Frozen: The Potential and Pitfalls of Ground-Penetrating Radar for Archaeology in the Alaskan Arctic

Ground-penetrating radar (GPR) offers many advantages for assessing archaeological potential in frozen and partially frozen contexts in high latitude and alpine regions. These settings pose several challenges for GPR, including extreme velocity changes at the interface of frozen and active layers, cryogenic patterns resulting in anomalies that can easily be mistaken for cultural features, and the difficulty in accessing sites and deploying equipment in remote settings. In this study we discuss some of these challenges while highlighting the potential for this method by describing recent successful investigations with GPR in the region. We draw on cases from Bering Land Bridge National Preserve, Cape Krusenstern National Monument, Kobuk Valley National Park, and Gates of the Arctic National Park and Preserve. The sites required small aircraft accessibility with light equipment loads and minimal personnel. The substrates we investigate include coastal saturated active layer over permafrost, interior well-drained active layer over permafrost, a frozen thermo-karst lake, and an alpine ice patch. These examples demonstrate that GPR is effective at mapping semi-subterranean house remains in several contexts, including houses with no surface manifestation. GPR is also shown to be effective at mapping anomalies from the skeletal remains of a late Pleistocene mammoth frozen in ice. The potential for using GPR in ice and snow patch archaeology, an area of increasing interest with global environmental change exposing new material each year, is also demonstrated.

[1]  J. A. Ford.  Eskimo Prehistory in the Vicinity of Point Barrow, Alaska , 1959 .

[2]  G. Cross,et al.  Diffraction-based velocity estimates from optimum offset seismic data , 1991 .

[3]  Glen MacKay,et al.  Archaeological Investigations of Alpine Ice Patches in the Selwyn Mountains, Northwest Territories, Canada , 2012 .

[4]  L. Conyers.  Ground-Penetrating Radar for Archaeology , 2004 .

[5]  A. P. Annan,et al.  Ground-penetrating radar for high-resolution mapping of soil and rock stratigraphy , 1989 .

[6]  Müller,et al.  GPR study of pore water content and salinity in sand , 2000 .

[7]  E. Blake,et al.  The Kwäday dän Ts'ínchi discovery from a glacier in British Columbia , 2000 .

[8]  C. Schweger,et al.  Ethnographic and Archaeological Investigations of Alpine Ice Patches in Southwest Yukon, Canada , 2004 .

[9]  Douglas D. Anderson.  Prehistory Of North Alaska , 1984 .

[10]  Benjamin M. Jones,et al.  Application of ground‐penetrating radar imagery for three‐dimensional visualisation of near‐surface structures in ice‐rich permafrost, Barrow, Alaska , 2007 .

[11]  Steven A. Arcone,et al.  Dielectric properties of thawed active layers overlying permafrost using radar at VHF , 1982 .

[12]  Christian Stolte.  E-migration: image enhancement for subsurface objects of constant curvature in ground probing radar reflection data , 1994 .

[13]  U. Molau,et al.  Ecology of Alpine Snowbeds and the Impact of Global Change , 2007 .

[14]  T. Urban,et al.  Ground‐Penetrating Radar Velocity Determination and Precision Estimates Using Common‐Midpoint (CMP) Collection with Hand‐Picking, Semblance Analysis and Cross‐Correlation Analysis: A Case Study and Tutorial for Archaeologists , 2016 .

[15]  Ancient Men of the Arctic , 1967 .

[16]  Dean Goodman,et al.  GPR Remote Sensing in Archaeology , 2013 .

[17]  S. Manning,et al.  Geophysical investigation of a Middle Holocene archaeological site along the Yukon River, Alaska , 2016 .

[18]  Craig M. Lee.  Withering Snow and Ice in the Mid-latitudes: A New Archaeological and Paleobiological Record for the Rocky Mountain Region , 2012 .

[19]  H. Wanner,et al.  Ice‐borne prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations , 2007 .

[20]  E. Blake,et al.  Multidisciplinary Investigations of Alpine Ice Patches in Southwest Yukon, Canada: Paleoenvironmental and Paleobiological Investigations , 2004 .

[21]  T. Urban,et al.  Geophysical analysis at the Old Whaling site, Cape Krusenstern, Alaska, reveals the possible impact of permafrost loss on archaeological interpretation , 2013 .

[22]  Multimethod geophysical investigations at an Inupiaq village site in Kobuk Valley, Alaska , 2012 .

[23]  J. Schaaf.  The Bering Land Bridge National Preserve : an archeological survey , 1988 .

[24]  James A. Doolittle,et al.  Detection of subsurface permafrost features with ground‐penetrating radar, Barrow, Alaska , 2001 .

[25]  Craig M. Lee,et al.  The Emerging Archaeology of Glaciers and Ice Patches: Examples from Alaska's Wrangell-St. Elias National Park and Preserve , 2005, American Antiquity.

[26]  F. Navarro,et al.  On the errors involved in ice-thickness estimates III: error in volume , 2016, Journal of Glaciology.

[27]  Douglas D. Anderson.  Onion Portage: the Archaeology of a Stratified Site from the Kobuk River, Northwest Alaska , 1988 .

[28]  B. Moorman,et al.  Morphology and Development of Ice Patches in Northwest Territories, Canada , 2012 .

[29]  Helge Larsen,et al.  Ipiutak and the Arctic Whale-Hunting Culture, Anthropological Papers of the American Museum of Natural History , 1949 .

[30]  M. Selby,et al.  Earth's Changing Surface: An Introduction to Geomorphology , 1986 .

[31]  John Darwent,et al.  OCCUPATIONAL HISTORY OF THE OLD WHALING SITE AT CAPE KRUSENSTERN , ALASKA , 2008 .

[32]  J. Hoffecker,et al.  1,000 Years of House Change at Cape Espenberg, Alaska: A Case Study in Horizontal Stratigraphy , 2013, American Antiquity.

[33]  Claire Alix,et al.  Archéologie du Cap Espenberg où la question du Birnirk et de l’origine du Thulé dans le nord-ouest de l’Alaska , 2015 .

[34]  J. L. Giddings.  The Arctic woodland culture of the Kobuk River , 1952 .