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上扬子区黔中古陆以北的陆表海底地貌、深度和浑浊度变化控制志留纪岩相和生物相的差异性。香树园组为黔东北志留纪兰多维列世鲁丹期—埃隆中期碳酸盐岩台地相地层单元,在近岸“白沙型”香树园组浅水灰岩地层中含有丰富的后生动物礁滩序列;同期远滨带是以印江合水小安土剖面为代表的“印江型”香树园组灰岩,其沉积环境处于最大的浪基面之下,岩性组份中粉砂质和泥质含量较高,粒度偏细,后生动物大化石含量很低,松软底质上存在潜穴生物栖居,但不是类似龙马溪组笔石页岩的缺氧带。印江型沉积区水深偏大和水温偏低的环境指标抑制了近岸“白沙型”后生动物礁滩分布向广海区的空间延伸。在黔东北地区,“印江型”香树园组正好位于“白沙型”礁滩相香树园组与缺氧底质的龙马溪组黑色笔石页岩之间的过渡带。
The variation of the sea surface seafloor topography, depth and turbidity in the upper Yangtze region north of Central Guizhou Province controlled the difference of lithofacies and biofacies in the Silurian. The Xiangshuyuan Formation is a unit of the Ludanian-Middle Permian carbonatite platform in the Silurian-Landed Victoria Depression in northeastern Guizhou Province and is rich in shallow-water limestone formations near the “Baisha-type” Xiangshuyuan Formation Of the Late Pleistocene reef bank sequence; the same period, the far coastal zone is the “Yinjiang-type” Xiangshuyuan limestone represented by the Xiaoan-Tu profile in Heshuihe, where the sedimentary environment is under the largest wave base, Sexual components in the silt and shale content is higher, the grain size is fine, metazoan large fossil content is very low, there is the existence of soft sediments buried habitat, but not similar to Longmaxi penolith shale anoxia band. The environmental indicators of high water depth and low water temperature in the Yinjiang sedimentary area suppress the spatial extension of the distribution of the reef beach near the “Baisha type” to the Guanghai area. In northeastern Guizhou, the “Yinjiang-type” Xiangshuyuan Formation is located in the transitional zone between the “Shusha-type” Reef-shuangxiangshuyuan Formation and the anoxic sediment of the Longmaxi Formation black penolith shale .