Chemical weathering and landscape development in mid-latitude alpine environments

This paper attempts to assess the role of chemical processes in the weathering, erosion, and denudation of periglacial alpine environments. It draws primarily from detailed chemical studies in the alpine zones of the Colorado Rocky Mountains, the Jotunheimen of Norway, and northwest Swedish Lapland. The nature or kind of chemical weathering processes has been found to be the same in periglacial environments as elsewhere. Comparison of weathering rates among various environments reveals periglacial chemical weathering to be generally slower than that in the tropical and temperate latitudes, but overlapping with the lower values reported from such environments. In broad terms, this statement is valid whether assessment is based on bedrock or regolith weathering estimates. Chemical weathering is found to be a substantial, sometimes the dominant, agent of mass removal in periglacial environments. Assessment of the role of chemical processes in denudation is complicated by the differing, sometimes conflicting, definitions of the term. It is important to view chemical processes primarily as a component of geomorphic work, rather than as an important land-forming agent, in periglacial environments. Given the intrinsic attribute of long distance transport out of a drainage basin implicit to denudation, chemical solute loads in periglacial river systems must be ranked highly in comparison to the, often dramatic, but nearly always highly localized contribution from alpine mass wasting. (c) 2004 Elsevier B.V. All rights reserved.