Natural SciencesEarth SciencesEnvironmental SciencesGeomorphologyPaleoclimatologyPeriglacial EnvironmentsPeriglacial GeologyPeriglacial GeomorphologyPeriglacial ProcessesPermafrostPermafrost GeologyPermafrost DistributionPermafrost EcologyPermafrost GeographyPermafrost GeomorphologyPermafrost Landforms
Knowledge of the distribution of permafrost in North America and related environmental factors which has been accumulated during the past ten years, 1963-73, since the First International Conference on Permafrost is reviewed. Several permafrost maps of Canada and Alaska were published. Considerable advance was made in the understanding of climatic and terrain factors such as relief, vegetation, hydrology, snow cover, fire, soil and rock, and glacier ice. Investigations on the distribution of ground ice features associated with permafrost, including pingos, ice wedges, palsas and thermokarst, are surveyed, and work on other periglacial features such as rock glaciers, altiplanation terraces, solifluction features, string bogs, extinct pingos, and ice wedge casts, are described. The past distribution and chronology of permafrost received considerable attention during the last decade. The paper ends with a list of recommendations for future investigations in this aspect of permafrost research.