摘要
晚二叠世—早三叠世地球经历了重大的气候环境—生物种类更替,该时期皖南地区发育了一套黑色页岩,不仅可以作为非常规油气资源的储层,而且为该时期气候环境演变研究提供了良好的载体。针对该套黑色页岩古环境演变及物源,前人采用多种手段和方法开展了研究,但仍存在不同的观点。因此,基于宏观—微观岩石学特征,结合地球化学数据,对皖南地区下二叠统大隆组—上三叠统殷坑组页岩古气候和物源输入及其有机质富集控制因素进行分析,开展页岩古环境演变及物源研究。结果表明:微量元素及草莓状黄铁矿(<6μm)指示页岩形成于温暖潮湿且波动频繁的缺氧—硫化环境,由大隆组至殷坑组,缺氧条件和古生产力整体呈逐渐降低趋势;w(Th)/w(Sc)—w(Zr)/w(Sc)、w(La)/w(Sc)—w(Co)/w(Th)和w(Hf)—w(La)/w(Th)图解以及稀土元素配分模式表明页岩物源主要来自后太古代上地壳花岗岩,w(La)—w(Th)—w(Sc)、w(Th)—w(Co)—w(Zr/10)和w(Th)—w(Sc)—w(Zr/10)判别图显示页岩物源的构造背景为大陆岛弧,兼具活动大陆边缘,推断其主要来自“江南造山带”;氧化还原条件和初级生产力是页岩有机质富集的主要控制因素。
From the Late Permian to the Early Triassic, the earth experienced significant climatic and biological changes. A set of black shale successions had developed in southern Anhui during this period that is not only served as a reservoir of unconventional oil and gas resources, but also completely records the evolution of climate and environment of this period. For this set of black shale paleoenvironmental evolution and provenance,predecessors have used a variety of means and methods to carry out research, but there are still different views.Therefore, based on macro-micro petrology and geochemical data, the paleoclimate and provenance input of the Lower Permian Dalong Formation-Upper Triassic Yinkeng Formation shale in southern Anhui, as well as the controlling factors of organic matter enrichment, were analyzed, and the evolution of shale paleoenvironment and provenance were studied. The result implies that trace elements and framboidal pyrites(<6 μm) indicate that shale was formed in a warm, humid and frequently fluctuating anoxic-sulfidic environment. The anoxic conditions and primary productivities of shale show an overall downward trend from the Dalong Formation to the Yinkeng Formation. The discriminant diagram of w(Th)/w(Sc)-w(Zr)/w(Sc),w(La)/w(Sc)-w(Co)/w(Th)and w(Hf)-w(La)/w(Th)and the REE partition model indicate that the shale source is mainly from the post-Archean upper crust granite. The discriminant maps of w(La)-w(Th)-w(Sc),w(Th)-w(Co)-w(Zr/10)and w(Th)-w(Sc)-w(Zr/10)show that the tectonic background of the shale is continental island arc with active continental margin, it is considered that the provenance may come from the southern“Jiangnan orogenic belt”.Redox conditions and primary productivity played important roles in organic matter accumulation.
作者
霍金钢
徐文礼
马义权
万慈昡
颜雪
霍飞
聂应
蒋欢
HUO Jingang;XU Wenli;MA Yiquan;WAN Cixuan;YAN Xue;HUO Fei;NIE Ying;JIANG Huan(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;No.6 Gas Production Plant,Changqing Oilfield Company,PetroChina,Xi’an 710018,China;Sichuan Institute of Nuclear Industry Geology,Chengdu 610052,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;Research Institute of Experiment and Detection,PetroChina Xinjiang Oilfield Company,Karamay 824000,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2022年第11期1819-1835,共17页
Natural Gas Geoscience
基金
国家重点研发计划项目(编号:2017YFE0106300)
国家自然科学基金项目(编号:41972109)联合资助.
关键词
古气候
物源
大隆组
殷坑组
皖南地区
Paleoclimate
Provenance
Dalong Formation
Yinkeng Formation
Wannan area
