HR: 0800h
AN: NS31B-0381    [Abstracts]
TI: Geophysical Investigation of the Arbuckle-Simpson Aquifer, Oklahoma, to Determine the Influence of Subsurface Structure on Groundwater Flow
AU: * Lewallen, E
EM: erin-lewallen@utulsa.edu
AF: The University of Tulsa, 600 South College, Tulsa, OK 74104, United States
AU: Ramachandran, K
EM: kumar-ramachandran@utulsa.edu
AF: The University of Tulsa, 600 South College, Tulsa, OK 74104, United States
AU: Tapp, B
EM: jbt@utulsa.edu
AF: The University of Tulsa, 600 South College, Tulsa, OK 74104, United States
AB: We investigate an area of the Arbuckle-Simpson aquifer in southern Oklahoma by employing near-surface geophysical surveying. This predominantly carbonate aquifer encompasses the Simpson, Arbuckle, and Timbered Hills Groups, which range in age from Upper Cambrian to Middle Ordovician. The aquifer serves as a principle water source for the surrounding area and feeds several major springs and creeks, including Pennington Creek, around which a number of rare species dwell. Due to the high amount of fracturing and faulting present in the aquifer system, the possible effects of large-scale groundwater withdrawal are poorly understood and have spurred increased interest in a comprehensive investigation of the aquifer. We seek to understand the subsurface structure of a small area of the aquifer, focused around Pilot Springs, by identifying and interpreting faults and their interaction with the groundwater hydrology. To this end, we have carried out electrical resistivity soundings using Wenner and Schlumberger array spreads. Analysis of these data is being performed to identify faults and estimate depths to the water table. Modeling of horizontal layers is carried out by means of the IPI2win Resistivity Sounding Interpretation algorithm from Moscow State University. This modeling approach allows us to obtain for each sounding point an optimized subsurface model that specifies the number of layers present and the apparent resistivity and depths to each layer. We are able to refine this model based on our prior understanding of the geology of the region. At least one sounding appears to reveal the presence of one of the major north bounding faults in the area. Further surveying is planned, including additional resistivity soundings as well as resistivity profiling and ground-penetrating radar.
DE: 0545 Modeling (4255)
DE: 0925 Magnetic and electrical methods (5109)
DE: 1829 Groundwater hydrology
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting