- to high-grade metamorphism and were intruded by synkinematic granitoid orthogneisses during Late Silurian to Early Devonian times. They were intruded by posttectonic Devonian granitic plutons and experienced rapid Devonian decompression and cooling. The chemical characteristics of the mafic metavolcanic rocks indicate that they are tholeiites formed in a volcanic-arc setting. The volcanic rocks of the Aspy terrane differ from many other Silurian and Silurian–Devonian successions in Atlantic Canada, which have chemical and stratigraphic characteristics of volcanic rocks formed in extensional within-plate settings, and are somewhat younger than the Aspy terrane sequences. Aspy terrane units are most similar to Ordovician–Silurian volcanic and metamorphic units in southwestern Newfoundland, including the La Poile Group and the Port aux Basques gneiss. Together with other occurrences of Late Ordovician to Early Silurian volcanic-arc units, they indicate that subduction-related compressional tectonics continued into the Silurian in parts of the northern Appalachian Orogen. The complex Late Silurian – Devonian tectonic history of the Aspy terrane may reflect collision with the southeastern edge of a Grenvillian crustal promentory.
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Terhune, Patrick J., Jeffrey A. Benowitz, Jeffrey M. Trop, Paul B. O’Sullivan, Robert J. Gillis, and Jeffrey T. Freymueller. "Cenozoic tectono-thermal history of the southern Talkeetna Mountains, Alaska: Insights into a potentially alternating convergent and transform plate margin." Geosphere 15, no. 5 (2019): 1539–76. http://dx.doi.org/10.1130/ges02008.1.
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Abstract The Mesozoic–Cenozoic convergent margin history of southern Alaska has been dominated by arc magmatism, terrane accretion, strike-slip fault systems, and possible spreading-ridge subduction. We apply 40Ar/39Ar, apatite fission-track (AFT), and apatite (U-Th)/He (AHe) geochronology and thermochronology to plutonic and volcanic rocks in the southern Talkeetna Mountains of Alaska to document regional magmatism, rock cooling, and inferred exhumation patterns as proxies for the region’s deformation history and to better delineate the overall tectonic history of southern Alaska. High-temperature 40Ar/39Ar thermochronology on muscovite, biotite, and K-feldspar from Jurassic granitoids indicates postemplacement (ca. 158–125 Ma) cooling and Paleocene (ca. 61 Ma) thermal resetting. 40Ar/39Ar whole-rock volcanic ages and 45 AFT cooling ages in the southern Talkeetna Mountains are predominantly Paleocene–Eocene, suggesting that the mountain range has a component of paleotopography that formed during an earlier tectonic setting. Miocene AHe cooling ages within ∼10 km of the Castle Mountain fault suggest ∼2–3 km of vertical displacement and that the Castle Mountain fault also contributed to topographic development in the Talkeetna Mountains, likely in response to the flat-slab subduction of the Yakutat microplate. Paleocene–Eocene volcanic and exhumation-related cooling ages across southern Alaska north of the Border Ranges fault system are similar and show no S-N or W-E progressions, suggesting a broadly synchronous and widespread volcanic and exhumation event that conflicts with the proposed diachronous subduction of an active west-east–sweeping spreading ridge beneath south-central Alaska. To reconcile this, we propose a new model for the Cenozoic tectonic evolution of southern Alaska. We infer that subparallel to the trench slab breakoff initiated at ca. 60 Ma and led to exhumation, and rock cooling synchronously across south-central Alaska, played a primary role in the development of the southern Talkeetna Mountains, and was potentially followed by a period of southern Alaska transform margin tectonics.
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Miall, Andrew D. "Logan Medallist 3. Making Stratigraphy Respectable: From Stamp Collecting to Astronomical Calibration." Geoscience Canada 42, no. 3 (2015): 271. http://dx.doi.org/10.12789/geocanj.2015.42.072.
