Holocene left-slip rate determined by cosmogenic surface dating on the Xidatan segment of the Kunlun fault (Qinghai, China)

摘要

Cosmogenic dating, using in situ ~(26) Al and ~(10)Be in quartz pebbles from alluvial terrace surfaces, constrains the late Holocene slip rate on the Xidatan segment of the Kunlun fault in northeastern Tibet. Two terrace risers risers offset by 24 ± 3 and 33 ± 4 m, having respective ages of 1788 ± 388 and 2914 ± 471 yr, imply a slip rate of 12.1 ± 2.6 mm/yr. The full range of ages obtained (≤22.8 k.y., most of them between 6.7 and 1.4 k.y.) confirm that terrace deposition and incision, hence landform evolution, are modulated by post-glacial climate change. Coupled with minimum offsets of 9-12 m, this slip rate rate implies that great earthquakes (M ～8) with a recurrence time of 800-1000 yr. rupture the Kunlun fault near 94°E.