Salt Water Intrusion on A barrier Island

by C. Rupple

Pseudo-section interpretation of dipole-dipole survey conducted with a Syscal Jr. resistivity meter along a transect perpendicular to the Atlantic coast and between tidally-influenced sloughs on a predominately sand barrier island on the Georgia coast. The low resistivity (high conductivity) region between 5 and 8 m depth is interpreted as corresponding to subsurface drainage though a saline-saturated lithology. The increase in resistivity with depth is well-constrained by data extending to 25m depth in the pseudo-section and may represent a change in lithology and /or permeability. Data courtesy of C. Ruppel and G. Schultz, Georgia Tech.

Schlumberger data collected with a Syscal Jr. resistivity meter along an airstrip running subparallel to a tidal creek on the landward side of a barrier island on the Georgia coast. Best-fitting, three-layer model parameters (layer thicknesses and apparent resistivities) are shown in the lower left part of the diagram and were derived by application of a linear filtering technique. The decrease in resistivity with depth is loosely consistent with the transition from unsaturated to saltwater saturated sediments with an intervening layer of freshwater-saturated material. Data courtesy of C. Rupple and G. Schultz, Georgia Tech.