The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

Scientific Investigations Report 2017-5134
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Abstract

This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.

In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.

The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.

Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

Suggested Citation

Van Gosen, B.S., and Hall, S.M., 2017, The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States: U.S. Geological Survey Scientific Investigations Report 2017–5134, 27 p., https://doi.org/10.3133/sir20175134.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Yeelirrie Calcrete Uranium Deposits
  • Regional Setting
  • Stratigraphy
  • Kerr-McGee Corporation’s Exploration Program and Discoveries in the Southern High Plains
  • Discussion
  • Conclusions
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States
Series title Scientific Investigations Report
Series number 2017-5134
DOI 10.3133/sir20175134
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Central Mineral and Environmental Resources Science Center
Description vi, 27 p.
Country United States
State Texas
Other Geospatial Southern High Plains
Online Only (Y/N) Y