不同岩性盐湖沉积物中挥发性有机质的特征

通过不同岩性盐湖沉积物中C/N值,确定其有机质的来源均为藻类,然后采用气相色谱—离子迁移谱(GC-IMS)联用技术对不同岩性盐湖沉积物中的挥发性有机质进行了研究。结果显示,不同岩性沉积物的挥发性有机质虽然来源相同,但是其种类和含量存在显著差异。在砂岩沉积物中,检测出16种挥发性有机质,而石盐中共检测出30种挥发性有机质。砂岩样品中未检测出酯类化合物,而检测出的醛类、酮类、醇类以及呋喃类化合物的含量均比石盐中的含量要小,硫化物的含量与石盐中的含量差距较小,但砂岩中酸类物质的含量比石盐中高。这可能是由于在不同沉积时期,湖泊中生产有机质的藻类物质种类和含量不同,以及在早期成岩过程中沉积环境对有机质的保存和降解不同所造成的。

Characteristics of Volatile Organic Matter in Salt Lake Sediments of Different Lithology

In this study,the source of organic matter in salt lake sediments was determined as algae with C/N ratio.Further,volatile organic matter (VOM) in salt lake sediments of different lithology was determined by gas chromatography-ion migration spectroscopy (GC-IMS).Results showed that although the sources of VOM in different lithologic sediments were similar,significant differences were observed in their types and contents.In total,16 and 30 kinds of volatile organic matter were detected in sandstone and halite,respectively.No esters were detected in sandstone samples,but the contents of aldehydes,ketones,alcohols and furans were lower than those in halite,and the contents of sulfide were similar in both samples.However,the difference between the content of sulfide in both samples was small,and the content of acid in sandstone was higher than that in halite.This may be attributed to different types and contents of algae producing organic matter in lakes in different sedimentary periods,as well as different preservation and degradation of organic matter in sedimentary environment during early diagenetic process.This paper provides theoretical guidance for further studying the geological significance of volatile organic matter in salt lake sediments.