Geophysical Surveys To Characterize The Hydrogeology Of The Arbuckle Uplift, South-Central Oklahoma

Airborne and ground electrical resistivity and magnetic surveys as well as ground gravity measurements have been conducted to map the subsurface geologic and hydrologic features of the<br>Arbuckle Uplift. The main target of these investigations is the Paleozoic Arbuckle-Simpson aquifer and the surrounding stratigraphic units of the Arbuckle Uplift in south-central Oklahoma. In March, 2007, helicopter-borne electromagnetic (resistivity) and magnetic survey was flown of four areas with distinctly different geology were flown using measurement systems. The airborne resistivity measurements were made at six different frequencies ranging from 400 Hz to 115,000 Hz which provided a depth of penetration from a few meters to about 80 m. Ground resistivity profiling has been conducted in several areas of the uplift for subsurface resistivity imaging. Two of the resistivity profiles are in the area encompassed by the airborne survey. Total field magnetic and high precision location (GPS and laser altimeter) measurements were also made as part of the airborne survey. Ground gravity and magnetic profiling was also conducted to refine location of structures in specific areas. The geology of the study area consists of dolomitic limestone (Arbuckle and Simpson Groups) that generally lies in fault contact with younger Paleozoic clastic and carbonate rocks. The formational units are gently dipping except on the flanks of the uplift. The geophysical maps, resistivity depth sections, and interpreted cross sections from the magnetic and gravity data are being used to improve the geologic mapping and better define hydrologic features of the area.