Petrogenesis and Tectonic Significance of the ~276 Ma Baixintan Ni-Cu Ore-Bearing Mafic-Ultramafic Intrusion in the Eastern Tianshan Orogenic Belt, NW China
| Autor: | Zhao-wei Zhang, Houmin Li, Wen-yuan Li, Min-xin You, Xin Li |
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| Rok vydání: | 2021 |
| Předmět: |
Basalt
lcsh:Mineralogy lcsh:QE351-399.2 Olivine Ni-Cu ore-bearing mafic-ultramafic intrusions 010504 meteorology & atmospheric sciences Gabbro Geochemistry Geology engineering.material 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology 01 natural sciences Mantle (geology) Ultramafic rock Early Permian engineering Eastern Tianshan Mafic Baixintan tectonic setting 0105 earth and related environmental sciences Petrogenesis Zircon |
| Zdroj: | Minerals, Vol 11, Iss 348, p 348 (2021) Minerals Volume 11 Issue 4 |
| ISSN: | 2075-163X |
| DOI: | 10.3390/min11040348 |
| Popis: | The Baixintan mafic-ultramafic intrusion in the Dananhu-Tousuquan arc of the Eastern Tianshan orogenic belt is composed of lherzolite, olivine gabbro, and gabbro. Olivine gabbros contain zircon grains with a U-Pb age of 276.8 ± 1.1 Ma, similar to the ages of other Early Permian Ni-Cu ore-bearing intrusions in the region. The alkaline-silica diagrams, AFM diagram, together with the Ni/Cu-Pd/Ir diagram, indicate that the parental magmas for the Baixintan intrusion were likely high-Mg tholeiitic basaltic in composition. The Cu/Pd ratios, the relatively depleted PGEs and the correlations between them demonstrate that the parental magmas had already experienced sulfide segregation. The lower CaO content in pyroxenites compared with the Duke Island Alaskan-type intrusion and the composition of spinels imply that Baixintan is not an Alaskan-type intrusion. By comparing the Baixintan intrusion with other specific mafic-ultramafic intrusions, this paper considers that the mantle source of the Baixintan intrusion is metasomatized by subduction slab-derived fluids’ components, which gives rise to the negative anomalies of Nb, Ti, and Ta elements. Nb/Yb-Th/Yb, Nb/Yb-TiO2/Yb, and ThN-NbN plots show that the Baixintan intrusion was emplaced in a back-arc spreading environment and may be related to a mantle plume. |
| Databáze: | OpenAIRE |
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