北极沉积物中正构烷烃的组合特征及古沉积环境的研究

报道了北极楚科奇海和白令海沉积物中正构烷烃的含量和分布类型,并通过因子分析方法对正构烷烃的来源和古沉积环境加以初步探讨.研究结果表明,正构烷烃碳数分布范围多数在nC₁₅～nC₃₃之间,分布类型有两种,第1种高分子碳范围,MH为nC₂₅～nC₂₇,CPI大于1,奇偶优势显著.第2种低分子碳范围,MH为nC₁₇～nC₂₀,奇偶优势不明显.以上特征指示了正构烷烃来源于陆源高等植物和海洋内生两个部分,并且以陆源贡献最大.楚科奇海和白令海大部分测站的Pr/Ph小于1,指示了缺氧还原沉积环境.因子分析结果与样品中正构烷烃不同分子组成特征相互对应.

The composition indexes of n-alkanes in sediments and study on paleoenvironment in the Arctic

Concentrations and different distribution patterns of n-alkanes in sediments from the Chukchi Sea and, Bering Sea in the Arctic are reported.Factor statistical analysis method is used to study the contaminated source of n-alkanes and paleoenv ironment.The result shows that n-alkanes is in the range of nC₁₅～nC₃₃,n-alkane distribution patterns are characterized by two modes.The first mode with high molecular range for nC₂₅～nC₂₇ being MH and CPI>1 indicates the abundances of terrigenous plantorigin.The second mode with low carbon range for nC₁₇～nC₂₀ being MH and CPI>1 shows that it had more marine biological inputs.The contribution of terrigenous origin is the larger one,with Pr/Ph>1 of the depositional environment,which has strong reducing action.The result of factor analysis is in correspondence with composition indexes of n-alkanes in the sediment.