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Journal articles on the topic 'Tectonic syntaxis'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Govin, Gwladys, Peter van der Beek, Yani Najman, Ian Millar, Lorenzo Gemignani, Pascale Huyghe, Guillaume Dupont-Nivet, Matthias Bernet, Chris Mark, and Jan Wijbrans. "Early onset and late acceleration of rapid exhumation in the Namche Barwa syntaxis, eastern Himalaya." Geology 48, no. 12 (July 21, 2020): 1139–43. http://dx.doi.org/10.1130/g47720.1.

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Abstract The Himalayan syntaxes, characterized by extreme rates of rock exhumation co-located with major trans-orogenic rivers, figure prominently in the debate on tectonic versus erosional forcing of exhumation. Both the mechanism and timing of rapid exhumation of the Namche Barwa massif in the eastern syntaxis remain controversial. It has been argued that coupling between crustal rock advection and surface erosion initiated in the late Miocene (8–10 Ma). Recent studies, in contrast, suggest a Quaternary onset of rapid exhumation linked to a purely tectonic mechanism. We report new multisystem detrital thermochronology data from the most proximal Neogene clastic sediments downstream of Namche Barwa and use a thermo-kinematic model constrained by new and published data to explore its exhumation history. Modeling results show that exhumation accelerated to ∼4 km/m.y. at ca. 8 Ma and to ∼9 km/m.y. after ca. 2 Ma. This three-stage history reconciles apparently contradictory evidence for early and late onset of rapid exhumation and suggests efficient coupling between tectonics and erosion since the late Miocene. Quaternary acceleration of exhumation is consistent with river-profile evolution and may be linked to a Quaternary river-capture event.
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2

Butler, Robert W. H. "Tectonic evolution of the Himalayan syntaxes: the view from Nanga Parbat." Geological Society, London, Special Publications 483, no. 1 (August 30, 2018): 215–54. http://dx.doi.org/10.1144/sp483.5.

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AbstractCurrent tectonic understanding of the Nanga Parbat–Haramosh massif (NPHM) is reviewed, developing new models for the structure and deformation of the Indian continental crust, its thermorheological evolution, and its relationship to surface processes. Comparisons are drawn with the Namche Barwa–Gyala Peri massif (NBGPM) that cores an equivalent syntaxis at the NE termination of the Himalayan arc. Both massifs show exceptionally rapid active denudation and riverine downcutting, identified from very young cooling ages measured from various thermochronometers. They also record relicts of high-pressure metamorphic conditions that chart early tectonic burial. Initial exhumation was probably exclusively by tectonic processes but the young, and continuing emergence of these massifs reflects combined tectonic and surface processes. The feedback mechanisms implicit in aneurysm models may have been overemphasized, especially the role of synkinematic granites as agents of rheological softening and strain localization. Patterns of distributed ductile deformation exhumed within the NPHM are consistent with models of orogen-wide gravitation flow, with the syntaxes forming the lateral edges to the flow beneath the Himalayan arc.
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3

Bossart, Paul, Dorothee Dietrich, Antonio Greco, Robert Ottiger, and John G. Ramsay. "The tectonic structure of the Hazara-Kashmir Syntaxis, southern Himalayas, Pakistan." Tectonics 7, no. 2 (April 1988): 273–97. http://dx.doi.org/10.1029/tc007i002p00273.

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4

Tiwari, V. M., D. C. Mishra, and A. K. Pandey. "The lithospheric density structure below the western Himalayan syntaxis: tectonic implications." Geological Society, London, Special Publications 412, no. 1 (October 2, 2014): 55–65. http://dx.doi.org/10.1144/sp412.7.

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5

Quanru, Geng, Pan Guitang, Lailin Zheng, Zhiliang Chen, Richard D. Fisher, Zhiming Sun, Chunsheng Ou, et al. "The Eastern Himalayan syntaxis: major tectonic domains, ophiolitic mélanges and geologic evolution." Journal of Asian Earth Sciences 27, no. 3 (August 2006): 265–85. http://dx.doi.org/10.1016/j.jseaes.2005.03.009.

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Otofuji, Yo-ichiro, Masahiko Yokoyama, Kazuya Kitada, and Haider Zaman. "Paleomagnetic versus GPS determined tectonic rotation around eastern Himalayan syntaxis in East Asia." Journal of Asian Earth Sciences 37, no. 5-6 (March 2010): 438–51. http://dx.doi.org/10.1016/j.jseaes.2009.11.003.

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7

Zhang, Hong-Fei, Wang-Chun Xu, Ke-Qing Zong, Hong-Lin Yuan, and Nigel Harris. "Tectonic Evolution of Metasediments from the Gangdise Terrane, Asian Plate, Eastern Himalayan Syntaxis, Tibet." International Geology Review 50, no. 10 (October 2008): 914–30. http://dx.doi.org/10.2747/0020-6814.50.10.914.

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8

Xu, Wang-Chun, Hong-Fei Zhang, Randall Parrish, Nigel Harris, Liang Guo, and Hong-Lin Yuan. "Timing of granulite-facies metamorphism in the eastern Himalayan syntaxis and its tectonic implications." Tectonophysics 485, no. 1-4 (April 2010): 231–44. http://dx.doi.org/10.1016/j.tecto.2009.12.023.

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9

Schneider, D. A., P. K. Zeitler, W. S. F. Kidd, and M. A. Edwards. "Geochronologic Constraints on the Tectonic Evolution and Exhumation of Nanga Parbat, Western Himalaya Syntaxis, Revisited." Journal of Geology 109, no. 5 (September 2001): 563–83. http://dx.doi.org/10.1086/322764.

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10

Xie, Chao, Bengang Zhou, Fan Yang, Zhengfang Li, Yueju Cui, Wei Pang, and Wei Li. "Geological and Geomorphological Evidence for Activity along the Motuo Fault, Eastern Side of the Namche Barwa Syntaxis, Tibetan Plateau." Seismological Research Letters 92, no. 4 (March 3, 2021): 2196–205. http://dx.doi.org/10.1785/0220200342.

