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Rapid denudation of Higher Himalaya during late Pliestocence, evidence from OSL thermochronology

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Title Rapid denudation of Higher Himalaya during late Pliestocence, evidence from OSL thermochronology
 
Creator DE SARKAR, S
MATHEW, G
PANDE, K
CHAUHAN, N
SINGHVI, AK
 
Subject OSL thermochronology
apatite fission track
Ar-40-Ar-39 thermochronology
Eastern Himalaya
erosion
denudation
REGENERATIVE-DOSE PROTOCOL
STIMULATED LUMINESCENCE
MOUNTAIN BELTS
QUARTZ
EROSION
TEMPERATURE
GLACIATIONS
EXHUMATION
TOPOGRAPHY
EVOLUTION
 
Description Optically Stimulated Luminescence (OSL) of quartz, with closure temperatures of 30-35A degrees C in conjunction with Apatite Fission Track (AFT; closure temp. similar to 120A degrees C) and Ar-40-Ar-39 (biotite closure temperature similar to 350A degrees C), were used to obtain cooling ages from Higher Himalayan crystalline rocks of Western Arunachal Himalaya (WAH). Cooling age data based on OSL, AFT and Ar-Ar thermochronology provide inference on the exhumation - erosion history for three different time intervals over million to thousand year scale. Steady-state exhumation of similar to 0.5 mm/yr was observed during Miocene (> 7.2 Ma) till Early Pleistocene (1.8 Ma). Onset of Pleistocene glacial/interglacial conditions from similar to 1.8 Ma formed glaciated valleys and rapid erosion with rivers incising deep valleys along their course. Erosion enables midcrustal partial melts to move beneath the weak zone in the valley and causes an erosion-induced tectonic uplift. This resulted in a rapid increase in exhumation rate. The OSL thermochronology results suggest increased erosion over similar to 21 ka period from Late Pleistocene (2.5 mm/yr) to Early Holocene (5.5 mm/yr) and these are to be contrasted with pre 1.8 Ma erosion rate of 0.5 mm/yr. Enhanced erosion in the later stage coincides with the periods of deglaciation during Marine Isotope Stages (MIS) 1 and 2. The results of the present study suggest that in the present setting OSL thermochronology informed on the short-term climatic effect on landscape evolution and techniques like the AFT and Ar-40-Ar-39 provided longer-term exhumation histories.
 
Publisher VERSITA
 
Date 2014-10-16T14:51:54Z
2014-10-16T14:51:54Z
2013
 
Type Article
 
Identifier GEOCHRONOMETRIA, 40(4)304-310
1733-8387
1897-1695
http://dx.doi.org/10.2478/s13386-013-0124-7
http://dspace.library.iitb.ac.in/jspui/handle/100/15831
 
Language en