Blueschists, eclogites, and subduction zone tectonics: Insights from a review of Late Miocene blueschists and eclogites, and related young high-pressure metamorphic rocks

2010 ◽  
Vol 18 (1) ◽  
pp. 167-188 ◽  
Author(s):  
Tsutomu Ota ◽  
Yoshiyuki Kaneko
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Late Miocene ◽  
Metamorphic Rocks

Zircon U-Pb and geochemical signatures in high-pressure, low-temperature metamorphic rocks as recorders of subduction zone processes, Sikinos and Ios islands, Greece

2021 ◽  
pp. 120447
Author(s):  
Eirini M. Poulaki ◽  
Daniel F. Stockli ◽  
Megan E. Flansburg ◽  
Michelle L. Gevedon ◽  
Lisa D. Stockli ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Subduction Zone ◽  
Metamorphic Rocks ◽  
Subduction Zone Processes

scholarly journals The dynamothermal aureole of the Donqiao ophiolite (northern Tibet)

1997 ◽  
Vol 34 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Mei-Fu Zhou ◽  
John Malpas ◽  
Paul T. Robinson ◽  
Peter H. Reynolds
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Greenschist Facies ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Mineral Paragenesis ◽  
Metasedimentary Rocks ◽  
Northern Tibet ◽  
Suprasubduction Zone ◽  
Ar Geochronology

Metamorphic rocks found at the base of the Jurassic Donqiao ophiolite of northern Tibet are interpreted as a basal dynamothermal aureole produced during obduction of the massif. The rocks form a sequence some 8 m thick, varying from high-grade amphibolites at the contact with overlying harzburgites to greenschist facies metasedimentary rocks lower down. The mineral paragenesis is similar to other such aureoles, and indicates that temperatures in excess of 750 °C may have been reached during metamorphism. The lack of high-pressure minerals suggests that the rocks were produced by subcretion in a relatively shallow dipping subduction zone. Ar–Ar geochronology on amphibole separates provides dates of 175–180 Ma for the displacement of the ophiolite, significantly older than the age of emplacement estimated from stratigraphie relationships. The ophiolite was clearly obducted very soon after its formation in a suprasubduction zone environment.

scholarly journals Up the down escalator: the exhumation of (ultra)-high pressure terranes during on-going subduction

2012 ◽  
Vol 4 (1) ◽  
pp. 745-781 ◽  
Author(s):  
C. J. Warren
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Continental Crust ◽  
Subduction Zones ◽  
Crustal Material ◽  
Time And Space ◽  
Ultra High Pressure ◽  
Tectonic Environment ◽  
Tectonic Style ◽  
Weak Material

Abstract. The exhumation of high and ultra-high pressure rocks is ubiquitous in Phanerozoic orogens created during continental collisions, and is common in many ocean-ocean and ocean-continent subduction zone environments. Three different tectonic environments have previously been reported, which exhume deeply buried material by different mechanisms and at different rates. However it is becoming increasingly clear that no single mechanism dominates in any particular tectonic environment, and the mechanism may change in time and space within the same subduction zone. In order for buoyant continental crust to subduct, it must remain attached to a stronger and denser substrate, but in order to exhume, it must detach (and therefore at least locally weaken) and be initially buoyant. Denser oceanic crust subducts more readily than more buoyant continental crust but exhumation must be assisted by entrainment within more buoyant and weak material such as serpentinite or driven by the exhumation of structurally lower continental crustal material. Weakening mechanisms responsible for the detachment of crust at depth include strain, hydration, melting, grain size reduction and the development of foliation. These may act locally or may act on the bulk of the subducted material. Metamorphic reactions, metastability and the composition of the subducted crust all affect buoyancy and overall strength. Subduction zones change in style both in time and space, and exhumation mechanisms change to reflect the tectonic style and overall force regime within the subduction zone. Exhumation events may be transient and occur only once in a particular subduction zone or orogen, or may be more continuous or occur multiple times.

High-pressure experimental verification of rutile-ilmenite oxybarometer: Implications for the redox state of the subduction zone

2017 ◽  
Vol 60 (10) ◽  
pp. 1817-1825 ◽  
Author(s):  
RenBiao Tao ◽  
LiFei Zhang ◽  
Vincenzo Stagno ◽  
Xu Chu ◽  
Xi Liu
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Experimental Verification ◽  
Redox State

scholarly journals Renewed tectonic extrusion of high-grade metamorphic rocks in the MCT footwall since Late Miocene (Sutlej Valley, India)

2008 ◽  
Vol 2 (4) ◽  
pp. 102-103 ◽  
Author(s):  
Vincent Baudraz ◽  
Jean-Claude Vannay ◽  
Elizabeth Catlos ◽  
Mike Cosca ◽  
Torsten Vennemann
Keyword(s):  
Late Miocene ◽  
Metamorphic Rocks ◽  
High Grade ◽  
Special Issue ◽  
Tectonic Extrusion

Himalayan Journal of Sciences Vol.2(4) Special Issue 2004 pp. 102-3

Under Pressure: High-Pressure Metamorphism in the Alps

Elements ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Lucie Tajčmanová ◽  
Paola Manzotti ◽  
Matteo Alvaro
Keyword(s):  
High Pressure ◽  
Structural Data ◽  
Metamorphic Rocks ◽  
Lithostatic Pressure ◽  
Mineral Inclusion ◽  
Crustal Material ◽  
Local Pressure ◽  
Ultra High Pressure ◽  
Mechanical Models ◽  
The Alps

The mechanisms attending the burial of crustal material and its exhumation before and during the Alpine orogeny are controversial. New mechanical models propose local pressure perturbations deviating from lithostatic pressure as a possible mechanism for creating (ultra-)high-pressure rocks in the Alps. These models challenge the assumption that metamorphic pressure can be used as a measure of depth, in this case implying deep subduction of metamorphic rocks beneath the Alpine orogen. We summarize petro-logical, geochronological and structural data to assess two fundamentally distinct mechanisms of forming (ultra-)high-pressure rocks: deep subduction; or anomalous, non-lithostatic pressure variation. Furthermore, we explore mineral-inclusion barometry to assess the relationship between pressure and depth in metamorphic rocks.

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