Tectonic control of regional ground-water flow in deeply buried aquifers of the northern Mississippi embayment, Missouri and Arkansas

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5046171

Brahana, J V ^[1]

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1. Geological Survey, Fayetteville, AR (United States)

Recent research focusing on the McNairy-Nacatoch aquifer of Cretaceous age and the Ozark aquifer of Cambrian-Ordovician age in the northern Mississippi embayment indicates that tectonics have significantly influenced the hydrogeology in this seismically active area of southeastern Missouri and northeastern Arkansas. Deep ground-water flow patterns in the McNairy-Nacatoch aquifer in the northern Mississippi embayment appear to be affected by three major tectonic features. Delineation of these flow patterns is based on an analysis of hydrogeologic, geochemical, and hydraulic data that includes geologic and geophysical well logs, and data on major-element geochemistry, water temperature, stable isotopes, radionuclides, and potentiometric heads. Anomalies in the areal distribution of hydraulic and geochemical characteristics in the McNairy-Nacatoch aquifer coincide with and overlie these three tectonic features. The first feature, the western margin of the Mississippi embayment rift, coincides with anomalous radium and uranium isotopic ratios, very old water ([sup 36]Cl) downgradient from the rift, and a trough in the potentiometric surface. The second feature, the Pascola arch, coincides with changes in inorganic geochemistry, uranium isotopic anomalies, and a [sup 14]C anomaly. The third feature, a fault-controlled paleokarst subcrop, coincides with a thermal anomaly of relatively young and relatively fresh meteoric water. Potentiometric heads in the aquifers increase with depth, and hydraulic gradients are upward throughout most f the embayment. Coupled with the constraints imposed by the geochemical and isotopic anomalies, discharge seems to be concentrated across regional confining units in the area of the anomalies.

• OSTI ID: 5046171
• Report Number(s): CONF-9303210--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540250* -- Environment
Terrestrial-- Site Resource & Use Studies-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
ACTINIDE ISOTOPES
ALKALINE EARTH ISOTOPES
AQUIFERS
ARKANSAS
CHEMICAL COMPOSITION
CHLORINE ISOTOPES
DEVELOPED COUNTRIES
ENVIRONMENTAL TRANSPORT
FLOW MODELS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROLOGY
ISOTOPE RATIO
ISOTOPES
MASS TRANSFER
MATHEMATICAL MODELS
MISSOURI
NORTH AMERICA
OXYGEN COMPOUNDS
RADIONUCLIDE MIGRATION
RADIUM ISOTOPES
URANIUM ISOTOPES
USA
WATER