新疆和田县大红柳滩一带花岗伟晶岩型稀有金属矿成矿地质特征、成矿时代及找矿方向

Metallogenic Geological Characteristics,Mineralization Age and Resource Potential of the Granite-Pegmatite-Type Rare Metal Deposits in Dahongliutan Area,Hetian County,Xinjiang

大红柳滩一带是帕米尔-昆仑山伟晶岩区中花岗伟晶岩分布最为集中、稀有金属成矿潜力最好的地区。近年来,该地区伟晶岩型稀有金属矿获得一系列找矿突破,引起了广大学者的广泛关注。笔者以新近发现的4处锂矿为重点,对矿床地质特征进行了研究,分析了区域伟晶岩的分带性特征,总结了控矿条件及找矿标志,并利用锡石LA-MC-ICP-MS U-Pb测年法获取含矿伟晶岩的206Pb/207Pb-238U/207Pb等时线年龄为(223±11)Ma(N=44,MSWD=2.1),207Pb/206Pb-238U/206Pb Tera-Wasserburg谐和年龄为(223.5±7.9)Ma(N=44,MSWD=6.7),表明伟晶岩的形成时代为晚三叠世,与区域花岗岩的形成时代基本一致。认为大红柳滩地区成矿地质背景、成矿时代及成矿地质特征与川西甲基卡矿田相似,外围及深部找矿潜力巨大。

The Dahongliutan is the most concentrated distribution of granite pegmatite and the best metallogenic potential of rare metals in the Pamir-Kunlun pegmatite area.In recent years,a series of ore-prospecting breakthroughs of pegmatite-type rare metals deposits have been made in this area,which has attracted the scholars'extensive attention.Based on the newly discovered four lithium deposits,the geological characteristics of these deposits has been studied,the regional zoning characteristics of pegmatite has been analyzed,and the ore-controlling conditions and prospecting criteria of these deposits have been summarized in this paper.By using cassiterite LA-MC-ICP-MS U-Pb dating method,the 206Pb/207Pb-238U/207Pb isochron age and 207Pb/206Pb-238U/206Pb Tera-Wasserburg concordia age of ore-bearing pegmatite have been obtained,they are(223+11)Ma(N=44,MSWD=2.1)and(223.5+7.9)Ma(N=44,MSWD=6.7),respectively,indicating that the pegmatite was formed in the Late Triassic.These ages are basically consistent with the formation age of regional granite.Thus,it is considered that the lithium deposits in Dahongliutan area are similar to the lithiun deposits in Jiajika ore field of West Sichuan in terms of metallogenic geological background,metallogenic epoch and metallogenic geological characteristics,and that the periphery and deep part of Dahongliutan area has tremendous prospecting potential.