T166 New Perspectives on Integrating Fault Zone Behavior through the Full Thickness of the Continental Lithosphere

Tuesday, 24 September 2019
8:00 AM - 12:00 PM
Room 131ABC, North Building

IMPACT OF LARGE-SCALE FAULTING ON THE SURFACE DEFORMATION OF INDIA-EURASIA COLLISION INFERRED FROM 3-D VISCOUS MODELING

Paper number: T166-2
Program: Technical Sessions
Time: 8:20 AM – 8:40 AM

Authors

Abstract

A key topic of contention involving continental deformation revolves around the relative importance of discrete faulting or distributed strain on the accommodation of observed deformation in the continental lithosphere. We use 3-D lithospheric, Stokes flow simulations of the India-Eurasia (IN-EU) collision zone to investigate the effect of large-scale lithospheric faults on surface deformation and derive allowable bounds for fault strength and spatial scale. Lithospheric strength is constrained by laterally-varying, lithospheric-average effective viscosities and partitioned vertically to capture strength anomalies corresponding to geophysically-imaged slabs and weak Tibetan lower crust. Finite zones of low viscosity are introduced representing major fault systems of the IN-EU collision zone: the Karakorum, Altyn-Tagh, Kunlun, Jinsha Suture-Xianshuihe, Jiali-Red River, and Sagaing. We find (1) narrow zones of lithospheric scale weakness in conjunction with a weak lower crust are important for reproducing rotation in Southeast Tibet and (2) cases with finite zones of weakness representing large-scale faults produce focused uplift at the Longmen Shan and extension across southern Tibet and thickening in northeastern Tibet consistent with observations.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-337783

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