扬子地台西缘铅锌矿床分布规律及矿源层探讨  

Space-Time Distribution,Source Bed and Stratabound Mechanisms of Zn-Pb Deposits in Western Margin of Yangtze Platform

作　　者：陈大 

机构地区：[1]贵州省有色金属和核工业地质勘查局地质矿产勘查院,贵阳550005

出　　处：《吉林大学学报（地球科学版）》2015年第5期1365-1383,共19页Journal of Jilin University：Earth Science Edition

基　　金：中国科学院知识创新工程重要方向项目群(KZCX2-YW-Q04-05);中国地质调查局全国矿产资源潜力评价项目(资〔2007〕038-01-23号)

摘　　要：为探索川滇黔相邻区铅锌矿床之成因规律,提升成矿理论认识及预测找矿效果,通过对区内铅锌矿床分布规律研究得出如下认识:1)发现矿床(点)之集群分布趋势,据此将成矿区域划分为3个矿集区;2)统计发现,震旦系和石炭系具有较高的成矿机率(51.57%),灯影组和摆佐组汇聚了区域80.98%的金属量;3)构造单元分级控制了成矿单元展布,而矿集区与二级构造单元之间具有不完全的对等性,矿集区Ⅰ、Ⅱ由康滇地轴和龙门山拗陷及二者向上扬子区域跨越地带联合控制;4)根据菱(赤)铁矿与铅锌矿空间耦合,以及菱(赤)铁矿伴生铅锌元素、铅锌矿物含量均较高等现象,论证了在盆地演化早期,古陆边缘拗陷带(或海盆)内之次级单元代表了浅海环境之低能较深水凹(断)陷或海湾环境,沉积了古生界志留系兰多维列统特列奇阶至下石炭统德坞阶和中元古界下昆阳群(会理群)两套含铁建造,形成了区域Pb、Zn成矿金属元素的初始富集,并于成岩-后生期经热液流体循环改造而成矿,含铁建造提供了成矿的主要矿质来源;5)本区成矿物质硫源-膏盐层主要赋存于灯影组和摆佐组下伏地层以及寒武系多个层位;6)矿源层、硫源共同决定了矿集区以及层控的形成机制,并成为控制其分布的决定性因素。In order to find the metallogenic pattern of the Zn-Pb deposits at the junction of Sichuan,Yunnan,and Guizhou provinces,comprehend the metallogenic theory and predict ore prospecting,the author studied the space-time distribution of these Zn-Pb deposits in this area.The conclusions are listed as follows：1）Zn-Pb deposits are distributed together,and can be divided into three ore-concentration areas.2）Statistically,Sinian and Carboniferous stratum have a higher metallogenic probability of 51.57%,and Dengying and Baizuo Formation hold 80.98% metal reserve.3）Tectonic units control thedistribution of ore-forming units,but ore-concentration area does not correspond to the second tectonic unit at all.Ore-concentration area Ⅰ and Ⅱ are jointly controlled by Kangdian axis,Longmenshan depression,and cross region of Yangtze platform.4）The space coupling between siderite（hematite）deposits,lead-zinc deposits,and close association of Pb-Zn minerals with siderite（hematite）indicate the genetic relationship between Zn-Pb deposits and Fe deposits.During the early stage of basin evolution,at the depression belt（or sea basin）in the edge of the ancient land mass,two types of iron formations were formed from Llandovery Telychian stratum of Silurian to Dewuan stratum of the Lower Carboniferous and the Lower Kunyang Group（Huili Group）in the middle of Proterozoic.Ore-forming elements,such as Pb and Zn,are pre-concentrated and further enriched by the later circulated hydrothermal fluids during diagenesis to form the deposit.Iron-formations provided the main oreforming materials for Pb-Zn deposits.5）The sulfur source,gypsum beds,is derived from the underlain Cambrian stratum of Dengying and Baizuo Formations.6）Both ore-forming elements and sulfur source beds control the formation of ore concentration areas and the strata bound distribution of orebodies,which are considered to be the most important controlling factors.

关 键 词：扬子地台 铅锌矿床 矿源层 含铁建造 矿集区 

分 类 号：P618.4[天文地球—矿床学] P62[天文地球—地质学]