Ground Penetrating Radar (GPR) survey over a melting blue ice area (BIA) at the south of Schirmacher Oasis, Dronning Maud Land, East Antarctica

Abstract

A blue ice area (BIA) is located in Dronning Maud Land, East Antarctica between Schiermacher Oasis (SO) and Ulthat mountain ranges. High-resolution ground-penetrating radar (GPR) survey has been carried out in the northern boundary of the BIA surrounded by Schirmacher Oasis (SO), Shivalinga and Veteheia nunataks to examine if the BIA in the area is wind-induced or melt-induced in nature. GPR study reveals that the glacier in this part of BIA is warm and showing prominent signatures of subsurface melting in the vicinity of the nunataks and other exposed rock masses. The signatures of bottom warming also have been detected in few profiles which are in agreement with the drilling results in nearby areas. Melting signatures vary over the area depending on the distances from the exposed rocks and proximity of subglacial bedrock topography. The results indicate the possible higher heat supply by the exposed rock mass to the BIA. Folding of the internal layers and the presence of two firn pockets also have been observed near the nunatak Veteheia. The present GPR study concludes that the survey area is predominantly melt-induced BIA. Further investigations are recommended to study the firn pockets and mass balance of the area.