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Abstract The Motuo fault (MTF) strikes along the Yarlung Zangbo suture zone on the eastern boundary of the Namche Barwa syntaxis. The movement pattern and Quaternary activity of the MTF remain unclear, which hampers efforts to undertake meaningful seismic hazard assessments near the southeastern part of the Tibetan plateau and to understand the tectonic evolution of the Namche Barwa syntaxis. In this study, the MTF is shown to feature left-lateral strike-slip movements with offset gullies and mountain ridges and appears to have ruptured during the late Pleistocene to Holocene, as evidenced from geological, paleoseismic, and radiocarbon dating investigations. Specifically, at least three surface-rupturing paleoseismic events are revealed; two events occurred after 2606 B.P. and after 18.2 ka. Combining this information with previous Global Positioning System results in southeastern Tibet, we suggest that, as a boundary fault, the MTF regulates the movements of the Namche Barwa and Chayu blocks. The velocity difference between the two blocks advancing to the north is the main mechanism of left-lateral strike-slip motion along the MTF. The accumulation and release of shear stress between the two blocks have led to strong activity along the MTF, since the late Quaternary.
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11

Tian, Z., M. Brown, Z. Zhang, P. M. Piccoli, and X. Dong. "Contrasting CW and CCW tectono-metamorphic belts in the eastern Himalayan syntaxis: quantification of P–T–t paths and tectonic interpretation." Gondwana Research 79 (March 2020): 1–26. http://dx.doi.org/10.1016/j.gr.2019.08.016.

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12

Huang, Xuemeng, Zhiqin Xu, Huaqi Li, and Zhihui Cai. "Tectonic amalgamation of the Gaoligong shear zone and Lancangjiang shear zone, southeast of Eastern Himalayan Syntaxis." Journal of Asian Earth Sciences 106 (July 2015): 64–78. http://dx.doi.org/10.1016/j.jseaes.2014.12.018.

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13

Pinel-Puysségur, B., R. Grandin, L. Bollinger, and C. Baudry. "Multifaulting in a tectonic syntaxis revealed by InSAR: The case of the Ziarat earthquake sequence (Pakistan)." Journal of Geophysical Research: Solid Earth 119, no. 7 (July 2014): 5838–54. http://dx.doi.org/10.1002/2013jb010564.

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14

Saha, Puspendu, S. K. Acharyya, V. Balaram, and Parijat Roy. "Geochemistry and tectonic setting of Tuting metavolcanic rocks of possible ophiolitic affinity from Eastern Himalayan syntaxis." Journal of the Geological Society of India 80, no. 2 (August 2012): 167–76. http://dx.doi.org/10.1007/s12594-012-0129-5.

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15

Liang, Wendong, Eduardo Garzanti, Sergio Andò, Paolo Gentile, and Alberto Resentini. "Multimineral Fingerprinting of Transhimalayan and Himalayan Sources of Indus-Derived Thal Desert Sand (Central Pakistan)." Minerals 9, no. 8 (July 26, 2019): 457. http://dx.doi.org/10.3390/min9080457.

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As a Quaternary repository of wind-reworked Indus River sand at the entry point in the Himalayan foreland basin, the Thal Desert in northern Pakistan stores mineralogical information useful to trace erosion patterns across the western Himalayan syntaxis and the adjacent orogenic segments that fed detritus into the Indus delta and huge deep-sea fan throughout the Neogene. Provenance analysis of Thal Desert sand was carried out by applying optical and semi-automated Raman spectroscopy on heavy-mineral suites of four eolian and 11 fluvial sand samples collected in selected tributaries draining one specific tectonic domain each in the upper Indus catchment. In each sample, the different types of amphibole, garnet, epidote and pyroxene grains—the four dominant heavy-mineral species in orogenic sediment worldwide—were characterized by SEM-EDS spectroscopy. The chemical composition of 4249 grains was thus determined. Heavy-mineral concentration, the relative proportion of heavy-mineral species, and their minerochemical fingerprints indicate that the Kohistan arc has played the principal role as a source, especially of pyroxene and epidote. Within the western Himalayan syntaxis undergoing rapid exhumation, the Southern Karakorum belt drained by the Hispar River and the Nanga Parbat massif were revealed as important sources of garnet, amphibole, and possibly epidote. Sediment supply from the Greater Himalaya, Lesser Himalaya, and Subhimalaya is dominant only for Punjab tributaries that join the Indus River downstream and do not contribute sand to the Thal Desert. The detailed compositional fingerprint of Thal Desert sand, if contrasted with that of lower course tributaries exclusively draining the Himalaya, provides a semi-actualistic key to be used, in conjunction with complementary provenance datasets and geological information, to reconstruct changes in paleodrainage and unravel the relationship between climatic and tectonic forces that controlled the erosional evolution of the western Himalayan-Karakorum orogen in space and time.
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16

Liu, Yan, Ziqing Yang, and Meng Wang. "History of Zircon Growth in a High-Pressure Granulite within the Eastern Himalayan Syntaxis, and Tectonic Implications." International Geology Review 49, no. 9 (September 2007): 861–72. http://dx.doi.org/10.2747/0020-6814.49.9.861.

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17

Ali, Asghar, Shah Faisal, Khaista Rehman, Suleman Khan, and Nijat Ullah. "Tectonic imprints of the Hazara Kashmir Syntaxis on the Northwest Himalayan fold and thrust belt, North Pakistan." Arabian Journal of Geosciences 8, no. 11 (March 17, 2015): 9857–76. http://dx.doi.org/10.1007/s12517-015-1874-8.

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18

Hughes, Nigel C., Peng Shanchi, and Luo Huilin. "Kunmingaspis(Trilobita) putatively from the Yunling collage, and the Cambrian history of the eastern Himalayan syntaxial region." Journal of Paleontology 76, no. 4 (July 2002): 709–17. http://dx.doi.org/10.1017/s0022336000041962.

