摘要
前寒武纪沉积物中的分子标志物对研究地球早期生命的起源和演化具有重要意义。通过岩心切片实验和气相色谱-质谱分析了华北地区高于庄组富有机质岩心的分子标志物特征,评估了污染和扩散对分子标志物的影响。结果表明,饱和烃受污染和扩散的影响较大,芳烃受影响较小。芳烃成熟度表明高于庄组有机质处于成熟-高成熟阶段。在最内层切片中,正构烷烃呈双峰分布,前峰C_(15)-C_(17)占优势,后峰具有强烈的奇偶优势,这可能指示蓝藻的贡献而非高等植物的污染型输入。内层切片中具有高丰度的C_(10)-C_(21)的单甲基烷烃,其中2-、5-和7-甲基异构体占优势,未检测到藿烷、甾烷类化合物。这些结果可能指示中元古界高于庄组的有机质主要来源于原核生物,尤其是蓝细菌。
The molecular markers in Precambrian sediments are of significance for researching the origin and evolution of early life on Earth. Characteristics of molecular markers in an organic-rich core from the Mesoproterozoic Gaoyuzhuang formation in North China were analyzed and impacts of contamination and diffusion on molecular markers were evaluated according to experiments of core slice and gas chromatography-mass spectrometry. The results showed that saturated hydrocarbons were more affected by contamination and diffusion, while aromatic hydrocarbons were less affected. The maturity parameters of aromatic hydrocarbons indicated that the organic matter of Gaoyuzhuang formation was at a stage of mature to high mature. In the innermost slice, the n-alkanes presented a bimodal distribution, the C_(15)-C_(17) alkanes domination showed in the low molecular weight region while the strong odd predominance appeared in the high molecular weight region, which might indicate the contribution of cyanobacteria rather than the contamination input of higher plants. In the inner slices, C_(10)-C_(21) monomethylalkanes showed high abundances, among them 2-, 5-, and 7-methyl isomers were predominant, while no hopanes, steranes and diasteranes were detected. All these results suggested that the organic matter of Gaoyuzhuang formation was mainly from prokaryotes, especially cyanobacteria.
作者
程如蛟
徐耀辉
CHENG Ru-jiao;XU Yao-hui(Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Yangtze University,Wuhan 430100,China;College of Resources and Environment,Yangtze University,Wuhan 430100,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2021年第3期635-643,共9页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金项目(41672117,41972122)
国家重大专项课题(2017ZX05001005-002-001)。
关键词
分子标志物
切片实验
单甲基烷烃
蓝细菌
高于庄组
molecular markers
slice experiment
monomethylalkanes
Cyanobacteria
Gaoyuzhuang formation
