STUDY OF OPTICALLY STIMULATED LUMINESCENCE (OSL) CHRONOLOGY AND SEDIMENTARY ENVIRONMENTS OF THE YELLOW RIVER DELTA AREA WITH CORE YRD-1402

A 40.3 m long core of YRD-1402 was recovered in the Yellow River Delta area. Based on the observation of sedimentary characters, in combination of OSL and AMS 14C dating, grain-size analysis, and benthic foraminifera identification, the core is subdivided into four depositional units, DU 1 to DU 4 in a descending order. The DU 4 was deposited in a shallow water environment from subtidal zone to coastal and corresponds to the so-called third marine sedimentary bed; and the DU 3, DU 2 and DU 1 were deposited in a fluvial environment, coastal marsh to coastal or shallow shelf, and the delta of the Yellow River in the period of AD 11-1048, respectively. The DU 2 and DU 1 correspond to the so-called first marine sedimentary bed. And the OSL chronology indicates that the DU 4 (the third marine sedimentary bed) was formed in marine isotope stages 5(MIS 5). The second marine sedimentary bed is absent from the core, probably due to the river erosion during the middle to late MIS 3 to early Holocene in the study area. The dating range of OSL is more than 100 ka and thus can effectively expand the dating limit of ¹⁴C dating. The experimental conditions of the samples show that the OSL dating could be effectively used for young sediment dating.