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Faunal data provide critical constraints upon tectonic models, particularly in such areas of extreme structural complexity as the region adjacent to the eastern syntaxis of the Himalaya. Trilobites reported to have been collected from the Yunling collage at Yinchangou, northwestern Yunnan, are here assigned toKunmingaspis yunnanensisChang, 1964, and the concept of the genusKunmingaspisis reconsidered. Although there is debate about to the paleogeographic affinities of the Yunling collage, the apparent presence of this species supports previous arguments for faunal links between the Yangtze platform and the Himalayan margin during Early and Middle Cambrian time. A significant tectonic event of Late Cambrian/Early Ordovician age present in the western central Himalayan margin suggests that the Lhasa block collided with India at that time, but the northward extent of that block remains unclear. The recently discovered Late Cambrian trilobite fauna of Bhutan may hold the key to establishing faunal relationships between the Tethyan Himalaya, Sibumasu, and the Yangtze platform during this interval. No Cambrian sedimentary rocks are yet known from the Lhasa or Qiangtang blocks of Tibet and so there is no direct evidence for the existence of Cimmeria during the Cambrian Period.
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19

Asghar, ALI, HABIB Umer, REHMAN Atta Ur, ZADA Noor, ABIDIN Zain Ul, and ISMAIL Muhammad. "Tectonic Imprints of the Hazara Kashmir Syntaxis on the Mesozoic Rocks Exposed in Munda, Mohmand Agency, Northwest Pakistan." Acta Geologica Sinica - English Edition 90, no. 2 (April 2016): 440–55. http://dx.doi.org/10.1111/1755-6724.12682.

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20

Tanaka, Kenji, Chuanlong Mu, Ken Sato, Kazuhiro Takemoto, Daisuke Miura, Yuyan Liu, Haider Zaman, et al. "Tectonic deformation around the eastern Himalayan syntaxis: constraints from the Cretaceous palaeomagnetic data of the Shan-Thai Block." Geophysical Journal International 175, no. 2 (November 2008): 713–28. http://dx.doi.org/10.1111/j.1365-246x.2008.03885.x.

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21

Skourtsos, E., and E. Lekkas. "THE TECTONIC SETTING OF THE OCTOBER 8 m 2005 EARTHQUAKE IN KASHMIR, NORTH PAKISTAN." Bulletin of the Geological Society of Greece 40, no. 1 (June 8, 2018): 463. http://dx.doi.org/10.12681/bgsg.16646.

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On the 8th of October 2005 an earthquake of magnitude 7.6 occurred in northern Pakistan. The earthquake epicenter was located in Pakistan Kashmir, 90 km north of Islamabad, the capital of Pakistan. The focal depth was 26 km triggered by a thrust fault striking NW-SE and of 40o dip angle towards the NE. The mean fault slip was estimated as 4 m. The aftershocks epicenters were located northeastwards of the Indus - Kohistan Seismic Zone. The structures that trace the activated fault were distributed along the southwestern limb of the Muzaffarabad anticline and grouped as structures of flexural-slip folding, structures that are correlated to folding and normal faults. The latter may represent overturned segments of the seismic fault on the high-angle limb of the Muzaffarrabad anticline. This anticline is located on the hanging wall of a thrust fault with geometry and kinematics characteristics similar to those of the Indus — Kohistan Seismic Zone. This zone, from the Hazara - Kashmir Syntaxis to the Swat River represents a blind thrust under the metamorphosed rocks of the Lower Himalayas, while in the region of Sub- Himalayas becomes a distinct structure. This thrust fault is linked in depth to the Main Himalaya Thrust through which, the cratonic basement of India is subducting under its sedimentary cover.
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22

Guilmette, C., A. Indares, and R. Hébert. "High-pressure anatectic paragneisses from the Namche Barwa, Eastern Himalayan Syntaxis: Textural evidence for partial melting, phase equilibria modeling and tectonic implications." Lithos 124, no. 1-2 (May 2011): 66–81. http://dx.doi.org/10.1016/j.lithos.2010.09.003.

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23

Xie, Chao, Bengang Zhou, Zhengfang Li, Fan Yang, Wei Pang, and Wei Li. "Features of terraces and the incision rate along the lower reaches of the Yarlung Zangbo River east of Namche Barwa: Constraints on tectonic uplift." Open Geosciences 12, no. 1 (December 17, 2020): 1645–52. http://dx.doi.org/10.1515/geo-2020-0215.

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AbstractAlong the lower reaches of the Yarlung Zangbo River, scattered alluvium sections appear on T1 and T2 terraces. The alluvial deposits on the T1 terrace in Linduo and Ximogou and the T2 terrace in Guoguotang are composed principally of coarse-grained sand particles and rock fragments, with no observable fine-grained components. The T1 terrace alluvium section is dominated by clay and silt and occurs near the town of Dexing, and optically stimulated luminescence dating of sample from this site revealed an age of 18.2 kyear, which indicates that the incision rate of the Yarlung Zangbo River has been 4.7 mm/year since the formation of this section. On the basis of the component characteristics of terraces in Motuo County, the provenance for the terraces is probably related to the breaking of the palaeo-dammed lakes in the middle reaches of the Yarlung Zangbo River. A 430 m elevation difference still exists between the study area and the local base level downstream of the Yalung Zangbo River (Assam Plain), although this river has a strong incision capability (4.7 mm/year), which suggests that tectonic uplift remains very intense east of the Namche Barwa syntaxis.
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24

Wang, Yang, Yuejun Wang, Peizhen Zhang, Lindsay M. Schoenbohm, Bo Zhang, Jinjiang Zhang, Renjie Zhou, et al. "Intracontinental deformation within the India-Eurasia oblique convergence zone: Case studies on the Nantinghe and Dayingjiang faults." GSA Bulletin 132, no. 3-4 (August 29, 2019): 850–62. http://dx.doi.org/10.1130/b35338.1.

