The Salair terrane located in the northern part of the Central Asian Orogenic Belt (CAOB) contains many epithermal deposits including volcanogenic massive sulphide (VMS) deposits. The host rocks mainly consist of felsic volcanic rocks such as lavas, volcanic breccias and tuffs that associated with thick strata of carbonates. In this study, we present zircon U–Pb ages, whole rock geochemistry, and Nd isotope data from the volcanic rocks, and results of geochemical and isotope (Sr, C, O) studies of carbonates to constrain their age and petrogenesis, and to characterize the tectonic setting. Zircon U–Pb dating reveals that the ore-bearing felsic lavas have age of 519.3 ± 1.9 Ma, while the felsic tuffs have age of 516.0 ± 0.9 Ma. These volcanic rocks are characterized by high SiO2 and Na2O contents, enrichment in light rare-earth elements, remarkable negative Eu anomalies, and pronounced depletion in Nb, Ta, P, and Ti. They have depleted ɛNd(t) values ranging from +4.9 to +6.3, and young two-stage Nd model ages (from 0.82 to 0.64 Ga). The felsic volcanic rocks from the Salair terrane are interpreted as highly evolved I-type magmatic rocks that might be produced by high degree partial melting of juvenile lower crust without a significant contribution of ancient crust and without crustal reworking.

中文翻译：

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同步长英质火山作用和碳酸盐沉积是中亚造山带东北部 Salair 地层 VMS 矿床定位的环境


Salair 地层位于中亚造山带 （CAOB） 的北部，包含许多浅成热液矿床，包括火山成因块状硫化物 （VMS） 矿床。主岩主要由熔岩、火山角砾岩和凝灰岩等长英质火山岩组成，这些岩层与厚厚的碳酸盐岩层有关。在这项研究中，我们介绍了火山岩的锆石 U-Pb 年龄、全岩地球化学和 Nd 同位素数据，以及碳酸盐的地球化学和同位素 （Sr， C， O） 研究结果，以限制它们的年龄和岩石成因，并表征构造环境。锆石 U-Pb 测年显示，含矿石的长英质熔岩年龄为 519.3 ± 1.9 马，而长英质凝灰岩的年龄为 516.0 ± 0.9 马。这些火山岩的特点是 SiO2 和 Na2O 含量高，富含轻稀土元素，显著的负 Eu 异常，以及 Nb、Ta、P 和 Ti 的明显消耗。它们的 ɛNd（t） 值从 +4.9 到 +6.3 不等，年轻的两阶段 Nd 模型年龄（从 0.82 到 0.64 Ga）。来自 Salair 地层的长英质火山岩被解释为高度进化的 I 型岩浆岩，可能是由幼年下地壳的高度部分熔化产生的，而没有古老地壳的显着贡献，也没有地壳再加工。