Stratigraphic Analyses Using GPR
Imaging fluvial architecture within a paleovalley fill using ground penetrating radar, Maple Creek, Guyana
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Published:January 01, 2007
A ground penetrating radar (GPR) survey was used to image the fluvial architecture within a buried paleovalley at Maple Creek, Guyana. The survey was part of a larger study of the stratigraphy and organization of fluvial elements within the valley fill. The survey consisted of 44 km of 50 and 100 MHz GPR profiles collected in a grid pattern. The 100 MHz antennae were used where depth to bedrock was less than 20 m, and the 50 MHz antennae were used where depth to bedrock exceeded 20 m. The survey grid consisted of 28 east-west–trending transects and 6 north-south–trending transects. East-west transects in the southern part of the study area were spaced 100 m apart. Those in the northern part of the study area were spaced 400 m apart, and north-south cross-transects were spaced at 500 m intervals. The survey imaged two strong reflectors interpreted to represent major bounding surfaces. The lower surface was confirmed to be the bedrock-sediment interface defining the valley boundary. The second major surface is the boundary between the fluvial valley fill and overlying bleached sand correlative with the White Sand Formation. In addition to the major surfaces, several minor surfaces were also imaged, resulting in the identification of 21 radar elements. Sixteen of the elements were interpreted to represent fluvial architectural elements. Four distinct morphological zones were recognized and were differentiated by variation in the geometry of the bedrock-sediment interface and by distinctive assemblages of architectural elements.
- bedrock
- buried valleys
- Cenozoic
- clastic sediments
- diamond deposits
- fluvial features
- geometry
- geomorphology
- geophysical methods
- geophysical surveys
- ground-penetrating radar
- Guyana
- Holocene
- imagery
- lithostratigraphy
- mineral exploration
- paleorelief
- placers
- Quaternary
- radar methods
- sedimentary structures
- sedimentation
- sediments
- South America
- surveys
- trenching
- valleys
- Demerara Formation
- Maple Creek
- Coropina Formation
- White Sand Formation
- Corentyne Group