南海北部陆架表层沉积物重矿物分布特征及物源意义

该文根据2007～2010年间对南海北部陆架采集的292个表层沉积物样品0．063～0．125mm粒级矿物的鉴定和分析结果，研究了该海域表层沉积物重矿物的分布特征和物质来源．结果表明：该海域矿物组成以轻组分矿物为主，平均质量百分数高达98．49％，重组分矿物的含量较低，平均值为1．51％，最高质量百分数仅为10．38％，共发现了60种重矿物．影响南海北部陆架表层沉积物重矿物的含量和分布的首要因素是水动力条件，其次是物质来源，其他因素如沉积环境、矿物自身的变质程度等也在一定程度上影响其分布特征．根据因子分析的因子荷载分布及南海北部陆架的地形地貌，研究区可划分为4个主要矿物组合区和2个亚区．分析结果表明，华南沿海的众多河流特别是珠江的入海泥沙是南海北部陆架表层沉积物的主要物质来源．海南岛东南部海底峡谷区处于相对稳定的沉积环境，胶结于有孔虫壳内的海洋自生黄铁矿含量丰富．

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.