Tonto Group
The Cambrian Tonto Group is the three-member sequence of geologic formations that represent the basal section of Paleozoic rocks in the Grand Canyon. The group is about 1,250 feet (381 m) thick. The base unit, the Cambrian Tapeats Sandstone was deposited upon the erosion surface of the Vishnu Basement Rocks, which is found in Granite Gorge (the Inner Gorge). The erosion resistant Tapeats Sandstone forms the platform, called Tonto Platform, that the two less erosion resistant upper layers, the Bright Angel Shale and Muav Limestone, rest on.
primaryTopic
Tonto Group
The Cambrian Tonto Group is the three-member sequence of geologic formations that represent the basal section of Paleozoic rocks in the Grand Canyon. The group is about 1,250 feet (381 m) thick. The base unit, the Cambrian Tapeats Sandstone was deposited upon the erosion surface of the Vishnu Basement Rocks, which is found in Granite Gorge (the Inner Gorge). The erosion resistant Tapeats Sandstone forms the platform, called Tonto Platform, that the two less erosion resistant upper layers, the Bright Angel Shale and Muav Limestone, rest on.
has abstract
The Cambrian Tonto Group is th ...... called the Great Unconformity.
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Link from a Wikipage to an external page
Wikipage page ID
35,812,738
Wikipage revision ID
729,818,424
age
Early to Middle Cambrian
Caption
Muav Limestone- and Bright Ang ...... m, inner canyon, Granite Gorge
country
imagesize
namedby
Gilbert , , and
namedfor
otherlithology
calcareous mudstone and glauconitic sandstone
overlies
Vishnu Basement Rocks, and 8)- ...... ation, 5–1)-Unkar Group,
period
prilithology
sandstone, conglomerate, siltstone, shale, limestone, and dolomite
region
northern Arizona and southern Nevada
type
underlies
Redwall Limestone. Locally ove ...... Limestone from Muav Limestone.
unitof
subject
hypernym
comment
The Cambrian Tonto Group is th ...... e and Muav Limestone, rest on.
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label
Tonto Group
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