Palo Duro Canyon State Park is located in the Panhandle of Texas (fig.
5) approximately 13 miles east of Canyon on State Highway 217 (_see_
fig. 7). It is about 12 miles south and 8 miles east of Amarillo via
Ranch Road 1541 which intersects State Highway 217. The park includes
more than 15,000 acres of Palo Duro Canyon, a complexly dissected area
which spreads into Randall, Armstrong, and Briscoe counties.
More specifically, the Palo Duro area is situated on the Llano Estacado
or High Plains area which comprises approximately 20,000 square miles of
Texas and New Mexico (_see_ fig. 5). Generally speaking, the Llano
Estacado is a high isolated plateau or broad mesa, rising above the
surrounding rolling plains in a nearly flat, island-like mass. On the
west, southwest, and south, the Llano Estacado is bounded by the valley
of the Pecos River, while its eastern escarpment is drained by the
headwaters of the Red, Brazos, and Colorado Rivers.
The rim of Palo Duro Canyon is formed by the Eastern Caprock Escarpment.
Caprock is the term used to describe a massive layer of calcareous rock
which supports the High Plains surface (_see_ p. 26). Because it is more
resistant to forces of erosion than the softer, underlying more or less
horizontal strata, the caprock forms an abrupt, precipitous escarpment
at the edge of the High Plains. With the exception of the resistant
caprock, however, the surficial deposits on the High Plains are for the
most part unconsolidated sediments.
The Llano Estacado is essentially devoid of native trees and is
characterized by a sparse, but uniform, covering of grasses. The surface
rocks are of Tertiary and Quaternary age (_see_ geologic time scale,
fig. 6) and have a general easterly to southeasterly slope of about 9½
feet per mile. In the vicinity of Palo Duro Canyon, rocks of Late
Cenozoic age are directly underlain by Permian and Triassic formations.
These Permian and Triassic rocks, which are discussed elsewhere in this
publication, are not normally exposed except in deeply eroded areas such
as the canyon.
[Illustration: Fig. 5. Generalized geologic map of the Texas
Panhandle showing location of Palo Duro Canyon.]
_Showing:_
Q & T Pleistocene and Pliocene undifferentiated
Trdo Dockum Group (Triassic)
P Permian undifferentiated