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Granitic magma evolution to magmatic-hydrothermal processes vital to the generation of HREEs ion-adsorption deposits: Constraints from zircon texture, U-Pb geochronology, and geochemistry.

Authors :
Zhao, Xu
Li, Ning-Bo
Marten Huizenga, Jan
Zhang, Qi-Bing
Yang, Yu-Yuan
Yan, Shuang
Yang, Wu-bin
Niu, He-Cai
Source :
Ore Geology Reviews. Jul2022, Vol. 146, pN.PAG-N.PAG. 1p.
Publication Year :
2022

Abstract

[Display omitted] • Two type zircons and volatile-rich HREE mineral are distributed in the granites for all HREEs ion-adsorption deposits. • Highly fractionated granite to a magmatic-hydrothermal stage is vital to the generation of HREEs ion-adsorption deposits. • Long-term extensional setting in South China during Mesozoic favors to magmatic differentiation. • Zircons could uncover the HREEs ion-adsorption mineralization potential of granites. The key point for further prospecting of heavy rare earth elements (HREE) ion-adsorption deposit is to figure out the granites that could generate HREE ion-adsorption mineralization in weathering processes. In this study, we present a detailed study of zircons from granites associated with Zudong, Dabu, and Xinfeng HREE ion-adsorption deposits in South China. The zircons were studied with regards to their texture, crystallinity, U-Pb dating, and geochemistry. The zircons from these granites all can be subdivided into two types. The type-1 zircons show oscillatory zonation and have Th/U and Zr/Hf mass ratios of 0.4–1.0 and 30–50, respectively. These textural and geochemical features indicate crystallization in a fractionated magma. The type-2 zircons are unzoned, occasionally porous, and have a low crystallinity. They occasionally rim type-1 zircons. The type-2 zircons show significantly higher F, P, Hf, Th, U, and REE contents, but display lower ZrO 2 and SiO 2 contents and lower Th/U, Zr/Hf, La/Yb ratios than those of the type-1 zircons. These geochemical features are consistent with zircon formation in a volatile-HREE-rich magmatic-hydrothermal transition stage. Under these conditions, the HREEs were also hosted in volatile-rich REE mineral phases including synchysite-(Y), aeschynite-(Y), calcybeborosilite-(Y), and atelisite-(Y), which have been observed in these HREE deposits. These volatile-rich REE-mineral phases can easily be dissolved during weathering and release HREE3+ to generate ion-adsorption HREE deposits. Therefore, we conclude that the granitic magma progression to a volatile-HREE-rich magmatic-hydrothermal system is vital for the generation of HREE ion-adsorption deposits. The long-term Mesozoic extension of the South China favors the generation of highly fractionated granites and is thus important for the generation of HREE ion-adsorption deposits. Furthermore, the zircons generated in a volatile-rich environment could be used to determine the HREE ion-adsorption mineralization potential of granites. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01691368
Volume :
146
Database :
Academic Search Index
Journal :
Ore Geology Reviews
Publication Type :
Academic Journal
Accession number :
157353300
Full Text :
https://doi.org/10.1016/j.oregeorev.2022.104931