摘要
四川盆地是中国南方页岩气勘探与开发的主要区块。对四川兴文县麒麟乡的麒新桥剖面和某浅井剖面的五峰组—龙马溪组黑色页岩开展了详细的生物地层研究工作,在该区建立了从上奥陶统凯迪阶上部的Dicellograptus complexus带至志留系兰多维列统埃隆阶顶部的Stimulograptus sedgwickii带的12个连续生物带和组合,这一生物地层序列可实现区域和全球的精确对比。在麒新桥剖面的新鲜露头上,我们观察到了从观音桥层碳酸盐岩到龙马溪组黑色笔石页岩的岩相和生物相的连续过渡变化。这一连续序列指示了从赫南特壳相动物群至Metabolograptuspersculptus带笔石群、从富氧环境至缺氧环境的连续、快速转换;从全球范围来看,这一地层序列也对应于奥陶纪末冰期结束后冰川快速消融导致的全球海平面上升事件。
The Sichuan South China. Recen xinqiao section and tly the Basin is the most important area for the exploration and development of shale gas in we investigated two sections at Qilin, Xingwen County, Sichuan Province, the Qi Qilin Well section. The biostratigraphic sequence of the Wufeng to Lungmachi black shales has been recognized, including eleven graptolite biozones and one shelly assemblage from the Dicellograptus complexus Zone of the Katian stage （Upper Ordovician） to the Stimulograptus sedgwickii Zone of the Aeronian Stage （Llandovery, Silurian）. The sequence can be correlated regionally and global- ly. From the unweathered outcrop at the Qixinqiao section, we found a continuous transition of litho-facies and bio-facies from the Kuanyinchiao Formation to the Lungmachi Formation, which represents the rapid change from the Hirnantia shelly fauna to the graptolite fauna of the Metabolograptus persculptus Zone, and the change from the well-oxygenated water to the anaerobic or dysaerobic water. This transition also represents the global sea-level rising resulted from the rapid glacial melting after the Hirnantian icehouse.
出处
《地层学杂志》
CSCD
北大核心
2013年第4期513-520,共8页
Journal of Stratigraphy
基金
国家自然科学基金(No.41221001
41272042
41290260)
中国科学院知识创新工程重要方向性项目(KZCX2-EW-111)资助
关键词
生物地层
黑色页岩
烃源岩
五峰组
龙马溪组
奥陶系
志留系
麒麟
兴文
四川
biostratigraphy, black shales, Wufeng Formation, Lungmachi Formation, Ordovician, Silurian, Qilin, Xingwen County, Sichuan Province
