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3091.jpg
TitleAngular unconformity between Proterozoic and Cambrian rocks, Grand Canyon, Arizona
DescriptionAn angular unconformity separates reddish shales and sandstones of the Proterozoic Unkar Group (dipping toward the right) from overlying sandstones and shales of the Cambrian Tonto Group (dipping toward the left). Paleotopographic relief on the unconformity is clearly visible at the lower left and center, where the Tapeats Sandstone onlaps the underlying reddish Hakatai Shale. Also visible are the Bright Angel Shale and Muav Limestone (overlying the Tapeats Sandstone) and the Shinumo Quartzite (forming a rugged spine at right center, where it conformably overlies the Hakatai Shale).
ChronostratigraphyProterozoic to Early Cambrian
LithostratigraphyUnkar Group (Hakatai Shale and Shinumo Quartzite), Tonto Group (Tapeats Sandstone, Bright Angel Shale, Muav Limestone)
Geologic provinceColorado Plateau
LocationUSA ▹ Arizona ▹ Coconino. Near Grand Canyon Village. View looking west from the New Hance Trail.
Coordinates36.016667,-111.933333
PhotographerMark Brandriss. 1989.
Key wordsUnconformity, angular unconformity, Grand Canyon
Tech details926 KB. Vista.
GeoDIL number3091
CopyrightMark Brandriss