广西古美测区1∶5万区调主要成果  

New Progresses in 1:50 000 Regional Geological Survey in Gumei area,Guangxi Province

作　　者：周开华[1] 陆刚[1] 陈春芳[1] 田青 蒋亮[1] 李新华[1] 吴立河[1] 

机构地区：[1]广西区域地质调查研究院,广西桂林541003

出　　处：《华南地质与矿产》2011年第4期342-351,共10页Geology and Mineral Resources of South China

基　　金：广西1:5万宾阳县;九塘;武陵;古美;五村;马隘;隆桑幅区调(编号:1212010610712)

摘　　要：桂西地区古美测区1∶5万区域地质调查,基本查明了测区地层格架、岩浆岩分布及时代、主要构造形迹特征、矿产分布规律以及盆地充填演化历史,主要取得了如下4个方面的进展:(1)查明测区晚古生代-中三叠世具有多阶段继承性发展演化的特征,完整的记录了华力西-印支期由裂至聚发展演化过程;查明早泥盆世晚期-中晚泥盆世存在台地前缘斜坡-盆地型、台地边缘型、远岸台地型、台地内部缓斜坡(或台洼)型四种类型的沉积;查明红泥坡地区寒武系的沉积特征,指出其应与桂北寒武系序列对比,发现其对测区晚古生代沉积分异具有重要的控制作用;通过对晚古生代地层中的大量多期次形成的沉积岩脉研究,获得了大量研究右江盆地演化和全球超大陆裂解的重要地层古生物学证据;在二叠纪环台地边缘发现的大量海绵藻礁滩建造丰富了中国南方二叠纪海绵藻礁的资料;首次发现了中上二叠统海绵礁灰岩与下三叠统罗楼组灰岩、中三叠统百逢组碎屑岩三者间的古岩溶超覆不整合接触关系;在下三叠统底部识别出一套广泛分布的与P/T界线发生的全球生物大灭绝事件之后的生物复苏、环境变迁密切相关的钙质微生物岩,将其作为非正式地层单位——"作登层"填图;对布兵第四纪盆地沉积进行了细致的调查,按成因从老至新划分为浔江组、白沙组、望高组、桂平组或临桂组。(2)采用"岩性+时代"填图方法对测区岩浆岩的构造背景进行了调查研究,新发现四个中细粒花岗岩、花岗斑岩小岩株、岩枝;首次发现花岗斑岩小岩枝与泥盆系郁江组泥质岩的"侵入状"接触关系。(3)对测区进行全面区域地质构造调查,基本查明了测区褶皱、断裂的分布、形状、产状及多期次构造活动与构造叠加特征,建立了构造格架,新发现浅层次大型滑脱构造及大规模的钙质糜棱岩-韧性剪切变形带Stratigraphic framework, temporal and spatial distribution of magmatic rocks, main tectonic framework, distributive law of mineral resources and filling history of basins of Gumei area, Guangxi province, are investigated in 1：50 000 regional geological survey. Multistage inheritance evolution of geological history Neopaleozoic Gumei area is illustrated, which records the complete process of Variscian-Indosinian evolution history. Four types of sedimentation： platform foreslope basin-, platform margin-, infralittoral platform- and intra-platform glacis- （or syneclise-） type, were developed in late of Early Devonian-middle of Late Devonian. Cambrian system in Hongnipo area which should be contrasted with the same strata sequence of northern Guangxi province, plays an important role in sediment differrntiation process of Neopaleozoic in Gumei area. Lots of sedimentary dikes in Neopaleozoic strata are providing a great deal of paleontologic and stratigraphic information for retrieving evolution history of Youjiang basin and global supercontinent cracking process. Lots of sponge reefs are found around Permian platform margin environment, and fossil karst uncon- formability of overlap among Mid-Upper Permian sponge reef-bearing limestone, limestone of Lower Triassic Luolou Formation and clastic rock of Middle Triassic Baifeng Formation are first discovered. Lower Triassic ＂Zuodeng Formation＂ which is composing of widely distributed calci-microbialite related to biotic recovery and environmental transition after end-Permian global mass extinction events, is a newly found informal strati- graphic unit. The sedimentary sequence of Bubing Quaternary basin can be subdivided into Xunjiang Formation, Baisha Formation, Wanggao Formation and Guiping Formation （or Lingui Formation）. Four middle-fine grained granite intrusions are newly found in magmatic rocks mapping by ＂lithology plus epoch＂ method, and the intrusion contact relationship between granite porphyry apophysis and argillaceous rock of Devonian Yu

关 键 词：地层划分对比 沉积岩脉 岩浆岩 区域地质构造 成矿规律及成矿预测 广西古美测区 

分 类 号：P566.7[天文地球—构造地质学]