The source of uranium minerals in Huayangchuan area of North Qinling

The Huayangchuan uranium deposit is located at the sandwiched part of the Laoniushan and the Huashan pluton.The ore body is strictly controlled by the NW-SE-trending Huayangchuan brittle-ductile shear zone.The ore-bearing rocks are mainly quartz carbonatite, followed by pegmatite.There have been no more credible research results on the material source of Huayangchuan uranium deposit.This study systematically collected airborne, geological, drilling, and metallurgical data, and used surface radioactive geophysical prospecting, geology, zircon U-Pb dating and other methods to calculate the radioactive energy spectrum characteristics and age characteristics of each plastid body (unit), study the structure distribution law of rock mass and dyke rock and the migration law of radioactive elements, and reveal the source of ore-forming materials of Huayangchuan uranium deposit.The characteristics of the surface gamma spectrum show that the content of the Wengyu granite of the Huashan pluton is 4.82×10^-6~6.46×10^-6, the thorium content is 23.03×10^-6~31.08×10^-6, and the Th/U ratios are 5.29~6.00.The uranium content of the main rock units of the Niushan pluton is 9.27×10^-6~11.18×10^-6, the thorium content is 24.39×10^-6~27.72×10^-6, the Th/U ratios are 2.64~3.55, both of which have the characteristics of high uranium and thorium.Geochemical characteristics of the Huashan pluton and the Laoniushan pluton are similar to adakitic rocks, which are the same source and rich uranium bodies of different stages.However, the Wengyu granite of the Huashan pluton has obvious uranium source characteristics.Radioactive aerial geophysical characteristics show that the ductile shear zone in Huayangchuan mining area has the characteristics of uranium migration and enrichment.Based on the geochronological background research, the diagenetic age of the Wengyu granite of the Huashan pluton is the same as that of the ore-bearing quartz carbonate in the Huayangchuan mining area, both formed in 235~200 Ma.The bottom of the multi-stage sub-brittle-ductile shear zone which is formed from the first land-making event (ca.1800 Ma) to the Indosinian period is directly connected to the Huashan pluton, which provides favorable conditions for the migration of activated uranium.Combined the above research, the author believes that after the uranium element in the Wengyu granite of the Huashan Pluton is activated and migrated, it provides a large amount of uranium source for the Huayangchuan uranium deposit.