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The modern science of stratigraphy is founded on a nineteenth-century empirical base – the lithostratigraphy and biostratigraphy of basin-fill successions. This stratigraphic record comprises the most complete data set available for reconstructing the tectonic and climatic history of Earth. However, it has taken two hundred years of evolution of concepts and methods for the science to evolve from what Ernest Rutherford scornfully termed “stamp collecting” to a modern dynamic science characterized by an array of refined methods for documenting geological rates and processes. Major developments in the evolution of the science of stratigraphy include the growth of an ever-more precise geological time scale, the birth of sedimentology and basin-analysis methods, the influence of plate tectonics and, most importantly, the development, since the late 1970s, of the concepts of sequence stratigraphy. Refinements in these concepts have required the integration of all pre-existing data and methods into a modern, multidisciplinary approach, as exemplified by the current drive to apply the retrodicted history of Earth’s orbital behaviour to the construction of a high-precision ‘astrochronological’ time scale back to at least the Mesozoic record. At its core, stratigraphy, like much of geology, is a field-based science. The field context of a stratigraphic sample or succession remains the most important starting point for any advanced mapping, analytical or modeling work.RÉSUMÉLa science moderne de la stratigraphie repose sur une base empirique du XIXe siècle, soit la lithostratigraphie et la biostratigraphie de successions de remplissage de bassins sédimentaires. Cette archive stratigraphique est constituée de la base de données la plus complète permettant de reconstituer l’histoire tectonique et climatique de la Terre. Cela dit, il aura fallu deux cents ans d’évolution des concepts et des méthodes pour que cette activité passe de l’état de « timbromanie », comme disait dédaigneusement Ernest Rutherford, à l’état de science moderne dynamique caractérisée par sa panoplie de méthodes permettant de documenter les rythmes et processus géologiques. Les principaux développements de l’évolution de la science de la stratigraphie proviennent de l’élaboration d’une échelle géologique toujours plus précise, l’avènement de la sédimentologie et des méthodes d’analyse des bassins, de l’influence de la tectonique des plaques et, surtout du développement depuis la fin des années 1970, des concepts de stratigraphie séquentielle. Des raffinements dans ces concepts ont nécessité l'intégration de toutes les données et méthodes existantes dans une approche moderne, multidisciplinaire, comme le montre ce mouvement actuel qui entend utiliser la reconstitution de l’histoire du comportement orbital de la Terre pour l’élaboration d’une échelle temporelle « astrochronologique » de haute précision, remontant jusqu’au Mésozoïque au moins. Comme pour la géologie, la stratigraphie est une science de terrain. Le contexte de terrain d’un échantillon stratigraphique ou d’une succession demeure le point de départ le plus important, pour tout travail sérieux de cartographie, d’analyse ou de modélisation.
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Rubey, Michael, Sascha Brune, Christian Heine, D. Rhodri Davies, Simon E. Williams, and R. Dietmar Müller. "Global patterns in Earth's dynamic topography since the Jurassic: the role of subducted slabs." Solid Earth 8, no. 5 (2017): 899–919. http://dx.doi.org/10.5194/se-8-899-2017.
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Abstract. We evaluate the spatial and temporal evolution of Earth's long-wavelength surface dynamic topography since the Jurassic using a series of high-resolution global mantle convection models. These models are Earth-like in terms of convective vigour, thermal structure, surface heat-flux and the geographic distribution of heterogeneity. The models generate a degree-2-dominated spectrum of dynamic topography with negative amplitudes above subducted slabs (i.e. circum-Pacific regions and southern Eurasia) and positive amplitudes elsewhere (i.e. Africa, north-western Eurasia and the central Pacific). Model predictions are compared with published observations and subsidence patterns from well data, both globally and for the Australian and southern African regions. We find that our models reproduce the long-wavelength component of these observations, although observed smaller-scale variations are not reproduced. We subsequently define geodynamic rules for how different surface tectonic settings are affected by mantle processes: (i) locations in the vicinity of a subduction zone show large negative dynamic topography amplitudes; (ii) regions far away from convergent margins feature long-term positive dynamic topography; and (iii) rapid variations in dynamic support occur along the margins of overriding plates (e.g. the western US) and at points located on a plate that rapidly approaches a subduction zone (e.g. India and the Arabia Peninsula). Our models provide a predictive quantitative framework linking mantle convection with plate tectonics and sedimentary basin evolution, thus improving our understanding of how subduction and mantle convection affect the spatio-temporal evolution of basin architecture.
