Distribution characteristics of heavy minerals on the surface sediments in continental shelf of northern South China Sea and its provenance significance

In this paper,we studies the distribution characteristics and the provenance of heavy minerals on the surface sediments according to the result of identification and analysis of minerals( fraction 0. 063 ~ 0. 125 mm) in 292 surface sediment samples which were collected from the continental shelf of northern South China Sea in 2007 ~ 2010. The results show that there are 60 species of heavy minerals in the study area. The light mineral fraction is predominant with an average content as high as 98. 49%,whereas the heavy mineral fraction is scarce with an average content of 1. 51% and a maximum content of only 10. 38%. The primary factor affecting the distribution and the contents of heavy mineral are hydrodynamics,source materials and factors,such as the sedimentary environments and mineral metamorphic grade to a certain extent. Four mineral assemblage zones and two sub-zones are classified according to the component distribution and the topography of northern South China Sea. The results show that the sand from rivers especially the Pearl River is the main provenance of the surface sediments in the continental shelf of northern South China Sea. The sediment environment of seabed canyon is relatively steady in the southeast Hainan Island and the authigenic pyrites that cemented in the foraminifer shells are abundant.