关键词: 蚀变分带, 成矿阶段, 斑岩铜矿, 铜陵桂花冲, 安徽省

Abstract:

Guihuachong copper deposit is a porphyry copper deposit newly discovered in the Tongling area, Anhui Province. Lithology of host intrusion is granodiorite porphyry, belonging to metaluminous high potassium calc-alkali granite. Wall rock alteration and mineralization study is an important porphyry deposit mineralization study on migration conducted alteration zone rock for geochemical composition of elements, which is based on the analysis of hydrothermal alteration processes. Wall rock alteration is strong in the Guihuachong mining area, and mainly consists of potassic alteration, sericitization, silicification, chloritization, and carbonatization. Alteration zoning is obvious, occurring potassic alteration, sericitization-silicification, and argillation-propylitization belts in outward succession. Major orebodies occur in the sericitization-silicification belt. Alteration and mineralization process of the hydrothermal stage from early to late is divided into four stages, i.e., potassic alteration, sericitization-silicification, quartz-polymetallic sulfide and carbonate stages. Mineralization took place mainly in the quartz-chalcopyrite sulfide stage. The results of migration quality of components in different alteration zones showed that variation of migration quality in the alteration process is high for the major elements except TiO₂, MnO, MgO and low for the trace elements except Cr and Cu, and rare earth elements are loss in strong mineralization area and enrichment in the zone of mineralization.low for the rare earth elements. The similar chondrite-normalized REE patterns of the intrusion and the altered rocks from the Guihuachong deposit show close connection of the intrusion with mineralization of the deposit and it is the result of continuous action of magmatic fluids.

Key words: alteration zoning, ore-forming stage, porphyry copper deposit, Guihuachong in Tongling, Anhui Province