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Abstract The most striking structural features in the interior of the Shan Plateau, southeast of the eastern Himalayan syntaxis, are a series of NE-trending faults that exhibit sinistral movement and an arcuate geometry. Their origin and tectonic evolution remain poorly understood. Furthermore, a switch in slip sense is recorded along many of these faults, but the timing of kinematic reversal is still unclear, hindering an understanding of the causal geodynamic mechanisms. We conducted an integrative study of apatite and zircon (U-Th)/He thermochronology, 40Ar/39Ar geochronology, and structural and geomorphic analysis to decipher the evolution of two major NE-trending faults: the Nantinghe and Dayingjiang faults. At least three deformation stages are identified within the Nantinghe fault zone, including top-to-the-SE/ESE thrusting, dextral ductile strike-slip shearing, and sinistral movement. Zircon and apatite (U-Th)/He data, collected from the northeastern terminus of the Nantinghe fault, reveal rapid cooling in the early Miocene. Combined with the 40Ar/39Ar data from sinistrally sheared mylonite, left-lateral movement on the Nantinghe fault is inferred to have initiated as early as ca. 20 Ma. The Dayingjiang fault reactivated as a sinistral brittle fault along the dextral Yingjiang shear zone. A two-stage thermal history is identified along the shear zone, with prominent cooling during dextral ductile shearing in the early- to mid-Miocene followed by a lower-magnitude cooling episode at ca. 11 Ma caused by sinistral transtension along the Dayingjiang fault. The evolution of the Nantinghe and Dayingjiang faults suggests that the NE-trending fault system in the Shan Plateau may have developed along preexisting structures and underwent diachronous slip-sense inversion in the late Cenozoic. The northward advance of the eastern Himalayan syntaxis caused a major change in both the regional stress field and fault geometries in the eastern India-Eurasia oblique convergence zone, contributing to the inversion of fault kinematics.
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25

Zhang, Ling, Shiming Liang, Xiaoping Yang, and Chenglong Dai. "The migration of the crustal deformation peak area in the eastern Himalayan Syntaxis inferred from present-day crustal deformation and morpho-tectonic markers." Geodesy and Geodynamics 12, no. 3 (May 2021): 165–74. http://dx.doi.org/10.1016/j.geog.2021.02.002.

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26

Guo, Liang, Hong-Fei Zhang, Nigel Harris, Wang-Chun Xu, and Fa-Bin Pan. "Detrital zircon U–Pb geochronology, trace-element and Hf isotope geochemistry of the metasedimentary rocks in the Eastern Himalayan syntaxis: Tectonic and paleogeographic implications." Gondwana Research 41 (January 2017): 207–21. http://dx.doi.org/10.1016/j.gr.2015.07.013.

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27

Treloar, Peter J., Richard M. Palin, and Michael P. Searle. "Towards resolving the metamorphic enigma of the Indian Plate in the NW Himalaya of Pakistan." Geological Society, London, Special Publications 483, no. 1 (2019): 255–79. http://dx.doi.org/10.1144/sp483-2019-22.

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AbstractThe Pakistan part of the Himalaya has major differences in tectonic evolution compared with the main Himalayan range to the east of the Nanga Parbat syntaxis. There is no equivalent of the Tethyan Himalaya sedimentary sequence south of the Indus–Tsangpo suture zone, no equivalent of the Main Central Thrust, and no Miocene metamorphism and leucogranite emplacement. The Kohistan Arc was thrust southward onto the leading edge of continental India. All rocks exposed to the south of the arc in the footwall of the Main Mantle Thrust preserve metamorphic histories. However, these do not all record Cenozoic metamorphism. Basement rocks record Paleo-Proterozoic metamorphism with no Cenozoic heating; Neo-Proterozoic through Cambrian sediments record Ordovician ages for peak kyanite and sillimanite grade metamorphism, although Ar–Ar data indicate a Cenozoic thermal imprint which did not reset the peak metamorphic assemblages. The only rocks that clearly record Cenozoic metamorphism are Upper Paleozoic through Mesozoic cover sediments. Thermobarometric data suggest burial of these rocks along a clockwise pressure–temperature path to pressure–temperature conditions of c. 10–11 kbar and c. 700°C. Resolving this enigma is challenging but implies downward heating into the Indian plate, coupled with later development of unconformity parallel shear zones that detach Upper Paleozoic–Cenozoic cover rocks from Neoproterozoic to Paleozoic basement rocks and also detach those rocks from the Paleoproterozoic basement.
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28

ARAÚJO FILHO, JOSÉ OSWALDO DE. "THE PIRINEUS SYNTAXIS: AN EXAMPLE OF THE INTERSECTION OF TWO BRASILIANO FOLD-THRUST BELTS IN CENTRAL BRAZIL AND ITS IMPLICATIONS FOR THE TECTONIC EVOLUTION OF WESTERN GONDWANA." Revista Brasileira de Geociências 30, no. 1 (March 1, 2000): 144–48. http://dx.doi.org/10.25249/0375-7536.2000301144148.

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29

Xu, Yan, Keith D. Koper, Relu Burlacu, Robert B. Herrmann, and Dan-Ning Li. "A New Uniform Moment Tensor Catalog for Yunnan, China, from January 2000 through December 2014." Seismological Research Letters 91, no. 2A (February 5, 2020): 891–900. http://dx.doi.org/10.1785/0220190242.

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Abstract Because of the collision of the Indian and Eurasian tectonic plates, the Yunnan Province of southwestern China has some of the highest levels of seismic hazard in the world. In such a region, a catalog of moment tensors is important for estimating seismic hazard and helping understand the regional seismotectonics. Here, we present a new uniform catalog of moment tensor solutions for the Yunnan region. Using a grid-search technique to invert seismic waveforms recorded by the permanent regional network in Yunnan and the 2 yr ChinArray deployment, we present 1833 moment tensor solutions for small-to-moderate earthquakes that occurred between January 2000 and December 2014. Moment magnitudes in the new catalog vary from Mw 2.2 to 6.1, and the catalog is complete above Mw∼3.5–3.6. The moment tensors are constrained to be purely double-couple and show a variety of faulting mechanisms. Normal faulting events are mainly concentrated in northwest Yunnan, while farther south along the Sagaing fault the earthquakes are mostly thrust and strike slip. The remaining area includes all three styles of faulting but mostly strike slip. We invert the moment tensors for the regional stress field and find a strong correlation between spatially varying maximum horizontal stress and Global Positioning System observations of horizontal ground velocity. The stress field reveals clockwise rotation around the eastern Himalayan syntaxis, with northwest–southeast compression to the east of the Red River fault changing to northeast–southwest compression west of the fault. Almost 88% of the centroid depths are shallower than 16 km, consistent with a weak and ductile lower crust.
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30

Safi, Ibrahim, Gohar Rehman, Muhammad Yaseen, Sohail Wahid, Muhammad Nouman, Sadaf Fida, Shehla Gul, and Muhammad Naveed Anjum. "Effects of transpression on the rocks exposed at the Jhelum Fault Zone in the east of Potwar Basin, Pakistan: implications on the subsurface deformation pattern." Journal of Petroleum Exploration and Production Technology 11, no. 6 (June 2021): 2407–24. http://dx.doi.org/10.1007/s13202-021-01224-z.

