Comprehensive study is made on saturated hydrocarbon for 80 samples col-lected from modern sediments and organisms in seas

lakes

deltas and rivers in eastern China.The n-alkane from modern sediments of semi-arid climatic zones(from Song-liao Basin to the Yellow Sea)in north China is mainly represented by a single peak with an odd-even predominance and a high-carbon major peak.This distribution pattern is similar to that of the n-alkane of Artemisia from modern organism in Songliao Basin

implying that the organic matters were derived from continental plants.The distribution pattern of n-alkane in modern sediments of the semi-humid climatic zone(along the middle to lower reaches of the Yangtzi River and the East China Sea paralic area)in south China is quite complicated

and represented by single or bimodal peak

partly with even carbon predominance.The modern sediments with normal alkane characterized by even carbon predominance werenot deposited in a strongly reduced environment

and microorganism remoulding might play an important part in the formation of even carbon predominance.