Constraints on the extent and kinetics of eclogitization processes in the Indian lower crust
Abstract
Earthquakes occurring in the Indian lower crust underthrusting Tibet can be related to the mineral transformations of subducted crustal rocks to denser eclogites. These intermediate-depth earthquakes are most likely linked to physical processes accommodating the significant volume change caused by dehydration reactions during eclogitization. However, while described by laboratory experiments and field samples, the kinetics of metamorphic reactions at large scale is not well known.We propose to constrain the extent and kinetics of eclogitization processes in the Indian lower crust, at large spatial scales, by combining Bouguer anomaly data with 2-D thermokinematic and petrological modeling.We derive lithospheric density profiles by coupling thermokinematic modeling with a realistic multi-layer petrological model depending on mineralogical composition, pressure and temperature. The density estimates are then used to compute the associated Bouguer anomalies, which are then constrained by observed data along profiles perpendicular to the Himalayan arc.We explore model parameters (model geometry, mineralogical composition, water content) to best fit observations along 10 profiles spanning from NW India to Bhutan and discuss lateral variations in eclogitization processes along the Himalayan arc, in relation with seismic activity in the region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.S34B..07C
- Keywords:
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- 3613 Subduction zone processes;
- MINERALOGY AND PETROLOGYDE: 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7215 Earthquake source observations;
- SEISMOLOGYDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS