Geologic Time: Concepts and Principles - The Changing Earth: Exploring Geology and Evolution - page 449

UTAH

Bryce
Canyon

Zion

Grand
Canyon

ARIZONA

Grand Canyon
National Park
Arizona

Zion
National Park
Utah

Bryce Canyon
National Park
Utah

Paleogene Period

Wasatch Fm

Kaiparowits Fm

Wahweap Ss

Cretaceous Period

Straight Cliffs Ss

Tropic Shale

Dakota Ss

Winsor Fm

Curtis Fm

Jurassic Period

Entrada Ss

Carmel Fm Carmel Fm

Navajo Ss

Navajo Ss

Kayenta Fm

Older rocks not exposed

Wingate Ss

Triassic Period

Chinle Fm

Moenkopi Fm

Moenkopi Fm
Kaibab Ls
Toroweap Fm

Kaibab Ls

Permian Period

Coconino Ss
Hermit Shale

Older rocks not exposed

Supai Fm

Pennsylvanian Period

Mississippian Period Redwall Ls

Temple Butte Ls Devonian Period*

Mauv Fm

Bright Angel Shale

Cambrian Period Colorado

River

Tapeats Ss

Vishnu Schist

Precambrian

Fm = Formation Ss = Sandstone Ls = Limestone

* Rocks of Ordovician and Silurian age are not present in the Grand Canyon.

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Figure 17.14 Correlation of Rock Units within the Colorado Plateau At each location, only a portion of the geologic record of the Colorado
Plateau is exposed. By correlating the youngest rocks at one exposure with the oldest rocks at another exposure, geologists can determine
the entire history of the region. For example, the rocks forming the rim of the Grand Canyon, Arizona, are the Kaibab Limestone and Moenkopi
Formation—the youngest rocks exposed in the Grand Canyon. The Kaibab Limestone and Moenkopi Formation are the oldest rocks exposed
in Zion National Park, Utah, and the youngest rocks are the Navajo Sandstone and Carmel Formation. The Navajo Sandstone and Carmel
Formation are the oldest rocks exposed in Bryce Canyon National Park, Utah. By correlating the Kaibab Limestone and Moenkopi Formation
between the Grand Canyon and Zion National Park, geologists have extended the geologic history from the Precambrian to the Jurassic.
And by correlating the Navajo Sandstone and Carmel Formation between Zion and Bryce Canyon National Parks, geologists can extend the
geologic history through the Paleogene Period. Thus, by correlating the rock exposures between these areas and applying the principle of
superposition, geologists can reconstruct the geologic history of the region.