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ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Petrology
Volume 12 - 2024 |
doi: 10.3389/feart.2024.1493594
This article is part of the Research Topic Structural Processes, Petrogenesis, Mineralization, and Geochronology in the Earth’s Crust View all articles
Petrogenesis of REE-rich two-mica granite from the Indosinian Xiekeng pluton in South China Block with Implications for REE metallogenesis
Provisionally accepted- 1 Key Laboratory of Ionic Rare Earth Resources and Environment, Ministry of Natural Resources, Ganzhou, China
- 2 School of Earth Sciences, East China University of Technology, Nanchang, Jiangxi Province, China
- 3 Ganzhou General Inspection and Testing Institute, Ganzhou, China
- 4 Jiangxi Mineral Resources Guarantee Service Center, Nanchang, Jiangxi Province, China
- 5 School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui Province, China
- 6 Jiangxi Nonferrous Geology and Mineral Exploration and Development Institute, Nanchang, China
The Xiekeng pluton, located in Huichang County, Jiangxi Province, is primarily composed of two-mica monzogranite. The rock features high contents of SiO2 (71.3-77.73 wt%), K2O (4.42-5.62 wt%), K2O/Na2O (1.36-1.87), and with an A/CNK value of 1.11-1.27, a differentiation index (DI) of 90.28-94.47, zircon saturation temperatures of 780℃-806℃, and K/Rb, Nb/Ta, and Zr/Hf ratios of 8. 40-11.04, 2.38-9.24, and 25.42-35.37, respectively. It also contains peraluminous minerals such as muscovite, classifying it as a highly fractionated S-type granite. The total rare earth element (ΣREY = ΣREE + Y) contents range from 224.7 to 353.12 ppm, with a relative enrichment in light rare earth elements (ΣLREE/ΣHREY) of 1.55-5.36, and significant fractionation between light and heavy rare earth elements with (La/Yb)N = 3.36-18.48, and pronounced negative Eu anomalies (Eu/Eu* = 0.08-0.41). Zircon U-Pb dating ages of twomica monzogranite samples are 241.2 ± 1.8 Ma and 238.3 ± 1.7 Ma, belonging to the Middle Triassic. Zircon εHf(t) values range from -14.93 to -9.12, with depleted mantle model ages (TDM2) of 1.86 to 2.03 Ga, and whole-rock Nd isotopic model ages (TDM2) are 1.90 to 1.93 Ga, indicating a source primarily from partial melting of Proterozoic continental crustal clay-rich mudstones. Based on muscovite chemistry, the average formation pressure of the Xiekeng pluton is calculated to be 8.35 kbar (~30 km paleodepth). This suggests the pluton formed through deep melting and intrusion under a thickened crustal compressional tectonic setting. The Xiekeng pluton is rich in total rare earth elements, with abundant rare earth minerals such as apatite, monazite, xenotime, fluocerite, and bastnäsite, showing geochemical characteristics similar to those of typical Indosinian ionadsorption REE deposit host rocks, indicating potential for the formation of ion-adsorption REE deposits.
Keywords: Two-mica monzogranite, Pb-Hf-Sr-Nd isotopes, S-type granites, metallogenic potential, Indosinian orogeny, Xiekeng pluton
Received: 09 Sep 2024; Accepted: 04 Dec 2024.
Copyright: © 2024 Zhang, Lv, Wang, Cao, Chen, Zhang and Gong. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Tingting Lv, Ganzhou General Inspection and Testing Institute, Ganzhou, China
Xiangaung Wang, School of Earth Sciences, East China University of Technology, Nanchang, 330013, Jiangxi Province, China
Mingxuan Cao, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui Province, China
Xiquan Chen, School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui Province, China
Yongwen Zhang, Jiangxi Mineral Resources Guarantee Service Center, Nanchang, Jiangxi Province, China
Liangxin Gong, Jiangxi Nonferrous Geology and Mineral Exploration and Development Institute, Nanchang, China
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