In-situ LA-ICP-MS trace element analyses of scheelite and wolframite: Constraints on the genesis of veinlet-disseminated and vein-type tungsten deposits, South China

Scheelite from 25 representative orogenic gold deposits from various geological settings was investigated by EPMA (electron probe micro-analyzer) and LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometer) to establish discriminant geochemical features to constrain indicator mineral surveys for gold exploration. Scheelite from orogenic gold deposits displays five REE patterns including a bell-shaped pattern with a (i) positive or (ii) negative Eu anomaly; (iii) a flat pattern with a positive Eu anomaly and, less commonly, (iv) a LREE-enriched pattern, and (v) a HREE-enriched pattern. The REE patterns are interpreted to reflect the source of the auriferous hydrothermal fluids and, perhaps, co-precipitating mineral phases. Scheelite from deposits formed in rocks metamorphosed at upper greenschist to lower amphibolite facies have low contents in REE, Y, and Sr, and high contents in Mn, Nb, Ta, and V, compared to scheelite formed in rocks metamorphosed below the middle greenschist facies. Scheelite from deposits hosted in sedimentary rocks has high Sr, Pb, U, and Th, and low Na, REE, and Y, compared to that hosted in felsic to intermediate rocks. Statistical analysis including elemental plots and multivariate statistics with PLS-DA (partial least square-discriminant analysis) reveal that the metamorphic facies of the host rocks as well as the regional host rock composition exert a strong control on scheelite composition. This is a result of fluid-rock exchange during fluid flow to gold deposition site. PLS-DA and elemental ratio plots show that scheelite from orogenic gold deposits have distinct Sr, Mo, Eu, As, and Sr/Mo, but indistinguishable REE signatures, compared to scheelite from other deposit types.

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Trace element composition of scheelite in orogenic gold deposits

Origin of the Muguayuan veinlet-disseminated tungsten deposit, South China: Constraints from in-situ trace element analyses of scheelite

Introduction to the special issue of Mesozoic W-Sn deposits in South China

Comparative geochemical study of scheelite from the Shizhuyuan and Xianglushan tungsten skarn deposits, South China: Implications for scheelite mineralization

Zheng Zhao

Papers

Constraints on the uptake of REE by scheelite in the Baoshan tungsten skarn deposit, South China