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AbstractJhelum Fault is the north–south-oriented major structural lineament originating from the Hazara-Kashmir Syntaxis and extending southwards towards the Mangla Lake. Geographic extent, nature and significance of Jhelum Fault are the subjects which have been approached by different researchers in the past. The previous research provides enough evidence for the presence of Jhelum Fault as well as they discourse its surface extent. None of the previous research addresses the subsurface model of this fault; consequently, its surface extent has been ambiguous and variably reported. The current research takes into account both the surface lineament as well as the subsurface behaviour of the deformed strata to draft the most reasonable depiction of this fault. Field data were coupled with satellite image of 1.5 m ground resolution to produce the geological map of the study area at 1:25,000 scale. The subsurface model was created along four traverse lines by considering the lateral extent of the structures and their shifting trends on the geological map. The stratigraphic package was taken from the nearby hydrocarbon exploratory well data (Missakeswal-01 well of OGDCL) as no rocks older than middle to late Miocene were exposed in the area. The consistent through-going map extents of many faults in the study area prove that faults are playing the major role in the tectonic evolution of the Jhelum Fault Zone. In the subsurface model, the same faults show very little stratigraphic throw, which signify the major stress component to be associated more with wrenching than pure compression. Therefore, most faults in the area are of transpressional nature having dominant lateral component with relatively smaller push towards west on steeply east dipping faults. The model also shows the positive flower structure with dominantly west verging fault system with few east verging back thrusts. The subsurface proposed model shows that the Jhelum Fault is extendible southwards to the Mangla Lake in the subsurface; however, it acts like a continuous shear zone on the surface where there all the shearing is accommodated by tight refolded fold axes. The east–west shortening does not exceed 14.5% which shows smaller compression in the study area. The 3D model further clarifies the model by showing the consistency of the fault system along strike.
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31

Ou, Xiong, Anne Replumaz, and Peter van der Beek. "Contrasting exhumation histories and relief development within the Three Rivers Region (south-east Tibet)." Solid Earth 12, no. 3 (March 4, 2021): 563–80. http://dx.doi.org/10.5194/se-12-563-2021.

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Abstract. The Three Rivers Region in south-east Tibet represents a transition between the strongly deformed zone around the Eastern Himalayan Syntaxis (EHS) and the less deformed south-east Tibetan Plateau margin in Yunnan and Sichuan. In this study, we compile and model published thermochronometric ages for two massifs facing each other across the Mekong River in the core of the Three Rivers Region (TRR), using the thermo-kinematic code Pecube to constrain their exhumation and relief history. Modelling results for the low-relief (< 600 m), moderate-elevation (∼ 4500 m) Baima Xueshan massif, east of the Mekong River, suggest regional rock uplift at a rate of 0.25 km/Myr since ∼ 10 Ma, following slow exhumation at a rate of 0.01 km/Myr since at least 22 Ma. Estimated Mekong River incision accounts for 30 % of the total exhumation since 10 Ma. We interpret exhumation of the massif as a response to regional uplift around the EHS and conclude that the low relief of the massif was acquired at high elevation (> 4500 m), probably in part due to glacial “buzzsaw-like” processes active at such high elevation and particularly efficient during Quaternary glaciations. Exhumation of the Baima Xueshan is significantly higher (2.5 km since ∼ 10 Ma) than that estimated for the most emblematic low-relief “relict” surfaces of eastern Tibet, where apatite (U–Th) / He (AHe) ages > 50 Ma imply only a few hundreds of metres of exhumation since the onset of the India–Asia collision. The low-relief Baima Xueshan massif, with its younger AHe ages (< 50 Ma) that record significant rock uplift and exhumation, thus cannot be classified as a relict surface. Modelling results for the high-relief, high-elevation Kawagebo massif, to the west of the Mekong, imply a similar contribution of Mekong River incision (25 %) to exhumation but much stronger local rock uplift at a rate of 0.45 km/Myr since at least 10 Ma, accelerating to 1.86 km/Myr since 1.6 Ma. We show that the thermochronometric ages are best reproduced by a model of rock uplift on a kinked westward-dipping thrust striking roughly parallel to the Mekong River, with a steep shallow segment flattening out at depth. Thus, the strong differences in elevation and relief of two massifs are linked to variable exhumation histories due to strongly differing tectonic imprint.
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32

Holt, William E., James F. Ni, Terry C. Wallace, and A. J. Haines. "The active tectonics of the eastern Himalayan syntaxis and surrounding regions." Journal of Geophysical Research: Solid Earth 96, B9 (August 10, 1991): 14595–632. http://dx.doi.org/10.1029/91jb01021.

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33

Bazhenov, M. L., and V. S. Burtman. "Tectonics and paleomagnetism of structural arcs of the Pamir-Punjab syntaxis." Journal of Geodynamics 5, no. 3-4 (September 1986): 383–96. http://dx.doi.org/10.1016/0264-3707(86)90017-7.

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34

Treloar, Peter J., Michael P. Searle, M. Asif Khan, and M. Qasim Jan. "Tectonics of the Nanga Parbat syntaxis and the western Himalaya: an introduction." Geological Society, London, Special Publications 170, no. 1 (2000): 1–6. http://dx.doi.org/10.1144/gsl.sp.2000.170.01.01.

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35

Godin, Laurent. "Book Review: Tectonics of the Nanga Parbat Syntaxis and the Western Himalaya." Progress in Physical Geography: Earth and Environment 24, no. 4 (December 2000): 619–20. http://dx.doi.org/10.1177/030913330002400415.

