| This study examines geologic, chemical, and hydrologic controls on mineral distribution in the Creede, Colorado, epithermal system. This work expands upon extensive research at Creede by many investigators, and develops interpretations which are the best possible of voluminous data from complex ore deposits.;Ore petrology studies (Part I) show that mineral distribution within the Bulldog Mountain (BDM) vein system was influenced by closing (opening) of fractures by mineral deposition (leaching) and structural activity during mineralization. Six BDM paragenetic stages are identified and correlated with stages in other central and southern district vein systems; spatially zoned stages reflect the chemical evolution of hydrothermal fluids in response to boiling and mixing.;Chemical modeling (Part II) suggests that hydrothermal brines initially boiled to varying degrees in the OH, P, northern exposed BDM, and central Amethyst vein systems: limited boiling deposited chlorite, pyrite, hematite, quartz, and fluorite with lesser base metal sulfides; more extensive boiling produced quartz, fluorite, adularia, and hematite. After boiling, the hydrothermal fluids mixed to the south with dilute overlying groundwaters. Initial mixing deposited sphalerite- and galena-rich assemblages; continued mixing produced progressively greater amounts of barite, native silver, and acanthite along the southern Amethyst and BDM vein systems.;Botryoidal pyrite, marcasite, and other late-stage sulfides record the collapse of the waning Creede hydrothermal system (Part III). Mineral distribution and textures indicate periodic shifts to vapor-dominated conditions. Steam and other gases boiled from deep hydrothermal fluids and formed a vapor-dominated zone: pyrite and marcasite were deposited when H... |
