黔东、湘西及桂北南华纪盆地充填序列与岩相古地理特征  

Sequences and lithofacies paleogeographic features of the eastern Guizhou province,western Hunan province,and northern Guangxi Zhuang autonomous region during the Nanhua Period

作　　者：龚桂源 彭成龙 陈建书 王文明 GONG Guiyuan;PENG Chenglong;CHEN Jianshu;WANG Wenming(Guizhou Geological Survey,Guiyang 550005,China)

机构地区：[1]贵州省地质调查院,贵阳550005

出　　处：《中国科技论文》2024年第10期1073-1088,共16页China Sciencepaper

基　　金：中国地质调查局资助项目(1212011121106)。

摘　　要：黔东、湘西及桂北发育一套超覆在雪峰运动界面上的南华纪寒冷气候沉积的楔状地层,该楔状地层沿湘黔桂裂谷盆地分布,跨越了上扬子陆块东南缘及江南造山带西南段。通过对区内不同位置典型岩相地层剖面对比研究,开展沉积相与沉积微相研究,推断古海岸线变化的范围及分布特征、古流向及古地理概貌,重塑了不同阶段盆地演化的岩相古地理面貌及沉积模式。岩相古地理特征显示,研究区南华纪为裂谷盖沉积期,其盆地充填演化划分为3个阶段,即隆升剥蚀及早期冰碛岩堆积阶段、间冰期充填阶段和晚期冰碛岩堆积阶段。南华冰期(长安、南沱冰期)为冰内、冰前、冰外冰水重力流沉积;富禄间冰期以河流、潟湖、三角洲沉积为主,发育含锰碎屑岩沉积。该成果为湘黔桂裂谷盆地充填演化、岩相古地理特征及成矿资源效应研究提供了新的基础资料,对地层、寻找矿源、研究其形成的构造地质背景具有一定的指导意义。A set of wedge-shaped strata overlying the Xuefeng tectonic interface deposited in a cold climate during the Nanhua Period has been developed in eastern Guizhou province,western Hunan province,and northern Guangxi Zhuang autonomous region.These wedge-shaped strata distribute along the rift basins of Hunan,Guizhou,and Guangxi,crossing the southeastern edge of the Upper Yangtze Block and the southwestern segment of the Jiangnan Orogenic Belt.The scope and distribution characteristics of paleoshoreline changes,paleocurrent directions,and paleogeographic features were inferred via comparative studies of typical lithofacies stratigraphic sections at different locations within the region as well as conducting research on depositional facies and micro⁃facies.This research reconstructs the lithofacies paleogeography and sedimentary models of the basin evolution at different stages.Lithofacies paleogeographic features indicate that the study area is in a rift cover deposition period during the Nanhua Period,with basin filling evolution divided into three stages:uplift and erosion with early glacial till deposition,interglacial filling stage,and late gla⁃cial till deposition stage.The Nanhua glaciation(Chang’an and Nantuo glaciations)involves glacial,preglacial,and postglacial grav⁃ity flow deposits.The interglacial period,especially the Fulu interglacial,is dominated by fluvial,lagoon,and deltaic deposits,with the development of manganese-bearing clastic rock deposits.This research provides new fundamental data for studying the rift basin filling evolution,lithofacies paleogeographic features,and mineralization effects in the Hunan-Guizhou-Guangxi rift basin and also sheds some light on the stratigraphic understanding,mineral exploration,and the tectonic geological background study of its formation.

关 键 词：南华纪 裂谷盆地 沉积微相 岩相古地理特征 

分 类 号：P548[天文地球—构造地质学]