Scheelite geochemical signature and calcite Sm-Nd dating of the Xianggou Au-W deposit in south Qinling orogen, central China: Constraints on the ore-forming process

The Xianggou scheelite deposit, discovered in the Wangjiaping-Longtougou-Xiajiadian gold metallgenic belt in recent years, is another new geology survey progress in south Qinling related to W mineralization. The composition of scheelite was analyzed by LA-ICP-MS, together with Sm-Nd isotope dating of symbiotic calcite, to clarify the origin of Xianggou scheelite. The results show that scheelite exists in three generations, from the early rhythmic zonal scheelite to the late aggregate one, indicating that the scheelite undergone multiple migrations. The scheelites have high F content with low Au content. The total amount of rare earths is high, ranging from 5.44×10^-6 to 382.67×10^-6, with an average of 95.48×10^-6. The REE pattern is flat without MREE enrichment, with negative Eu anomaly, similar to the type Ⅱ REE type classified by Ghaderi et al. (1999). All these data support that the W mineralization in the Xianggou area might be related to W-bearing quartz vein with genetic links to magmatic hydrothermal activities. The Sm-Nd isotope dating result of the symbiotic calcite (195 Ma) indicates that the deposit was formed in the late Indosinian.