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上扬子区陆表海志留纪早期龙马溪组下部多为黑色笔石页岩,是全球海进期平缓海底缺氧状态的特有标志。滇东北大关黄葛溪剖面属埃隆阶下部Demirastrites triangularis带至Lituigraptus convolutus笔石带的龙马溪组页岩中夹含厚度约3m的薄层灰岩,其地理分布局限。对该灰岩的岩相特征分析显示,其中的蠕滑构造是碳酸钙沉积物在成岩固结前因海底坡度偏大产生的变形,粒度韵律层则属快速沉积单元,偶见风暴级强水流远源携带的小砾石。推测滇黔桂古陆西侧近岸区短暂时间段出现了小型浅水灰岩台地,大关黄葛溪剖面正处于小型台地向东延伸与斜坡交界的位置,这里的海底坡度较大,出现富氧带灰岩与缺氧环境黑色碎屑岩穿插的沉积。
The lower part of the Longmaxi Formation in the Upper Yangtze Silurian of the Upper Yangtze region is mostly black penolith shale, which is the unique sign of the slow sea-level hypoxia during the global sea phase. Geological distribution is limited in the Longmaxi Formation shale with the Degerastrites triangularis and Lituigraptus convolutus lithosphere strata in the Lower Geluon area of the northeastern Yunnan mark. The analysis of lithofacies characteristics of the limestone shows that the creep structure is the deformation of the calcium carbonate sediments due to the large slope of the seabed prior to diagenetic consolidation, and the granular rhythm layer belongs to the rapid deposition unit. Occasionally, the storm-level strong water flow Far-grained carrying small gravel. It is speculated that a small shallow-water limestone platform appears in the short-term time zone near the western coast of Yunnan, Guizhou and Guangxi. The section of Huanggexi in the mark is located at the boundary between eastward extension and slope of the small platform, where the seabed is steeper, Deposition of Oxygen Limestone and Interstitial Black Clastic Rocks in Hypoxia.