By: magic-gigapans
Image: Jeffrey Rollins, Mid-Atlantic Geo-Image Collection
License: Creative Commons Non Commercial ⧉

Uploaded: 29 Apr 2020
Last Updated: 2 Jun 2020

314 megapixels
35,480 x 8,864 pixels
118.3 in X 29.5 in at 300dpi

44* 36' 46'' N / 108* 9' 24'' W - Facing South Located midway between the nose of the Sheep Mountain Anticline and Sheep Canyon, the “thumb” is a parasitic anticlinal fold whose axis runs roughly from north to south, oblique to the axis of the main fold (northwest-southeast). The outcrop above lies in the synclinal valley to the south of the thumb – the major anticlinal fold is to the left, the thumb is to the right. Notice the smooth curvature of the thick carbonates of the upper Phosphoria Formation as they form the synclinal fold from left to right. Heavy fracturing of less competent beds as well as minor low angle thrusts (such as the one seen behind my concerned-looking field assistant) may have provided a means for these thick Permian beds of brittle limestone to bend while retaining their general structure.