Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia
Multiple stages of igneous rocks occur in the recently discovered Nianzigou Mo deposit in Chifeng, Inner Mongolia, which can provide insights into the late Mesozoic geodynamic evolution of the southern Da Hinggan Range. The mineralization age is similar to the age of local granites, but there are fe...
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MDPI AG
2022-06-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/7/791 |
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| author | Yang Li Yongqiang Yang Lei Hua Yaxing Leng Jiang Xin |
| author_facet | Yang Li Yongqiang Yang Lei Hua Yaxing Leng Jiang Xin |
| author_sort | Yang Li |
| collection | DOAJ |
| description | Multiple stages of igneous rocks occur in the recently discovered Nianzigou Mo deposit in Chifeng, Inner Mongolia, which can provide insights into the late Mesozoic geodynamic evolution of the southern Da Hinggan Range. The mineralization age is similar to the age of local granites, but there are few detailed studies of the tectonic setting during Cu-Mo mineralization in this area. The Nianzigou Mo deposit is located close to the northern margin of the North China Craton and in the eastern Central Asian Orogenic Belt and is a typical quartz-vein-type Mo deposit in the Xilamulun Mo ore belt. The granite in this deposit has high SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, K<sub>2</sub>O, and Na<sub>2</sub>O contents, and low MgO, CaO, and Fe<sub>2</sub>O<sub>3</sub><sup>t</sup> contents. The granite is characterized by enrichments in large-ion lithophile elements and depletions in high-field-strength elements and, in particular, Sr, Ti, and P. The granite has high contents of rare-earth elements, is enriched in light rare-earth elements, and has marked negative Eu anomalies. The granite is an alkaline and calc-alkaline and metaluminous A-type granite. The zircon U-Pb ages of the monzogranite and granite porphyry are 157.2 ± 0.3 and 154.4 ± 0.4 Ma. The model age obtained by Re-Os isotopic dating is 154.3 ± 1.7 Ma, indicating that molybdenite mineralization also occurred during the Late Jurassic period. Given that the molybdenite Re contents are 7.8–24.9 ppm (average = 16.8 ppm), the ore-forming materials of the Nianzigou Mo deposit had a mixed crust–mantle source, but were mainly derived from the lower crust. Based on the geology and geochemistry, we propose that the Nianzigou Mo deposit formed in a postorogenic extensional tectonic setting associated with the southward subduction of the Mongol–Okhotsk oceanic plate. |
| first_indexed | 2024-03-09T06:09:53Z |
| format | Article |
| id | doaj.art-f06b2425858748feaf292a289b847fee |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T06:09:53Z |
| publishDate | 2022-06-01 |
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| record_format | Article |
| series | Minerals |
| spelling | doaj.art-f06b2425858748feaf292a289b847fee2023-12-03T11:59:43ZengMDPI AGMinerals2075-163X2022-06-0112779110.3390/min12070791Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner MongoliaYang Li0Yongqiang Yang1Lei Hua2Yaxing Leng3Jiang Xin4State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, ChinaState Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, ChinaState Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, ChinaInstitute of Geology, CAGS, Beijing 100037, ChinaWest Gold Ltd., Co., Urumqi 830002, ChinaMultiple stages of igneous rocks occur in the recently discovered Nianzigou Mo deposit in Chifeng, Inner Mongolia, which can provide insights into the late Mesozoic geodynamic evolution of the southern Da Hinggan Range. The mineralization age is similar to the age of local granites, but there are few detailed studies of the tectonic setting during Cu-Mo mineralization in this area. The Nianzigou Mo deposit is located close to the northern margin of the North China Craton and in the eastern Central Asian Orogenic Belt and is a typical quartz-vein-type Mo deposit in the Xilamulun Mo ore belt. The granite in this deposit has high SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, K<sub>2</sub>O, and Na<sub>2</sub>O contents, and low MgO, CaO, and Fe<sub>2</sub>O<sub>3</sub><sup>t</sup> contents. The granite is characterized by enrichments in large-ion lithophile elements and depletions in high-field-strength elements and, in particular, Sr, Ti, and P. The granite has high contents of rare-earth elements, is enriched in light rare-earth elements, and has marked negative Eu anomalies. The granite is an alkaline and calc-alkaline and metaluminous A-type granite. The zircon U-Pb ages of the monzogranite and granite porphyry are 157.2 ± 0.3 and 154.4 ± 0.4 Ma. The model age obtained by Re-Os isotopic dating is 154.3 ± 1.7 Ma, indicating that molybdenite mineralization also occurred during the Late Jurassic period. Given that the molybdenite Re contents are 7.8–24.9 ppm (average = 16.8 ppm), the ore-forming materials of the Nianzigou Mo deposit had a mixed crust–mantle source, but were mainly derived from the lower crust. Based on the geology and geochemistry, we propose that the Nianzigou Mo deposit formed in a postorogenic extensional tectonic setting associated with the southward subduction of the Mongol–Okhotsk oceanic plate.https://www.mdpi.com/2075-163X/12/7/791geochronologyzircon U-Pb datingpostcollisionalA-type graniteLate JurassicNianzigou Mo deposit |
| spellingShingle | Yang Li Yongqiang Yang Lei Hua Yaxing Leng Jiang Xin Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia Minerals geochronology zircon U-Pb dating postcollisional A-type granite Late Jurassic Nianzigou Mo deposit |
| title | Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia |
| title_full | Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia |
| title_fullStr | Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia |
| title_full_unstemmed | Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia |
| title_short | Geochronology and Tectonic Implications of the Nianzigou Granites and Associated Mo Deposit, Inner Mongolia |
| title_sort | geochronology and tectonic implications of the nianzigou granites and associated mo deposit inner mongolia |
| topic | geochronology zircon U-Pb dating postcollisional A-type granite Late Jurassic Nianzigou Mo deposit |
| url | https://www.mdpi.com/2075-163X/12/7/791 |
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