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Modes of extensional faulting controlled by surface processes
Author(s) -
Olive JeanArthur,
Behn Mark D.,
Malatesta Luca C.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl061507
Subject(s) - geology , tectonics , fault (geology) , rift , extensional fault , erosion , extensional definition , brittleness , seismology , basin and range topography , extensional tectonics , scaling , geomorphology , geometry , physics , mathematics , thermodynamics
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.