Mount Gould and Grinnell Glacier, Montana
July 18, 2011
Mount Gould rises above the Grinnell Glacier cirque, in Glacier National Park. The bedrock consists of carbonate and clastic sedimentary rock of the Belt Supergroup, deposited during the Late Proterozoic. The prominent dark band in the middle of the cliff is the Purcell sill, an igneous rock that intruded the sedimentary rock; the light-colored areas on either side of the sill are zones bleached white from the interaction of the hot igneous rock with the carbonate rock. The cliff itself and the lake-filled depression define a bowl-shaped region called a cirque, which along with the striations in the lower left of the photo, are products of glacial erosion. Image taken July 2004.
Photo Details: Camera: Canon EOS 10D; Focal Length: 19.0mm; Aperture: f/7.4; Exposure Time: 0.0055 s; ISO equiv: 100.