Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean
Owing to tectonic, magmatic, and metamorphic controls, pegmatites associated with different spatiotemporal distributions exhibit varying mineralisation characteristics. The petrogenesis of pegmatites containing rare metals can improve the understanding of geodynamic processes in the deep subsurface....
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MDPI AG
2023-08-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/13/9/1127 |
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| author | Mengtao Wang Xin Zhang |
| author_facet | Mengtao Wang Xin Zhang |
| author_sort | Mengtao Wang |
| collection | DOAJ |
| description | Owing to tectonic, magmatic, and metamorphic controls, pegmatites associated with different spatiotemporal distributions exhibit varying mineralisation characteristics. The petrogenesis of pegmatites containing rare metals can improve the understanding of geodynamic processes in the deep subsurface. In order to understand the difference of petrogenesis between Devonian and Permian pegmatites, zircon U-Pb geochronological and Hf-O isotope analyses were performed on samples of the Jiamanhaba, Amulagong, and Tiemulete pegmatites from the Chinese Altay. According to the results obtained, the Amulagong and Tiemulete pegmatites were formed during the Devonian, and samples that were analysed yielded zircon U-Pb ages of 373.0 ± 7.8 and 360 ± 5.2 Ma, respectively. Samples from these pegmatites produced εHf(t) values of 2.87–7.39, two-stage model ages of 900–1171 Ma and δ<sup>18</sup>O values of 9.55‰–15.86‰. These results suggest that the pegmatites were formed via an anatexis of mature sedimentary rocks deep in the crust. In contrast, the Jiamanhaba pegmatite was formed during the Permian, and its samples produced εHf(t) and δ<sup>18</sup>O values of 2.87–4.94 and 6.05‰–7.32‰, respectively, which indicate that the associated magma contained minor amounts of mantle/juvenile materials. The petrogenesis of pegmatites containing rare metals can reveal tectonic settings of their formation. A combination of data that were generated in the present study and existing geochronological and Hf-O isotope data for felsic igneous and sedimentary rocks in the Chinese Altay shows that the εHf(t) sharply increased while the δ<sup>18</sup>O suddenly decreased between Late Carboniferous and Early Permian. These changes highlight a tectonic transformation event during this critical period. This tectonic event promoted mantle–crustal interactions, and thus, it was probably linked to assemblages of the Altay orogen and the Junggar Block. The present study provides evidence that the Irtysh–Zaisan Ocean probably closed during the Late Carboniferous (~300 Ma). |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-10T22:26:17Z |
| publishDate | 2023-08-01 |
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| spelling | doaj.art-9b8c76b7bf3a493182c6341e580911a82023-11-19T12:04:43ZengMDPI AGMinerals2075-163X2023-08-01139112710.3390/min13091127Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan OceanMengtao Wang0Xin Zhang1School of Geography and Planning, Ningxia University, Yinchuan 750021, ChinaSchool of Geography and Planning, Ningxia University, Yinchuan 750021, ChinaOwing to tectonic, magmatic, and metamorphic controls, pegmatites associated with different spatiotemporal distributions exhibit varying mineralisation characteristics. The petrogenesis of pegmatites containing rare metals can improve the understanding of geodynamic processes in the deep subsurface. In order to understand the difference of petrogenesis between Devonian and Permian pegmatites, zircon U-Pb geochronological and Hf-O isotope analyses were performed on samples of the Jiamanhaba, Amulagong, and Tiemulete pegmatites from the Chinese Altay. According to the results obtained, the Amulagong and Tiemulete pegmatites were formed during the Devonian, and samples that were analysed yielded zircon U-Pb ages of 373.0 ± 7.8 and 360 ± 5.2 Ma, respectively. Samples from these pegmatites produced εHf(t) values of 2.87–7.39, two-stage model ages of 900–1171 Ma and δ<sup>18</sup>O values of 9.55‰–15.86‰. These results suggest that the pegmatites were formed via an anatexis of mature sedimentary rocks deep in the crust. In contrast, the Jiamanhaba pegmatite was formed during the Permian, and its samples produced εHf(t) and δ<sup>18</sup>O values of 2.87–4.94 and 6.05‰–7.32‰, respectively, which indicate that the associated magma contained minor amounts of mantle/juvenile materials. The petrogenesis of pegmatites containing rare metals can reveal tectonic settings of their formation. A combination of data that were generated in the present study and existing geochronological and Hf-O isotope data for felsic igneous and sedimentary rocks in the Chinese Altay shows that the εHf(t) sharply increased while the δ<sup>18</sup>O suddenly decreased between Late Carboniferous and Early Permian. These changes highlight a tectonic transformation event during this critical period. This tectonic event promoted mantle–crustal interactions, and thus, it was probably linked to assemblages of the Altay orogen and the Junggar Block. The present study provides evidence that the Irtysh–Zaisan Ocean probably closed during the Late Carboniferous (~300 Ma).https://www.mdpi.com/2075-163X/13/9/1127petrogenesiszircon U-Pb datingzircon Hf-O isotopesthe Irtysh–Zaisan Ocean |
| spellingShingle | Mengtao Wang Xin Zhang Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean Minerals petrogenesis zircon U-Pb dating zircon Hf-O isotopes the Irtysh–Zaisan Ocean |
| title | Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean |
| title_full | Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean |
| title_fullStr | Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean |
| title_full_unstemmed | Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean |
| title_short | Petrogenesis of Devonian and Permian Pegmatites in the Chinese Altay: Insights into the Closure of the Irtysh–Zaisan Ocean |
| title_sort | petrogenesis of devonian and permian pegmatites in the chinese altay insights into the closure of the irtysh zaisan ocean |
| topic | petrogenesis zircon U-Pb dating zircon Hf-O isotopes the Irtysh–Zaisan Ocean |
| url | https://www.mdpi.com/2075-163X/13/9/1127 |
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