TECTONIC CHARACTERISTICS AND DIVISION OF THE BEIKANG BASIN

Located in mid Nansha waters, the Beikang basin is a Cenozoic sedimentary basin where Cenozoic sedimentary cover rock is extensively developed. The cover rock consists of three structural layers according to seismic reflection. There lies Tingjia fault along southwest boundary of Beikang basin, which originated from Wan'an basin in the west and reached Kalimantan in the east. From Oligocene through Miocene to late Miocene and Quaternary, the fault experienced three tectonic movements on large scales. Northwest fault of the Nansha Trough lies on the southeast boundary of the Beikang basin and has separated Beikang basin from Nansha Trough. There are three series of faults (NE, NW and N S faults) in Beikang basin, and the first fault is always cut by the last two. On the basis of the analysis of the faults and characteristics of the cover layer, the secondary tectonic units were further discussed in this paper.