Ground Penetrating Radar Imaging of Cap Rock, Caliche and Carbonate Strata

Field experiments show ground penetrating radar (GPR) can be used to image shallow carbonate stratigraphy effectively in a variety of settings. In south Florida, the position and structure of cap rock cover on limestone can be an important control on surface water flow and vegetation, but larger scale outcrops (tens of meters) of cap rock are sparse. GPR mapping through south Florida prairie, cypress swamp and hardwood hammock resolves variations in thickness and structure of cap rock to ∼3 m and holds the potential to test theories for cap rock–vegetation relationships. In other settings, carbonate strata are mapped to test models for the formation of local structural anomalies. A test of GPR imaging capabilities on an arid caliche (calcrete) horizon in southeastern Nevada shows depth penetration to ∼2 m with resolution of the base of caliche. GPR profiling also succeeds in resolving more deeply buried (∼5 m) limestone discontinuity surfaces that record subaerial exposure in south Florida.