crustal shortening
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2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiashun Hu ◽  
Lijun Liu ◽  
Michael Gurnis

AbstractGrowth of the Andes has been attributed to Cenozoic subduction. Although climatic and tectonic processes have been proposed to be first-order mechanisms, their interaction and respective contributions remain largely unclear. Here, we apply three-dimensional, fully-dynamic subduction models to investigate the effect of trench-axial sediment transport and subduction on Andean growth, a mechanism that involves both climatic and tectonic processes. We find that the thickness of trench-fill sediments, a proxy of plate coupling (with less sediments causing stronger coupling), exerts an important influence on the pattern of crustal shortening along the Andes. The southward migrating Juan Fernandez Ridge acts as a barrier to the northward flowing trench sediments, thus expanding the zone of plate coupling southward through time. Consequently, the predicted history of Andean shortening is consistent with observations. Southward expanding crustal shortening matches the kinematic history of inferred compression. These results demonstrate the importance of climate-tectonic interaction on mountain building.


2021 ◽  
Vol 362 ◽  
pp. 106322
Author(s):  
Jiří Žák ◽  
Filip Tomek ◽  
Martin Svojtka ◽  
František Vacek ◽  
Václav Kachlík ◽  
...  

Author(s):  
Tapos Kumar Goswami ◽  
Devojit Bezbaruah ◽  
Bashab Nandan Mahanta ◽  
Ranjan Kumar Sarmah

2021 ◽  
Author(s):  
Saptarshi Dey ◽  
Naveen Chauhan ◽  
Debashis Nath ◽  
Niklas Schaaf ◽  
Rasmus Thiede ◽  
...  

We present new Late Pleistocene-Holocene shortening rates across the frontal fold-and-thrust belt, namely as, the Sub-Himalaya (SH) from the far-western Himalayan sector of Jammu. OSL-dated offset/ folded fluvial strath terraces suggest that the intraplate convergence is partitioned among several active structures in the SH. Estimated cumulative Late Pleistocene- Holocene shortening rate in the SH is ~9.5±1.3 mm/yr, which is ~70–75% of the measured geodetic convergence rates. Our study invokes the existence of a ~350–400 km-long out-of-sequence fault-boundary within the SH which accommodates ~5.3±2.3 mm/yr shortening since Late Pleistocene-Holocene. Our study also highlights that ongoing crustal shortening is not accommodated only at the toe of the Himalayan wedge.


Author(s):  
Denis Gapais ◽  
Gilian Alimoenadi ◽  
Nicole Balraadjsing ◽  
Benoît Poupeau

The Rosebel gold district belongs to the Paleoproterozoic Trans-Amazonian belt associated with sub-meridian crustal shortening. Here, we present new structural observations (cleavage, stretching lineations, veins, fault slip data, aeromagnetic maps). Regional cleavages are steeply dipping and bear steeply plunging stretching lineations. Finite strains are of flattening type. Fault slip data reveal a complex deformation history. The overall strain pattern of the reflects vertical motions, a feature consistent with pop-down tectonics involving vertical stretch and burial of supracrustal deposits during horizontal shortening of a hot and weak continental lithosphere.


2021 ◽  
Author(s):  
Tania Habel ◽  
Robin Lacassin ◽  
Martine Simoes ◽  
Daniel Carrizo ◽  
Germán Aguilar
Keyword(s):  

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
K. A. McKenzie ◽  
K. P. Furlong

AbstractSeveral tectonic processes combine to produce the crustal deformation observed across the Cascadia margin: (1) Cascadia subduction, (2) the northward propagation of the Mendocino Triple Junction (MTJ), (3) the translation of the Sierra Nevada–Great Valley (SNGV) block along the Eastern California Shear Zone–Walker Lane and, (3) extension in the northwestern Basin and Range, east of the Cascade Arc. The superposition of deformation associated with these processes produces the present-day GPS velocity field. North of ~ 45° N observed crustal displacements are consistent with inter-seismic subduction coupling. South of ~ 45° N, NNW-directed crustal shortening produced by the Mendocino crustal conveyor (MCC) and deformation associated with SNGV-block motion overprint the NE-directed Cascadia subduction coupling signal. Embedded in this overall pattern of crustal deformation is the rigid translation of the Klamath terrane, bounded on its north and west by localized zones of deformation. Since the MCC and SNGV processes migrate northward, their impact on the crustal deformation in southern Cascadia is a relatively recent phenomenon, since ~ 2 –3 Ma.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dillon A. Brown ◽  
Laura J. Morrissey ◽  
John W. Goodge ◽  
Martin Hand

AbstractThe cratonic elements of proto-Australia, East Antarctica, and Laurentia constitute the nucleus of the Palaeo-Mesoproterozoic supercontinent Nuna, with the eastern margin of the Mawson Continent (South Australia and East Antarctica) positioned adjacent to the western margin of Laurentia. Such reconstructions of Nuna fundamentally rely on palaeomagnetic and geological evidence. In the geological record, eclogite-facies rocks are irrefutable indicators of subduction and collisional orogenesis, yet occurrences of eclogites in the ancient Earth (> 1.5 Ga) are rare. Models for Palaeoproterozoic amalgamation between Australia, East Antarctica, and Laurentia are based in part on an interpretation that eclogite-facies metamorphism and, therefore, collisional orogenesis, occurred in the Nimrod Complex of the central Transantarctic Mountains at c. 1.7 Ga. However, new zircon petrochronological data from relict eclogite preserved in the Nimrod Complex indicate that high-pressure metamorphism did not occur in the Palaeoproterozoic, but instead occurred during early Palaeozoic Ross orogenesis along the active convergent margin of East Gondwana. Relict c. 1.7 Ga zircons from the eclogites have trace-element characteristics reflecting the original igneous precursor, thereby casting doubt on evidence for a Palaeoproterozoic convergent plate boundary along the current eastern margin of the Mawson Continent. Therefore, rather than a Palaeoproterozoic (c. 1.7 Ga) history involving subduction-related continental collision, a pattern of crustal shortening, magmatism, and high thermal gradient metamorphism connected cratons in Australia, East Antarctica, and western Laurentia at that time, leading eventually to amalgamation of Nuna at c. 1.6 Ga.


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