Skarn Mineral Characteristics of the Ahetala Copper Deposit and Its Geological Significance

The Ahetala copper deposit is located in Arheqi County, Xinjiang Uygur Autonomous Region. It is located in the South Tianshan orogenic belt, northern margin of Tarim Basin. The deposit belongs to a typical skarn type deposit.

In order to determine the types of skarn minerals, as well as the metallogenic process and environment of the deposit.

Based on detailed field and indoor microscopic observations, electron probe microanalysis (EPMA) was carried out to determine the chemical composition of skarn minerals in the Ahetala copper deposit. RESULTS: The results showed that the skarn minerals were garnet, pyroxene, wollastonite, chlorite and epidote. The EPMA results showed that garnets were grossular and andradite. Pyroxene was diopside (Di_77.74-95.46), chlorite was minnesotaite. The Mn/Fe value of diopside was 0.00-0.12, indicating the copper mineralization of this deposit.

The skarn of the Ahetala copper deposit is a typical calcium skarn of metasomatic skarn. According to the mineral paragenetic association and metasomatism, the mineralization stages of the deposit can be divided into early skarn stage, late skarn stage (retrograde alteration), oxide stage and early sulfide stage. From the skarn period to the quartz-sulfide period, the metallogenic environment generally underwent changes from the high temperature, high oxygen fugacity, intermediate-acidic, weak oxidizing-weak reducing environment, to the low temperature, high sulfur fugacity, alkaline reducing environment.