南沙海洋柱状沉积物的有机地球化学研究

STUDY ON ORGANIC GEOCHEMISTRY OF MARINE CORE SEDIMENTS FROM CHINESE NANSHA SEA AREAS

研究了南沙海域NS90—103柱样有机碳含量、各类生物标志化合物的组成和分布及其地球化学意义.结果表明,该柱样中有机碳含量高于南沙海域其他沉积环境,这表明南沙海域中大陆坡最适合于有机质的聚集.各类生物标志化合物组成和分布指示了沉积有机质主要起源于海洋浮游生物和细菌,其次为陆源高等植物,而气溶胶输入可能是后者来源的途径之一;沉积环境具有强原还性;有机质处于未成熟阶段,并存在较小的成岩变化.

The organic carbon contents, compositions and distributions of various biomarker compounds were examined in leg NS90-103 of marine sediment core from chinese Nansha sea areas. As a result, the organic carbon contents in the core are higher than those of other sedimentary environments , showing that the middle continental slope of Nansha sea areas is fit for the accumulation of organic matter. The compositions and distributions of various biomarker compounds indicate that the organic matter in the sediments is principally from marine plankton and bacteria and secondly from land-higher plants which one of their input way probably is aeolian transport. The low Pr/Ph ratios reflect strong reducing environments. The presence of hopanes and ββ-hopanes and the conversion between hopane configurations with burial depth indicate that the organic matter is immature and lesser diagenetic variation of the organic matter has occurred.