云南永善－大关地区五峰组－龙马溪组黑色页岩生物地层划分与沉积环境探讨:以新地2井为例

由于缺乏对四川盆地西南缘永善-大关地区五峰组-龙马溪组生物地层的详细划分与对比，黑色页岩分布时限及其沉积背景不明确.对新地2井五峰组-龙马溪组黑色页岩岩心开展生物地层研究，识别出了从上奥陶统凯迪阶上部WF1 Dicellograptus complanatus带至志留系兰多维列统埃隆阶顶部LM8 Stimulograptus sedgwickii带的9个生物带和组合.新地2井与宁211井、焦页1井、威202井、巫溪2井黑色页岩生物地层对比结果显示，新地2井的顶界与宁211井、焦页1井黑色页岩笔石带相近，但与威202井、巫溪2井相比低了1个笔石带.结合TOC值标定，新地2井富有机质页岩沉积期为WF2-LM6笔石带，其顶界高于宁211井的LM4笔石带.在笔石生物地层框架内对比了各井黑色页岩的沉积厚度、沉积速率及TOC值，探讨了它们的沉积演化差异及构造背景.靠近古隆起或古陆的沉积区，海侵-海泛稳定期时间呈缩短的趋势，富有机质页岩上界可低至LM5笔石带或以下；远离古隆起或古陆的沉积区，富有机质页岩上界可达LM8-LM9笔石带.受沉积水体深浅差异及古隆起陆源碎屑输入的影响，威远、焦石坝及巫溪地区出现了沉积分异现象.阶段性的海退事件及古隆起的状态变化（隆升与扩大）是广西运动的构造响应. 

Graptolite Biozonation of the Wufeng and Longmaxi Formations and Its Environmental Implications from the Xindi 2 Borehole in Yongshan-Daguan Area,NE Yunnan

Due to the lack of detailed division and comparison of graptolite biozonation in Wufeng and Longmaxi formations of Yongshan-Daguan area, the distribution time of black shale and its sedimentary background are unclear. Nine graptolite biozones of the Wufeng and Longmaxi formations are recognized in the Xindi 2 borehole from the Yongshan-Daguan area, NE Yunnan in this paper. They are Dicellograptus complanatus, D. complexus, P. pacificus-M. extraordinarius, A. ascensus-P. acuminatus, C. vesiculosus, C. cyphus, D. triangulatus, L. convolutes, and S. sedgwickii biozones. A correlation of the Wufeng-Longmaxi graptolite biozones among the Xingdi 2, Ning 211, Jiaoye 1, Wei 202, and Wuxi 2 boreholes are indicated. The top of the Longmaxi black shale is diachronous, from which the top of the Longmaxi black shale of the Xindi 2, Ning 211, and Jiaoye 1 boreholes are one biozone lower than those of the Wei 202 and Wuxi 2 boreholes. High TOC content in the Longmaxi black shale is measured from WF2 (D. complexus Biozone) to LM6 (D. triangulatus Biozone) in the Xindi 2 borehole but only up to LM 5 (C. cyphus Biozone) in the Ning 211 borehole near the Central Guizhou uplift. However, the top of the Longmaxi black shale in Wei 202 and Wuxi 2 boreholes may reach to the level of LM9 (S. guerichi Biozone).According to our study, the transgression to maximum flooding period is shortened near the uplift or the old land, and the upper limit of high-quality black shale can be as low as LM5 (or below). Sedimentary differentiation occurred in Weiyuan, Jiaoshiba and Wuxi areas, which was affected by sedimentary water depth and the debris input from the uplift.