上扬子地区五峰组-龙马溪组主要地质事件及岩相沉积响应

发布时间：2018-03-29 17:05

本文选题：地质事件　切入点：岩相　出处：《地球科学》2017年07期

【摘要】：上扬子地区广泛发育上奥陶统五峰组和下志留统龙马溪组富有机质页岩,前人研究较少涉及其岩相类型和沉积过程对主要地质事件的响应.细粒沉积物高精度层序地层学研究表明,晚奥陶世至龙一段充填沉积期,经历了3次大的地质事件,形成了2个三级层序(五峰组层序Sq1和龙一段层序Sq2)、12个准层序组和13个笔石带.在生物地层约束的等时格架中,识别出火山喷发事件形成的富碳、富有机硅的硅质页岩相,底流侵入事件及陆源输入浊流事件沉积的贫碳、贫有机硅的混合质页岩相和泥质页岩相,建立了五峰组-龙马溪组富有机质页岩的成因模式,该套页岩主要为该时期的火山喷发(包括冰期和生物绝灭)、底流侵入和陆源输入等地质事件导致的古气候、古海洋等各要素协同作用的结果.
[Abstract]:The Wufeng formation of Upper Ordovician and the Longmaxi formation of Lower Silurian are rich in organic matter shale in Upper Yangtze area. Previous studies have rarely involved the response of lithofacies types and sedimentary processes to major geological events. High-precision sequence stratigraphic studies of fine-grained sediments show that the filling sedimentary period from late Ordovician to Long-1 member has experienced three major geological events. Two third-order sequences (Wufeng sequence Sq1 and Longyi formation sequence Sq2N, 12 quasi-sequence formations and 13 graptolite zones) were formed. In biostratigraphic isochronous framework, the siliceous shale facies rich in carbon and organic silicon formed by volcanic eruptions were identified. A genetic model of organic shale rich in Wufeng formation and Longmaoxi formation is established, which is composed of low carbon, mixed shale facies and shale-shale facies deposited by the underflow intrusive events and terrestrial turbidite events, and the muddy shale facies, which are rich in organic silicon, are formed in the formation of Wufeng formation and Longmaxi formation. The shale series is mainly the result of the synergistic action of various elements such as paleoclimate and paleo-ocean caused by volcanic eruptions (including glacial and biological extinction, underflow intrusion and land-based input, etc.) during this period.
【作者单位】：中国地质大学资源学院;
【基金】：国家自然科学基金重大项目(No.41690131) 国家科技重大专项(No.2016ZX05060-004)
【分类号】：P512.2;P535

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