Isotope geochemistry, chronology and genesis of the Yangshan gold deposit, Gansu
Isotope geochemistry, chronology and genesis of the Yangshan gold deposit, Gansu
复制标题
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Qi Jin-zhong
中科院分区：
文献类型：
--
作者：
Qi Jin-zhong
阳山金矿床位于川陕甘交界地区，是中国新近发现的超大型细浸染型金矿床。矿石中石英细脉的δ D和δ~(18)O_（H2O）分析表明，矿床流体以岩浆水为主；各种硫化物的δ~(34)S分析表明，金矿区沉积硫和岩浆硫共存，δ~(34)S差异显著，矿石中金属硫化物中的硫主要为岩浆成因。δ~(14)C分析表明，金矿床中既有岩浆成因碳，也有沉积碳。K-Ar、~(39)Ar-~(40)Ar、Rb-Sr和U-Pb同位素测年表明，斜花岗斑岩脉起源于早侏罗世，此外，金矿区还存在早白垩世和早古近纪的隐伏侵入体，其相关热液活动也表现出反复出现的特征。在此基础上，作者进一步对矿床成因进行了探讨，认为该区泥盆系形成了一系列热液碳质、硅质和泥质沉积物，金主要集中在印支期变质作用的区域性低变质作用过程中；此后该区发生多次岩浆活动，成矿流体和成矿物质沿安昌河—瓜音坝断裂迁移，在有利的构造部位集中堆积，形成了阳山金矿床。
The Yangshan gold deposit,located in the Sichuan-Shaanxi-Gansu border region,is a superlarge finely disseminated gold deposit recently found in China.δ D and δ~(18)O_(H2O) analysis of quartz veinlets in ores shows that the ore fluids of the deposit are dominated by magmatic water,and the δ~(34)S analysis of various sulfides indicates that sedimentary sulfur and magmatic sulfur coexist in the gold district and show significant difference in δ~(34)S, while the sulfur in metal sulfides in the ores is mainly of magmatic origin.δ~(14)C analysis indicates that both magmogenic carbon and sedimentary carbon exist in the gold deposit.K-Ar,~(39)Ar-~(40)Ar,Rb-Sr and U-Pb isotopic datings show that plagiogranite porphyry dikes originated in the Early Jurassic,and in addition,Early Cretaceous and early Paleogene buried intrusions do also exist in the gold district and their related hydrothermal activities also exhibit the feature of repeated occurrence.Based on the data and other analyses,the authors further discuss the genesis of the deposit and think that:a sequence of hydrothermal carbonaceous,siliceous and argillaceous sediments formed in the area in the Devonian and gold was primarily concentrated in the process of regional low-grade metamorphism in the Indosinian metamorphism; afterwards multiple magmatic activities occurred in the district and their related ore fluids and materials migrated along the Anchanghe-Guayinba fault and were concentrated and stacked in favorable structural sites,thus resulting in the formation of the Yangshan gold deposit.