Geochemical characteristics and LA-ICP-MS zircon U-Pb dating of ore-bearing granite of Chuankou intrusion-related tungsten deposit, Hunan Province

The tungsten deposits in the Chuankou orefield occur in the outer contact zone and the inner part of the Chuankou pluton. The deposit types are mainly quartz-veinlet belt type and quartz-big vein type of magmatic-hydrothermal origin. In recent years, a breakthrough in prospecting has been made in the Chuankou orefield, and a new type of intrusion-related tungsten deposits has been found. In this paper, LA-ICP-MS zircon U-Pb dating and rock geochemical characteristics of biotite adamellite and ore-hosting rock muscovite monzogranite are studied. The diagenetic age of the Chuankou pluton is (223.1±0.78) Ma, MSWD=0.98, n=24, and the ore-forming age of the intrusion-related tungsten deposit is (224.6±1.31) Ma, MSWD=0.33, n=9, all of which are in Indosinian period. The Chuankou granite is characterized by high SiO₂ and K₂O + Na₂O, low CaO and MgO. It belongs to the peraluminous high-K calc-alkaline series S-type granites, which was formed under the weak compression tectonic system in the collision environment. The Chuankou pluton is characterized by low total REE (∑REE), relatively rich LREE, strong negative Eu anomaly, enrichment of large ion lithophile elements Ba, K, and high field strength element Ta, and depletion of large ion lithophile elements Sr and compatible elements P, Ti, which indicates that the granites of each stage of the granites came from the same magma source and experienced a high degree of evolution. Compared with other granites, the ore-bearing granite (muscovite monzogranite) with lower δEu value and (La/Yb)_N value has a higher crystallization differentiation degree.