Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials
ABSTRACT: Numerous dark enclaves with different shapes are found in Jiuling Neoproterozoic granitoids. Precise LA-ICP-MS U-Pb dating was conducted on zircons extracted from two microcrystalline enclave samples, yielding crystallization ages of 822.6±5.8 Ma and 822.2±6.2 Ma, respectively. The consist...
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KeAi Communications Co., Ltd.
2018-09-01
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| Series: | China Geology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2096519219300631 |
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| author | Zheng Duan Guang-fu Xing Sheng-bing Liao Ping-li Chu Wen-cheng Huang Yan-hui Zhu Xu-jie Shu Chang-bo Li |
| author_facet | Zheng Duan Guang-fu Xing Sheng-bing Liao Ping-li Chu Wen-cheng Huang Yan-hui Zhu Xu-jie Shu Chang-bo Li |
| author_sort | Zheng Duan |
| collection | DOAJ |
| description | ABSTRACT: Numerous dark enclaves with different shapes are found in Jiuling Neoproterozoic granitoids. Precise LA-ICP-MS U-Pb dating was conducted on zircons extracted from two microcrystalline enclave samples, yielding crystallization ages of 822.6±5.8 Ma and 822.2±6.2 Ma, respectively. The consistent ages within analytical errors with the host granitoids suggested that they were the products of the same magmatism. The microcrystalline-dioritic enclaves commonly show plastic forms and contain similar plagioclase megacrysts to the host rocks, and both of the enclaves and host granitoids showed a complex composition and structural imbalance in plagioclases. Furthermore, the apatites with a euhedral acicular shape occurred widely in the microcrystalline-dioritic enclaves. All of these petrographic features above imply magma mixing is involved in their diagenesis. The enclaves and host granitoids show a marked zircon trace element difference and Hf isotopic signatures without correlation in zircon trace element pairs but form their own system between enclaves and host granitoids. Additionally, most of the zircons show extremely high εHf (t) with εHf (t) =3.54–11.94 from the southern samples, and εHf (t) =1.0–9.09 from the central region. Some zircons with the higher εHf (t) are similar to the zircons from the juvenile island arc in the eastern segment of Jiangnan Orogen. Integrated geological and Hf isotopic characteristics suggest microcrystalline-dioritic enclaves were derived from the partial melting process of the Mesoproterozoic crust which enriched juvenile island arc materials and mixed with the granitic magma that remelted from the Mesoproterozoic continental crust which relatively enriched ancient sediments and mixed with the host granitoid in diagenesis. |
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| issn | 2096-5192 |
| language | English |
| last_indexed | 2024-04-10T16:59:07Z |
| publishDate | 2018-09-01 |
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| spelling | doaj.art-f6e439fa95cb4b96a763447fc6eb33d12023-02-07T04:21:45ZengKeAi Communications Co., Ltd.China Geology2096-51922018-09-0113374391Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materialsZheng Duan0Guang-fu Xing1Sheng-bing Liao2Ping-li Chu3Wen-cheng Huang4Yan-hui Zhu5Xu-jie Shu6Chang-bo Li7Nanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, China; Corresponding author: E-mail address: njxgfu@163.com (Guang-fu Xing).Nanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, ChinaNanjing Center of China Geological Survey, Nanjing 210016, ChinaABSTRACT: Numerous dark enclaves with different shapes are found in Jiuling Neoproterozoic granitoids. Precise LA-ICP-MS U-Pb dating was conducted on zircons extracted from two microcrystalline enclave samples, yielding crystallization ages of 822.6±5.8 Ma and 822.2±6.2 Ma, respectively. The consistent ages within analytical errors with the host granitoids suggested that they were the products of the same magmatism. The microcrystalline-dioritic enclaves commonly show plastic forms and contain similar plagioclase megacrysts to the host rocks, and both of the enclaves and host granitoids showed a complex composition and structural imbalance in plagioclases. Furthermore, the apatites with a euhedral acicular shape occurred widely in the microcrystalline-dioritic enclaves. All of these petrographic features above imply magma mixing is involved in their diagenesis. The enclaves and host granitoids show a marked zircon trace element difference and Hf isotopic signatures without correlation in zircon trace element pairs but form their own system between enclaves and host granitoids. Additionally, most of the zircons show extremely high εHf (t) with εHf (t) =3.54–11.94 from the southern samples, and εHf (t) =1.0–9.09 from the central region. Some zircons with the higher εHf (t) are similar to the zircons from the juvenile island arc in the eastern segment of Jiangnan Orogen. Integrated geological and Hf isotopic characteristics suggest microcrystalline-dioritic enclaves were derived from the partial melting process of the Mesoproterozoic crust which enriched juvenile island arc materials and mixed with the granitic magma that remelted from the Mesoproterozoic continental crust which relatively enriched ancient sediments and mixed with the host granitoid in diagenesis.http://www.sciencedirect.com/science/article/pii/S2096519219300631Zircon U-Pb ageZircon trace element compositionsHf isotopic compositionsMagma mixingJiuling Pluton |
| spellingShingle | Zheng Duan Guang-fu Xing Sheng-bing Liao Ping-li Chu Wen-cheng Huang Yan-hui Zhu Xu-jie Shu Chang-bo Li Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials China Geology Zircon U-Pb age Zircon trace element compositions Hf isotopic compositions Magma mixing Jiuling Pluton |
| title | Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials |
| title_full | Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials |
| title_fullStr | Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials |
| title_full_unstemmed | Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials |
| title_short | Petrogenesis of the microcrystalline-dioritic enclaves from Jiuling granitoids in the eastern segment of Jiangnan Orogen and constraints on magma source materials |
| title_sort | petrogenesis of the microcrystalline dioritic enclaves from jiuling granitoids in the eastern segment of jiangnan orogen and constraints on magma source materials |
| topic | Zircon U-Pb age Zircon trace element compositions Hf isotopic compositions Magma mixing Jiuling Pluton |
| url | http://www.sciencedirect.com/science/article/pii/S2096519219300631 |
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