MAGNETOSTRATIGRAPHY OF CORE DZS2 OFF THE YANGTZE RIVER ESTUARY

The outside estuary of the Yangtze River, as a link between the land and sea, is an important area for the study of sea-land interactions and terrestrial materials transportation into the sea. The core DZS2, collected from the northwest of East Sea shelf, is the longest and oldest core so far in this region. Combined with the methods of paleomagnetism, sediment lithological analysis and AMS¹⁴C dating, a relatively complete and reliable chronostratigraphic framework of the Core DZS2 in the outside estuary of Yangtze River estuary has been established. The paleomagnetic data of the Core DZS2 reveals a distinct M/B geomagnetic polarity boundary in the sequence, in addition to several magnetic excursions, which can be correlated with the standard palaeomagnetic polarity record, including the Gothenburg, Blake, Emperor, Jaramillo and Olduvai events. The events have provided further age constraints on stratigraphic sequences. Comparing to other cores drilled in the Yangtze River delta, the core DZS2 does not have similar sedimentary cyclicity, probably due to the swollen bedrock in the estuary preventing transportation of a part of the materials from the Yangtze River to the offshore.