Weathering status of present-day eolian infall and alpine tundra surfaces, front range, colorado

Present-day eolian infall to the alpine zone of the Front Range, Colorado has been identified as an important geomorphic and pedogenic process. Development of a semiquantitative, grain-surface, scanning electron microscopic analysis technique (Darmody, 1985), as well as a surface peel sampling technique (Thorn and Darmody, 1985b) have permitted a preliminary evaluation of interaction between eolian infall and both depositional and deflationary surfaces within alpine tundra. Eolian samples were retrieved from the centers of large, seasonal snow patches, while depositional samples were from vegetated soil surfaces, and deflationary samples were from obviously eroded, unvegetated soil surfaces. Crains of present-day eolian infall are generally more freshly fractured, uncoated, and unweathered than those from depositional and deflationary surfaces, the latter two being indistinguishable. This suggests that the source area of the eolian material is not the deflationary surfaces, and/or that the eolian material that falls onto vegetated surfaces is quickly incorporated into the more weathered matrix.