Characterization of U(-V) Deposits in the La Sal District, UT and CO and Their Relationship to Paradox Basin Fluid Flow

Research output: Contribution to journalArticlepeer-review

Abstract

This paper synthesizes new and previous work on the tabular sandstone-hosted uranium and vanadium deposits of the La Sal district, one of the principal U-V districts of the Colorado Plateau. Deposits form a 1–3 km wide, E-W trending 30 km long trend spanning the Utah-Colorado border, approximately orthogonal to the Uravan belt. Ore is hosted in the uppermost fluvial subarkosic sandstones of the Salt Wash Member of the Jurassic Morrison Formation and typically forms channel-parallel, elongate orebodies up to 180 m long, 90 m wide, and 1 m thick. Sandstones are interbedded with silty, muddy, and calcareous units. Principal mineralogical changes include quartz overgrowths accompanied by destruction of early diagenetic hematite. Precipitation of compositionally distinct carbonate cements and clays followed. Bleaching was prior to and/or contemporaneous with mineralization, which is restricted to bleached rocks. Petrography shows that ore minerals (uraninite, coffinite, and montroseite) in part predate growth of authigenic quartz and calcite cements, followed by the formation of ferroan dolomites. Abundant V-rich phyllosilicates may reflect back-reaction of montroseite with quartz and other minerals. New U-Pb dating of ore-hosting calcite (~144 Ma) and K-Ar dating of V-clays (~42–36 Ma) parallel published results for elsewhere on the Plateau. Sedimentary structures (e.g., crossbedding), primary porosity, and the distribution of lithofacies in the local Salt Wash channel system control mineral growth. The thin section- to district-scale observations suggest that mineralization formed either by mixing of two fluids, or alternatively by reaction of oxidized fluids with a reductant earlier introduced during bleaching, as has been suggested in other Plateau deposits.

Original languageEnglish (US)
Pages (from-to)2693-2721
Number of pages29
JournalMining, Metallurgy and Exploration
Volume41
Issue number5
DOIs
StatePublished - Oct 2024
Externally publishedYes

Keywords

  • Paleofluids
  • Paradox Basin
  • Sandstone-hosted uranium

ASJC Scopus subject areas

  • Control and Systems Engineering
  • General Chemistry
  • Geotechnical Engineering and Engineering Geology
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'Characterization of U(-V) Deposits in the La Sal District, UT and CO and Their Relationship to Paradox Basin Fluid Flow'. Together they form a unique fingerprint.

Cite this