Boulder Streams, Debris Fans, and Pleistocene Climate Change in the Blue Ridge Mountains of Central Virginia

The west slope of the Blue Ridge mountains in central Virginia is a polygenetic landscape containing interglacial and periglacial features. This paper proposes a general model relating the distribution and origin of hillslope and toeslope Quaternary landforms to climatically influenced geomorphic processes. Two generations of interglacial debris fans in the study area differ in their degree of soil development and clast weathering. Boulder streams, which clog debris flow chutes for the upper debris fans, are interpreted as solifluction features formed during successive periglacial episodes. Growth of the boulder streams and associated talus slopes can influence the magnitude and frequency of debris flows and fan formation during interglacials.