Alpine Subnival Boulder Pavements in Colorado Front Range
Boulder pavements on valley floors in or near stream channels, downstream from breaks in slope, beneath persistent snowbanks, and above treeline occur in four glaciated valleys east of the Continental Divide, Boulder District, Colorado Front Range. They are at altitudes of 3,230 to 3,620 m, triangular to rectangular in ground plan, slope a few degrees downvalley with nearly all blocks or boulders tightly packed with a flat face upward, and made of local bedrock or till. These alpine subnival boulder pavements may be due to the joint effort of frost action, meltwater saturation and removal of fine sediment, and rotation and flattening of blocks by rock weight, snow pressure, and possible snow creep.