Mineral Systems of the Ancestral and Modern Cenozoic Cascades Arcs and central California Coast Ranges, Western USA

Staff

Tasks

Project summary:

Robust quantitative mineral resource assessments require both comprehensive knowledge of the regional geology and the mineral deposits of the assessment areas, and detailed genetic models of deposit types used in the assessments. A comprehensive understanding of the geology, hydrothermal systems, and mineral resources of the Cascades arcs and central California Coast Ranges is essential for land-use managers to be able to plan for future multiple uses and for increasing reliability of the forthcoming National Mineral Resource Assessment. Areas to the east of the western Great Basin (including the Humboldt River Basin), as well as the Western Cascades arc in Oregon and Washington, recently have received comprehensive geologic and mineral resource investigations. However, mineral resource information for much of the northwestern Great Basin and Modoc Plateau south of the High Cascades in California and for the central Coast Ranges is not comprehensive or the existing data compilations are outdated, creating a critical gap in regional geologic and resource knowledge and databases.

Major objectives of the project are:

• to develop and enhance regional databases, interpretations, and mineral deposit models and develop comprehensive metallogenic model for Cenozoic magmatically-related deposits of the ancestral Cascades arc (NE California to SW Nevada), central California Coast Ranges, and eastern Sierra Nevada
• begin to integrate these data and interpretations with better-studied areas to the north (Western Cascades arc in Washington, Oregon, and northernmost California) and east (northern Great Basin) to develop high quality regional geologic and mineral-resource frameworks
• improve genetic understanding and models of mineral deposits related to shallow hydrothermal systems, especially epithermal precious and base metal deposits
• improve understanding of the differences between barren and productive arc terranes and their contained hydrothermal systems
• improve understanding and distinguish types of hydrothermal systems and hydrothermal mineral deposits that form in magmatic arcs and those that form in extensional environments
• ensure that the results of the project meet the geologic and natural-resource needs of land-use agencies.