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Vizán, Haroldo, Claudia Beatriz Prezzi, Silvana Evangelina Geuna, et al. "Paleotethys slab pull, self-lubricated weak lithospheric zones, poloidal and toroidal plate motions, and Gondwana tectonics." Geosphere 13, no. 5 (2017): 1541–54. http://dx.doi.org/10.1130/ges01444.1.
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Duque-Trujillo, José, Camilo Bustamante, Luigi Solari, Álvaro Gómez-Mafla, Gloria Toro-Villegas, and Susana Hoyos. "Reviewing the Antioquia batholith and satellite bodies: a record of Late Cretaceous to Eocene syn- to post-collisional arc magmatism in the Central Cordillera of Colombia." Andean Geology 46, no. 1 (2018): 82. http://dx.doi.org/10.5027/andgeov46n1-3120.
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The Antioquia batholith represents the magmatic record of the interaction between the Farallón and Caribbean plates with the NW part of the South American Plate during the Meso-Cenozoic. Several authors have reported zircon U-Pb ages and whole rock geochemistry in order to constrain the crystallization history of this batholith and its formation conditions. The present work aims to gather the existing data with new data obtained from the Ovejas batholith and La Unión stock, both genetically related to the main intrusion. Gathering our new data with information obtained in previous works, we conclude that the Antioquia batholith was constructed by successive pulses from ca. 97 to 58 Ma in an arc-related setting. The initial pulses are related to syn-collisional tectonics, during the early interaction between the Farallón plate and NW South America. The final pulses, that record Eocene ages, are related to a post-collisional setting, similar to that recorded in other plutons of the Paleogene magmatic arc of the Central Cordillera.
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Van Kranendonk, M. J. "Gliding and overthrust nappe tectonics of the Barberton Greenstone Belt revisited: A review of deformation styles and processes." South African Journal of Geology 124, no. 1 (2021): 181–210. http://dx.doi.org/10.25131/sajg.124.0017.
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Abstract Interpretations of the structural/tectonic evolution of the Barberton Greenstone Belt (BGB) and its surrounding granitoid rocks remain controversial, with proponents for both horizontal thrust-accretion (plate tectonic) and partial convective overturn (vertical tectonic) models. Here, an area of complex folds that was used to support the operation of plate tectonic-derived gliding and overthrust nappe tectonics is re-investigated in detail and placed within the broader structural development of the BGB and surrounding granitoid domains via a re-analysis of structures, and geochronological, stratigraphic and metamorphic data across the whole of this important geological terrain. The results of detailed field mapping show that the complex folds, which occur on the northern limb of the 20 km wavelength, vertically plunging, Onverwacht Anticline, do not represent a re-folded, originally recumbent, isoclinal fold, as previously interpreted. Instead, the folds represent a moderately shallow east-plunging fold train that formed from a single episode of deformation. Fold asymmetry is consistent with formation during originally north-side-up reverse shear on bounding faults, consistent with the offset direction required to explain the fault-repeated slices of Mendon Formation + Fig Tree Group rocks that uniquely occur across the northern limb of the Onverwacht Anticline. More broadly, a review of the BGB and surrounding granitoid rocks show that formation was likely through two discrete, ~120 Ma long, episodes of mantle upwelling, or plume, magmatism, each of which led to crustal melting and partial convective overturn (PCO), a tectonic mechanism that arises from the gravity-driven interaction between dense, upper crustal greenstones and partially melted, more buoyant, granitoid-dominated