Tsegyi Canyon

Tsegyi Canyon Image

Near the north end of Black Mesa [Dzilyíjiin], the valley through which the highway passes narrows drastically as the Shonto Plateau rises to the north. The Organ Rock monocline lies north of the highway and tilts the Navajo Sandstone layers that lie well beneath Black Mesa [Dzilyíjiin] sharply up and exposes them as the Shonto Plateau and Skeleton Mesa [Tsin Kíikaad].
Where Tségyi' Canyon cuts through, even older layers are exposed. The Navajo Sandstone has steep, sweeping cross-beds with fine, even grains of sand, typical of rock formed from sand dunes.

This Navajo Sandstone is the important aquifer for this area. The rain water sinks into the sandstone on the Shonto Plateau and the narrow area between the plateau and Black Mesa [Dzilyíjiin]. This area of approximately 100 square miles must supply water to a much larger area, including the Hopi lands [Kiis'áanii bikéyah] as well as the Navajo [Diné bikéyah]. The current rate of water withdrawal exceeds the recharge rate. Much of this water is used by the Peabody Coal Company in its slurry lines to move the coal it mines from Black Mesa [Dzilyíjiin]. Many local wells are going dry because of this use.

If, like me, you are confused by the terms used to designate geologic time, a chart, based upon one given in Roadside Geology of Arizona by H. Chronic is available.

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Navajo Sacred Places, Klara Bonsack Kelley, Harris Francis, Indiana Univ Press.
Native Roads : The Complete Motoring Guide to the Navajo and Hopi Nations,
Fran Kosik, George Hardeen, Creative Solutions Pub.
Named in Stone and Sky : An Arizona Anthology, Gregory McNamee (Editor),
Univ of Arizona Press.
Talking to the Ground : One Family's Journey on Horseback Across the Sacred Land of the Navajo
Douglas Preston, Univ of New Mexico Press.
Basin and Range, John McPhee, Noonday Press.
Navajo Country : A Geology and Natural History of the Four Corners Region, Donald Baars, Univ. New Mexico Press.
The Colorado Plateau : A Geologic History, Donald L. Baars, Univ of New Mexico Press.
Roadside Geology of Arizona, Halka Chronic, Mountain Press.

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© 1994 Karen M. Strom
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