Results of Electrical Resistivity Data Collected near the Town of Guernsey, Platte County, Wyoming

As part of a study to investigate subsurface geologic conditions as they relate
to ground-water flow in an abandoned landfill near the town of Guernsey,
Wyoming, geophysical direct current (DC) resistivity data were collected. Eight
vertical resistivity soundings and eight horizontal resistivity profiles were
made using single channel and multi-channel DC instruments. Data collected in
the field were converted from apparent resistivity to inverted resistivity with
depth using a numerical inversion of the data. Results of the inverted
resistivity data are presented as horizontal profiles and as profiles derived
from the combined horizontal profile and vertical sounding data. The data sets
collected using the single-channel and multi-channel DC systems provided for
the resistivity investigation to extend to greater depth. Similarity of the
electrical properties of the bedrock formations made interpretation of the
resistivity profiles more difficult. High resistivity anomalies seen in the
profiles are interpreted as quartzite lenses and as limestone or metadolomite
structures in the eastern part of the study area. Terrace gravels were mapped
as resistive where dry and less resistive in the saturated zone. The DC
resistivity methods used in this study illustrate that multi-electrode DC
resistivity surveying and more traditional methodologies can be merged and used
to efficiently map anomalies of hydrologic interest in geologically complex
terrain.

[Summary provided by the USGS.]