Characterising Relict Cryogenic Macrostructures in Mid-Latitude Areas of the USA with Three-Dimensional Ground-Penetrating Radar

Ground-penetrating radar (GPR) has considerable potential for the detection and identification of sediment-filled wedges and relict polygonal patterns in mid-latitude areas. Relict cryogenic macrostructures have been described previously both within and outside the maximum extent of the Late Wisconsinan glacial border in many regions of the USA. The features were formed under climatic conditions associated with permafrost and periglacial conditions and provide evidence of climate change. In this study, buried relict cryogenic macrostructures were identified with GPR. On some two-dimensional GPR (2D GPR) records, boundaries with the host materials are indistinguishable or blurred resulting in the features being overlooked, misinterpreted and/or imprecisely delineated. Three-dimensional GPR (3D GPR) was able to delineate buried networks of sediment-filled wedges and provided more meaningful information than 2D radar records. When supplemented with adequate ground-truth observations, GPR offers considerable potential for imaging, interpreting and mapping near-surface cryogenic macrostructures in former periglacial environments. Copyright (C) 2009 John Wiley & Sons, Ltd.