Cassiterite U-Pb Dating of No.134 Pegmatite Vein in the Jiajika Rare Metal Deposit, Western Sichuan and Its Geological Significances

BACKGROUND The pegmatite lithium deposit has become important for modern industries with strategic value, which is a key mineral resource in urgent need in China. However, the mineralization age restricts the research on the mineralization process and mechanism of this type of lithium deposit. The Jiajika rare metal deposit is the largest pegmatite lithium deposit of China in the western Sichuan, and the No.134 vein is the most typical pegmatite vein. The No.134 pegmatite vein is mainly composed of spodumene, tantalite, zircon, beryl, cassiterite, plagioclase, orthoclase, quartz and muscovite. OBJECTIVES To accurately constrain the mineralization age of the No.134 pegmatite vein. METHODS Laser ablation-multiple collector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) U-Pb geochronology was used on cassiterite. RESULTS The concordant age in the ore samples was 203.7±4.6Ma, which represented the mineralization age of No.134 pegmatite vein. This age indicated mineralization in the Late Indosinian period. CONCLUSIONS The stable tectonic environment in the Late Indosinian movement is the favorable condition for accumulation and mineralization of rare metals, which is beneficial for the formation of the super-large Jiajika rare metal deposit.