washington pass rockslide

View from the toe of an ancient rockslide within the alkali granite of the Golden Horn Batholith near Washington Pass. Washington State Route 20 was cut through the rockslide mass during its construction (the highway crosses midway through the photo). The rockslide transported alkali granite from above the tree line to the current highway level. Rock fragments contain abundant miarolitic cavities with microcline, smokey quartz, arfvedsonite, zektzerite and a multitude of other species. This area now coincides with an active snow avalanche path (notice downed trees in foreground).
Golden Horn Batholith, Washington Pass, Washington, USA

Photo Copyright © 2015 Jeffrey M. Schwartz