SUBSIDENCE OF BEIBUWAN BASIN SINCE LATE MIOCENE

Based on the 3000km of high resolution multichannel seismic profile data recently acquaired from the Beibuwan Basin, three sets of strata were identified and contoured respectively according to major sedimentary interfaces and stratigraphic sequences. Isopach map of the strata shows that the depositional center of the basin gradually moved from the Weixinan Depression to Haizhong Depression and then to Haitoubei Depression in the period from Late Miocene to Holocene. It suggests an nonununiform subsidence in the Beibuwan basin and the shifting of the major subsidence area from north to south.