南沙海洋沉积物中生物标志化合物的组成及地化意义

COMPOSITION AND GEOCHEMICAL SIGNIFICANCE OF BIOMARKERS IN MARINE SEDIMENTS FROM NANSHA ISLANDS WATERS,THE SOUTH CHINA SEA

对1990年取自南沙海域102站位岩芯柱样中饱和烃进行色谱－质谱分析，研究沉积物中生物标志化合物组成和地球化学意义。结果表明，正构烷烃、类异成二烯烷烃、甾烷和藿烷组成特征指示了其先质主要为海洋浮游生物和细菌，部分为陆源高等植物，反映了南沙海洋沉积有机质起源于这些生物；较丰富的胡萝卜烷存在和Pr／Ph比值低，说明沉积环境具强还原性；随沉积物理藏深度增加，藿烯和藿烷以及藿烷异构体之间，均存在明显的成岩转化关系。

The saturated hydrocarbon in core samples collected from trg NS90- 102(12° 02’N, 111° 00’E) From Nansha islands waters, the South China Sea in 1990were analysed by GC-MS. boosition and distribution of biomarker compoundsin the samples were studied. As a result, compositional characteristics of n-alkanes,isoprenoid alkanes, steranes and hopanes indicate that they come from marine planktons and baCteria as well as smal amounts of landhigher plants, which reflect thatthe sedimentary orgaaic matter From Nansha islands waters, the South ChinaSea is derived from these organisms. The ekistence of more abundantcarotanes and lower Pr /Ph ratios show that depositional environment is anokic. Withincreasing burial depth, the relationship of diagenetic transformation between hopenesand hopares and those between hopane isomers are found.