middle crust. The first mantle upwelling episode, at 3 530 to 3 410 Ma, commenced with long-lived eruption of ultramafic-mafic lavas of the Sandspruit, Theespruit, Komati, and lower Hooggenoeg formations (3 530 to 3 470 Ma). Heat from this magmatic event gave rise to partial melting of the crust that, combined with fractionation of mafic magma chambers produced widespread felsic magmatism at 3 470 to 3 410 Ma (upper Hooggenoeg Formation and Buck Reef Chert), the latter parts of which were accompanied by the formation of D1 dome-and-keel structures via PCO in deeper-levels of the crust represented by the Stolzburg Domain in the far southwest part of the belt. The second mantle upwelling, or plume, episode commenced at 3 334 to 3 215 Ma with the eruption of ultramafic-mafic lavas of the Kromberg, Mendon and Weltevreden formations. Heat from this magmatic event gave rise to renewed partial melting of the crust that, combined with fractionation of mafic magma chambers, produced widespread felsic magmatism at 3 290 to 3 215 Ma. A second, longer-lived and more complex, multi-stage episode of PCO (D2-D4) accompanied deposition of the Fig Tree and Moodies groups from 3 250 to 3 215 Ma. Late D5 deformation accompanied emplacement of the Mpulizi and Piggs Peak batholiths at ca. 3.01 Ga, as previously identified. The Inyoka and Kromberg faults, which separate domains with distinct structural styles, represent neither terrane boundaries nor suture zones, but rather axial faults that separate deformed but generally inward-facing greenstone panels that sank inwards off rising granitoid domains that surround the BGB.
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Coianiz, Lisa, Uri Schattner, Guy Lang, Zvi Ben‐Avraham, and Michael Lazar. "Between plate and salt tectonics—New stratigraphic constraints on the architecture and timing of the Dead Sea basin during the Late Quaternary." Basin Research 32, no. 4 (2019): 636–51. http://dx.doi.org/10.1111/bre.12387.
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Isla, Federico Ignacio, and Marcela Espinosa. "Quaternary glaciolacustrine deposits around a Triple Junction site: Paleolakes at the foot of the Northern Patagonian Ice field (Argentina and Chile)." Andean Geology 48, no. 1 (2021): 94. http://dx.doi.org/10.5027/andgeov48n1-3173.
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The area involved by the triple junction between the South American, Nazca and Antarctic plates activity was affected by Quaternary glaciations. Before 12,800 yrs BP an extended ice field occupied the top of the Patagonian Andes, irradiating glaciers towards the east and the west dominantly. Towards the east, the ice melted in piedmont lakes; towards the west, fjords melted into the Pacific Ocean. The Upper-Pleistocene climate amelioration caused the recession of those glaciers. Some piedmont lakes reversed their Atlantic outflow towards to the Pacific Ocean. The glaciers retreat caused the fluvial reactivations along crustal former faults that were located below the ice. The Patagonian ice field became therefore split into present Northern and Southern fields. At the second largest lake of South America, the Buenos Aires-General Carrera Lake, the water level dropped from about 500 m over present mean sea level to 230 m. Several glaciolacustrine deposits from this area are indicating significant variations caused by climatic changes, volcanism and tectonics, differing in spatial and temporal magnitudes. The triple junction activity involved subduction of the Chile Ridge below the continental South American plate, volcanic activity and faulting. During the glacier melting the Baker River captured three eastern-moving glacial systems towards the southwest, towards the Pacific Ocean. This rapid event is thought to occur 12,800 yrs BP. The lowering of these glaciolacustrine systems should be also interpreted in terms of the tectonic activity in the region and considering other processes operating in the lakes and within the watersheds.
