华北克拉通大湾斑岩钼矿锆石SHRIMP U-Pb年龄、Hf同位素、辉钼矿Re-Os年龄及其地质意义OA

Currently,scholars at home and abroad have gained profound insights into the genesis mechanisms of porphyry molybdenum deposits developed in arc and rift environments.However,scientific questions regarding the diagenesis,mineral source regions,and other aspects of porphyry molybdenum deposits within the North China Cra-ton remain controversial and warrant further investigation.This paper reports the(rhyolitic porphyry)diagenetic and mineralization ages,along with the Hf isotopic composition of mineralized rhyolitic porphyry from the Dawan por-phyry molybdenum deposit within the Laiyuan Complex.The study reveals:the SHRIMP zircon U-Pb age of the rhyolitic porphyry is 137.1±0.6 Ma,the Re-Os isochron age of six molybdenite samples is 140.6±1.9 Ma,and the rhyolitic porphyry has εHf(t)values of-28.2～-22.3,the Re isotopic content of Dawan porphyry molybdenum deposit ranges from 19×10-6 to 26×10-6,showing characteristics of a crust-mantle mixed source with a predominant crustal component.The Mujicun porphyry copper deposit and Dawan porphyry molybdenum deposit are spatially as-sociated with relatively consistent diagenetic and mineralization ages.Furthermore,the Hf isotopic compositions of the gabbro-diorite from the Laiyuan complex,the mineralized dioritic porphyry from Mujicun,and the mineralized rhyolitic porphyry from Dawan are similar,suggesting a possible common magmatic source for the gabbro-diorite,dioritic porphyry,and rhyolitic porphyry.Within Late Mesozoic extensional tectonic setting,the ore-bearing rhy-olitic porphyry originated from gabbroic parent magma formed by partial melting of enriched lithospheric mantle.During its ascent,the gabbroic magma underwent significant lower crustal mixing.Thermal erosion may be the deep mechanism for the formation of ore-bearing porphyry of Dawan Porphyry Mo deposit in the North China Craton.