【摘要】 泌阳凹陷古近系核三段泥页岩是主要烃源岩,可划分出5套富有机质泥页岩层,页岩层系中有机质在层序地层格架内呈规律性分布。利用常量、微量元素和生物标志化合物等参数分析了5号和3号页岩层内有机质富集及其与沉积环境(气候、盐度、生产力、氧化还原条件)的相关性,并探讨了层序地层格架内有机质富集的主控因素(生产力和保存条件)。研究表明:15号页岩层有机质主要富集于湖扩体系域中下部,3号页岩层有机质主要富集于最大湖泛面附近;2浊流活动对沉积层中有机质含量起稀释作用,导致深凹周缘区有机碳质量分数变化较大且频繁,但深凹中心区变化相对较小;35号和3号页岩层有机碳质量分数变化与氧化还原指标(V/Cr,Pr/Ph)均呈线性相关,其中3号页岩层有机碳质量分数变化还与古生产力指标(Cu、Ni)呈较好的相关性,表明干旱炎热气候下咸化水体的盐度分层有利于形成良好的保存条件,是5号页岩层有机质富集的关键,而温暖潮湿气候下藻类勃发对应的高生产力水平,以及湖盆深处缺氧底水环境决定了3号页岩层有机质的富集。更多还原

【Abstract】 The shales in He-3Member of Paleogene Hetaoyuan Formation in the Biyang Depression mainly consists of hydrocarbon source rocks,and can be divided into five organic-matter-rich intervals(ORIs),where organic matter(OM)is distributed regularly in the sequence stratigraphic framework.The present work addresses the distribution of major elements,trace elements and biomarker parameters of shales from5 th and 3rd ORIs for discussion of the relationships between the enrichment of organic matter and the changes of climate,salinity,redox condition,productivity,and identification of the mechanism of OM accumulation in the sequence stratigraphic framework.The results show that OM of 5th and 3rd ORI is mainly enriched in the middle and lower of expanding system tract,and near the maximum flooding surface,respectively.The total organic carbon content(TOC)varied widely and frequently in periphery of deep depression due to dilution of organic matter by turbidity flow,and had a slight change in the center of the deepest sag.The linear relationship between TOC and paleoredox coefficient of V/Cr and Pr/Ph is observed in 5th and3 rd ORI.TOC in the 3rd ORI shows a positive correlation well with the paleoproductivity coefficient of Cu and Ni contents.The evidence indicates that stratified water column with high salinity and anoxic conditions under arid climate enhanced OM storage in 5th ORI,and the conjunction of high productivity following phytoplankton bloom coupled with oxygen-depleted bottom water in the relatively deep basin are favorable for OM preservation and accumulation in 3rd ORI.更多还原