关键词: 喷流沉积, 叠加改造, 矿床成因, 铜铅锌多金属矿, 拉屋

Abstract:

The Lawu copper-lead-zinc deposit in Dangxiong, Tibet, is hosted in the Upper Carboniferous-Lower Permian Laigu Group in the southern part of the Namucuo-Jiali fault belt. The ore bodies are controlled by the Riyinna anticline and faults of different directions. The mineralization in the deposit can be divided into two types, the early layered and laminated and the later veined ores. The derivation of the ore-forming materials and the genesis of the deposit are discussed by studying on the geological characteristics of the deposit, the stable isotope and REE of the ores and their host rocks. It shows that the REE of the host rocks is characterized by weak negative anomalies of Ce/ Ce^* （0.89-0.95）and  moderately depleted Eu/ Eu^* （0.56-0.64）. δ³⁴S  value of the sulfide  is from -2.92‰ to -0.42‰, averaging -1.68‰，indicating that sulfur might come from a deep-source. Hydrogen and oxygen isotope compositions of the fluid inclusions in quartz in the ores indicate that the ore-forming fluid of the deposit was dominantly formed by the mixing of the deeply circulated seawater and the magmatic water at the early period of mineralization. However, the late stage of mineralization was featured by long time of involvement and dominance of meteoric waters. The study shows that the Lawu copper-lead-zinc deposit belongs to a sedimentary exhalative Cu-Pb-Zn deposit superimposed by the Yanshanian magmaic hydrothermal activity.

Key words: sedimentary-exhalative, superimposition reformation, deposit genesis, copper lead zinc mines, Lawu