Geochemical characteristics and genesis of the Zhuoma lead-zinc deposit in Yunnan Province

Abstract: The Zhuoma lead-zinc deposit is located in the southern segment of the Indosinian Yidun-Zhongdian island-arc belt. The ore body occurs in the Indosinian quartz monzonite porphyry and is controlled by faulted zones. Studies of REE of non-ore porphyry (porphyrite), fragmentation-porphyry ore, vein ore and sulfur and lead isotopes of ore galena show that REE geochemical characteristics of porphyry (porphyrite) and ores are similar to each other, and ores and porphyry (porphyrite) were from the same source. Galena δ³⁴S values range from-0.01 to-2.90‰, indicating that sulfur was derived from the mantle, lead isotopic ratios of ²⁰⁶6Pb/²⁰⁴Pb vary from 18.0959 to 18.1119, ²⁰⁷Pb/²⁰⁴Pb from 15.6118 to 15.6191, and ²⁰⁸Pb/²⁰⁴Pb from 38.2515 to 38.2918, suggesting that lead of ores was derived from an orogenic environment, with the source area belonging to mixed crust-mantle source dominated by mantle lead. Lead-zinc mineralization in the ore district was closely related to the late Indosinian Zhuoma duplex porphyry (porphyrite), and the ore deposit belongs to magmatic hydrothermal filling metasomatic type controlled by fractures.