Texture and Geochemistry of Scheelites in the Tongshankou Deposit in Daye, Hubei, China: Implication for REE Substitution Mechanism and Multistage W Mineralization Processes

Abstract

The Tongshankou skarn deposit in the Edong ore district is a typical metasomatic deposit associated with adjacent granodiorite porphyry and carbonate rocks. Using comprehensive microscopic observations, mineralogical and geochemical analysis, scheelite grains in the skarns can be classified into three major types, showing multi-stage mineralization characteristics. In the redox fluid environment, scheelites that occur with garnets usually have affinity to garnets, while in later skarn phases others exist with oxides and sulfides. They can be subdivided by trace elements, such as Nb and Eu, to discuss the detailed ore-forming process. Scheelites have three typical substitution mechanisms including: 2Ca2 + ⇌ REE3 + +Na+ (1); Ca2 + + W6 + ⇌ REE3 + +Nb5+(2); and 3Ca2 + ⇌ 2REE3++ □Ca (□Ca = Ca site vacancy) (3). Plagioclase or various hydrothermal stages can cause Eu anomalies to fluctuate from positive to negative, and these processes can cause particular zonation in W and Mo contents in scheelites. This study highlights the use of texture and geochemistry of scheelites in skarn deposits, depicting the W mineralization processes.

Process Mineralogy of Lithium and Rubidium in the Diantan Polymetallic Mining Area, Tengchong, Southwest China

“…The Diantan Sn-Pb-Zn polymetallic deposit in Tengchong, Yunnan, is located in the Tengchong Block of the Southwest Three Rivers Tethys tectonic domain. It represents the northern extension of the well-known southeast Asian tin polymetallic mineralization belt [13][14][15][16][17], primarily yielding Sn, Pb, Zn, and fluorite deposits. Recent mineral exploration has shown that the granite associated with the Sn-Pb-Zn deposits in the mining area is highly differentiated and evolved, suggesting significant mineralization potential for key metals such as Li and Rb.…”