McDermitt Caldera

Region West, Southwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Outline of caldera and surrounding rocks from geologic maps.
Identified resources None.
Production None.
Status Unknown.
Estimated resources Unknown.
Geologic maps Jenks and others (2007), scale 1:100,000; Henry and others (2016), scale 1:70,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Eocene intermediate volcanism and major Miocene volcanism, including eruption of meta-aluminous to peraluminous biotite rhyolite lavas and domes in caldera wall (created by eruption of the McDermitt Tuff) (Henry and others (2017).
Deposits None.
Evidence from mineral occurrences Rytuba and others (2003).
Geochemical evidence Unknown.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments The McDermitt caldera region is a unique environment with aspects of at least four overlapping and interrelated mineral systems. Possible systems include: Magmatic REE system related to plume-related basalt-peralkaline rhyolite magmatism (Peralkaline syenite/ granite/rhyolite /alaskite/pegmatites deposit type). A related Climax-type mineral system, with steamed-heated Lithocap alunite (K, Al, Ga) and Volcanogenic uranium deposit types (U); Meteoric convection system with Low sulfidation epithermal Hg, and, most importantly at this time, a Lacustrine evaporite system (Lithium clay and Residual brine deposit types) that created the large Li enrichments in caldera sediments. No known deposits related to the Magmatic REE system are currently recognized.
Cover thickness and description Unknown.
Authors Albert H. Hofstra.
New data needs Mapping focused on hydrothermal alteration and mineralization, geophysics.
Geologic mapping and modeling needs Updated geologic mapping.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar inadequate.