【作者】 王丽娟；

【导师】 杨锋杰；

【作者基本信息】 山东科技大学 ， 矿产普查与勘探， 2009， 硕士

【摘要】 徐淮地区位于中朝板块的东部,属徐淮胶辽分区,以蚌埠隆起为界分为苏皖北部和淮南两个亚区,因地处蓟县、湖北峡东之间的过渡地带,且具有青白口系至原震旦系的连续海相剖面,是研究我国新元古代地层南北衔接的关键地段。然而对于这套地层的时代、层序以及与邻区对比等问题,至今仍存在较大的分歧和争议,尤其是在国际地层委员会公布“2004年国际地层表”之后,对本区的重新划分和对比就显得尤为重要。本文以实测剖面和前人资料为基础,依据多重地层划分的原理,结合臼齿碳酸盐岩、风暴沉积、高温蒸发及最大海泛事件研究,运用Sr、C同位素年龄、地球化学、古地磁资料、古生物化石等,对徐淮地区各地层分区的新元古代地层进行垂向划分,探讨存在争议的组段的时代归属以及两地层分区的衔接与对比;同时结合区域地质背景,展开了与邻区新元古代地层的横向对比;最后在划分与对比的基础上,通过岩石组合与沉积构造特征分析区域沉积模式,识别出沉积相与亚相,探讨研究区新元古界海平面变化、沉积环境演化及古地理格局。研究表明:徐淮地区新元古代地层除凤台组外沉积时限大约在距今900～650Ma之间,为青白口系-南华系之间的沉积;江苏“史家组”为魏集组的一部分,史家村史家组位于南华系底部,层位与淮南刘老碑组相当,魏集组与望山组属于同时异相岩组;凤台组应归属于震旦系,成因为海底扇的水道沉积;苏皖北部与淮南地区的新元古代地层可进行衔接与对比,淮南地区的新元古代地层基本上相当于苏皖北部的下部层位:徐淮地区新元古代地层与辽南、鲁中地区可对比,新于蓟县地区,与峡东地区只能通过同位素数据进行对比;研究区可识别出5个沉积相、10个亚相,沉积演化分为三个阶段,包括两个完整的海进-海退旋回和一个海进过程。更多还原

【Abstract】 XuHuai Region which is the subregion of the XuHuai-JiaoLiao region is located in the east of China-Korea plate and can be divided into the Northern Jiangsu and Anhui and Southern Anhui which is bounded by BengBu uplift.XuHuai Region is the key area of studying the north and south connection of China’s Neoproterozoic stratum because it is located in the transition zone of JiXian and HuBei XiaDong and has the continuous sea sections from Qingbaikou system to Sinian system.However,there is still much divergence and controversy about the stratigraphic age,sequence and the comparision of the adjacent area especially after the publishing of 2004 international stratigraphic chart by International Commission on Stratigraphy.So the redivision and comparision of the stratum in this region is very important.According to the multiple stratigraphic classification principle,with the study of molartooth carbonates,storm deposit,high temperature evaporation and maximum flooding event,we use Sr、C isotopic age,geochemistry,paleomagnetic data and paleontological fossils to classify the Neoproterozoic stratum vertically in XuHuai region basing on the measured section and previous data.We also study the age assignment of the controversial formation and the classification’s connection and comparison of the two regions.Combining with regional geological background,we carry out the Neoproterozoic stratum lateral comparison with the adjacent area in the meantime.Finally basing on the classification and comparison,we analyse regional sedimentary pattern through the rock association and sedimentary structures,identify the sedimentary facies,intrafacies and study the Neoproterozoic sea level change、sedimentary environment evolution and paleogeography pattern.The results show that Neoproterozoic stratum in XuHuai region deposit between Qingbaikou and Nanhua for about 650～900Ma ago except Fengtai Formation;"Shijia" formation in JiangSu is part of WeiJi formation;ShiJia formation in Shijiacun is at the bottom of Nanhua and its horizon is equivalent to Liulaobei formation in Southern Anhui;WeiJi formation and Wangshan formation are contemporaneous heterotopic facies petrofabric; Fengtai formation which is resulted from the channel sedimentation of the submarine fan should be assigned to Sinian period;Neoproterozoic stratum in the Northern Jiangsu and Anhui and Southern Anhui can be connected and compared and Neoproterozoic stratum in Southern Anhui is nearly equivalent to the stratum at the bottom of the Northern Jiangsu and Anhui;Neoproterozoic stratum in Xuhuai is newer than the stratum in Jixian and can be compared with the stratum in Southern Liaodong peninsula and middle areas in Shandong Province,while it can only be compared with Xiadong through the isotopic data;Five sedimentary facies and ten intrafacies can be identified in the research area,and Sedimentary evolution can be divided into three stages including two complete cycles from progression to regression and a transgression progress.更多还原