One-dimensional gravity calculation and Paleozoic structure and plutons at Reelfoot Scarp

Technical Report · Fri Aug 01 04:00:00 EDT 1986

OSTI ID:5274661

Stearns, R G; Wilson, S L

At Reelfoot Scarp closely spaced gravity data occur in the same place as several seismic lines. Gravity data are used as a supplement to seismic data to construct seven structure maps at an increasing level of detail. Of these seven, five use gravity data to calculate elevation of the Paleozoic-Cretaceous boundary. This boundary is about 2000 feet below the land surface: above it density is low, below it density is high. On a map constructed from 14 widely-spaced shot points which were also gravity stations, structure was estimated from gravity alone at 85 gravity stations. Twenty two of these 85 gravity stations were near other seismic shot points; here elevations calculated from gravity were compared with elevations measured by seismic reflection. The difference had a standard deviation of 29 feet. A 29-foot error is acceptable for this area where structural offsets of over 100 feet occur. A positive 0.4 to 1.0 milligal gravity anomaly unrelated to Paleozoic structure indicates a high density rock mass near Reelfoot Scarp. It must be below the top of the Paleozoic section, because it was not seen on seismic lines, so its minimum depth is about 2100 feet. Its maximum depth of about 4000 feet is estimated from its half width assuming a spherical mass. A somewhat shallower laccolith is possible.

• Research Organization: Vanderbilt Univ., Nashville, TN (USA)
• OSTI ID: 5274661
• Report Number(s): NUREG/CR-4703; ON: TI86901687
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
FEDERAL REGION IV
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
GRAVITY SURVEYS
NORTH AMERICA
RIFT ZONES
SURVEYS
TENNESSEE
USA