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36

Chiu, Yu-Ping, Meng-Wan Yeh, Kuang-Hsuan Wu, Tung-Yi Lee, Ching-Hua Lo, Sun-Lin Chung, and Yoshiyuki Iizuka. "Transition from extrusion to flow tectonism around the Eastern Himalaya syntaxis." GSA Bulletin 130, no. 9-10 (April 26, 2018): 1675–96. http://dx.doi.org/10.1130/b31811.1.

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37

Capitanio, Fabio A., and Anne Replumaz. "Subduction and slab breakoff controls on Asian indentation tectonics and Himalayan western syntaxis formation." Geochemistry, Geophysics, Geosystems 14, no. 9 (September 2013): 3515–31. http://dx.doi.org/10.1002/ggge.20171.

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38

Nettesheim, Matthias, Todd A. Ehlers, David M. Whipp, and Alexander Koptev. "The influence of upper-plate advance and erosion on overriding plate deformation in orogen syntaxes." Solid Earth 9, no. 6 (November 5, 2018): 1207–24. http://dx.doi.org/10.5194/se-9-1207-2018.

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Abstract. Focused, rapid exhumation of rocks is observed at some orogen syntaxes, but the driving mechanisms remain poorly understood and contested. In this study, we use a fully coupled thermomechanical numerical model to investigate the effect of upper-plate advance and different erosion scenarios on overriding plate deformation. The subducting slab in the model is curved in 3-D, analogous to the indenter geometry observed in seismic studies. We find that the amount of upper-plate advance toward the trench dramatically changes the orientation of major shear zones in the upper plate and the location of rock uplift. Shear along the subduction interface facilitates the formation of a basal detachment situated above the indenter, causing localized rock uplift there. We conclude that the change in orientation and dip angle set by the indenter geometry creates a region of localized uplift as long as subduction of the down-going plate is active. Switching from flat (total) erosion to more realistic fluvial erosion using a landscape evolution model leads to variations in rock uplift at the scale of large catchments. In this case, deepest exhumation again occurs above the indenter apex, but tectonic uplift is modulated on even smaller scales by lithostatic pressure from the overburden of the growing orogen. Highest rock uplift can occur when a strong tectonic uplift field spatially coincides with large erosion potential. This implies that both the geometry of the subducting plate and the geomorphic and climatic conditions are important for the creation of focused, rapid exhumation.
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39

Johnston, S. T. "The Cape Fold Belt and Syntaxis and the rotated Falkland Islands: dextral transpressional tectonics along the southwest margin of Gondwana." Journal of African Earth Sciences 31, no. 1 (July 2000): 51–63. http://dx.doi.org/10.1016/s0899-5362(00)00072-5.

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40

Turab, Syed Ali, Kurt Stüwe, Finlay M. Stuart, David M. Chew, and Nathan Cogne. "Tectonics drives rapid exhumation of the western Himalayan syntaxis: Evidence from low-temperature thermochronometry of the Neelum valley region, Pakistan." Lithosphere 9, no. 6 (September 14, 2017): 874–88. http://dx.doi.org/10.1130/l626.1.

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41

Pavlis, Gary L., Mark A. Bauer, Julie L. Elliott, Peter Koons, Terry L. Pavlis, Natalia Ruppert, Kevin M. Ward, and Lindsay L. Worthington. "A unified three-dimensional model of the lithospheric structure at the subduction corner in southeast Alaska: Summary results from STEEP." Geosphere 15, no. 2 (January 29, 2019): 382–406. http://dx.doi.org/10.1130/ges01488.1.

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Abstract We merge structural results from the ST. Elias Erosion/tectonics Project (STEEP), other studies, and seismicity data to build a comprehensive, three-dimensional model of the lithosphere of the subduction corner in southern Alaska. The model is defined by three surfaces: (1) a top of the subducting lithosphere surface, (2) Moho surfaces, and (3) a base of subducting lithosphere surface. We model the eastern edge of the subducting lithosphere using the southern tip of the Yakutat microplate as an anchor. Kinematic reconstructions using that anchor suggest the modern Fairweather fault is likely inherited from motion of the margin in the 6–10 Ma period. We constructed a 4D kinematic model of crustal deformation in the vicinity of Mount St. Elias. We call this model the middlebuster model because the geometry is similar to a two-sided plow with that name. The west side of the plow is the eastern limit of the Aleutian megathrust constructed from the union of constraints from STEEP seismic results and slip models of the 1979 St. Elias earthquake. The east side is inferred from geologic mapping and slip models of the 1899 Yakutat Bay earthquake sequence. The top of the plow is near the Seward Glacier, where previous studies showed near world-record exhumation rates. GPS velocity vectors show a large rotation across the syntaxis at Mount St. Elias. West of the syntaxis, faults inferred from inversion of the GPS data are above the megathrust inferred from seismic imaging. That and other evidence suggest the presence of a wedge of ductile crust that partially decouples the subducting mantle lithosphere from the upper crust in the area near the suture with the Yakutat microplate.
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42

Wang, Erchie, and B. C. Burchfiel. "Interpretation of Cenozoic Tectonics in the Right-Lateral Accommodation Zone Between the Ailao Shan Shear Zone and the Eastern Himalayan Syntaxis." International Geology Review 39, no. 3 (March 1997): 191–219. http://dx.doi.org/10.1080/00206819709465267.

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43

Clift, Peter D., and A. Alexander G. Webb. "A history of the Asian monsoon and its interactions with solid Earth tectonics in Cenozoic South Asia." Geological Society, London, Special Publications 483, no. 1 (July 18, 2018): 631–52. http://dx.doi.org/10.1144/sp483.1.

