https://www.usgs.gov/publications/pre-ore-potassium-metasomatism-creede-mining-district-colorado
PRE-ORE POTASSIUM METASOMATISM, CREEDE MINING DISTRICT, COLORADO. | U.S. Geological Survey
Rhyolitic welded-tuff wallrocks of the epithermal base and precious metal veins of the Creede district were pervasively altered by the addition of more than...