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Leclerc, Frédérique, and Nathalie Feuillet. "Quaternary coral reef complexes as powerful markers of long-term subsidence related to deep processes at subduction zones: Insights from Les Saintes (Guadeloupe, French West Indies)." Geosphere 15, no. 4 (2019): 983–1007. http://dx.doi.org/10.1130/ges02069.1.
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Abstract Geodetic measurements reveal modern rates of tectonic deformation along subduction zones, but the kinematics of long-term deformation are typically poorly constrained. We explore the use of submarine coral reefs as a record of long-term coastal vertical motion in order to determine deformation rate and discuss its origins. The Lesser Antilles arc results from the subduction of the American plates beneath the Caribbean plate and undergoes regional vertical deformation. Uplifted reefs along forearc islands are markers of the interplay between tectonics and sea-level variations since the late Pleistocene. We compared results from a numerical model of reef-island profile development to high-resolution marine geophysical measurements of Les Saintes reef plateau (Guadeloupe, French West Indies), a ∼20-km-wide, 250-m-thick submerged platform that lies at 45 m below sea level along the volcanic arc, to constrain its vertical deformation history. Models explore different scenarios over wide parameter domains including start time, basement morphology, sea level variations, reef growth rate, subaerial erosion rate, and vertical motion history. The major features of the plateau (its depth, internal structure, unusual double-barrier) is only reproduced in a context of subsidence, with a constant rate of −0.3 to −0.45 mm/yr since the late Pleistocene, or in a context of increasing subsidence, presently of ∼–0.2 mm/yr. Discussed in the framework of the forearc vertical deformation history, this result indicates subsidence is promoted by local faulting, volcanic, and deep subduction processes. Coseismic deformation accumulation could be a mechanism by which deformation builds up in the long-term. We show that subduction can drive long-term subsidence of a volcanic arc, and demonstrate that submarine reefs are powerful markers of long-term vertical motion.
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Gómez-García, Ángela María, Eline Le Breton, Magdalena Scheck-Wenderoth, Gaspar Monsalve, and Denis Anikiev. "The preserved plume of the Caribbean Large Igneous Plateau revealed by 3D data-integrative models." Solid Earth 12, no. 1 (2021): 275–98. http://dx.doi.org/10.5194/se-12-275-2021.
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Abstract. Remnants of the Caribbean Large Igneous Plateau (C-LIP) are found as thicker than normal oceanic crust in the Caribbean Sea that formed during rapid pulses of magmatic activity at ∼91–88 and ∼76 Ma. Strong geochemical evidence supports the hypothesis that the C-LIP formed due to melting of the plume head of the Galápagos hotspot, which interacted with the Farallon (Proto-Caribbean) plate in the eastern Pacific. Considering plate tectonics theory, it is expected that the lithospheric portion of the plume-related material migrated within the Proto-Caribbean plate in a north–north-eastward direction, developing the present-day Caribbean plate. In this research, we used 3D lithospheric-scale, data-integrative models of the current Caribbean plate setting to reveal, for the first time, the presence of positive density anomalies in the uppermost lithospheric mantle. These models are based on the integration of up-to-date geophysical datasets from the Earth's surface down to 200 km depth, which are validated using high-resolution free-air gravity measurements. Based on the gravity residuals (modelled minus observed gravity), we derive density heterogeneities both in the crystalline crust and the uppermost oceanic mantle (<50 km). Our results reveal the presence of two positive mantle density anomalies beneath the Colombian and the Venezuelan basins, interpreted as the preserved fossil plume conduits associated with the C-LIP formation. Such mantle bodies have never been identified before, but a positive density trend is also indicated by S-wave tomography, at least down to 75 km depth. The interpreted plume conduits spatially correlate with the thinner crustal regions present in both basins; therefore, we propose a modification to the commonly accepted tectonic model of the Caribbean, suggesting that the thinner domains correspond to the centres of uplift due to the inflow of the hot, buoyant plume head. Finally, using six different kinematic models, we test the hypothesis that the C-LIP originated above the Galápagos hotspot; however, misfits of up to ∼3000 km are found between the present-day hotspot location and the mantle anomalies, reconstructed back to 90 Ma. Therefore, we shed light on possible sources of error responsible for this offset and discuss two possible interpretations: (1) the Galápagos hotspot migrated (∼1200–3000 km) westward while the Caribbean plate moved to the north, or (2) the C-LIP was formed by a different plume, which – if considered fixed – would be nowadays located below the South American continent.
