【摘要】 本文着重论述了珊瑚钨锡矿床中主要矿脉内黑钨矿的标型特征,进而讨论了黑钨矿形成的条件。但愿对此类矿床的成因研究有所裨益。不当之处,望指正。更多还原

【Abstract】 The Shanhu tungsten-tin deposit occurs in the middle early Devonian limestone, sandstone and shale. It consists of six ore vein systems. Among them Ⅱ, ⅢI and Ⅵ systems, which merge at depth into a single whole, are the largest in size. A multi-stage mineralization can be observed. The ore veins formed in stage Ⅱ have an assemblage of cassiterite-wolframite-sulfide-quartz, and constitute the main part of the deposit. A reverse vertical zoning of precipitation is clearly recognized. Wolframite belongs to huebnerite and Fe huebnerite. FeO and MnO show a opposite correlation. MnO/FeO ratio decreases progressively from the upper level to the lower as well as from the earlier generations to the later ones. The regular variation of compo- sition causes changes in physical properties of wolframite. From earlier to later generation, hardness, specific gravity, magnetic susceptibility and reflective power increase, while the average temperature of formation decreases. wolframite in this deposit formed from a weak acidic to weak alkaline and Mn-rich to Fe-rich solution in a oxidation to weak reduction envi- ronment. In some of the veins, a change from Ta-rich to Nb-rich is also observed. The affinity of S^2- and Fe²⁺ is bigger than WO₄²-and Fe²⁺, so Fe²⁺ prefer to combine with S^2- to form arsenopyrite. During the mine ralization process, Fe²⁺ in the ore-bearing fluid decreases. Country rocks show a significant influence on the mineralization as well.更多还原