Permafrost

Abstract

Contains text of a lecture delivered before the Permafrost Symposium at the First Alaskan Science Conference, Nov. 1950, Washington, D.C., dealing with the history of knowledge and exploration of permafrost; definitions and terminology; distribution and character: its vertical distribution, zones, kinds, etc; relation to climatic fluctuations; ice in permafrost; relation to vegetation; ground water, etc. "Permafrost or perennially frozen ground extends over one-fifth of the land area of the earth. Regions of permafrost has been classed as: continuous, discontinuous and sporadic. Permafrost has been observed to depths of approximately 2000 ft. in Siberia and 1000 ft in Alaska. The temperature below the level of zero amplitude within the permafrost ranges from slightly less than 0° C. The surface layer above the permafrost thaws partially or completely and is called the active zone. Plants are rooted in it and all churning and soil movements take place in the active zone. An unfrozen layer between the permafrost table and the active zone, or...within or below the permafrost, is called talik. Observations indicate that the southern boundary of permafrost is slowly moving northward due to present climatic flucuations. Utilization of permafrost and the problems involved are discussed."--SIPRE. Bibliography (16 items).