Ground penetrating radar of northern lacustrine deltas

Abstract

Ground penetrating radar (GPR) was used in several selected deltaic sedimentary environments to better understand subsurface stratigraphy and reconstruct former depositional environments. The profiles provide high-resolution, continuous subsurface data on facies thickness and depths, orientation of major sedimentary structures, postdepositional failure planes, and depth of peat deposits.Field experiments were carried out on six river deltas. Records from four of the deltas exhibit sedimentary facies; a record from one delta shows a possible slump; and records from another delta reveal the thickness and stratigraphic relationships of peat deposits. The delta types are (i) sandy, wave influenced; (ii) sandy, immature wave influenced (steeper middle and lower shoreface); (iii) sandy braided; and (iv) gravelly, fan–foreset.In areas of limited subsurface control (stratigraphic logs from drill core, cutbank exposure, or geophysical logs), radar profiles can provide ''big picture'' perspectives of the subsurface, a view only available in laterally extensive exposures. High-resolution profiles of subsurface stratigraphy and sedimentary facies from GPR provide an opportunity for geomorphologists and sedimentologists to further advance field research. Although GPR has limited success in silt and clay, results from sand and gravel deposits often reveal detailed facies assemblages.