Abstract Almost all areas of the UK have been affected by periglaciation during the Quaternary and, as such, relict periglacial geohazards can provide a significant technical and commercial risk for many civil engineering projects. The processes and products associated with periglaciation in the relict periglacial landscape of the UK are described in terms of their nature and distribution, the hazards they pose to engineering projects, and how they might be monitored and mitigated. A periglacial landsystems classification is applied here to show its application to the assessment of ground engineering hazards within upland and lowland periglacial geomorphological terrains. Techniques for the early identification of the susceptibility of a site to periglacial geohazards are discussed. These include the increased availability of high-resolution aerial imagery such as Google Earth, which has proved to be a valuable tool in periglacial geohazard identification when considered in conjunction with the more usual sources of desk study information such as geological, geomorphological and topographical publications. Descriptions of periglacial geohazards and how they might impact engineering works are presented, along with suggestions for possible monitoring and remediation strategies.

ABSTRACT Landscape features that formed when buried ice melted and overlying sediment collapsed are abundant and widespread in the part of Wisconsin’s Northern Highland region glaciated by the Wisconsin Valley Lobe and the western part of the Langlade Lobe. Stagnation and burial of ice of the Wisconsin Valley Lobe are documented by broad tracts of hummocky moraine topography that record the position of the maximum extent of the lobe, and by extensive pitted and collapsed heads-of-outwash and outwash plains deposited during recession. Recession of the Wisconsin Valley Lobe was characterized by episodes of stagnation interspersed with episodes of readvance, documented by small west-east–trending heads-of-outwash. Advances of the western margin of the Langlade Lobe deposited large northwest-southeast–trending heads-of-outwash characterized by extensive areas of pitted and collapsed outwash plains with obscure but recognizable ice-contact faces. Following recession of the Wisconsin Valley and Langlade Lobes, the Ontonagon Lobe advanced out of the Superior Basin and over sediment containing abundant buried ice. Permafrost and debris cover combined to delay the melting of buried ice and the formation of the postglacial landscape. Regional correlation of ice-margin positions, combined with geomorphic and stratigraphic relationships, indicates that ice buried in north-central Wisconsin persisted in some places for up to 5000 yr or more following the recession of active ice.

Numerous landforms with traits that are suggestive of formation by periglacial processes have been observed in Utopia Planitia, Mars. They include: small-sized polygons, flat-floored depressions, and polygon trough or junction pits. Most workers agree that these landforms are late Amazonian and mark the occurrence of near-surface regolith that is (was) ice rich. The evolution of the Martian landforms has been explained principally by two disparate hypotheses. The first is the “wet hypothesis.” It is derived from the boundary conditions and ice-rich landscape of regions such as the Tuktoyaktuk Coastlands, Canada, where stable liquid water is freely available as an agent of landscape modification. The second is the “dry” hypothesis. It is adapted from the boundary conditions and landscape-modification processes in the glacial Dry Valleys of the Antarctic, where mean temperatures are much colder than in the Tuktoyaktuk Coastlands, liquid water at or near the surface is rare, and sublimation is the principal agent of glacial mass loss. Here, we (1) describe the ice-rich landscape of the Tuktoyaktuk Coastlands and their principal periglacial features; (2) show that these features constitute a coherent assemblage produced by thaw-freeze cycles; (3) describe the landforms of Utopia Planitia and evaluate the extent to which “wet” or “dry” periglacial processes could have contributed to their formation; and (4) suggest that even if questions concerning the “wet” or “dry” origin of the Martian landforms remain open, “dry” processes are incapable of explaining the origin of the ice-rich regolith itself, from which the landforms evolved.

Abstract Permafrost is ground (soil or rock and included ice and organic material) that remains at or below 0 °C for at least two consecutive years. Permafrost terrain consists of an “active layer” at the surface that freezes and thaws each year, underlain by perennially frozen ground. The top of permafrost is at the base of this active layer. The base of permafrost occurs where the ground temperature rises above 0 °C at depth ( Osterkamp and Burn, 2002 ). In some cases, temperature measurements over a period of two years are required to determine the presence or absence of permafrost. Temperature measurements are also required to determine the status of the permafrost. Permafrost that is warm and/or warming is in danger of thawing. Approximately 25% of the exposed land area of Earth and ~80% of Alaska are underlain by permafrost. Mountain permafrost occurs at high elevations in western North America and on Mount Washington in New Hampshire. Permafrost has also been found near the summit of Mauna Kea in Hawaii. Permafrost is a product of cold climates. The first permafrost on earth must have existed prior to or formed coincidentally with the first glaciation, ~2.3 billion years ago. Permafrost occurrences, distribution, and thicknesses must have increased during periods of cold climates and decreased during warm intervals. Permafrost may have disappeared in the Arctic ~50 million years ago. The current permafrost in Alaska appears to have been initiated during the climatic cooling that began ~2.5 million years ago. During the past