西北地质2026，Vol.59Issue(1)：130-145,16.DOI:10.12401/j.nwg.2024008
柴北缘赛坝沟金矿床成因探讨:来自流体包裹体及H-O-S-Pb同位素证据
Genesis of the Saibagou Gold Deposit in the Northern Margin of Qaidam:Evidence from Fluid Inclusions and H-O-S-Pb Isotopes
摘要
Abstract
The Saibagou gold deposit,located in the Wulan area,eastern part of the northern Qaidam metallo-genic belt,is one of the representative gold deposits in the northern Qaidam metallogenic belt.Recently,new breakthroughs have been made in prospecting at the deep and peripheral areas,but the genetic mechanism of the deposit is still controversial.Fluid inclusions and H-O-S-Pb isotopes of gold-bearing quartz veins from the Saibagou deposit are examined in this study.The results show that the fluid inclusions in the Saibagou gold de-posit are mainly characterized by gas-liquid two-phase inclusions and CO2-bearing three-phase inclusions.The homogenization temperature of the inclusions ranges from 200℃to 320℃,the salinity ranges from 0.18%Na-Cleqv to 14.67%NaCleqv,and the fluid density ranges from 0.67 g/cm3 to 1.13g/cm3.These lines of evidence sup-port an ore-forming fluid characterized by medium temperature,medium-low salinity and low density,and be-longing to the H2O-NaCl-CO2 system.The δDV-SMOW values are between-75.1‰ and-65.2‰,and δ18OH2O val-ues are between 2.3‰ and 3.3‰,suggesting that the ore-forming fluid is mainly derived from magmatic water with a small amount of metamorphic fluid.S isotope studies show that δ34S of pyrite is between-2.52‰ and 2.61‰,which is within the composition range of meteorite S,reflecting that the sulfur in the deposit mainly comes from deep mantle,which may be related to magmatic activity.The pyrite 206Pb/204Pb ranges from 18.031 4 to 18.250 3,the 207Pb/204Pb ranges from 15.590 7 to 15.730 8,and the 208Pb/204Pb ranges from 38.172 6 to 38.432 6,indicating that Pb is mainly derived from magmas,and to a lesser extent,the Cambrian-Ordovician strata.Com-bined with the geological characteristics,fluid inclusions and H-O-S-Pb isotope research results,as well as the regional tectonic evolution background,it can be concluded that the Saibagou gold deposit is an orogenic gold deposit formed by continental collision between the Qaidam Block and Olongbuk Block and its genesis is close-ly related to the dike activities in the mining area.关键词
流体包裹体/H-O-S-Pb同位素/矿床成因/赛坝沟金矿/柴北缘/青海省Key words
fluid inclusion/H-O-S-Pb isotope/genesis of deposit/Saibagou gold deposit/northern Qaidam/Qinghai Province分类
天文与地球科学引用本文复制引用
苏生顺,张勇,林贵,舒树兰,刘永乐,张大明,刘智刚,赵芙蓉..柴北缘赛坝沟金矿床成因探讨:来自流体包裹体及H-O-S-Pb同位素证据[J].西北地质,2026,59(1):130-145,16.基金项目
国家自然科学基金重大研究计划项目(92062217),青海省"昆仑英才·高端创新创业人才"项目(青地矿科[2022]32号)和"青海省乌兰县阿哈大洼地区1∶2.5万地质矿产调查"(2022012015jc009)联合资助. （92062217）
