Continental collision slowing due to viscous mantle lithosphere rather than topography

Nature ◽  
2012 ◽  
Vol 483 (7387) ◽  
pp. 74-77 ◽  
Author(s):  
Marin Kristen Clark
Keyword(s):  
Continental Collision ◽  
Mantle Lithosphere

scholarly journals Origin of potassic postcollisional volcanic rocks in young, shallow, blueschist-rich lithosphere

2021 ◽  
Vol 7 (29) ◽  
pp. eabc0291
Author(s):  
Yu Wang ◽  
Stephen F. Foley ◽  
Stephan Buhre ◽  
Jeremie Soldner ◽  
Yigang Xu
Keyword(s):  
Temporal Trend ◽  
Volcanic Rocks ◽  
Continental Collision ◽  
Mantle Lithosphere ◽  
Source Regions ◽  
Himalayan Belt ◽  
Potassic Rocks

Potassium-rich volcanism occurring throughout the Alpine-Himalayan belt from Spain to Tibet is characterized by unusually high Th/La ratios, for which several hypotheses have brought no convincing solution. Here, we combine geochemical datasets from potassic postcollisional volcanic rocks and lawsonite blueschists to explain the high Th/La. Source regions of the volcanic melts consist of imbricated packages of blueschist facies mélanges and depleted peridotites, constituting a new mantle lithosphere formed only 20 to 50 million years earlier during the accretionary convergence of small continental blocks and oceans. This takes place entirely at shallow depths (<80 km) without any deep subduction of continental materials. High Th/La in potassic rocks may indicate shallow sources in accretionary settings even where later obscured by continental collision as in Tibet. This mechanism is consistent with a temporal trend in Th/La in potassic postcollisional magmas: The high Th/La signature first becomes prominent in the Phanerozoic, when blueschists became widespread.

Insights from geodynamical modeling on possible fates of continental mantle lithosphere: collision, removal, and overturnThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.

2010 ◽  
Vol 47 (4) ◽  
pp. 541-563 ◽  
Author(s):  
Russell N. Pysklywec ◽  
Oguz Gogus ◽  
J. Percival ◽  
A. R. Cruden ◽  
C. Beaumont
Keyword(s):  
Late Stage ◽  
Continental Collision ◽  
Density Stratification ◽  
Mantle Lithosphere ◽  
Special Issue ◽  
Tectonically Active ◽  
Tectonic Environments

Geodynamic modeling demonstrates various modes of behaviour of the tectonically active continental mantle lithosphere. At continental collision, mantle lithosphere below thickening crust can be accommodated by mixed subduction-like consumption and viscous drip-like instability, depending on the material rheology, temperature, and convergence velocity. Late-stage slab steepening, dual-sided and ablative consumption, and breakoff can occur as the buoyant crust resists subduction. Removal of accreted crust by erosion can modify how even the deepest portions of the mantle lithosphere evolves during contraction. When gravitational forcing rather than plate shortening dominates, mantle lithosphere may be removed through viscous dripping-like instability or delamination. The removal induces crustal heating, modified topography, and deformation, but distinctive styles of these develop depending on whether mantle lithosphere delaminates or drips. With a modified density stratification postulated for the Archean, relatively buoyant mantle lithosphere may undergo an in-situ overturn when triggered by unstable dense eclogite and basal traction. This causes a pulse of rapid crustal heating as hot lowermost lithosphere is brought into contact with the base of the crust. As an interpretive tool, the geodynamic experiments illustrate some of the dynamically feasible modes of behaviour and controlling parameters for the continental mantle lithosphere in ancient to modern tectonic environments.

THETYS SUBDUCTION AND CONTINENTAL COLLISION FROM POTENTIAL FIELD MODELLING

2018 ◽  
Author(s):  
Hans Thybo ◽  
◽  
Vahid Teknik ◽  
Vahid Teknik ◽  
Abdolreza Ghods ◽  
...  
Keyword(s):  
Potential Field ◽  
Continental Collision ◽  
Field Modelling ◽  
Potential Field Modelling

THE EVOLUTION OF CONTINENTAL COLLISION CONTROLLED BY THE WIDTH OF ADJACENT SUBDUCTION ZONE

2018 ◽  
Author(s):  
David Willis ◽  
◽  
Peter Betts ◽  
Louis Moresi ◽  
Laurent Ailleres ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Continental Collision
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