--> Abstract: Spectral Analyses of 3-D GPR Data Reveal the Morphology of Shoreface Deposits in the Upper Cretaceous Ferron Sandstone Formation, Utah, by Lee Keumsuk, Robert B. Szerbiak, and George A. McMechan; #90078 (2008)

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Spectral Analyses of 3-D GPR Data Reveal the Morphology of Shoreface Deposits in the Upper Cretaceous Ferron Sandstone Formation, Utah

Lee Keumsuk1, Robert B. Szerbiak2, and George A. McMechan3
1Jackson School of Geosciences, The Bureau of Economic Geology, Austin, TX
2Center for Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID
3Center for Lithospheric Studies, University of Texas at Dallas, Dallas, TX

Wavelengths of hummocky cross-stratified (HCS) beds (a common sedimentary feature of storm-dominated shorefaces), are documented, for the first time, using measurements in 3-D GPR data for a well-developed Upper Cretaceous lower-shoreface succession in the Ferron Sandstone Formation, Utah. The shallow-marine sequence consists of subparallel HCS sand beds alternating with interstorm deposits; systematic joints extend through the stacked beds.

The GPR interpretation contains three conformable, high-continuity, high-amplitude reflections throughout the GPR data cube. The interpreted radar surfaces are well correlated with erosive tops of HCS sand beds seen in the adjacent cliff face (and thus paleotopographic surfaces); the associated radar units have a uniform thickness (on average ~ 0.8 m). The radar units and outcrop observations suggest that the shoreface sandstone at the Dry Wash site has a simple layered internal architecture. The hummocky-swale surfaces generally dip westerly, as a product of tectonically induced structural alterations mostly in the shoreline direction, containing various sized, smoothly, rounded, tens-of-centimeter high features.

2-D Fourier Transforms of the three GPR surfaces after removal of the tectonic trend suggests that the HCS-bearing surfaces are dominated by equi-dimensional features with ~ 7-m-wavelength. A 2-D continuous wavelet transform (CWT) analysis on the same surfaces reconstructs the multi-resolution storm-induced features. The CWT technique can provide high-resolution images of various sedimentary reservoir bedforms.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas