Metallogenesis Of Lailisigaoer-kendenggaoer Copper-molybdenum-lead-zinc Ore Cluster In Western Tianshan, Xinjiang, China

Lailisigaoer-Kendenggaoer Copper-Molybdenum-Lead-Zinc ore cluster lies at the Midwest of Boluokenu copper, gold, molybdenum, lead, zinc, iron, phosphorus, pyrite ore belt in West Tianshan, Xinjiang. The tectonic setting of the ore cluster is the north slope of Late Paleozoic Boluokenu active continental margin. Ore mineralization is closely related to acid intrusive rocks in the region in the late Paleozoic in space and time. Mainly related rocks are granodiorite/granodiorite porphyry, monzogranite and moyite. Skarn deposit forms in contact section between acid intrusive rock and carbonate rock, while porphyry-type deposits and mid-low temperature heat vein type deposits related to postmagmatic hydrothermal. Granodiorite porphyry is enriched in silicon, aluminum, alkali and large ion lithophile elements such as Rb, Ba and Sr, but depleted in high field strength elements such as Ta, Hf, Zr, Sm, Th, Y and Yb. Ocean ridge granite normalized trace element distribution patterns are similar with continental margin arc distribution patterns. The Rare Earth Elements content of Granodiorite porphyry was significantly lower than that of S-type granites and has the nature of I-type or M-type granitic magma.The initial strontium value is 0.7079-0.7103 and theεNd(t) value is-0.61 to-3.71 indicating that magma derived from the lower crustal source or crust-mantle mixing source.The average oreδ34Sv-CDT value of Kendenggaoe copper-molybdenum ore, Lailisigaoer copper-molybdenum ore and Qixing copper zinc polymetallic ore deposits in this ore district is 1.14‰,3.8‰and 4.0‰respectively, the former shows sulfur source for the mantle and the latter two for the crust-mantle mixing source; lead isotopes show that the source have a mixture of crust and mantle characteristics; forming fluids are low salinity and low-density fluid. Hydrogen and oxygen isotopes show hot forming magmatic fluids by meteoric water and mixing. The three typical deposits are significantly different in genesis, element association and mineralization times, and these elements association can be divided into the Cu-Mo, Fe-Cu, Pb-Zn, Au-Ag ore-forming elements and other combinations. In which, Cu-Mo mineralization outputs in granodiorite/ granodiorite porphyry and associated hornfels and skarn, with Lailisigaoer-3571 copper-molybdenum mine and Kendonggaoer copper-molybdenum mine represented. Fe-Cu deposit output in the inner (outer) skarn of granite and limestone contact metasomatic zone parts, with Halegati deposit represented. Pb-Zn and Au-Ag mineralizations as the representative of Qixing lead and zinc deposit are related to postmagmatic hydrothermal and structural. Distributions of elements in the ore region are associated with granite and structural.Contact parts between granite and terrigenous clastic rocks (as Boluohuoluoshan formation clastic rocks of upper Silurian) had thermal contact metamorphism and formed hornfels and copper-molybdenum deposit; while in the contact area between granite and carbonate formed skarn and copper-molybdenum and copper-iron mineralization. Away from the rock, mid-low hydrothermal vein type lead-zinc and gold-silver mine controlled by structures in the rock fractures, the ore formation age elements associations have obvious rule:Cu-Mo ore formed in the Early Carboniferous, Fe-Cu ore formed in the Late Devonian-Early Carboniferous, Pb-Zn ore formation in the Late Triassic-Early Jurassic, and Au-Ag ore may form in Carboniferous or Mesozoic because of lacking relevant dating data. From Late Devonian-Carboniferous-Late Triassic-Early Jurassic, forming elements were combined Fe-Cu, Fe-Cu-Mo-(Au-Ag?) and Pb-Zn-(Au-Ag?). The mineralization of Lailisigaoer-Kendenggaoer polymetallic ore cluster area and regional tectonic magmatism were the product of the same geological-tectonic-magmatic processes at different stages and the results of the combined effects in the same region diagenetic-mineralization system.