Seminar

Scheelite is the main ore mineral in skarn-type tungsten deposits, and a common accessory mineral in a variety of rock-types. The Baoshan deposit in South China is one of the most important polymetallic scheelite skarn deposits in China. At Baoshan, scheelite occurs in both the prograde and retrograde skarns, and is complexly zoned. REE concentrations and chondrite-normalized REE profiles of scheelite from Baoshan vary with the distribution of major elements. Crystal structure provided the first-order control on the minor and trace element composition of the scheelite. Incorporation of REE3+ into scheelite was controlled partly by a coupled substitution involving Mo. The lattice strain model was used to estimate scheelite-fluid partition coefficients for the REE from the contents of these elements in the scheelite and to predict the relative distributions of the REE in the ore-forming fluids. Our study shows that the composition of scheelite recorded the history of the Baoshan hydrothermal system, and that the behaviour of the REE could be used to quantitatively reconstruct the changing physicochemical conditions during ore formation.