Preliminary study of rock alteration in the Catheart Mountain molybdenum-copper deposit, Maine

Abstract

Studies of drill cores from the Catheart Mountain molybdenum-copper deposit indicate that the deposit is of the porphyry type. Hydrothermal alteration and sulfide mineralization are probably distributed in complex but systematic alteration zones. Most or all mineralization at Catheart Mountain is in a medium-fine-grained quartz monzonite enclosed within a larger mass of Attean Quartz Monzonite; no ore and little hydrothermal alteration have been seen in the Attean. Much of the ore and hydrothermal alteration seem to be and presumably are spatially related to irregular intrusive masses of porphyry. Only certain porphyry intrusives are mineral bearing, however, and many have no associated ore and alteration. Studies of hydrothermal alterations in surface exposures supplemented by rock analyses of bulk samples indicate that alteration features and sulfide zone characteristics of an area northwest of the mountain crest are, when measured against accepted porphyry models, very favorable for the occurrence of ore. Even though this favorable area has already been tested by some drilling, the presence together here of the strong center of potassic enrichment, the well-developed pyrite zone, and the strong and extensive phyllic alteration suggest that some further evaluation may be warranted.