南秦岭陕西镇安西口二叠系剖面牙形刺生物地层

发布时间：2018-04-26 00:16

本文选题：牙形刺 + 二叠系　；参考：《微体古生物学报》2017年01期

【摘要】：陕西镇安西口地区构造上属于南秦岭微板块,二叠纪时该地区与华南板块被勉略洋(东古特提斯洋的一个分支)分隔,而成为南秦岭微板块上的一个孤立台地。由于其二叠纪时处于华北和华南板块的汇聚带,同时又位于沟通古特提斯和泛大洋的重要通道上,其特殊的古地理位置使其具备与华南乃至全球其它地区二叠系对比的重要古地理和古环境意义,具有成为二叠系经典剖面的潜力。本次研究共分析60件样品,从中发现具有地层划分对比意义的平台型牙形刺分子4属18种。这些化石分布于上石炭统至上二叠统的地层中,且主要产于中二叠统水峡口组和上二叠统的西口组、熨斗滩组及龙洞川组。根据牙形刺的产出情况将研究区二叠系划分出13个带,自上而下为:长兴阶(Changhsingian)的Clarkina subcarinata带和C.changxingensis带;吴家坪阶(Wuchaipingian)的C.postbitteri带,C.dukouensis带,C.liangshanensis带和C.orientalis带;卡匹敦阶(Capitanian)的Mesogondolella posterserrata带,M.shannoni带,M.altudaensis带和M.granti带;罗德阶(Roadian)的M.nanjingensis带;亚丁斯克阶(Artinskian)的Sweetognathus whitei带;阿瑟尔阶(Asselian)-萨克马尔阶(Sakmarian)的S.inornatus带。最后,主要依据牙形刺带对陕西镇安西口二叠系剖面的生物地层进行重新划分,确立了3统9阶,从而能够更好地进行洲际对比。
[Abstract]:The Xikou area, Zhenan, Shaanxi belongs to the South Qinling microplate structurally. During the Permian period, the area was separated from the South China plate by Mianliuyang (a branch of the East Tethys Ocean) and became an isolated platform on the South Qinling microplate. During the Permian period, it was located in the convergence zone of the North and South China plates, and at the same time it was located on an important channel connecting the Paleotertes and the Pan Ocean. Because of its special paleogeographic location, it has important paleogeography and paleoenvironmental significance compared with other parts of South China and even other parts of the world, and has the potential to become a classical section of Permian. A total of 60 samples were analyzed and 18 species of platform conodont molecules with stratigraphic classification and correlation were found. These fossils are distributed in the Upper Carboniferous and Permian strata, and mainly occur in the Middle Permian Shuixiakou formation and the Upper Permian Xikou formation, the iron flat formation and the Longdongchuan formation. According to the occurrence of conodonts, the Permian in the study area was divided into 13 zones, from top to bottom: the Clarkina subcarinata belt and C.changxingensis belt of Changhsingian. the C.postbitteri belt of Wujiaping stage Wuchaipingianensis belt C. liangshanensis belt and C.orientalis belt, the Mesogondolella posterserrata belt of Capidon stage capitaniananananananensis belt, M. shannoni belt, M. altudaensis belt and M.granti belt. The M.nanjingensis band of Roadian, the Sweetognathus whitei band of Artinskianin, and the S.inornatus band of Asseliana-Sakmarian in the Athensk stage. Finally, according to the conodont belt, the biostratigraphy of the Permian section in Zhenan, Shaanxi Province, is reclassified, and the 3rd series and 9th order are established, so that the intercontinental correlation can be better carried out.
【作者单位】：合肥工业大学资源与环境工程学院;
【基金】：国家自然科学基金项目(No.41172097) 中国地质调查局项目(No.12120113094300)资助~~
【分类号】：Q915

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