Acid-Sulfate Epithermal Processes and the Relationship of the Deep Summitville System to the Shallow Gold Ore

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Summitville is a classic example of the acid sulfate type of ore deposit, but deep drilling shows that there are "porphyry-type" vein stockworks and alteration at depth beneath. The deep mineralization has not been carefully studied or dated. This project is to describe in detail the veins and alteration of the deep mineralization and to date them (K-Ar on sericite and alunite) and the shallow alunite associated with gold. It should be possible to establish the nature of the relationship of the "porphyry-type" mineralization to the shallow copper-gold and the relation of both to other occurrences of enargite-covellite lodes such as those in Butte, Montana. Another aspect is numerical modeling of covellite-enargite-gold precipitation by the newly recognized process of boiling with decreasing pH. Magmatically-derived waters with admixed meteoric waters will be used. It is also planned to model processes of mixing and wall rock reaction. A clear understanding of the processes of ore precipitation and wall rock reaction in acid-sulfate-type epithermal ore deposits should be established.