黔北地区高成熟烃源岩地球化学的古海洋环境指示意义  

Geochemical characteristics of high mature hydrocarbon source rocks as indices of paleooceanographic environment in northern Guizhou,China

作　　者：杜秋定[1] 杨平[1] 谢渊[1] 汪正江[1] 刘家洪[1] 

机构地区：[1]中国地质调查局成都地质矿产研究所,成都610082

出　　处：《成都理工大学学报（自然科学版）》2014年第1期68-77,共10页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学青年基金资助项目(41302091);国家自然科学基金重点资助项目(41030315);国家自然科学基金资助项目(41072088);中国地质调查局计划项目(1212010782003);中国地质调查局基础地质科研项目(1212011121111)

摘　　要：中国南方中上扬子地区发育多套烃源岩,其中震旦系和下寒武统黑色页岩分布广泛,厚度大、有机质含量丰富、生烃潜力好。研究表明:有效烃源岩形成及发育主控因素的研究是预测优质烃源岩的基础;古生产力及氧化还原条件是全球气候变化和海洋环境研究的重要内容,也是重建有效烃源岩发育环境的主要参数。作者通过对控制海洋氧化还原条件的[U,V,Mo,Tu/U,V/Sc,V/(V+Ni)]等氧化还原敏感痕量元素在沉积物或沉积岩中的富集程度的研究,利用沉积物或沉积岩中这些痕量元素的含量来重建古海洋的氧化还原状态和沉积环境。从无机地球化学角度分析发育有效烃源岩的沉积环境。结果显示:下寒武统牛蹄塘组早期为较深水弱还原环境,之后逐渐演变为深水盆地严重缺氧的还原环境,可能受热液作用的影响,富集了V和Mo等金属的含矿层,最后又逐渐演变为水体变浅的弱还原环境。The Early Cambrian and Sinian black shales enrich in organic matter are widely preserved in the South China Block.They have a vital hydrocarbon-generating potential.Paleo-productivity and redox conditions are the key variables to study the global marine environment changes and the paleoenvironment of the effective hydrocarbon source rocks.This paper presents the geochemical data of [U,V,Mo,Tu/U,V/Sc,V/（V＋Ni）] in shales and mudrocks rich in diverse suites of major elements and trace metals.These data reflect the depositional environment,provenance and diagenesis of the shales and mudrocks.From the angle of inorganic geochemistry,this paper analyses the sedimentary environment to generate effective hydrocarbon source rocks.The results show that the lower Niutitang Formation shales deposited in a weak reduction environment and subsequently,V and Mo were enriched caused by hydrothermal process and the environment gradually evolved into a strongly anoxic environment of the deep water.Finally,the sedimentary environment of the midupper Niutitang Formation shales gradually evolved into a weak reduction environment in which water bodies shoaled.

关 键 词：高成熟 有效烃源岩 痕量元素 氧化还原条件 古环境 

分 类 号：TE122.113[石油与天然气工程—油气勘探] P736.2[天文地球—海洋地质]