Geology and mineralization of the Songpan-Ganze-West Kunlun pegmatite-type rare-metal metallogenic belt in China:An overview and synthesis  

作　　者：Jiankang LI Peng LI Qinggao YAN Denghong WANG Guangli REN Xin DING 

机构地区：[1]MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China [2]Xi’an Center of Geological Survey,China Geological Survey,Xi’an 710054,China [3]School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China

出　　处：《Science China Earth Sciences》2023年第8期1702-1724,共23页中国科学（地球科学英文版）

基　　金：supported by the Chinese National Key R&D Program (Grant No. 2019YFC0605200);the National Natural Science Foundation of China (Grant Nos. 41872096 and 42002109);the China Geological Survey Project (Grant Nos. DD20221684 and DD20230289)。

摘　　要：The Songpan-Ganze orogenic belt on the northeastern margin of the Tibetan Plateau extends westward from the Songpan-Ganze terrain in western Sichuan to the Tianshuihai region in West Kunlun,Xinjiang.It hosts numerous giant spodumene pegmatite deposits and ore fields,including Jiajika and Ke’eryin in western Sichuan Province,Zhawulong on the border between the Sichuan and Qinghai Provinces,and Dahongliutan in Xinjiang Region.These form the Songpan-Ganze-West Kunlun(SP-GZ-WK) pegmatite-type rare-metal metallogenic belt.The pegmatite type rare-metal deposits in this belt are hosted in the metamorphic thermal domes in the metamorphosed flysh of the Triassic Xikang and Bayankalashan Groups.The mineralized pegmatites are intimately related to the Li-and volatile-rich two-mica granites that are peraluminous and have high(Li+Na+K)/(Mn+Fe+Mg+Ca+Ti) ratios.Pegmatites and granites in individual ore field throughout the belt typically form a cogenetic granite-pegmatite system,in which pegmatite dikes commonly surround granites.Spodumene is the predominant ore mineral in most pegmatites with limited hydrothermal alteration.In the granite-pegmatite systems,granitic magmas were emplaced under P-T conditions of 800–850°C and ~550 MPa,while spodumene crystallized in an alkaline environment.The granite-pegmatite systems share similar Sr-Nd-Hf-Li isotopic compositions to the metasediments of the Xikang and Bayankalashan Groups.The δ7Li values tend to increase from the granites to the Li-poor pegmatites,whereas the reverse is observed between the Li-poor and Li-rich pegmatites.These geochronological data suggest that the granite-pegmatite systems formed in the Late Triassic and tend to be progressively younger from the outer to the inner zones of the metallogenic belt.These characteristics show that the granitic-pegmatitic melts were derived from the anatexis of the Xikang and Bayankalashan Groups during the Paleo-Tethyan orogeny in the Late Triassic.The separation of pegmatitic melts from granitic magmas can be best explained

关 键 词：Songpan-Ganze-West Kunlun metallogenic belt Rare-metal deposit Granitic pegmatite SPODUMENE Metallogenic regularity 

分 类 号：P618.6[天文地球—矿床学]