Alteration and mineralization in the eastern part of the Soldier Mountains, Camas County, Idaho

The eastern part of the Soldier Mountains in Camas
County, south-central Idaho, is underlain principally by plutonic
rocks of Cretaceous and Eocene age that locally have undergone
propylitic, potassic, and muscovite-quartz alteration. Muscovite-
quartz alteration is Cretaceous in age and is localized along
joints and fractures, some of which are filled with quartz. Associated
veins have yielded minor amounts of gold. Potassic alteration
is probably both Cretaceous and Eocene in age but is
weakly developed and limited in extent. Propylitic alteration is
Eocene in age and is pronounced around biotite granite plutons.
Despite a clear association between plutons of biotite granite and
widespread propylitic alteration, mineralization associated with
these rocks was minimal. Mineralized areas within more mafic
Eocene plutons are characterized by veins and (or) stockworks(?)
enriched in copper, molybdenum, and silver, but these
areas are restricted in size and have not been productive.