Yankuang ceshi (Mar 2021)
Chemical Composition of Minerals in Xuebaoding W-Sn-Be Deposit, Sichuan Province: Constraints on Ore Genesis
Abstract
BACKGROUND The Xuebaoding deposit, located in the Songpan-Ganzi orogenic belt, Sichuan Province, is famous for coarse-grained W-Sn-Be-F-P-bearing minerals. Many studies have been carried out on this deposit, but there is a lack of research on major and trace elements of coarse-grained minerals. OBJECTIVES To obtain major and trace element composition of minerals and provide constraints on ore genesis of the Xuebaoding deposit. METHODS In this study, X-ray fluorescence spectrometry (XRF) and electron probe microanalysis (EMPA) were used to analyze the major elements of minerals in the deposit, and the trace elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS The results showed that beryl, scheelite, cassiterite, muscovite, fluorite, apatite and tourmaline in the Xuebaoding deposit were rich in major ore-forming elements (W, Sn, Be, Na, K, Ca) and alkali metal elements such as Li, Rb, Cs, and volatiles such as F, B, and P. Beryl in the Xuebaoding deposit was rich in Li (3484-4243μg/g), Rb (39.3-71.1μg/g) and Cs (2955-3526μg/g). The content of Li, Rb and Cs in muscovite was as high as 4243μg/g, 72.3μg/g and 3526μg/g, respectively. The content of F in apatite and B in tourmaline were 4.48%-5.21% and 30990-32880μg/g, respectively. The granites in the Xuebaoding deposit were relatively rich in W, Sn, Be, Li, Rb, Cs, F, B, P, with relatively low CaO content (0. 46%-0. 82%). Li, Rb, Cs, F, B, P were conducive to the enrichment of ore-forming elements in fluids. Marble in the mining area was calcite marble, which provided a large amount of Ca for mineralization and was conducive to the large-scale precipitation of coarse-grained minerals. CONCLUSIONS W, Sn, Be, Li, Rb, Cs, F, B and P in coarse-grained minerals are mainly derived from magmatic fluids, where the marble strata provide a large amount of Ca for coarse-grained minerals.
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