Cenozoic epeirogeny of the Indian peninsula
Author(s)
Richards, FD
Hoggard, MJ
White, NJ
Type
Journal Article
Abstract
Peninsular India is a cratonic region with asymmetric relief manifest by eastward tilting from the 1.5 km high Western Ghats escarpment toward the floodplains of eastward‐draining rivers. Oceanic residual depth measurements on either side of India show that this west‐east asymmetry is broader scale, occurring over distances of > 2000 km. Admittance analysis of free‐air gravity and topography shows that the elastic thickness is 10 ± 3 km, suggesting that regional uplift is not solely caused by flexural loading. To investigate how Indian physiography is generated, we have jointly inverted 530 river profiles to determine rock uplift rate as a function of space and time. Key erosional parameters are calibrated using independent geologic constraints (e.g., emergent marine deposits, elevated paleosurfaces, uplifted lignite deposits). Our results suggest that regional tilt grew at rates of up to 0.1 mm a−1 between 25 Ma and the present day. Neogene uplift initiated in the south and propagated northward along the western margin. This calculated history is corroborated by low‐temperature thermochronologic observations, by sedimentary flux of clastic deposits into the Krishna‐Godavari delta, and by sequence stratigraphic architecture along adjacent rifted margins. Onset of regional uplift predates intensification of the Indian monsoon at 8 Ma, suggesting that rock uplift rather than climatic change is responsible for modern‐day relief. A positive correlation between residual depth measurements and shear wave velocities beneath the lithosphere suggests that regional uplift is generated and maintained by temperature anomalies of ±100 °C within a 200 ± 25 km thick asthenospheric channel.
Date Issued
2016-12-01
Date Acceptance
2016-11-10
Citation
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences, 2016, 17 (12), pp.4920-4954
ISSN
1525-2027
Publisher
American Geophysical Union
Start Page
4920
End Page
4954
Journal / Book Title
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences
Volume
17
Issue
12
Copyright Statement
© 2016. American Geophysical Union.All Rights Reserved.
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GC006545
Subjects
Geochemistry & Geophysics
02 Physical Sciences
04 Earth Sciences
Publication Status
Published
Date Publish Online
2016-11-17