Alteration and ore-forming processes at Mattagami Lake Mine, Quebec
Alteration and ore-forming processes at Mattagami Lake Mine, Quebec
复制标题
魁北克马塔加米湖矿的蚀变和成矿过程
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
E. Reardon
中科院分区：
文献类型：
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作者：
R. G. Roberts;E. Reardon
The altered rocks of the Mattagami Lake Mine, a stratabound, volcanogenic, massive sulphide deposit, were examined using whole rock analyses and electron microprobe studies of the constituent minerals. The significant chemical and mineralogical transformations involved in the progressive alteration of the footwall, vitroclastic tuff of rhyodacitic composition, are: (1) the removal of alkalies (sodium followed by potassium), and the addition of magnesium and iron during initial chloritization; (2) substantial removal of silica by the solution of quartz, to produce a chlorite-rich rock, and (3) gradual removal of aluminum and the transformation of chlorite (Mg2.5 Fe2.5Al2Si3O10(OH)8) to talc (MG2.5FE0.5Si4O10(OH)2 to produce units of talc–actinolite schist. The reaction: 3 chlorite + 10H2S(g) + 2.5 O2 + 11,H4SiO4 + 5Mg2+ = 5talc + 5pyrite + + 19H2O + 16H+ (log K, 25 °C = +145; log K, 100 °C = +102; log K, 250 °C = +68.2) is favoured by high temperature and Mg2+ activity, and low activity of aluminum.The al...