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Decker, Kurt. "Plate tectonics and pelagic facies: Late Jurassic to Early Cretaceous deep-sea sediments of the Ybbsitz ophiolite unit (Eastern Alps, Austria)." Sedimentary Geology 67, no. 1-2 (1990): 85–99. http://dx.doi.org/10.1016/0037-0738(90)90028-r.
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Krabbenhoeft, Anne, Roland von Huene, John J. Miller, and Dirk Klaeschen. "Subducting oceanic basement roughness impacts on upper-plate tectonic structure and a backstop splay fault zone activated in the southern Kodiak aftershock region of the Mw 9.2, 1964 megathrust rupture, Alaska." Geosphere 17, no. 2 (2021): 409–37. http://dx.doi.org/10.1130/ges02275.1.
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Abstract In 1964, the Alaska margin ruptured in a giant Mw 9.2 megathrust earthquake, the second largest during worldwide instrumental recording. The coseismic slip and aftershock region offshore Kodiak Island was surveyed in 1977–1981 to understand the region’s tectonics. We re-processed multichannel seismic (MCS) field data using current standard Kirchhoff depth migration and/or MCS traveltime tomography. Additional surveys in 1994 added P-wave velocity structure from wide-angle seismic lines and multibeam bathymetry. Published regional gravity, backscatter, and earthquake compilations also became available at this time. Beneath the trench, rough oceanic crust is covered by ∼3–5-km-thick sediment. Sediment on the subducting plate modulates the plate interface relief. The imbricate thrust faults of the accreted prism have a complex P-wave velocity structure. Landward, an accelerated increase in P-wave velocities is marked by a backstop splay fault zone (BSFZ) that marks a transition from the prism to the higher rigidity rock beneath the middle and upper slope. Structures associated with this feature may indicate fluid flow. Farther upslope, another fault extends &gt;100 km along strike across the middle slope. Erosion from subducting seamounts leaves embayments in the frontal prism. Plate interface roughness varies along the subduction zone. Beneath the lower and middle slope, 2.5D plate interface images show modest relief, whereas the oceanic basement image is rougher. The 1964 earthquake slip maximum coincides with the leading and/or landward flank of a subducting seamount and the BSFZ. The BSFZ is a potentially active structure and should be considered in tsunami hazard assessments.
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Fu, Dong, Timothy M. Kusky, Simon A. Wilde, et al. "Structural anatomy of the early Paleozoic Laohushan ophiolite and subduction complex: Implications for accretionary tectonics of the Proto-Tethyan North Qilian orogenic belt, northeastern Tibet." GSA Bulletin 132, no. 9-10 (2020): 2175–201. http://dx.doi.org/10.1130/b35442.1.
