Regional hydrodynamics and hydrochemistry of the uranium-bearing Oakville aquifer (Miocene) of south Texas. Report of investigations No. 124
The Oakville Formation consists of sediments deposited by several major fluvial systems that traversed the Texas Coastal Plain during the Miocene Epoch. Facies geometry and composition, together with superimposed structure and topography, are important determinants of ground-water flow, aquifer transmissivity, and regional hydrochemical evolution. Topographically high areas along the Oakville outcrop are ground-water recharge zones. Downdip movement of ground water is deflected along strike into major incised stream valleys and modified by local ground-water pumping, resulting in discharge of Oakville water from relatively shallow sections of the aquifer. Discharge from local and intermediate-scale flow cells, as well as influx along growth faults of high-salinity water from deeper stratigraphic horizons, is readily shown by field phenomena. Introduction of exotic evolved connate waters is demonstrable by the distribution of sulfate, chloride, and reduced sulfur species. Shallow Oakville ground waters exhibit a clearly defined compositional change from predominantly sodium chloride waters in the southwest to calcium bicarbonate waters in the northeast. Redox potential (Eh) of Oakville ground water decreases from +470 mV (oxidizing) to -170 mV (reducing) with increasing depth and coincides with an increase in pH and tempertaure. Dissolved oxygen content exhibits an inverse relationship to Eh and reduced sulfur. Higher recharge in the northeast results in a deeper subsurface penetration of oxygenated ground waters. The regional distribution of trace amounts of uranium, molybdenum, selenium, and arsenic in Oakville ground water demonstrates a good correlation with known sites of uranium mineralization, and defines elevated trace metal contents unrelated to known uranium occurrences. These same elements exhibit an overall increased background level in the southwestern section of the study area. 26 figures, 1 table.
- Research Organization:
- Texas Univ., Austin (USA). Bureau of Economic Geology
- OSTI ID:
- 6146550
- Report Number(s):
- NP-3901761; ON: DE83901761
- Country of Publication:
- United States
- Language:
- English
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ACID CARBONATES
ACTINIDES
ALKALI METALS
ALKALINE EARTH METALS
AQUIFERS
ARSENIC
CALCIUM
CENOZOIC ERA
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
COPPER
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ELEMENTS
EXPERIMENTAL DATA
EXPLORATION
FEDERAL REGION VI
FLUID MECHANICS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
GROUND WATER
HALIDES
HALOGEN COMPOUNDS
HYDRODYNAMICS
HYDROGEN COMPOUNDS
HYDROLOGY
INFORMATION
IRON
MANGANESE
MECHANICS
METALS
MINERAL RESOURCES
MINERALIZATION
MOLYBDENUM
NORTH AMERICA
NUMERICAL DATA
OXYGEN COMPOUNDS
PH VALUE
REDOX POTENTIAL
RESOURCES
SELENIUM
SEMIMETALS
SODIUM
STRATIGRAPHY
SULFATES
SULFUR COMPOUNDS
TERTIARY PERIOD
TEXAS
TRACE AMOUNTS
TRANSITION ELEMENTS
URANIUM
URANIUM DEPOSITS
USA
WATER