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AbstractAlthough there is some evidence for an Eocene monsoon, the most important intensification of rainfall appears to start at c. 24 Ma in the Early Miocene. Many palaeoceanographical proxies for monsoon intensity are linked to wind and do not correlate well with humidity of the continental climate over tectonic timescales. Rainfall peaked in the middle Miocene (c. 15 Ma) with strong drying after 8 Ma. This timing does not correlate well with either initial uplift of the Tibetan Plateau or with the retreat of shallow seas from central Asia. The c. 24 Ma onset of strengthening rainfall is associated with the initiation of rapid erosion and cooling of Himalayan metamorphic rocks. The progressive detachment of the subducting Indian lithosphere from the eastern and western syntaxes at c. 25 Ma to the east-central Himalaya at c. 13–11 Ma would have produced corresponding propagation of rising Himalayan topography following release of the weight of the detached slab. Rapid uplift of the Himalayan barrier, blocking moisture-laden winds, is considered the most likely trigger for a stronger summer monsoon in South Asia, which in turn allowed faster erosion and exhumation of the Greater Himalaya after 24 Ma.
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44

Hu, Shaoqian, and Huajian Yao. "Crustal velocity structure around the eastern Himalayan syntaxis: Implications for the nucleation mechanism of the 2017 M 6.9 Mainling earthquake and regional tectonics." Tectonophysics 744 (October 2018): 1–9. http://dx.doi.org/10.1016/j.tecto.2018.06.006.

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45

Quandt, Dennis, W. Kurz, and P. Micheuz. "Post-magmatic fracturing, fluid flow, and vein mineralization in supra-subduction zones: a comparative study on vein calcites from the Troodos ophiolite and the Izu–Bonin forearc and rear arc." International Journal of Earth Sciences 110, no. 2 (February 13, 2021): 627–49. http://dx.doi.org/10.1007/s00531-020-01978-7.

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AbstractBased on the published data of pillow lava-hosted mineralized veins, this study compares post-magmatic fracturing, fluid flow, and secondary mineralization processes in the Troodos and Izu–Bonin supra-subduction zone (SSZ) and discusses the crucial factors for the development of distinct vein types. Thin section and cathodoluminescence petrography, Raman spectroscopy, fluid inclusion microthermometry, and trace element and isotope (87Sr/86Sr, δ18O, δ13C, Δ47) geochemistry indicate that most veins consist of calcite that precipitated from pristine to slightly modified seawater at temperatures < 50 °C. In response to the mode of fracturing, fluid supply, and mineral growth dynamics, calcites developed distinct blocky (precipitation into fluid-filled fractures), syntaxial (crack and sealing), and antitaxial (diffusion-fed displacive growth) vein microtextures with vein type-specific geochemical signatures. Blocky veins predominate in all study areas, whereas syntaxial veins represent subordinate structures. Antitaxial veins occur in all study areas but are particularly abundant in the Izu–Bonin rear arc where the local geological setting was conducive of antitaxial veining. The temporal framework of major calcite veining coincides with the onset of extensional faulting in the respective areas and points to a tectonic control on veining. Thus, major calcite veining in the Troodos SSZ began contemporaneously with volcanic activity and extensional faulting and completed within ~ 10–20 Myr. This enabled deep seawater downflow and hydrothermal fluid upflow. In the Izu–Bonin forearc, reliable ages of vein calcites point to vein formation > 15 Myr after subduction initiation. Therefore, high-T mineralization (calcite, quartz, analcime) up to 230 °C is restricted to the Troodos SSZ.
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46

André, Grégoire, Christian Hibsch, Bernard Beaudoin, Cédric Carpentier, Serge Fourcade, Michel Cathelineau, and Pascal Élion. "Oxfordian sedimentary dykes : tectonic and diagenetic implications for the eastern Paris basin." Bulletin de la Société Géologique de France 175, no. 6 (November 1, 2004): 595–605. http://dx.doi.org/10.2113/175.6.595.

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Abstract Vertical fractures in Oxfordian limestones of the eastern part of the Paris Basin are interpreted as resulting from synsedimentary extensional deformations which occurred during the Mesozoic. These NNE-SSW striking fractures are 10 to 20 meters in height, and filled with microgranular material. The fractures mainly affect crinoidal and oolitic grainstones. Their micritic to microsparitic, lithoclast-bearing infills may have resulted from the solidification of an ancient mud injected from non-lithified, overlying layers of marine sediments. They should therefore be referred to as sedimentary dykes. Graded layering suggests deposition under turbulent flow conditions, whereas later plastic deformation and breccia formation indicate a syndiagenetic reworking. Such observations are consistent with a predominance of the sedimentary dykes in grainstones, which are more rapidly lithified and therefore subject to early fracturing. On the contrary, these dykes are rare in mudstones which may constitute the source of the material for the infills in the grainstones. Both the analysis of the wall geometry and the reconstruction of the diagenetic history of the infills make possible to distinguish two types of sedimentary dykes. The first type corresponds to a fracturation characterized by irregular walls around the rock-constituting grains (i.e. crinoidal debris or ooids), whereas the walls in the second type are cross-cutting the grains and present a fringe of sparite predating the microsparite infill. The following scenario is proposed for the first type of sedimentary dykes: i) syntaxial cementation of crinoidal debris and early cementation of ooids; ii) fracturing along grain boundaries under low burial strain; iii) filling of fractures and open porosity by the mud. The second type of sedimentary dykes was formed under deeper burial conditions, which is indicated by both pre-existing bedding-parallel stylolites and the precipitation of sparite on the walls before the sedimentary infill. This early fracturation and the availability of a sedimentary filling, non-lithified material point to a late Jurassic age for these sedimentary dykes. The δ18OSMOW isotopic signatures measured for the infilling sparite and microsparite materials indicate that these were precipitated from meteoric waters, either early during the formation of the sedimentary dykes or during a later recrystallization event. The sedimentary dykes have recorded an E-W extension during the Oxfordian-Kimmeridgian period, which is in good agreement with the late Jurassic tectonic history of the western European platform. This early Oxfordian-Kimmeridgian fracturing and its associated fluid paleocirculations is of major interest in the context of the tectonic history of the Paris Basin, since most of these N-S to NNE-SSW tension gashes have been previously attributed to the Eocene Pyrenean shortening and Oligocene rifting stages.
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47

Kumar, Anil, and Pradeep Srivastava. "The role of climate and tectonics in aggradation and incision of the Indus River in the Ladakh Himalaya during the late Quaternary." Quaternary Research 87, no. 3 (May 2017): 363–85. http://dx.doi.org/10.1017/qua.2017.19.

