The Great Unconformity in Blacktail Canyon. Cambrian Tapeats Sandstone resting upon Early Proterozoic Vishnu Schist.

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Exposed in Blacktail Canyon, a side canyon joining the Grand Canyon of Arizona at (Colorado) river mile 120, the Great Unconformity represents approximately billion years of missing geologic history. The horizontally bedded early Cambrian Tapeats Sandstone, age of approximately 525 million years, is resting directly on vertically foliated early Proterozioc Vishnu Schist, age of approximately billion years. The thin contact between the two rock types represents a vast period of time when sediments were not deposited or were later removed through erosion.

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Size: 3872px × 2592px
Location: Blacktail Canyon, Grand Canyon National Park, Arizona, USA.
Photo credit: © Earth Gallery Photography / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: america, arizona, basal, blacktail, cambrian, canyon, colorado, conglomerate, contact, earth, erosion, evolution, exposure, gap, geologic, geology, grand, great, metamorphic, metamorphosed, missing, national, nature, nonconformity, outcrop, paleozoic, park, phanerozoic, precambrian, proterozoic, river, rock, sandstone, schist, science, states, stone, stratigraphic, stratigraphy, tapeats, travel, unconformity, united, usa, vishnu