GPR FACIES INTERPRETATION: REVEALING THE HIDDEN DUNES-RIVER COMPLEX OF UPSTATE NEW YORK

Ground Penetrating Radar (GPR) is a non-destructive geophysical method that uses electromagnetic waves to obtain subsurface structure information. The primary purpose of this research was the identification of radar facies in upstate New York that could help us better understand the relationships between landforms, surficial geology, and subsurface architecture.

Sand bodies are located throughout the region that are related to the retreat of the last great ice sheet and the subsequent flooding and draining of the Champlain Sea. This research presents GPR data collected over a sand-rich landform adjacent to the Raquette River with the MALA Ground Explorer (GX), using the 160 MHz and 450 MHz frequency antennas. The antenna was pulled by hand in a grid pattern through the Union Cemetery and adjacent areas. Processing for the GPR data was performed in GPR-SLICE v7.MT Ground Penetrating Radar Imaging Software.

A large sandy area was identified on Google Earth to the north of Potsdam, adjacent to the Union Cemetery, and based on radar data processing and interpretation, the initial exploratory GPR survey suggested the presence of features such as dunes, deltas, and beaches similar to those that dot the landscape between Potsdam and the St. Lawrence River. Also, aeolian dunes have been recognized for a long time in the lowlands of St Lawrence, but the description of their morphology and distribution has not been possible due to low relief and vegetation cover. However, with the help of GPR, it was feasible to map the subsurface structure of the area and identify the landform as fluvial sands and dunes with a rough parabolic form. The internal stratigraphy coupled with surficial morphology suggests a migration direction of WSW. The results reveal the internal structure related to the river and wind processes that built the landform. A river plain was formed followed by a migration of sand dunes over the river system. This initial investigation found findings that deserve to be studied in more detail.