世界核地质科学2025，Vol.42Issue(6)：1227-1238,12.DOI:10.3969/j.issn.1672-0636.2025.06.007
北秦岭东段商丹地区花岗岩型铀矿成矿流体特征及来源探讨
Discussion on the characteristics and sources of ore-forming fluids in granite-type uranium deposits in Shangdan area,eastern segment of north Qinling
摘要
Abstract
The Shangdan area,located in the eastern segment of the North Qinling metallogenic belt,is an important uranium mineralization concentration zone in China.The area is bounded by the Watershed fault,with pegmatite-type uranium deposits developed to the north and granite-type uranium deposits to the south.Previous research has primarily focused on pegmatite-type deposits,while studies on granite-type deposits are relatively limited,having focused mainly on the metallogenic geological background,structural ore-controlling mechanisms,petrogeochemistry,and isotopic geochronology,with no studies reported on the characteristics and sources of the ore-forming fluids.Based on detailed field investigations,this study focused on fluid inclusions and C-O isotopes in calcite from the metallogenic period.The results indicated that the fluid inclusions in calcite from the granite-type uranium mineralization period in the Shangdan area were primarily two-phase aqueous inclusions.The homogenization temperatures ranged from 78 ℃ to 132 ℃,with salinities between 1.74%and 7.74%NaCleqv.Calculated values indicated an ore-forming fluid density of 0.96-1.02 g·cm-3,a mineralization depth of 0.19-0.39 km,and an ore-forming pressure of 5.65-11.61 MPa,classifying it as an epithermal uranium deposit.The ore-forming fluids were characterized by low pressure,low salinity,and moderate density.C-O isotope analysis revealed that the δ¹³CV-PDB and δ18OV-SMOW values of calcite from the mineralization period ranged from-4.8 ‰ to-0.3 ‰,and 15.5 ‰ to 17.8 ‰,respectively,suggesting that the initial ore-forming fluids were likely derived mainly from marine carbonate rocks of the Yanlinggou formation(Pt1y)in the Qinling Group.关键词
花岗岩型铀矿/包裹体特征/流体来源/C-O同位素/商丹地区Key words
granite-type uranium deposit/inclusion characteristics/fluid origin/C-O isotopes/Shangdan area分类
天文与地球科学引用本文复制引用
ZHANG Liang,WANG Jiangbo,WU Zhengqian,LIU Kunpeng,PEI Liuning,YU Teng,ZHAO Youdong..北秦岭东段商丹地区花岗岩型铀矿成矿流体特征及来源探讨[J].世界核地质科学,2025,42(6):1227-1238,12.基金项目
中国核工业地质局铀矿地质项目(编号:202217、202417-2、202417-1),陕西省自然科学基础研究计划(编号:2024JC-YBMS-235)联合资助 Supported jointly by Uranium Geology Project of the Nuclear Industry Geological Bureau of China(No.202217,202417-2,202417-1),National Science Basic Research Program of Shaanxi Province(No.2024JC-YBMS-235). （编号:202217、202417-2、202417-1）
