Lead Isotope Geochemistry in the Qulong-Jiama-Bangpu Ore Concentrated Area of Tibet

The Qulong-Jiama-Bangpu copper polymetallic ore concentration area is one of the most important areas in the Gangdese metallogenic belt of Tibet with more than 15 million tons of copper resources. Ore-forming materials for three deposits were considered to be derived from magma. However, the relationship between magma with different degrees of mineralization and times and copper mineralization are unknown, especially on a regional scale. By collecting the published lead isotope data of ores, intrusions and strata from these three deposits, the lead isotopic composition of ores from Qulong, Jiama and Bangpu are were found to be similar to those of Miocene ore-bearing porphyries but different from those of intrusions unrelated to mineralization. Spatially, from Qulong in the southwest, to Jiama, and to Bangpu in the northeast, the mineralization ages range from old to young, and lead isotopes evolve obviously with radiogenic lead increments (average ²⁰⁶Pb/²⁰⁴Pb values of ores 18.521→18.644→18.684). Lead isotope geochemistry not only indicates the magma source, but also can differentiate between ore-related intrusions from ore-barren intrusions and suggest the relationship between intrusion and mineralization.