| The Barluk region is located in the western margin of the West Junggar, Xinjiang, bordering the metallogenic belt of Balkhash to the west, and the metallogenic region of Baogutu to the east. Based on existing studies of this field, this paper has confirmed the spatial-temporal differences, petrogenesis, tectonic setting of Jiamantieliek and Shiwu mineralized porphyry and its metallogenic significance and potential, by fieldwork observation and analyzing the petrography, geochemistry, isotope and zircon U-Pb chronology and other studies. Some advances have been obtained below:1. Zircon LA-ICP-MS U-Pb dating for Jiamantieliek pluton granodiorites yielded ages of 318.2±3.6Ma, and Shiwu in Shiwu pluton granodiorites yielded ages of 322.1±1.5Ma, indicating that they crystallized in Late Carboniferous. With the package ancient figure porphyry ore formation is the same, slightly later than the balkhash porphyry ore region.2. The plutons in Jiamantieliek and are mainly composed of granodiorites. These granodiorites are characterized by high Al2O3, low MgO contents, high Sr, depletion of Y and HREE and a weak negative Eu anomaly, all of which indicate that the granodiorites have geochemical characteristics similar to those of adakite. The granodiorites belong to quasi-aluminous and moderately potassic calc-alkaline granites? The plutons in Shiwu consist of granodiorites and quartz diorites. The granodiorites are characterized by high Al2O3, low MgO contents, high Sr, depletion of Y and HREE and a weak negative Eu anomaly. The granodiorites belong to granite with geochemical characteristics transitioning from weakly peraluminous calc-alkaline to low-potassic tholeiite series.3. The ore-bearing porphyry in Jiamantieliek and Shiwu formed in the island background of subduction during late Carboniferous and show geochemical characteristics similar to those of adakite, indicating that the granitic magma display an evolutionary trend to the adakite, which was formed by partial melting of subducted oceanic crust. Considering the Sr-Nd-Pb isotopic feature, we infer that the source region of Barluk ore-bearing intrusion be depleted mantle, and the the melt could be a product of the partial melting of a west part of Junggar oceanic slab, mixed with some material from mantle source, and involved the participation of subducting fluid and sediments in the process of rising.4. The ore-bearing porphyry pluton in Barluk region may be a metallogenic series. Faults are ubiquitous and there are strong alteration of pluton in Barluk region, suggested that the fluid was relatively active, all of which offered necessary condition of structure, magma, sources, and fluids for the porphyry copper mineralization, thus implying good prospecting potential of porphyry copper deposits. In addition, it share similar characteristics in tectonic settings, spatiotemporal evolution, and feature of source area with those in both Balkhash and Baogutu porphyry copper deposit. This suggested that porphyry copper deposit in the study area might be the eastern extending part of metallogenic belt of Balkhash, which shows great prospecting potential of porphyry copper deposit. Intermediate-felsic porphyry intrusions of late Carboniferous may probably be the target geologic body assisting to seek out the porphyry copper and molybdenum ?gold? deposits. |
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