Star Valley Landscape

The Story of a Landscape, Star Valley, Wyoming – Lead by Robert Palmquist

Star Valley is a sister to Jackson Hole.  They both lie at the base of a fault-block mountain and both reflect the influences of past glaciations and recent fault movement.  They differ in that no glaciers occupied Star Valley.  Rather meltwater and sediments from mountain snowfields and glaciers spilled out into the valley and deposited alluvial fans.  Several episodes of fan building followed by stability and dissection left a landscape of benches, terraces, and mid-valley hills; some of which are loess-mantled others of gravel.  These features range in age from over 100,000 years to as recent as 13,000 years.  Continued activity along the South Star Valley Fault has offset fans at their canyon mouths. This fault activity also has pushed up older rock that abruptly narrows the valley in two places and establishes conditions for the preservation of older fan remnants.