江苏南通QC_5孔第四系碎屑矿物特征及其地质意义

南通QC_5孔第四系碎屑矿物达40余种。不同重矿物的含量垂向分布与沉积环境有关而呈“波状”变化。重矿物的组合分段大多与第四系中地层界线相对比。第四系碎屑矿物母岩以中酸性火成岩为主。F/Q值之大小是沉积物生成时间长短、古气候冷暖与沉积速率高低综合作用的结果。

FEATURES AND GEOLOGICAL SIGNIFICANCE OF QUATERNARY DETRITAL MINERALS FROM HOLE QC_5 IN NANTONG OF JIANGSU PROVINCE

In this paper, our attention is paid to the features of Quaternary detrital minerals from hole QC5 in Nantong. The vertical distribution of heavy mineral contents has shown a wavy change. In sediments, epidote, hornblende, garnet, sphene, metallic mineral, apatite and zircon tend to increase and decrease in content synchronously, only with the exception of biotite. Biotite usually has an increasing content in river-mouth and terrestrial environment while the other heavy minerals decrease in content; and biotite content decreases in littoral environment, while the other heavy minerals increase relatively. Segments of minerals correspond to boundary of Quaternary strata. Parent rocks in the Quaternary sediments are dominated by intermediate-acidic igneous rocks and secondarily by metamorphic rocks. F/Q ratio depends on the formation time of sediments, palaeoclimate and sedimentation rate.