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黔东北石阡志留系兰多维列统埃隆阶上部的雷家屯组属灰岩和碎屑岩混合相,其分布限于滇黔桂古陆以北离岸几十千米范围内的浅海区。出露于枫香铺子沟、雷家屯、白沙龙口—筷子山、白沙均田和本庄岩门的5个剖面存在生物-沉积相的差异性。铺沟村粉砂岩—泥岩含量高于灰岩,达到4∶1,壳相化石丰度最低且无生物礁滩灰岩沉积;其它4个剖面的碎屑岩—灰岩比例约1∶1,雷家屯壳相化石最丰富,上部出现米级厚度的珊瑚-层孔虫点礁;筷子山剖面的雷家屯组下部开始出现雏形礁,之上的礁核灰岩现已被剥蚀掉,但从礁基的菲利普构造和礁翼塌积岩推测,点礁的正向隆起规模是很明显的;均田剖面仅出露雷家屯组上部约7m的地层,多为粉砂岩和生屑灰岩薄层;岩门剖面多为薄层细颗粒生屑滩相灰岩,近顶部出现钙质微生物形成的叠层石。偏西剖面的雷家屯组顶部展现侵蚀面、泥裂等现象,是桐梓上升期海底暴露的证据,唯有最靠东的铺沟村雷家屯组顶部未见暴露标志,与之上马脚冲组呈整合接触。
Qiandongbei Shiqian Silurian Langdouwei column Upper Erlian upper Lei Jiatun group limestone and clastic rock mixed phase, the distribution is limited to dozens of kilometers away from the coast of Yunnan, Guizhou and Guangxi ancient land within the shallow sea area . There are biologic-sedimentary facies differences in the five sections exposed in Fengzhongpuzigou, Leijiatun, Baisha Longkou-Chopsticks Mountain, Baishajun and Yanzhuangmen. Pudian siltstone - mudstone content is higher than limestone, reached 4: 1, lowest abundance of shell facies fossils and no reef littoral limestone deposition; the other four profiles of clastic rock - limestone ratio of about 1: 1, The most abundant fossil in the shell of Leijiatun is the coral-layer foraminifera at the upper part of the thickness. The lower part of the Leijiatun Formation in the section of the Kaozishan section begins to appear the rudimentary reef, and the reef-core limestone above it has been eroded away. However, from the reef-based Phillip tectonics and the reef-wing syndepositional rocks, the positive uplift scale of the reefs is quite obvious. In the Jundian section, only about 7m of the upper part of the Leijiatun Formation is exposed, mostly siltstone and shale Limestone thin layer; the Yanmen section is mostly fine-grained boulder-shoal facies limestone, and the calcareous microbial strata appear near the top. The top of the Leijiatun Formation in the western part of the profile shows erosion and mud-splitting phenomena. It is evidence of the seafloor exposure during the ascent of Tongzi. Only the top of the Leijiatun Formation at the ditch in the east reaches no signs of exposure, Chong group was integrated contact.