Figure 16. Just beneath the shallow lake bottom, the GPR data reveal patterns characteristic of ice wedge polygons. The interface of the silty lake bottom, upon which the mammoth bones rest is wedge polygons. The interface of the silty lake bottom, upon which the mammoth bones rest is indicated in the profile (top). A deeper interface seen in the profiles may be due to a textural transition indicated in the profile (top). A deeper interface seen in the profiles may be due to a textural transition in the substrate, from finer-grain sediment to coarse gravel. in the substrate, from finer-grain sediment to coarse gravel.

Figure 16. Just beneath the shallow lake bottom, the GPR data reveal patterns characteristic of ice
wedge polygons. The interface of the silty lake bottom, upon which the mammoth bones rest is
wedge polygons. The interface of the silty lake bottom, upon which the mammoth bones rest is
indicated in the profile (top). A deeper interface seen in the profiles may be due to a textural transition indicated in the profile (top). A deeper interface seen in the profiles may be due to a textural transition
in the substrate, from finer-grain sediment to coarse gravel.
in the substrate, from finer-grain sediment to coarse gravel.

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.

National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457

Email: ncptt[at]nps.gov
Phone: (318) 356-7444
Fax: (318) 356-9119