| 摘要: |
| 在系统分析柴达木盆地西部第三系咸水湖相生油岩样品的微量元素、有机物、粘土矿物组成的基础上,揭示了研究区生油岩的无机元素和有机质组成特征;并结合沉积环境的无机与有机地球化学指标,重建了生油岩沉积时的古沉积环境。生油岩的B、Cl-及伽玛蜡烷含量表明,沉积时的水介质条件是半咸水—咸水环境,并伴随湖盆沉积中心北迁过程各层位地层的盐度发生规律性时空]化;生油岩的Fe2+/Fe3+、S2-、Pr/Ph比值、藿烷碳数分布模式及黄铁矿含量反映其沉积时的沉积环境为强还原性;粘土矿物组合特征及含量揭示这些生油岩的沉积相带介于中心咸湖相和边缘咸湖相之间。 |
| 关键词: 微量元素 粘土矿物 有机物 咸水湖相 古沉积环境 地球化学 柴达木盆地 |
| DOI： |
| 分类号: |
| 基金项目:中国石油天然气集团公司95重点科技攻关项目资助,970207号 |
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| GEOCHEMICAL AND SEDIMENTARY FEATURES OF TERTIARY SALINE LACUSTRINE SOURCE ROCKS IN QAIDM BASIN |
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YE Ai-Juan, ZHU Yang-Ming
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Department of Earth Sciences, Zhejiang University, Hangzhou, 310027
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| Abstract: |
| The Tertiary saline lacustrine source rocks in oil-gas resources were sampled from exploration wells in western Qaidm Basin (90°10'–92°40'E, 37°20'–38°50'N) in the northwest China, to which chemical and mineralogical analyses were performed on trace-element, organic or inorganic matters, pyrite abundance and clay mineral composition. Geochemical indicators were used to determine the sedimentary environment during the age in the region. The concentrations of Cl-, B and gammacerane show that the water mass was semi-brine to brine. The deposition center was moved northward with a gradual change in salinity. In terms of Fe2+/Fe3+ ratio, Pr/Ph ratio, the amounts of S2- and pyrite, and hopane distribution, the local Tertiary sedimentary environment featured strong reduction. The geochemical and mineral composition of clay suggests that the sedimentary facies of the source rocks was between marginal and central salt lake facies. |
| Key words: Trace element, Clay mineral, Organic matter, Salt lake facies, Sedimentary environment, Geochemistry, Qaidam Basin |
