Geochemical Characteristics and Indication Significance of Jinshachang Lead-zinc Deposit,Yunnan Province
The Sichuan-Yunnan-Guizhou lead-zinc ore cluster at the southwest margin of the Yangtze Plate is an important part of the large area of low-temperature metallogenic field in southwest China.The Jinshachang lead-zinc deposit is one of the typical deposits in the Sichuan-Yunnan-Guizhou lead-zinc ore cluster.Some studies have been carried out on the sources of metals and the characteristics of ore-forming fluids in the Jinshachang lead-zinc deposit.However,the contribution of surrounding rocks to mineralization and the genesis of the deposits are still unclear.In view of this problem,trace element compositions of sphalerite and surrounding rocks in the deposit were systematically analyzed.According to the REE characteristics of surrounding rocks and fluorite,the contribution of the surrounding rocks to mineralization was discussed and the genesis of the deposit was determined.The study shows that sphalerite is characterized by high Cd,Ge,Cu and Ga contents and low Fe,Mn,In,Co and Ni content,which are mainly formed and enriched in sphalerite due to isomorphous substitution.The contents of elements such as Cu and Ge vary greatly,which may be related to the low-temperature fluid.The multicolor sphalerite from the deposit may be attributed to the synergistic effect of Cu,Ge,As,Ag and other elements.The surrounding rocks near the ore-forming end are enriched in Zn,Pb,Ba,Cd and other elements,which are also enriched in the sphalerite,indicating that the surrounding rocks provide some metallic elements for mineralization.Fluorite inherits the negative Eu and Ce anomalies of the surrounding rocks and is affected by the ore-forming fluids with highly negative Ce anomalies.The fluorite has a higher Y/Ho ratio than the surrounding rock,indicating that part of the Y in fluorite originates from the surrounding rock,resulting in the fluorite having a higher Y/Ho ratio.Overall,the sulfur trace element composition of sphalerite in this deposit is consistent with that of MVT type deposits,which is obviously different from exhalative sedimentary deposits,magmatic hydrothermal deposits and distant source skarn-type deposits.The metallogenic temperature belongs to the low-temperature range.Combined with the geological and geochemical characteristics of the deposit,this study inferred that the Jinshachang lead-zinc deposit belongs to the MVT Pb-Zn deposit.
Jinshachang Pb-Zn depositsphaleritesurrounding rocktrace elements and rare earth elementsgenesis of mineral deposit
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