Geochemistry,monazite geochronology,and metallogenic relation of Kajiya two-mica granite and rare-metal pegmatite in Zhawulong deposit,western Sichuan Province,China
Rare lithium-beryllium metals are critical resources,both nationally and globally.The United States,Australia,and Japan have long listed Li-Be minerals among the raw materials prohibited for export,which only strengthens their strategic potential.In China,Li-Be mineral resources are not only abundant but also possess a superior metallogenic setting.However,their distribution is uneven and often covered by substantial Quaternary deposits.In recent years,field research has shed light on the presence of extensive granitic pegmatite lithium deposits in the Tianshuihai-Songpan-Ganze orogenic belt,thereby capturing the attention of both the domestic and international scholarly communities.The prominent Zhawulong granitic pegmatite lithium deposit in Shiqu County,western Sichuan Province,lies in the middle part of this orogenic belt.Identifying the main controlling factors of lithium resource accumulation and the rules of rare metal enrichment for this deposit will provide a foundation and guidance for the next stage of strategic prospecting along the Tianshuihai-Songpan-Ganze orogenic belt.This study presents a comprehensive analysisof systematically sampled lithologies,including spodumene-albite pegmatite dike,muscovite-albite pegmatite,tourmaline-albite pegmatite dike,Kajiya two-mica granite pluton,fibrous tourmaline aplite,and staurolite-biotite schist from the pluton's periphery.LA-ICP-MS monazite U-Th-Pb isotope dating precisely identifies the formation age of the ZhawulongKajiya two-mica granite in the Late Triassic at 213～211 Ma,followed by fibrous tourmaline aplite at～210 Ma,muscovite-albite pegmatite at 210～200 Ma,and Li-rich pegmatite at～205 Ma.Combined with previous geochronological data,our analysis suggests a narrative of progressive formation from the two-mica granite and fibrous tourmaline aplite to the muscovite-albite pegmatite and spodumene-albite pegmatite.After 210 Ma,the magma gradually transitioned to the magma-hydrothermal stage,with an approximate 10 Ma period of continuous and multistage magmatic-hydrothermal activities.The observed geochemical trends,including decreasing REE,K/Rb,Nb/Ta,and Zr/Hf ratios from granite to pegmatites,coupled with negative Nd and Eu anomalies in the monazite from highly evolved pegmatite,collectively underscore the pivotalrole of granitic magma crystallization and differentiation in the process of rare metal enrichment for the Zhawulong deposit.
Tianshuihai-Songpan-Ganze orogenic beltgneiss domerare metal pegmatitegranitemetallogenic mechanism
万方数据
维普
