滇东北羊场磷矿床成因与找矿前景  

Genesis and prospecting potential of Yangchang phosphorus deposit in north⁃eastern Yunnan Province

作　　者：胡清华 周骞 夏建峰 黄太平 王玉卿 王云晓 段文婷 HU QingHua;ZHOU Qian;XIA JianFeng;HUANG TaiPing;WANG YuQing;WANG YunXiao;DUAN WenTing(Yunnan Institute of Geological Survey,Kunming 650216,Yunnan,China;MNR Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,Kunming 650051,Yunnan,China;Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,Kunming 650051,Yunnan,China;Kunming University of Science and Technology,Kunming 650200,Yunnan,China;Yunnan Geological Survey Foundation Management Center,Kunming 650224,Yunnan,China)

机构地区：[1]云南省地质调查院,云南昆明650216 [2]自然资源部三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [3]云南省三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [4]昆明理工大学,云南昆明650200 [5]云南省地质勘查基金管理中心,云南昆明650224

出　　处：《矿床地质》2024年第5期1127-1148,共22页Mineral Deposits

基　　金：云南省地质勘查基金项目(编号:D202001、D202101、K202301、Y202301)资助。

摘　　要：云南镇雄县羊场磷矿经地勘工作测算确认为大型隐伏磷矿床,已探获资源量27亿t,远景资源量超百亿t。磷矿体赋存于寒武系梅树村组碳酸盐岩-泥质碎屑岩沉积建造中部的一套含磷岩系中,岩性以磷质岩和磷块岩为主,少量含磷灰质白云岩和含磷硅质白云岩。矿体产状与地层产状一致,呈层状、似层状展布于近东西向延伸的宽阔羊场箱状背斜两翼。钻探数据表明:矿体平均厚度达34 m,磷(w(P_(2)O_(5)))平均品位达24.3%,埋深450~1500 m;矿石主要矿物氟磷灰石(胶磷矿)形成于陆表海海底封闭或半封闭的还原环境,在海水氧化还原界面附近析出;成矿过程包括生物化学沉积,成岩以及物理富集3个阶段。已有研究表明,该磷矿形成于上扬子西南缘的滇东被动陆缘昭通陆棚半封闭的浅水台地相中,磷矿层的形成受古构造、沉积环境及岩相古地理条件控制,地层与构造控矿明显。在“成磷盆地-聚磷沉积相-磷矿层”的磷矿找矿思想指引下,综合成矿地质背景、矿床成因、控矿因素和区域成矿地质条件,笔者认为羊场磷矿所在的镇雄-威信地区,因与羊场相似的沉积相和地层层序,找矿前景巨大。文章为该区早寒武世海相沉积型磷矿的找矿提供理论依据与对比线索。The Yangchang phosphate deposit in Zhenxiong County has been confirmed as a super-large hidden phosphate deposit,and the explored resource is exceeding 2.7 billion tons and potential resource exceeding 10 billion tons.The phosphate orebodies occur in a set of phosphorous-bearing in the middle part of a carbate-argillaceous clastic sedimentary Formation of the Cambrian Newfoundland System Meishucun Formation.The lithology is dominated by phosphorous rock and phosphate rock,with a small amount of phosphorous-bearing dolomite and siliceous dolomite.The occurrence of the orebodies are consistent with that of the stratum,and it is distributed in layered and/or quasi layered that occurred in two sides of the Yangchang broad anticline with nearly East-West extension.The drilling data indicate that the average thickness of the orebodies is 34 m,the average grade of phosphorus w(P_(2)O_(5))is 24.3%,and the buried depths are 450~1500 m.The dominant mineral phase,fluorapatite(collophanite),is formed in a closed or semi-closed sea and precipitates near the REDOX interface of seawater.The metallogenic process includes three stages:biochemical deposition,diagenesis and physical enrichment.Previous studies have shown that the phosphate deposit formed in a semi-enclosed shallow platform facies of the Zhaotong shelf in a passive continental margin of eastern Yunnan,which is controlled by paleostructure,sedimentary paleoenvironment,and lithofacies or paleogeographic conditions.Stratigraphic and structural ore control effects are obvious.Comprehensive study of metallogenic geological background,ore genesis,ore control factors and regional metallogenic geological conditions,the authors views that the Zhenxiong-Weixin region where Yangchang phosphate deposit is located has great prospects and resource potential based on the similar sedimentary facies and stratigraphic sequence.This study provides theoretical basis and comparative clues for prospecting for phosphate deposits in the Early Cambrian marine sedimentary facies in this regi

关 键 词：磷块岩矿体 羊场背斜 梅树村组 羊场磷矿 镇雄-威信 

分 类 号：P619.2[天文地球—矿床学]