IMPACTS OF FLUIDS ON THE MINERALOGICAL RECORD IN SUBDUCTION ZONES; IMPLICATIONS FOR PRESSURE-TEMPERATURE-TIME-DEFORMATION RECONSTRUCTIONS

2017 ◽  
Author(s):  
Pierre Lanari ◽  
◽  
Laura Airaghi ◽  
Jörg Hermann
Keyword(s):  
Subduction Zones ◽  
Time Deformation ◽  
Temperature Time

scholarly journals Pressure–temperature–time–deformation path of kyanite-bearing migmatitic paragneiss in the Kali Gandaki valley (Central Nepal): Investigation of Late Eocene–Early Oligocene melting processes

Lithos ◽  
2015 ◽  
Vol 231 ◽  
pp. 103-121 ◽  
Author(s):  
Salvatore Iaccarino ◽  
Chiara Montomoli ◽  
Rodolfo Carosi ◽  
Hans-Joachim Massonne ◽  
Antonio Langone ◽  
...  
Keyword(s):  
Late Eocene ◽  
Deformation Path ◽  
Time Deformation ◽  
Early Oligocene ◽  
Central Nepal ◽  
Temperature Time

Numerical simulation of subduction zone pressure-temperature-time paths: constraints on fluid production and arc magmatism

1991 ◽  
Vol 335 (1638) ◽  
pp. 341-353 ◽  
Keyword(s):  
Heat Transfer ◽  
Partial Melting ◽  
Subduction Zone ◽  
Subduction Zones ◽  
Mantle Wedge ◽  
Thermal Structure ◽  
Oceanic Lithosphere ◽  
Transfer Model ◽  
Temperature Time ◽  
Subducting Slab

The location and sequence of metamorphic devolatilization and partial melting reactions in subduction zones may be constrained by integrating fluid and rock pressure-temperature-time ( P-T-t ) paths predicted by numerical heat-transfer models with phase diagrams constructed for metasedimentary, metabasaltic, and ultramafic bulk compositions. Numerical experiments conducted using a two-dimensional heat transfer model demonstrate that the primary controls on subduction zone P-T-t paths are: (1) the initial thermal structure; (2) the amount of previously subducted lithosphere; (3) the location of the rock in the subduction zone; and (4) the vigour of mantle wedge convection induced by the subducting slab. Typical vertical fluid fluxes out of the subducting slab range from less than 0.1 to 1 (kg fluid) m -2 a -1 for a convergence rate of 3 cm a -1 . Partial melting of the subducting, amphibole-bearing oceanic crust is predicted to only occur during the early stages of subduction initiated in young (less than 50 Ma) oceanic lithosphere. In contrast, partial melting of the overlying mantle wedge occurs in many subduction zone experiments as a result of the infiltration of fluids derived from slab devolatilization reactions. Partial melting in the mantle wedge may occur by a twostage process in which amphibole is first formed by H 2 O infiltration and subsequently destroyed as the rock is dragged downward across the fluid-absent ‘hornblende-out’ partial melting reaction.

Gneiss Dome Formation in the Himalaya and southern Tibet

2019 ◽  
Vol 483 (1) ◽  
pp. 401-422 ◽  
Author(s):  
Micah J. Jessup ◽  
Jackie M. Langille ◽  
Timothy F. Diedesch ◽  
John M. Cottle
Keyword(s):  
Tibetan Plateau ◽  
Late Miocene ◽  
Shear Zones ◽  
Crustal Thickening ◽  
Southern Tibet ◽  
Gneiss Domes ◽  
Time Deformation ◽  
Temperature Time ◽  
The Himalaya ◽  
Parallel Extension

AbstractGneiss domes in the Himalaya and southern Tibet record processes of crustal thickening, metamorphism, melting, deformation and exhumation during the convergence between the Indian and Eurasian plates. We review two types of gneiss domes: North Himalayan gneiss domes (NHGD) and later domes formed by orogen-parallel extension. Located in the southern Tibetan Plateau, the NHGD are cored by granite and gneiss, and mantled by the Tethyan sedimentary sequence. The footwall of these were extruded southwards from beneath the Tibetan Plateau and subsequently warped into a domal shape. The second class of domes were formed during displacement on normal-sense shear zones and detachments that accommodated orogen-parallel extension during the Late Miocene. In some cases, formation of these domes involved an early stage of southwards-directed extrusion prior to doming. We review evidence for orogen-parallel extension to provide context for the formation of these gneiss domes. Compilations of pressure–temperature–time–deformation data and temperature–time paths indicate differences between dome types, and we accordingly propose new terminology. Type 1 domes are characterized by doming as an artefact of post-high-temperature exhumation processes in the Middle Miocene. Type 2 domes formed in response to exhumation during orogen-parallel extension in the Late Miocene that potentially post-dates south-directed extrusion.

Sign in / Sign up

Export Citation Format

Share Document