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Abstract Recognition of accretionary tectonics in ancient orogenic collages is important for reconstructing the long-term subduction, accretion, and erosional history of fossil convergent margins, and for understanding crustal growth and supercontinent assembly. The North Qilian orogenic belt (NQOB), located between the Alxa block and the Central Qilian–Qaidam block in northeastern Tibet, is a typical Phanerozoic accretionary-to-collisional orogenic belt that represents the termination of the northern branch of the Proto-Tethys Ocean. It contains two subparallel ophiolitic belts, arcs, and subduction complexes; the ophiolitic rocks in the northern belt have generally been considered to have formed in a back-arc setting. However, the subduction-accretion-collision history, subduction polarity, and timing of closure of the back-arc ocean remain equivocal. To address these problems, we conducted detailed field, structural, and geochronological investigations of the Laohushan ophiolite–accretionary complex and related sedimentary rocks in the eastern NQOB. The Laohushan Complex is divisible into (1) a northern sedimentary forearc, and a supra-subduction zone-type ultramafic-mafic forearc (ca. 450 Ma) composed of serpentinized harzburgite, gabbro, basalt, and plagiogranite; and (2) a southern accretionary complex, which consists of relatively coherent basalt-chert-mudstone ocean plate stratigraphy that is structurally repeated many times, trench-fill turbidites, mélanges, and widespread thrust imbricates and duplexes, block-in-matrix and asymmetric structures. Kinematic analysis indicates that the accretionary complex underwent southward thrusting and shearing; coupled with the spatial architecture of the different tectonic units, which suggests northward subduction beneath the northern forearc on the southern margin of the Alxa block. Detrital zircon ages of forearc clastic sandstones, pelagic mudstones, trench-fill turbidites, and the matrix of mélanges, together with the zircon ages of igneous ophiolitic rocks and post-accretionary intrusions, indicate that the terminal accretion and tectonic stacking of the Laohushan subduction complex was between ca. 447 and 430 Ma. We propose a geodynamic model involving back-arc basin opening (ca. 517–449 Ma), intra-oceanic subduction-accretion (ca. 449–430 Ma), and final obduction of the northern forearc to account for the evolutionary processes of the North Qilian back-arc basin. The anatomy of the forearc ophiolite and structurally lower accretionary complex indicates the complicated origins and mechanism of emplacement of the ophiolitic rocks. Field-based reconstruction of accretionary complexes and upper plate ophiolites, together with provenance analysis of related sedimentary sequences, provide crucial constraints on the prolonged evolution of paleo-ocean basins and accretionary-to-collisional orogens.
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Padgett, J. Scott, Harvey M. Kelsey, and David Lamphear. "Upper-plate deformation of Late Pleistocene marine terraces in the Trinidad, California, coastal area, southern Cascadia subduction zone." Geosphere 15, no. 4 (2019): 1323–41. http://dx.doi.org/10.1130/ges02032.1.
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Abstract Forming at sea level, uplifted shore platforms serve as long-term geodetic markers. The spatial distribution and elevation of marine terrace sequences offer insight into regional tectonics. In the Trinidad coastal area (California, USA), active tectonic processes reflect upper-plate deformation above the southern extent of the Cascadia subduction megathrust. A set of five uplifted and deformed Late Pleistocene marine terraces is preserved in the Trinidad region and provides an opportunity to analyze regional uplift, folding, and faulting. Using lidar imagery embedded within a GIS, we employ a surface classification model (SCM) that identifies uplifted marine terraces on the basis of their micro-topographical characteristics, i.e., low slope and low roughness. The SCM-based identification of marine terraces both supplements and verifies existing field mapping. We demonstrate the utility of the SCM, which can be applied to a variety of surface terrain analysis investigations that seek to identify smooth and/or rough terrain features, e.g., terraces and fault scarps. Age assignments for the five marine terraces, which range from 80 ka to <500 ka, are based on paleo–sea cliff geomorphology and soil development trends. Specifically, the steepest, highest, and most prominent paleo–sea cliff, which is associated with terrace number 3, is correlated to the long-duration sea-level highstand centered at 125 ka (marine isotope stage 5e), exemplifying a novel method in relative age assignment for Pleistocene geomorphic features. Based on these age assignments, the average maximum uplift rates in the Trinidad coastal area are ∼1.0 m/k.y., and the average long-term uplift rate diminishes westward to ∼0.4 – 0.5 m/k.y. on the downthrown side of the Trinidad fault. Based on analysis of deformation using the high-resolution lidar imagery of the marine terraces, the Trinidad hanging-wall anticline represents a fault propagation fold that ceased to be active when the associated reverse fault, the Trinidad fault, daylighted to the surface ca. 80–100 ka. Based on deformation tilts of a marine terrace with an assigned age of 200 ka, the Trinidad anticline has accommodated at least 1 km of shortening in the last 200 k.y., which represents at least 2% of the convergence of the Juan de Fuca plate relative to North America over the same time period. Overall, both the hanging wall and the footwall of the Trinidad fault show long-term positive rock uplift, which implies that the Trinidad anticline and fault are contained within the hanging wall of a deeper structure. Therefore, the Trinidad fault likely splays off of the Cascadia subduction zone megathrust or off of a deeper thrust fault that splays off of the megathrust.
