摘要
采用气相色谱、气相色谱-质谱技术,对凌源-宁城盆地中元古界铁岭组烃源岩生物标志化合物特征进行研究,剖析其蕴含有机质生源、沉积环境、有机质热演化程度等方面的信息及地球化学意义.铁岭组烃源岩饱和烃气相色谱以“前峰型”的单峰分布为主,主峰碳多为nC18,表明有机质来源以低等生物为主;Pr/Ph比值主要分布于0.16~0.73之间,植烷优势较明显,指示为强还原的沉积环境,少部分为还原环境.铁岭组烃源岩具有长侧链三环萜烷丰富、伽马蜡烷含量高和C27甾烷分布占优势的分子化石组合特征,伽马蜡烷指数(Ga/C_(30)H)为0.10~0.31,平均值0.19,反映出铁岭组烃源岩形成于微咸水-半咸水环境;Ts/Tm比值为0.54~1.19,平均值为0.88,表明烃源岩热演化程度较高;甾烷与藿烷的含量比值主要分布于0.24~0.59之间,平均值0.42,表明低等生物藻类的贡献较低,而细菌等微生物的贡献相对较大.铁岭组烃源岩甾烷呈现C27甾烷占优势的“L”型,表明生烃母质生源构成是低等水生生物来源的有机质特征.
Based on gas chromatography and gas chromatography-mass spectrometry,the paper studies the characteristics of biomarker compounds in the source rocks of Tieling Formation in Lingyuan-ningcheng Basin,and analyzes the organic source,sedimentary environment and thermal evolution degree of organic matter,as well as geochemical implication.The saturated hydrocarbon gas chromatography of source rocks is front-peak type unimodal distribution dominated,with the main peak carbon mostly nC18,indicating that the organic matter is mainly derived from lower organism.The Pr/Ph ratio mainly ranges from 0.16 to 0.73,with obviously more phytane,indicating a strongly reducing sedimentary environment.The source rocks of Tieling Formation are characterized by abundant long-side chain tricyclic terpane,high content of gamacerane and dominant distribution of C27 sterane,with Ga/C_(30)H of 0.10-0.31,averagely 0.19,reflecting the source rocks were formed in slight saline water-brackish water environment.The Ts/Tm ratio of 0.54-1.19(averagely 0.88)shows the thermal evolution degree of source rocks is relatively high.The ratio of sterane/hopane contents is mainly in the range of 0.24-0.59,averagely 0.42,reflecting the lower organism of algae contributes little to organic matter,while the microorganisms such as bacteria contribute a lot.The sterane in the source rocks are L-shape with dominant C27 sterane,indicating the hydrocarbon generating parent material is of lower aquatic biological organism origin.
作者
石蕾
宗文明
孙求实
郜晓勇
李永飞
孙守亮
张涛
SHI Lei;ZONG Wen-ming;SUN Qiu-shi;GAO Xiao-yong;LI Yong-fei;SUN Shou-liang;ZHANG Tao(Shenyang Center of China Geological Survey,Shenyang 110034,China)
出处
《地质与资源》
CAS
2023年第5期547-554,615,共9页
Geology and Resources
基金
中国地质调查局项目“东部重点盆地新区新层系油气资源调查评价”(DD20230078).
关键词
生物标志化合物
烃源岩
铁岭组
中元古界
凌源-宁城盆地
biomarker compound
source rock
Tieling Formation
Mesoproterozoic
Lingyuan-Ningcheng Basin