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AbstractThe geomorphic evolution of the upper Indus River that traverses across the southwest (SW) edge of Tibet, and the Ladakh and Zanskar ranges, was examined along a ~350-km-long stretch of its reaches. Based on the longitudinal river profile, stream length gradient index, and river/strath terraces, this stretch of the river is divided into four segments. Valley fill river terraces are ubiquitous, and strath terraces occur in the lower reaches where the Indus River cuts through deformed Indus Molasse. Optically stimulated luminescence ages of river/strath terraces suggest that valley aggradation occurred in three pulses, at ~52, ~28, and ~16 ka, and that these broadly coincide with periods of stronger SW Indian summer monsoon. Reconstructed longitudinal river profiles using strath terraces provide an upper limit on the bedrock and provide incision rates ranging from 1.0±0.3 to 2.2±0.9 mm/a. These results suggested that rapid uplift of the western syntaxes aided by uplift along the local faults led to the formation of strath terraces and increased fluvial incision rates along this stretch of the river.
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48

Heinlein, Sarah N., Terry L. Pavlis, and Ronald L. Bruhn. "Development of surface ruptures by hanging-wall extension over a thrust ramp along the Ragged Mountain fault, Katalla, Alaska, USA: Applications of high-resolution three-dimensional terrain models." Geosphere 17, no. 2 (January 21, 2021): 582–601. http://dx.doi.org/10.1130/ges02097.1.

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Abstract High-resolution three-dimensional terrain models are used to evaluate the Ragged Mountain fault kinematics (Katalla, Alaska, USA). Previous studies have produced contradictory interpretations of the fault’s kinematics because surface ruptures along the fault are primarily steeply dipping, uphill-facing normal fault scarps. In this paper, we evaluate the hypothesis that these uphill-facing scarps represent extension above a buried thrust ramp. Detailed geomorphic mapping along the fault, using 20-cm-resolution aerial imagery draped onto a 1-m-resolution lidar (light detection and ranging) elevation model, was used to produce multiple topographic profiles. These profiles illustrate scarp geometries and prominent convex-upward topographic surfaces, indicating significant disturbance by active tectonics. A theoretical model is developed for fault-parallel flow over a thrust ramp that shows the geometric relationships between thrust displacement, upper-plate extension, and ramp dip. An important prediction of the model for this study is that the magnitude of upper-plate extension is comparable to, or greater than, the thrust displacement for ramps with dips greater than ∼45°. This model is used to analyze profile shapes and surface displacements in Move software (Midland Valley Ltd.). Analyses of scarp heights allow estimates of hanging-wall extension, which we then use to estimate slip on the underlying thrust via the model. Assuming a low-angle (30°) uniformly dipping thrust and simple longitudinal extension via normal faulting, variations in extension along the fault would require a slip gradient from ∼8 m in the north to ∼22 m in the south. However, the same north-south variation in extension with a constant slip of 8–10 m may infer an increase in fault dip from ∼30° in the north to ∼60° in the south. This model prediction has broader implications for active-fault studies. Because the model quantifies relationships between hanging-wall extension, fault slip, and fault dip, it is possible to invert for fault slip in blind thrust ramps where hanging-wall extension is the primary surface manifestation. This study, together with results from the St. Elias Erosion and Tectonics Project (STEEP), clarifies the role of the Ragged Mountain fault as a contractional structure within a broadly sinistral shear system in the western syntaxis of the St. Elias orogeny.
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49

Rolland, Yann, Michel Corsini, and Antoine Demoux. "Metamorphic and structural evolution of the Maures-Tanneron massif (SE Variscan chain): evidence of doming along a transpressional margin." Bulletin de la Société Géologique de France 180, no. 3 (May 1, 2009): 217–30. http://dx.doi.org/10.2113/gssgfbull.180.3.217.

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Abstract The Variscan metamorphic and structural evolution of the Maures-Tanneron massif is divided in two main post-collisional phases: (1) a MP-MT regional gradient is developed during nappe-piling process between 350 and 320 Ma, followed by (2) LP-HT regional gradient coeval with doming between 320 and 300 Ma. During this late phase, the tectonic context was dominated by E-W shortening, which produced crustal-scale upright folds and major strike-slip displacement along trans-crustal faults. Symmetric extensional fabrics are observed on the limbs of crustal-scale anticlines, and are ascribed to local accommodation of lower crust exhumation. Heat and magma transfer are allowed by these large vertical strike-slip faults, and are thought to be the cause of the late metamorphic evolution. Therefore, structures and metamorphism argue for a transpressional context at the SE branch of the Variscan chain. Comparisons with current collisional settings such as syntaxial domains of the Himalayan belt show that the timing and PT conditions of metamorphic events are similar. These observations lead us to propose that the situation of the Variscan chain during the period 320-300 Ma was still a syn-convergent setting similar to the current situation of the Himalayan-Tibet system, and that extensional movements are not the cause of, but the result of exhumation of the lower crust in this ongoing shortening context along a transpressional wrench boundary.
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50

BEDNARIK, ROBERT G. "The tribology of cupules." Geological Magazine 152, no. 4 (March 5, 2015): 758–65. http://dx.doi.org/10.1017/s0016756815000060.

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AbstractThis paper describes a newly observed phenomenon, a rare form of lamina protecting petroglyphs from weathering, and it attempts an explanation of such features. These laminae are not precipitates but represent the floors of the original cupules that have become more resistant to erosion through conversion to tectonite. The process involves crystallization of the syntaxial quartz overgrowths on quartz grains that constitute the cement component of quartzite and silica-rich schist. It is attributed to the cumulative application of kinetic energy that derives from the tens of thousands of hammerstone blows that produced the cupule. The tribological process results in products similar to those formed in ductile shear zones when sandstone has been subjected to great kinetic stresses. In the cupules reported here, the re-metamorphosed lamina preserves their original surface and prevents the erosion of the protolith (parent rock) concealed by the modified layer. The thickness of the layer is a function of the cumulative amount of energy applied to the rock's cement, and the process of alteration is defined as ‘kinetic energy metamorphosis’.
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