地质通报2012，Vol.31Issue(11)：1910-1921,12.
黔北下寒武统牛蹄塘组烃源岩的生物标志物特征和沉积环境
The biomarker characteristics and sedimentary environment of Lower Cambrian Niutitang Formation source rock in northern Guizhou
摘要
Abstract
In order to investigate source material and sedimentary environment of Lower Cirnbrian Niuritang Formation source rock in northern Guizhou, the authors studied the biomarkers. The results show that they have the following characteristics: (1) OEP values of the n-alkanes are close to 1.0, showing no odd-even carbon dominance; N-alkanes mostly have bimodal performance(C18/C25), and the ratios of (nC21 +nC22)/(nC28+nC29)are 0.54-1.01, indicating a. dominant cole of heavy hydrocarbon components; the average ratios of Pr/Ph vary from 0.51 to 0.82, showing phytane dominance. (2) According to the relative abundance, tncyclic terpane＞pentacychc triterpane＞ quart-cyclic terpane. The tricyclic terpane contents of C21, C23 and C24 show inverted V-shaped distribution, and the ratios of Ts/ (Tm+Ts) are between 0,45 and 0.50. (3) The average ratio of C27 and C29 of the sterane is slightly smaller than or close to 1. Aromatic compounds DBT/P are between 0.05 and 0.09. Based on these features combined with the isotope of kerogen and the isotope of the monomer hydrocar bon composition and variation, the authors believe that the black rock of Niutitang Formation was formed in a reduction environment in shallow water in the Early Cambrian, with high degree of thermal evolution of organic matter, and the main sources were the bacteria, algae and other aquatic organisms. The constant index of MnO/TiO2, the trace indicators of Ba, Sr/Ba, U/Th, V/(V+Ni), and the combination of organic geochemical indicators depict the aquatic environment from Upper Sinian Dengying Formation to Lower Cambrian Niutitang Formation and Mingxinsi Formation, and the source rocks of Niutitang Formation hydrocarbon are divided into three stages, the first stage being the initial rapid transgression stage in Early Cambrian , the second stage being a stage of deep-water reducing environment with high organic matter productivity, and the third stage being a stage of shallow waters with high organic matter productivity. The deposition period of Mingxinsi Formation nonhydrocarbon source rocks was a shallow water oxidation stage.关键词
牛蹄塘组/烃源岩/生物标志物/有机碳同位素/微量元素/黔北Key words
Niutitang Formation/ source rocks/ biomarker/ organic carbon isotope/ trace elements/ northern Guizhou分类
天文与地球科学引用本文复制引用
杨平,汪正江,谢渊,杜秋定,陈厚国,贺永忠..黔北下寒武统牛蹄塘组烃源岩的生物标志物特征和沉积环境[J].地质通报,2012,31(11):1910-1921,12.基金项目
中国地质调查局地质调查项目《雪峰山西侧地区海相油气地质调查》(编号:1212010782003)和国家自然科学基金项目《黔东新元古代中期沉积盆地演化与地层划分对比研究》(批准号:41072088) （编号:1212010782003）
