An integrated geological, geophysical, and geochemical investigation of the major fractures on the east side of the New Madrid earthquake zone

Technical Report · Fri May 01 04:00:00 EDT 1987

OSTI ID:6607962

Stearns, R G; Reesman, A L

The eastern edge of the Mississippi Valley graben (Reelfoot rift) is a series of offset segments marked by offset ''ridges'' of gravity anomaly. The most prominent offsetting fault is the Dyersburg line that is a least 60 miles long and cuts completely through the graben. The Dyersburg line is traced by earthquakes, the pattern of the geothermal gradient, offset gravity anomalies, and surface linears. Composition of ground water from the Cretaceous McNairy Formation, the Eocene Wilcox and Claiborne formations, and Holocene alluvium are all significant for the structure of the rift. Trends for some chemical species are parallel to the rift or the Dyersburg line (and probably the pre-Cretaceous Pascola arch). Barium and lithium show parallelism to both; strontium isotope ratios trend parallel to the rift whereas carbon isotope ratios trend parallel to the Pascola arch. Upward leakage along faults of mineralized and high pressure water from the McNairy is the likely explanation for localized occurrence of mineralized water in younger aquifers. The best example is chloride water in Holocene alluvium on the Dyersburg line. Sodium bicarbonate waters could be candidates for igneous input. Sodium bicarbonate waters could be candidates for igneous input. Perhaps a more likely explanation is that they evovled by ion exchange between ground water and fermenting sediment containing sodium-rich clays and siderite. In central Tennessee, the Beech Grove lineament is shown to be non-tectonic. It could have originated as streams flowing parallel to NNE-trending cuestas. Later, after downcutting, the streams still flow in the same aligned trend.

• Research Organization: Vanderbilt Univ., Nashville, TN (USA). Dept. of Geology; Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering
• OSTI ID: 6607962
• Report Number(s): NUREG/CR-4936; ON: TI87900686
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
CHEMICAL COMPOSITION
CHEMISTRY
FEDERAL REGION IV
GEOCHEMISTRY
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
GRAVITY SURVEYS
GROUND WATER
HYDROGEN COMPOUNDS
NORTH AMERICA
OXYGEN COMPOUNDS
RIFT ZONES
SURVEYS
TENNESSEE
USA
WATER