Date of Award
Master of Science
Geological and Environmental Sciences
Dr. John D. Grace
Dr. Cynthia Wood
Dr. Christopher Schmidt
Masters Thesis-Open Access
The Summit Creek stock, a molybdenum prospect located in the Pioneer Mountains of central Idaho, is a 46.7 m.y. old medium grained, slightly porphyritic quartz monzonite, which has intruded the late Ordovician Phi Kappa formation. Trend surface analysis shows that the stock is the product of one intrusive event. Pervasive mineral alteration usually associated with such porphyry (stockwork) molybdenum deposits is not present in this pluton, and the alteration that is present is confined to local faults and fractures.
Geochemical and petrographic evidence suggest that the pluton is a felsic differentiate from a melt which originated at a depth of 220-260 kilometers along an east-dipping subduction zone. Whole rock major element geochemical analysis indicates that the stock is a high potassium calc-alkaline intrusion. Trace element analysis shows similarities to other stocks associated with economic molybdenum deposits. In addition, chemical analysis of argillic assemblages are similar to those of porphyry molybdenum deposits.
Hanna, Thomas Murray, "The Geology and Geochemistry of the Summit Creek Molybdenum Prospect, Custer County, Idaho" (1983). Masters Theses. 1599.