Discussion on the Relationship Between the Longwangshan Granite Mass and the Huashixia W-Mo Deposit in the Transitional Belt of Northdern-Central Qilian

The Huashixia tungsten-molybdenum deposit is located in Huzhu County, Eastern Qinghai Province, which is tectonically ocurred in the southern margin of North Qilian orogenic belt. This deposit belongs to a typical skarn-type W-Mo deposit, which is related to the magma intrusion. In this paper, the LA-ICP-MS zircon U-Pb dating method has been used to study the chronology of monzonite granites from the peripheral area of the Huashixia W-Mo deposit, obtained an U-Pb age of (418.2±1.1)Ma. The geochemical results show that these monzonite granites belong to high potassium cal-alkaline series, with LREE enrichment and HREE loss. Their δEu values vary from 0.50 to 0.88, with weak negative Eu anomaly. The trace element results suggest that these granites are enriched in large ion lithotropic elements, but depleted in high field elements and heavy rave earth elements. Geochemical characteristics indicate that the Longwangshan granite was the product of plate collision and sourced from lower crust, belonging to I-type granite. The isotopic results of the Longwangshan granite indicate that the ore-forming period of the Huashixia W-Mo deposit is similar to the ones of magmatic intrusion, and both of them were formed in Late Silurian Epoch. The Longwangshan monzonite granite had provided the heat and material sources for the formation of the Huashixia deposit.