Pegmatite magmatic evolution and rare metal mineralization of the Dahongliutan pegmatite field, Western Kunlun Orogen: Constraints from the B isotopic composition and mineral-chemistry

Cao，Rui1,2; Gao，Yongbao2; Chen，Bin3; Bagas，Leon2; Yan，Shengchao4; Huang，Chao5; Zhao，Hui3

2021

10.1080/00206814.2021.1899062

INTERNATIONAL GEOLOGY REVIEW   影响因子和分区

0020-6814

1938-2839

The Dahongliutan rare-metal pegmatite deposit, associated with the pegmatite dikes hosted by Dahongliutan pluton and metasedimentary rocks, is a new discovered Li–Be deposit in the the West Kunlun orogen, Northwest China. The Dahongliutan pegmatite is a classic and typical example of a highly fractionated Li-Ce-Ta (LCT) type pegmatite, with distinct regional zonation composed of well-developed garnet-tourmaline-microcline (GTM), beryl-tourmaline-muscovite (BTM) and spodumene-albite (SA) pegmatites from the barren core inward to outer zone. Detailed field studies, together with B-isotope studies of tourmaline and the chemistry of feldspar, muscovite and tourmaline, were undertaken to investigate the differentiation processes in a pegmatite magma and the different mineralizing episodes of the Dahongliutan rare-metal pegmatite deposit. Alkali metal fractionation trends (Rb, Cs and K/Rb) in the pegmatitic K-feldspar and muscovite define a primitive to evolved magmatic evolution. From low to high degrees of evolution, the mineralization stages of Dahongliutan pegmatite field are metal barren in centre, Be-rich in the intermediate and Li-rich in the outer zone. Furthermore, besides the magmatic tourmaline in the GTM pegmatite dikes, the fine-grained euhedral magmatic BTM-I type and subhedral to anhedral coarse-grained magmatic-hydrothermal BTM-II type in the BTM pegmatite dikes have been identified. The average δB values of the magmatic tourmalines in the GTM-type is −8.82, BTM-I type is −8.53‰, and BTM-II type is −7.85‰. Combined with petrography and chemical data, we suggest that the Dahongliutan pegmatite dikes were derived from metasedimentary source within the continental crust and the BTM-II type tourmaline is correlated with separation of an immiscible B-rich fluid during the magmatic-hydrothermal evolution. Consequently, highly fractional crystallization, albite alteration and liquid immiscibility were the main factors controlling the spatial and temporal decoupling of rare element mineralization in the Dahongliutan pegmatite deposit.

b-isotope mesozoic dahongliutan pegmatite Pegmatite magmatic evolution rare metal mineralization Western Kunlun Orogen

SCI

英语

其他

WOS:000639756300001

GEOSCIENCES

2-s2.0-85104301999

Scopus

1.Key Laboratory of Earth Exploration and Information Technology,Ministry of Education,Chengdu University of Technology,Chengdu,China
2.Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits of Ministry of Natural Resources,Xi’an Center of China Geological Survey,Xi’an,China
3.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,China
4.Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,China
5.School of Resources and Environmental Engineering,Hefei University of Technology,Hefei,China

Cao，Rui,Gao，Yongbao,Chen，Bin,et al. Pegmatite magmatic evolution and rare metal mineralization of the Dahongliutan pegmatite field, Western Kunlun Orogen: Constraints from the B isotopic composition and mineral-chemistry[J]. INTERNATIONAL GEOLOGY REVIEW,2021.

Cao，Rui.,Gao，Yongbao.,Chen，Bin.,Bagas，Leon.,Yan，Shengchao.,...&Zhao，Hui.(2021).Pegmatite magmatic evolution and rare metal mineralization of the Dahongliutan pegmatite field, Western Kunlun Orogen: Constraints from the B isotopic composition and mineral-chemistry.INTERNATIONAL GEOLOGY REVIEW.

Cao，Rui,et al."Pegmatite magmatic evolution and rare metal mineralization of the Dahongliutan pegmatite field, Western Kunlun Orogen: Constraints from the B isotopic composition and mineral-chemistry".INTERNATIONAL GEOLOGY REVIEW (2021).