Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision
Demingding is a promising porphyry Mo-dominated deposit recently discovered in the eastern Gangdese metallogenic belt in Tibet, China. We present zircon U-Pb-Lu-Hf isotopic studies, as well as geochemical data of the late monzogranites and the prior rhyolites from the Demingding porphyry deposit to...
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MDPI AG
2022-10-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/10/1266 |
| _version_ | 1797471033493553152 |
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| author | Yigan Lu Kai Dong Hui Zhou Zhuoyang Li |
| author_facet | Yigan Lu Kai Dong Hui Zhou Zhuoyang Li |
| author_sort | Yigan Lu |
| collection | DOAJ |
| description | Demingding is a promising porphyry Mo-dominated deposit recently discovered in the eastern Gangdese metallogenic belt in Tibet, China. We present zircon U-Pb-Lu-Hf isotopic studies, as well as geochemical data of the late monzogranites and the prior rhyolites from the Demingding porphyry deposit to uncover their origin and geodynamic mechanism. Zircon U–Pb dating yielded precise crystallization ages of 17.3 ± 0.6 Ma (MSWD = 2.5) and 186.5 ± 3.0 Ma (MSWD = 2.0) for monzogranite and rhyolite, respectively. The monzogranite is characterized by high-K calc-alkaline, adakitic affinities, and positive zircon ε<sub>Hf</sub>(t) values (+0.9∼+5.6, avg.+3.1) with T<sub>DM2</sub> (0.73–1.04 Ga), while the rhyolite has ε<sub>Hf</sub>(t) values of (+2.1∼+7.3, avg.+5.2) and T<sub>DM2</sub> of (0.76–1.09 Ga) similar to the monzogranite. Our results suggest that the Demingding porphyry Mo (Cu) deposit is related to magma generated from the Neo-Tethyan oceanic subduction. The subsequent monzogranite porphyry was likely formed by the remelting of previously subduction-modified arc lithosphere, triggered by continental collision crustal thickening in Miocene. The lower positive ε<sub>Hf</sub>(t) values of monzogranites suggest minor inputs from the Mo-rich ancient crust, suggesting that Mo favors the silicate melt. Such magmatic events and special metallogenesis typify intracontinental processes and porphyry copper deposits, which are normally confined to oceanic subduction and Cu-dominated style, thereby making the continental setting and Mo-dominated style of Demingding exceptional and possibly unique. |
| first_indexed | 2024-03-09T19:43:49Z |
| format | Article |
| id | doaj.art-de47599616384415abefec8e606a45c5 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T19:43:49Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-de47599616384415abefec8e606a45c52023-11-24T01:29:43ZengMDPI AGMinerals2075-163X2022-10-011210126610.3390/min12101266Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental CollisionYigan Lu0Kai Dong1Hui Zhou2Zhuoyang Li3School of Natural Resources and Surveying, Nanning Normal University, Nanning 530001, ChinaSchool of Natural Resources and Surveying, Nanning Normal University, Nanning 530001, ChinaSchool of Civil and Architectural Engineering, Nanning University, Nanning 530001, ChinaSchool of Natural Resources and Surveying, Nanning Normal University, Nanning 530001, ChinaDemingding is a promising porphyry Mo-dominated deposit recently discovered in the eastern Gangdese metallogenic belt in Tibet, China. We present zircon U-Pb-Lu-Hf isotopic studies, as well as geochemical data of the late monzogranites and the prior rhyolites from the Demingding porphyry deposit to uncover their origin and geodynamic mechanism. Zircon U–Pb dating yielded precise crystallization ages of 17.3 ± 0.6 Ma (MSWD = 2.5) and 186.5 ± 3.0 Ma (MSWD = 2.0) for monzogranite and rhyolite, respectively. The monzogranite is characterized by high-K calc-alkaline, adakitic affinities, and positive zircon ε<sub>Hf</sub>(t) values (+0.9∼+5.6, avg.+3.1) with T<sub>DM2</sub> (0.73–1.04 Ga), while the rhyolite has ε<sub>Hf</sub>(t) values of (+2.1∼+7.3, avg.+5.2) and T<sub>DM2</sub> of (0.76–1.09 Ga) similar to the monzogranite. Our results suggest that the Demingding porphyry Mo (Cu) deposit is related to magma generated from the Neo-Tethyan oceanic subduction. The subsequent monzogranite porphyry was likely formed by the remelting of previously subduction-modified arc lithosphere, triggered by continental collision crustal thickening in Miocene. The lower positive ε<sub>Hf</sub>(t) values of monzogranites suggest minor inputs from the Mo-rich ancient crust, suggesting that Mo favors the silicate melt. Such magmatic events and special metallogenesis typify intracontinental processes and porphyry copper deposits, which are normally confined to oceanic subduction and Cu-dominated style, thereby making the continental setting and Mo-dominated style of Demingding exceptional and possibly unique.https://www.mdpi.com/2075-163X/12/10/1266geochemistryzircon U-Pb ageHf isotopeDemingding porphyry depositTibet |
| spellingShingle | Yigan Lu Kai Dong Hui Zhou Zhuoyang Li Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision Minerals geochemistry zircon U-Pb age Hf isotope Demingding porphyry deposit Tibet |
| title | Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision |
| title_full | Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision |
| title_fullStr | Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision |
| title_full_unstemmed | Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision |
| title_short | Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision |
| title_sort | origin and geodynamic mechanism of the tibetan demingding porphyry mo cu deposit from oceanic subduction to continental collision |
| topic | geochemistry zircon U-Pb age Hf isotope Demingding porphyry deposit Tibet |
| url | https://www.mdpi.com/2075-163X/12/10/1266 |
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