云南镇雄二叠系栖霞组—茅口组沉积微相及沉积环境演变  

CARBONATE MICROFACIES ANALYSIS AND EVOLUTION OF DEPOSITIONAL ENVIRONMENT OF THE CHIHSIA FORMATION AND THE MAOKOU FORMATION(MIDDLE PERMIAN) IN ZHENXIONG,YUNNAN

作　　者：山克强[1,2] 孟晓荣 SHAN Ke Qiang;MENG Xiao Rong(Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004;Kunming Natural Resources Comprehensive Investigation Center,China Geological Survey,Kunming 650000)

机构地区：[1]中国地质科学院岩溶地质研究所,广西桂林541004 [2]中国地质调查局昆明自然资源综合调查指挥中心,云南昆明650000

出　　处：《地层学杂志》2022年第1期68-85,共18页Journal of Stratigraphy

基　　金：中国地质调查局地质调查项目(DD20190672);中国地质科学院岩溶地质研究所基本科研业务项目(DD2012011)共同资助。

摘　　要：本研究采用碳酸盐岩微相分析的方法,对位于扬子板块西缘云南镇雄栖霞组—茅口组碳酸盐岩的生物组合、微相类型和岩相古地理进行了研究,将剖面碳酸盐岩归纳为24个微相:小有孔虫-假蠕孔藻生物碎屑粒泥岩、海绵骨针粒泥岩、生物碎屑密集堆积的泥粒岩、苔藓虫生物碎屑泥粒岩、发育孔隙的棘皮颗粒岩、粗枝藻-小有孔虫泥粒岩、似球粒内碎屑生物碎屑颗粒岩、二叠钙藻粒泥岩、含生物碎屑细晶白云岩、小有孔虫泥状灰岩、二叠钙藻生物碎屑泥粒岩、二叠钙藻-古串珠虫-苔藓虫泥粒岩、古串珠虫生物碎屑颗粒岩、细粒生物碎屑粒泥岩、生物扰动细粒生物碎屑粒泥岩、海绵骨针粒泥岩、叶状藻障积岩、包壳颗粒翁格达藻颗粒岩、翁格达藻-?颗粒岩、冲洗差的生物碎屑粒泥岩、棘皮-苔藓虫泥粒岩、小有孔虫-钙藻生物碎屑泥粒岩、裸海松藻生物碎屑泥粒岩、似球粒颗粒岩。剖面垂向微相特征指示其时代为亚丁斯克期末期—空谷期,栖霞组形成于碳酸盐缓坡环境,以假蠕孔藻组合为特征。栖霞组顶部为白云岩,为区域性不整合面,该不整合面标志着扬子板块碳酸盐缓坡被填平,形成较为平缓的台地地形。瓜德鲁普世早期,随着相对海平面升高,上扬子区域为较深水所覆盖,形成非镶边碳酸盐台地环境,以二叠钙藻组合为特征;随着扬子板块南侧台地边缘礁的形成,瓜德鲁普世中晚期转变为镶边碳酸盐台地环境,以翁格达藻组合为特征。Zhenxiong area locates at the west margin of the middle Yangtze Platform,where successive Middle to Upper Permian marine carbonates were deposited.By means of carbonate microfacies analysis,this paper conducted analysis on the biotic assemblages,microfacies types,and sedimentary environments of the Chihsia and Maokou formations in this area.In total,24 types of microfacies were recognized:foraminiferal Pseudovermiporella bioclastic wackstone,spiculitic wackstone,densely packed bioclastic packstone,bryozoan bioclastic packstone,voids echinoderm grainstone,dasyclad foraminiferal packstone,peloids interclast bioclastic grainstone,Permocalculus wackstone,bioclastic fine-crystal dolomite,foraminiferal mudstone,Permocalculus bioclastic packstone,Permocalculus palaeotextularia bryozoan packstone,palaeotextularia bioclastic grainstone,fine bioclastic wackstone,bioturbated fine bioclastic wackstone,spiculitic wackstone,Eugonophyllum bafflestone,bioclastic grainstone with coated and abraded skeletal grains,Ungdarella fusulinid grainstone,poorly reworked wackstone,echinoderm bryozoan grainstone,foraminiferal coralline algae packstone,Gymnocodium bioclastic packstone,and peloids grainstone.The vertical variation of these microfacies indicates that the Chihsia Formation was mainly deposited in a carbonate ramp environment from the late Artinskian to Kungurian and is characterized by the Pseudovermiporella assemblage.The top strata of the Chihsia Formation are composed of dolomites.The microfacies change suggests that a sequence boundary occurs at the top of the Chihsia Formation and is a regional sequence unconformity surface.The carbonate ramp was filled to form a relatively gentle platform during the Chihsia stage.The early Guadalupian deposition was mainly controlled by the large scale of transgression to form an unrimmed carbonate platform which is characterized by the Gymnoporella assemblage.Subsequently the sedimentary environment has been changed into the rimmed carbonate platform where the edge reefs were built around

关 键 词：栖霞组 茅口组 碳酸盐岩微相 碳酸盐缓坡 非镶边碳酸盐台地 镶边碳酸盐台地 

分 类 号：P534.46[天文地球—古生物学与地层学]