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King, Rosalind C., Guillaume Backé, Christopher K. Morley, Richard R. Hillis, and Mark R. P. Tingay. "Balancing deformation in NW Borneo: Quantifying plate-scale vs. gravitational tectonics in a delta and deepwater fold-thrust belt system." Marine and Petroleum Geology 27, no. 1 (2010): 238–46. http://dx.doi.org/10.1016/j.marpetgeo.2009.07.008.
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Zhu, Bei, Zhaojie Guo, Shaonan Zhang, Ingrid Ukstins, Wei Du, and Runchao Liu. "What triggered the early-stage eruption of the Emeishan large igneous province?" GSA Bulletin 131, no. 11-12 (2019): 1837–56. http://dx.doi.org/10.1130/b35030.1.
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Abstract The formation of the Emeishan large igneous province is widely regarded as being related to a mantle plume, but plate tectonics may also have played an important role. We analyzed the regional facies architecture of the early-stage subaqueous volcanic rocks of the central Emeishan large igneous province. The results suggest that these rocks were emplaced in a N-S–striking subaqueous rift, which existed immediately before the onset of volcanism and was persistently maintained during the early eruption stage. By linking this conclusion with the background information indicating that (1) the basaltic geochemistry in this section is indicative of a subcontinental lithospheric mantle source rather than a mantle plume source, and (2) the western Yangtze plate, where the Emeishan large igneous province was developed, was located in the back-arc region of the Permian Paleo-Tethys subduction system, we propose a new view that the early-stage eruptions of the Emeishan large igneous province were triggered by back-arc extension. The dominant functioning of the mantle plume occurred shortly after this process and inherited it, as evidenced by the following: (1) The subaqueous volcanic architecture showing back-arc geochemical affinity is laterally restricted in the presumed rift, but the overlying subaerial lavas showing plume-related geochemical features overwhelmingly flooded the whole province; (2) vertically, the source of the basaltic component in these intrarift sequences underwent a gradual transition from lithospheric origin to mantle plume origin along the stratigraphic order, as evidenced by an intercalated basaltic succession showing mixed geochemical features from the two contextual origins.
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Petersen, Robert I., Dave R. Stegman, and Paul J. Tackley. "The subduction dichotomy of strong plates and weak slabs." Solid Earth 8, no. 2 (2017): 339–50. http://dx.doi.org/10.5194/se-8-339-2017.
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Abstract. A key element of plate tectonics on Earth is that the lithosphere is subducting into the mantle. Subduction results from forces that bend and pull the lithosphere into the interior of the Earth. Once subducted, lithospheric slabs are further modified by dynamic forces in the mantle, and their sinking is inhibited by the increase in viscosity of the lower mantle. These forces are resisted by the material strength of the lithosphere. Using geodynamic models, we investigate several subduction models, wherein we control material strength by setting a maximum viscosity for the surface plates and the subducted slabs independently. We find that models characterized by a dichotomy of lithosphere strengths produce a spectrum of results that are comparable to interpretations of observations of subduction on Earth. These models have strong lithospheric plates at the surface, which promotes Earth-like single-sided subduction. At the same time, these models have weakened lithospheric subducted slabs which can more easily bend to either lie flat or fold into a slab pile atop the lower mantle, reproducing the spectrum of slab morphologies that have been interpreted from images of seismic tomography.