Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia
Abstract: The amalgamation of the Yangtze and the Cathaysia Block in Neoproterozoic time led to the formation of the South China Block (SCB) and generated the Jiangnan Orogen with the occurrences of juvenile magmatic rocks. After this orogeny, a typical collisional orogen formed during the early Pal...
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Frontiers Media S.A.
2023-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2023.1137157/full |
| _version_ | 1811167217314693120 |
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| author | Xu-Jie Shu Wei Jiang Dan Wang Cheng Cheng Hong-Zuo Wang |
| author_facet | Xu-Jie Shu Wei Jiang Dan Wang Cheng Cheng Hong-Zuo Wang |
| author_sort | Xu-Jie Shu |
| collection | DOAJ |
| description | Abstract: The amalgamation of the Yangtze and the Cathaysia Block in Neoproterozoic time led to the formation of the South China Block (SCB) and generated the Jiangnan Orogen with the occurrences of juvenile magmatic rocks. After this orogeny, a typical collisional orogen formed during the early Paleozoic period in Southeast Asia which is mainly distributed in the Wuyi-Nanling-Yunkai area in the SCB. However, the transitional time from syn-collisional compression to post-collisional extension is debatable. Here, we present new data on zircon U-Pb zircon ages, Lu-Hf isotopes, and geochemistry for the Guzhang and Shadi granites from the Nanling area, South China. Both plutons have similar zircon 238U/206Pb ages of ca. 430 Ma. Petrographic and geochemical characteristics (e.g., FeOt/(FeOt+MgO) = 0.82–0.95) indicate that both granites are peraluminous A-type, with high Ga/Al ratios (2.43–2.91) as well as high concentrations of Zr, Nb, Ce, Y (sum values from 327 to 527 ppm), and formation temperature (820°C–845°C). Shadi granite exhibit high positive εHf(t) values (clustering within 0 to +6) while Guzhang granite show relatively lower εHf(t) values (−8.7 to −2.9). Their mildly negative to positive zircon εHf(t) values are higher than that of many coeval granites and can be derived from anhydrous melting of tonalitic genesis in the middle crustal depth, with the Shadi pluton having more orthometamorphite in the source. The ages and Hf isotopic compositions of inherited zircons (εHf(t = 960 Ma) = 9.2, εHf(t = 950 Ma) = 7.3) suggest that the Neoproterozoic juvenile magmatic rocks in the Jiangnan Orogen were a significant source for these granites. We interpret these A-type granites derived at the post-collisional stage. Their occurrence indicates that the geological setting of this Paleozoic orogen shifted from compression to extension no later than 430 Ma. |
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| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-10T16:05:31Z |
| publishDate | 2023-02-01 |
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| spelling | doaj.art-0e6e8e452ac74879b6bb0e7e190d64ac2023-02-10T04:46:44ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632023-02-011110.3389/feart.2023.11371571137157Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast AsiaXu-Jie ShuWei JiangDan WangCheng ChengHong-Zuo WangAbstract: The amalgamation of the Yangtze and the Cathaysia Block in Neoproterozoic time led to the formation of the South China Block (SCB) and generated the Jiangnan Orogen with the occurrences of juvenile magmatic rocks. After this orogeny, a typical collisional orogen formed during the early Paleozoic period in Southeast Asia which is mainly distributed in the Wuyi-Nanling-Yunkai area in the SCB. However, the transitional time from syn-collisional compression to post-collisional extension is debatable. Here, we present new data on zircon U-Pb zircon ages, Lu-Hf isotopes, and geochemistry for the Guzhang and Shadi granites from the Nanling area, South China. Both plutons have similar zircon 238U/206Pb ages of ca. 430 Ma. Petrographic and geochemical characteristics (e.g., FeOt/(FeOt+MgO) = 0.82–0.95) indicate that both granites are peraluminous A-type, with high Ga/Al ratios (2.43–2.91) as well as high concentrations of Zr, Nb, Ce, Y (sum values from 327 to 527 ppm), and formation temperature (820°C–845°C). Shadi granite exhibit high positive εHf(t) values (clustering within 0 to +6) while Guzhang granite show relatively lower εHf(t) values (−8.7 to −2.9). Their mildly negative to positive zircon εHf(t) values are higher than that of many coeval granites and can be derived from anhydrous melting of tonalitic genesis in the middle crustal depth, with the Shadi pluton having more orthometamorphite in the source. The ages and Hf isotopic compositions of inherited zircons (εHf(t = 960 Ma) = 9.2, εHf(t = 950 Ma) = 7.3) suggest that the Neoproterozoic juvenile magmatic rocks in the Jiangnan Orogen were a significant source for these granites. We interpret these A-type granites derived at the post-collisional stage. Their occurrence indicates that the geological setting of this Paleozoic orogen shifted from compression to extension no later than 430 Ma.https://www.frontiersin.org/articles/10.3389/feart.2023.1137157/fullorogenic magmatismA-type graniteearly PaleozoicSoutheast Asiageological setting |
| spellingShingle | Xu-Jie Shu Wei Jiang Dan Wang Cheng Cheng Hong-Zuo Wang Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia Frontiers in Earth Science orogenic magmatism A-type granite early Paleozoic Southeast Asia geological setting |
| title | Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia |
| title_full | Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia |
| title_fullStr | Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia |
| title_full_unstemmed | Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia |
| title_short | Origin and implication of two newly identified peraluminous A-type granites in the early Paleozoic orogeny, Southeast Asia |
| title_sort | origin and implication of two newly identified peraluminous a type granites in the early paleozoic orogeny southeast asia |
| topic | orogenic magmatism A-type granite early Paleozoic Southeast Asia geological setting |
| url | https://www.frontiersin.org/articles/10.3389/feart.2023.1137157/full |
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