Dating faulted alluvial fans with cosmogenic 10Be in the Gurvan Bogd mountain range (Gobi-Altay, Mongolia): Climatic and tectonic implications

Abstract

The Gurvan Bogd mountain range is a fault system characterized by strong earthquakes (M ∼ 8) separated by long periods of quiescence. Further to the previous works in the area, our study provides new data concerning the tectonic and climatic processes in the Gobi-Altay. To quantify the slip rates along the faults, we dated offset alluvial fans analysing the in situ produced 10Be along profiles at depth. The slip rates along the Bogd strike-slip fault and its associated thrust faults over the Upper Pleistocene-Holocene period are 0.95 ± 0.29 mm yr-1 and comprised between 0.12 ± 0.02 and 0.13 ± 0.02 mm yr-1, respectively. The surfaces ages account for a cyclic formation of the fans over the past ∼360 ka, in correlation with the terminations of the marine isotope stages 2, 6, 8 and 10. © 2005 Blackwell Publishing Ltd.