T281 Quantifying Geomorphic Processes and Rates of Landscape Evolution I

Wednesday, 28 September 2016
8:00 AM - 12:00 PM
Room 405

EXHUMATION AND UPLIFT COUPLED WITH PRECIPITATION ALONG THE WESTERN MARGIN OF THE DEAD SEA RIFT

Paper number: T281-14
Program: Technical Sessions
Time: 11:25 AM – 11:40 AM

Authors

Abstract

Denudation of carbonate terrains is dominated by chemical weathering and can therefore be treated as a rain gauge proxy where the mass lost by dissolution over time is proportional to the time-integrated precipitation. Hence, the denudation history of carbonate landscapes may provide paleo-precipitation data and can shed light on the interactions between climate, denudation and tectonic uplift. We apply this approach to constrain the average long-term precipitation pattern over a period of 104–107 yr along the western margin of the Dead Sea Rift (DSR). The analyzed terrain is predominantly underlain by carbonate rocks and maintains a steep gradient from Mediterranean to hyper-arid climate separating the windward and leeward flanks of the Judean Mountains. Comparing the total cumulative denudation (relative to a top Turonian key horizon), with 36Cl-derived denudation rates indicates that: (1) The total denudation magnitude correlates with 36Cl-derived denudation rates and both correlate with the present day mean annual precipitation, and (2) Over the lifetime of the range (10–20 Myr), the effective precipitation gradient across the range was higher than the present gradient by at least 40%. Since the denudation gradient along this ~450 km-long range, is most probably compensated by isostatic uplift we suggest that along the western DSR margin, and possibly also in other carbonate terrains (below a threshold precipitation of ~1000 mm yr–1), precipitation may control the long-term denudation rate and the subsequent compensating uplift.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-283067

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