1)Key Laboratory of Crustal Dynamics,Institute of Crustal Dynamics, CEA, Beijing 100085;2)School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083
Abstract：We use simplified multiple aliquot regenerativedose(SMAR) protocol from fine grain quartz(4～11μm) to systematically date samples from Sunjialou trench across Tangshan earthquake zone in 1976. OSL signals of these samples dominated by fast component show that they are suitable for OSL dating. On the basis of the optical ages and the burial depth of samples, the agedepth curve and function of the trench are obtained. Through it we inferred depositional rate. The results suggest that depositional rate curves on both sides of the fault show two parallels between 50 and 7.16 ka, which indicates sedimentary environment are stable and no tectonic movement happened during that time interval. The depositional rate is about 0.03 m/ka and 0.6 meters distance in the range of two parallels is vertical offsets generated by the 1976 Tangshan earthquake. Activity caused by the main fault in about 50 ka leads to depositional rate increase, which is 0.1 m/ka. Coeval activity in the secondary faults causes depositional rate in western segment about twice that of eastern segment, which is 0.2 m/ka. In conclusion, tectonic movement is main factor for depositional rate change in study area but climate change. The depositional rate change may be useful approaches for the palaeoseismic events.
Zhao Junxiang,Jiang Wali ,Guo Hui et al. OPTICAL DATING OF SUNJIALOU TRENCH IN TANGSHAN AND ITS SIGNIFICANCE FOR PALAEOSEISMIC EVENTS[J]. jgg, 2012, 32(5): 12-16.
