Presenters-0100

From CSDMS
CSDMS 2015 annual Meeting - Models meet data, data meet models


Modes of extensional faulting controlled by surface processes



Jean-Arthur Olive

MIT / WHOI Joint Program in Oceanography, United States
jaolive@ldeo.columbia.edu
Mark Behn WHOI United States
Luca Malatesta Caltech United States

Abstract
We investigate the feedbacks between surface processes and tectonics in an extensional setting by coupling a 2-D geodynamical model with a landscape evolution law. Focusing on the evolution of a single normal fault, we show that surface processes significantly enhance the amount of horizontal extension a fault can accommodate before being abandoned in favor of a new fault. In simulations with very slow erosion rates, a 15 km- thick brittle layer extends via a succession of crosscutting short-lived faults (heave < 5 km). By contrast, when erosion rates are comparable to the regional extension velocity deformation is accommodated on long-lived faults (heave >10 km). Using simple scaling arguments, we quantify the effect of surface mass removal on the force balance acting on a growing normal fault. This leads us to propose that the major range-bounding normal faults observed in many continental rifts owe their large offsets to erosional and depositional processes.



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Of interest for:
  • Terrestrial Working Group
  • Geodynamics Focus Research Group