Soils, vegetation and permafrost across an active meander of Indian River, central Yukon, Canada

Abstract

Examination of soil profiles on concentric point bars dated by tree ring counts within a meander loop of the Indian River in central Yukon has been used as the basis for the interpretation of soil evolution and river meander migration associated with the reestablishment of permafrost. The soils heve evolved from immature Regosols at the river's edge, into complexly horizonated Luvisols with permafrost on the oldest, measurable, 140 year old point bar. Permafrost re-entered the ground after about 100 years, contrasting with almost immediate re-entry of permafrost three degrees further north. This difference in latitude defines a narrow ecotone representing a very rapid transition from the Discontinuous into the Continuous Permafrost Zones.