Uranium mineralization in fluorine-enriched volcanic rocks

Technical Report · Mon Sep 01 00:00:00 EDT 1980

DOI:https://doi.org/10.2172/6844645· OSTI ID:6844645

Burt, D. M.; Sheridan, M. F.; Bikun, J.; Christiansen, E.; Correa, B.; Murphy, B.; Self, S.

Several uranium and other lithophile element deposits are located within or adjacent to small middle to late Cenozoic, fluorine-rich rhyolitic dome complexes. Examples studied include Spor Mountain, Utah (Be-U-F), the Honeycomb Hills, Utah (Be-U), the Wah Wah Mountains, Utah (U-F), and the Black Range-Sierra Cuchillo, New Mexico (Sn-Be-W-F). The formation of these and similar deposits begins with the emplacement of a rhyolitic magma, enriched in lithophile metals and complexing fluorine, that rises to a shallow crustal level, where its roof zone may become further enriched in volatiles and the ore elements. During initial explosive volcanic activity, aprons of lithicrich tuffs are erupted around the vents. These early pyroclastic deposits commonly host the mineralization, due to their initial enrichment in the lithophile elements, their permeability, and the reactivity of their foreign lithic inclusions (particularly carbonate rocks). The pyroclastics are capped and preserved by thick topaz rhyolite domes and flows that can serve as a source of heat and of additional quantities of ore elements. Devitrification, vapor-phase crystallization, or fumarolic alteration may free the ore elements from the glassy matrix and place them in a form readily leached by percolating meteoric waters. Heat from the rhyolitic sheets drives such waters through the system, generally into and up the vents and out through the early tuffs. Secondary alteration zones (K-feldspar, sericite, silica, clays, fluorite, carbonate, and zeolites) and economic mineral concentrations may form in response to this low temperature (less than 200 C) circulation. After cooling, meteoric water continues to migrate through the system, modifying the distribution and concentration of the ore elements (especially uranium).

• Research Organization: Arizona State Univ., Tempe (USA). Dept. of Geology
• DOE Contract Number: AC13-76GJ01664
• OSTI ID: 6844645
• Report Number(s): GJBX-225(80)
• Country of Publication: United States
• Language: English

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ACTINIDES
ALKALINE EARTH METALS
BERYLLIUM
CHEMISTRY
ELEMENTS
FLUORINE
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGY
HALOGENS
IGNEOUS ROCKS
MAGMA
MATHEMATICAL MODELS
METALS
MINERAL RESOURCES
MINERALIZATION
MOLYBDENUM
NEW MEXICO
NIOBIUM
NONMETALS
NORTH AMERICA
PERMEABILITY
PETROLOGY
REFRACTORY METALS
RESOURCES
RHYOLITES
ROCKS
ROCKY MOUNTAIN REGION
SOUTHWEST REGION
TANTALUM
THORIUM
TIN
TRANSITION ELEMENTS
TUFF
TUNGSTEN
URANIUM
URANIUM DEPOSITS
USA
UTAH
VOLCANIC ROCKS