下扬子早古生代碳酸盐岩微相与沉积环境演化  

Early Paleozoic Carbonate Microfacies and Sedimentary Environment Evolution in the Lower Yangtze Area

作　　者：陈臻 王丽娟[2] 李娟 何佳伟 杨用彪[2] 邓涛 关俊朋[2] 龚海艇 胡修棉[5] CHEN Zhen;WANG LiJuan;LI Juan;HE JiaWei;YANG YongBiao;DENG Tao;GUAN JunPeng;GONG HaiTing;HU XiuMian(State Energy Group Taizhou Power Generation Co.,LTD.,Taizhou,Jiangsu 225300,China;Geological Survey of Jiangsu Province,Nanjing 210018,China;Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;School of Earth Sciences and Engineering,Nanjing University,Nanjing 210093,China)

机构地区：[1]国家能源集团泰州发电有限公司,江苏泰州225300 [2]江苏省地质调查研究院,南京210018 [3]中国科学院南京地质古生物研究所,南京210008 [4]成都理工大学沉积地质研究院,成都610059 [5]南京大学地球科学与工程学院,南京210093

出　　处：《沉积学报》2024年第6期2191-2203,共13页Acta Sedimentologica Sinica

基　　金：江苏省碳达峰碳中和科技创新专项资金(BE2022859,BE2022034)。

摘　　要：【目的】早古生代下扬子地区发育巨厚的碳酸盐岩沉积序列,是油气资源和地热资源有利的潜在储层。2021年,江苏省地质调查研究院在苏北盆地钻探的苏热1井在早古生代碳酸盐岩中成功探获高温干热岩型地热资源,首次发现并证实苏北盆地蕴藏丰富的干热岩资源,这一发现使得一直以来缺乏研究的苏北盆地早古生代碳酸盐岩沉积微相和沉积环境演化得到学术界的广泛关注。【方法】对苏北盆地苏热1井钻孔岩心和南京宁镇山脉地区三条野外露头剖面早古生代碳酸盐岩地层,开展了详细的沉积微相分析,重建了其沉积环境演化,以期为研究区干热岩勘探提供关键的基础地质资料。【结果】根据碳酸盐岩岩性、岩石结构、颗粒组成、生物组合以及沉积构造等特征,将苏热1井钻孔岩心和南京宁镇山脉地区早古生代碳酸盐岩划分为13种沉积微相,主要为潮坪和高能浅滩沉积环境,古水深无明显变化。寒武系幕府山组、炮台山组、观音台组主要为含灰粉晶白云岩(MF1)、粉晶白云岩(MF2)和纹层状粉晶白云岩(MF3),局部见窗格藻黏结白云岩(MF4)、细晶白云岩(MF5)、含灰细晶白云岩(MF7)、角砾白云岩(MF8),缺乏化石,但见纹层结构、鸟眼构造、窗格孔构造等,指示主要为潮间上部和潮上带下部沉积环境。下奥陶统仑山组下部和红花园组主要为云质似球粒灰岩(MF6)、残余砂屑白云岩(MF9)、白云石化鲕粒灰岩(MF10)、残余鲕粒白云岩(MF11)、砂屑灰岩(MF12)和海百合茎鲕粒灰岩(MF13),指示高能浅滩沉积环境。【结论】寒武系幕府山组、炮台山组和观音台组以潮间带环境为主,而下奥陶统仑山组下部和红花园组以浅滩环境为主,古水深相对变深。下扬子地区寒武系观音台组是未来干热岩储层勘探的有利靶区。[Objective]In the Lower Yangtze area,thick Early Paleozoic carbonates are potential reservoirs for oil,gas and geothermal resources.In 2021,well Sure1,drilled by the Geological Survey of Jiangsu province in the Subei Basin,successfully detected high-temperature hot-dry rock geothermal resources in the Early Paleozoic carbonates,bringing the Early Paleozoic carbonate sedimentary microfacies and environmental evolution widespread academic attention.[Methods]A detailed microfacies analysis was conducted on well Sure 1 in Subei Basin and three field outcrops in the Ningzhen Mountains to reconstruct the sedimentary environmental evolution of the Early Paleozoic carbonates in the Lower Yangtze area and provide key basic geological information for the exploration of hot-dry rock geothermal resources in the study area.[Results]Thirteen microfacies,corresponding to peritidal and shoal environments in an inner carbonate platform setting with no significant change in paleowater depth,were identified by integrating sedimentological and paleontological observations.The Cambrian Mufushan Formation and Guanyintai Formation and Early Ordovician Lunshan Formation are mainly silty dolomites with micrite(MF1),silty dolomite(MF2),laminated silty dolomite(MF3),scarce fenestrae bonded dolomite(MF4),fine crystalline dolomite(MF5),fine crystalline dolomite with micrite(MF7).and breccia dolomite(MF8).These strata lack fossils,but laminations,birdeyes,and fenestral structures indicate upper intertidal to lower supratidal environments.The Early Ordovician Honghuayuan Formation is mainly dolomitized peloidal limestone(MF6),intraclastic dolomite(MF9),dolomitized oolitic limestone(MF10),oolitic dolomite(MF11),intraclastic limestone(MF12),and oolitic limestone with echinoderm fragments(MF13),indicating a high-energy shoal environment.[Conclusions]The Cambrian Mufushan Formation,Paotaishan Formation,and Guanyintai Formation were dominated by an intertidal environment,while the lower part of the Early Ordovician Lunshan Formation and the Honghua

关 键 词：下扬子地区 早古生代 碳酸盐岩微相 沉积环境 

分 类 号：P618.13[天文地球—矿床学]