Reassessment of local paleocurrent directions in the Miami oolitic limestone with 3D ground-penetrating radar

Abstract

Active oolitic sand bars like the modem ones in the Bahamas as well as those in the ancient exhibit a complex internal architecture with a multitude of stacked sedimentary structures. As a result, the internal anatomy of these sand bars is usually too complex to be captured with two-dimensional outcrop and one-dimensional well information. In order to improve fluid flow modeling used in water and hydrocarbon resource management, closely spaced three-dimensional (3-D) data is needed to accurately map sedimentary structures. To improve our understanding of ancient oolitic sand bar anatomy we collected a 3-D 100 MHz Ground-Penetrating Radar (GPR) data cube covering an area of 24x46 m with 7 m penetration depth. A grid spacing of 0.1x0.2 meters is needed to fully exploit the imaging capability of the 100 MHz antennae. The high-resolution 3-D GPR data enable: ○ Volume imaging of oolitic sand bar architecture. ○ Understanding of spatial relationships of sedimentary structures. ○ Reconstruction of depositional environment and assessment of paleocurrent and sandwave migration directions.