Date of Award


Degree Name

Master of Science


Geological and Environmental Sciences

First Advisor

Dr. John D. Grace

Second Advisor

Dr. Cynthia Wood

Third Advisor

Dr. Christopher Schmidt

Access Setting

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.

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