矿床地质2025，Vol.44Issue(2)：413-431,19.DOI:10.16111/j.0258-7106.2025.02.009
镇旬盆地南缘淋湘金矿床流体来源及其成因探讨:C-H-O-Fe同位素、磷灰石裂变径迹的证据
Discussion on fluid source and genesis of Linxiang gold deposit in southern mar-gin of Zhenxun Basin:Evidence from C-H-O-Fe isotope and apatite fission track
摘要
Abstract
The Linxiang gold deposit,located on the southern margin of the Zhen'an-Xunyang Basin in the South Qin-ling Mountains,Shaanxi Province,is a typical fine disseminated gold deposit.There are divergent views regard-ing the sources of ore-forming materials and fluids,and the understanding of the metallogenic mechanism re-mains insufficient.This study focuses on quartz and pyrite from the main mineralization stages(Ⅱ-Ⅲ),C-H-O isotope and Fe isotope analyses are conducted,respectively.Additionally,apatite fission track analysis was per-formed on Silurian strata from both sides of the Renhekou-Shuanghezhen fault.The results reveal that during the main mineralization period,the 813CV-PDB values of the Linxiang gold deposit range from-10.59‰ to-9.22‰,δ18OV-SMOW values from 14.06‰ to 15.57‰,δ18OV-SMOW values from-82.10‰ to-68.30‰,and δ18Owater values from 4.52‰ to 8.97‰,indicating that the ore-forming fluids extracted materials from the strata along structural path-ways during migration,with deep magmatic contributions in the late mineralization stage.The δ56Fe values range from-0.87‰ to 0.23‰,and δ57Fe values from-0.43‰ to 0.18‰,suggesting that the ore-forming materials were primarily crust-derived in the early stage,followed by mantle-derived contributions.Fission track analysis shows that the Leishigou area experienced three stages from 120 Ma to the present,while the Nanshagou area underwent four stages.The subduction of the Pacific Plate beneath the Eurasian Plate,closely related to gold mineralization in the Xunyang Basin,persisted until approximately 90 Ma.The far-field effects of the collision between the Indi-an Plate and the Eurasian Plate reached the Renhekou-Shuanghezhen fault around 45 Ma.The total erosion thick-ness is(4.98±0.33)km,with minimal erosion of the ore bodies,indicating favorable deep gold mineralization con-ditions and significant exploration potential.Integrating previous insights into the tectonic evolution of the South Qinling Mountains,this study proposes that abundant Au-bearing metamorphic fluids formed during the Triassic intracontinental orogenic evolution.In the late stage of intracontinental orogeny,the basin basement evolved into an extensional or post-collisional transitional environment,where mantle-derived materials and fluids ascended along deep faults under decompression,providing heat,volatiles,and minor ore-forming materials for the forma-tion of gold deposits.关键词
C-H-O同位素/Fe同位素/裂变径迹/成矿机制/淋湘金矿床/镇旬盆地Key words
C-H-O isotope/Fe isotope/fission track/metallogenic mechanism/Linxiang gold deposit/Zhenan-Xunyang Basin分类
天文与地球科学引用本文复制引用
薛仲凯,范堡程,李航,高永宝,魏立勇,马承..镇旬盆地南缘淋湘金矿床流体来源及其成因探讨:C-H-O-Fe同位素、磷灰石裂变径迹的证据[J].矿床地质,2025,44(2):413-431,19.基金项目
本文得到中国地质调查局地质调查项目(编号:DD20230206403、DD20251173、DD20230060)和新一轮找矿突破战略行动科技支撑项目(编号:ZKKJ202409)联合资助 （编号:DD20230206403、DD20251173、DD20230060）
