秦岭造山带栾川Mo-W矿集区和柞水-山阳Cu-Mo矿集区斑岩型矿床成矿差异性对比OA北大核心CSTPCD

The Luanchuan Mo-W ore district and the Zhashui-Shanyang Cu-Mo ore district are two typical por-phyry ore districts formed in the post-collision setting during 152-140Ma in the Qinling Orogenic Belt.Despite significant differences in their mineralization,the controlling factors remain unclear.This study collected whole-rock geochemical data,Sr-Nd-Hf isotopes,and the compositions of zircon and apatite from both ore districts.A comparative analysis was conducted on aspects such as magmatic source,water content,oxygen fugacity,volatiles(F,Cl)and sulfur content to reveal the key controlling factors of their metallogenic differences.The Zhashui-Shanyang Cu-Mo ore district shows εHf(t)and εNd(t)variations ranging from-5 to 2 and-6.6 to-1.5,with(87Sr/86Sr)i value close to the upper mantle(averaging 0.7051),indicating a mixture of melting of thickened juvenile lower crustal components with mantle-derived magmas in the magma source.The Luanchuan Mo-W ore district exhibits relatively low εHf(t)and εNd(t)values(averaging-18.38 and-14.63)and older Hf two-stage model ages,suggesting that the Mo-W-rich porphyries originated from the ancient Taihua Group base-ment and partial melting of the Yangtze Plate subducted continental crust sediment.Both ore districts'mineral-ized porphyries have high Sr and low Y,whole-rock Eu/Eu*＞0.6,low zircon saturation temperatures(＜750℃),zircon Eu/Eu*＞0.3,zircon CeN/CeN*＞100,Ce/Nd＞10,whole-rock V/Sc＞5,and oxidation state＞FMQ+3,indicating characteristics of high water content and high oxygen fugacity in their mineralizing magmas.Further-more,the Cu-Mo system in the Zhashui-Shanyang ore district is enriched in Cl,while the Mo-W system in the Luanchuan ore district is enriched in F,with similar S contents.These differences in the magma source are the fundamental reasons for the mineralization disparities between the two districts.Cl and F,as the main ligands for the migration of Cu and Mo in magmatic hydrothermal fluids,are another key factor causing the mineralization differences between the two ore districts.Enriched water,high S,and high oxygen fugacity magmas are impor-tant conditions for the formation of porphyry ore deposits in both districts,but they are not the direct causes of the mineralization differences.