Part 2

HISTORY OF MAN IN THE AREA

Archeological studies indicate that the earliest known inhabitants of Palo Duro Canyon lived in the canyon from about 10,000 to 5,000 B.C. These early men hunted bison and now-extinct elephant-like mammoths that roamed the area during the Pleistocene Ice Age. Their stone weapons and artifacts have been found in the canyon. Presumably these primitive people, like those who came later, were attracted by streams and springs in the canyon, and by game that came to feed there. Rock exposed in the canyon provided material for tools and weapons.

Through the centuries, various tribes of Plains Indians, including Apache, Cheyenne, Arapahoe, Kiowa, and Comanche, made use of the canyon as a camping ground. After the arrival of the white man, the canyon became a favorite resting place for buffalo hunters and Indian traders who travelled the Plains. White men first established residence there in 1876.

The last Indian battle in Texas was fought in the canyon south of the Park. Col. Ranald Mackenzie and his raiders, on September 25, 1874, attacked a large encampment of Comanche, Cheyenne, Kiowa, and Arapahoe in the canyon. They destroyed about 100 lodges and 1400 horses and mules. The damage inflicted was severe and by the following spring most of the Indians were returned to the reservation in Oklahoma.

GEOLOGIC HISTORY

The age of the earth is calculated in terms of billions of years. For convenience, geologic time is divided into units, called PERIODS, of different lengths (Figure 1). Sediments deposited during each period and the fossilized remains of animals and plants found in these sediments give a partial record of the events and life of that period.

A nearly homogeneous (uniform composition) rock layer may be identified as a FORMATION. Formations are usually spread over a wide area like a large blanket and are stacked on top of each other with the oldest at the bottom and the youngest at the top. When viewed in the walls of the canyon, they resemble a huge layer cake and may be traced along the canyon walls.

GEOLOGIC TIME-SCALE AGE M.Y. CENOZOIC QUAT. HOLOCENE PLEISTOCENE 2 TERTIARY PLIOCENE 13 MIOCENE 25 OLIGOCENE 36 EOCENE 58 PALEOCENE 63 MESOZOIC CRETACEOUS 135 JURASSIC 181 TRIASSIC 230 PALEOZOIC PERMIAN 280 PENNSYLVANIAN 310 MISSISSIPPIAN 345 DEVONIAN 405 SILURIAN 425 ORDOVICIAN 500 CAMBRIAN 600 PRECAMBRIAN

The lowest and oldest exposed formation in Palo Duro Canyon is the Quartermaster. It was deposited near the edge of a shallow sea that occupied a wide area in Texas some 280 to 230 million years ago (Figure 3). This was during the Permian Period, the last period of the Paleozoic Era. The sediments in the park area were carried from the east and deposited in a nearshore environment. Sedimentary structures, such as crossbeds and ripplemarks, are present throughout the Quartermaster Formation. Halite casts suggest that there was a high rate of evaporation as sedimentation occurred. Gypsum (altered anhydrite) is also interpreted to be an evaporite deposit. The gypsum is now seen as horizontal white layers of alabaster and satin-spar varieties within the Quartermaster Formation.

The Quartermaster Formation is mostly siltstone and shale, and is commonly a distinctive red color. This red color is the result of combining oxygen from the air with the iron in the sediments (oxidation) much as a nail rusts after it has been exposed for a long period. The bedded gray zones represent times when there was enough fresh water from the land to offset temporarily the oxidation process. Smaller circular gray areas have organic nuclei that produced local areas of chemically altered iron by a process called reduction.

At the close of the Permian Period and the Paleozoic Era, the Panhandle region was uplifted and a period of widespread erosion followed. Consequently there are no sediments in this area to represent the early or middle portions of the Triassic Period. Breaks, such as this, in the sedimentary record are called UNCONFORMITIES. They may have been caused by a lack of deposition in the area or by an interval during which erosion removed earlier sediments.

The Tecovas Formation was deposited in swamps, lakes, and streams approximately 200 million years ago during the Late Triassic (Figure 4). The Tecovas is mostly purplish lavender, yellow, orange, and buff siltstone and shale. The bright-colored shale of the Tecovas Formation is easily followed for many miles. Amarillo (the Spanish word for yellow) got its name from Amarillo Creek where the yellow bed of the Tecovas Formation crops out far from Palo Duro Canyon. The shale of the Tecovas forms the less steep portions of the canyon walls and often is covered by talus (weathered, broken rock) or vegetation. The uppermost Tecovas is usually mantled with boulders from the overlying sandstone of the Trujillo Formation.

The Tecovas Formation contains numerous concretions or irregularly shaped, weathered rocks. The unusual shape of a concretion is the result of the hardening of the sediments around a nucleus. As the rock weathers, the resistant material surrounding the nucleus remains. Most of the concretions are composed of limonite, hematite, manganite or calcite. Some of the calcite concretions are a variety termed “septarian.” These concretions have calcite ridges in a honeycomb pattern throughout the rock. Some of the concretions are simply nodular or spherical aggregates. Also in the Tecovas, geodes filled or lined internally with calcite crystals are found.

Overlying the Tecovas is the Trujillo Formation. It was deposited by streams that probably originated in an ancient highland southeast of the present Panhandle. These streams were flowing more than 181 million years ago. The sandstone contains some alternating layers of shale and marl-pebble conglomerate. The Trujillo Formation is a resistant formation and forms some of the upper portions of the canyon walls. The steep portions are, in part, the result of a persistent fracture system common in the Trujillo Formation. The sandstone and conglomerate of the Trujillo characteristically exhibit well-developed crossbedding. Their gray color is sometimes obscured by a crust of red mud or iron stain. The uppermost red shale contains mineralized wood. The gray micaceous sandstone has many round sandstone concretions. Some of these are septarian concretions with cracks filled by calcite. Others may contain leaf imprints.

There is no evidence that Jurassic sediments were ever deposited in the region. Cretaceous rocks are also missing in this area although water-worn fossil oysters occur in the gravel at the base of the overlying Ogallala. These fossils indicate that marine Cretaceous sediments were deposited nearby and possibly covered the Triassic deposits in the region. The rocks were then eroded away some time between the end of the Cretaceous Period and the beginning of the Pliocene Epoch, a span of about 50 million years.

During the Pliocene Epoch, approximately 2-10 million years ago, the Rocky Mountains were again uplifted. Sediments in streams and floodplains were deposited on the erosional surface of the Trujillo Formation (Figure 5). These stream-deposited sediments are the Ogallala Formation.

The Ogallala Formation, which forms the upper part of the sequence of rocks exposed in the canyon, is present throughout most of the Panhandle. The formation is important as it is the principal aquifer of the Panhandle and supplies many farms and cities in the region with water. The Ogallala is a siltstone and sandstone that has, in places, been cemented by silica which came from groundwater. The formation contains many pockets of common opal and the basal part is in many places almost a chert. There are also some thin gray shale lenses.

Scattered over the Ogallala are Late Pliocene and Pleistocene playa lake deposits up to 3 million years old. Some of these are fresh water lake deposits of silt, limestone, and wind-transported sediments or loess. Below these sediments is a layer of caliche which was deposited by evaporation of groundwater rich in calcium carbonate during Late Pliocene and Pleistocene time.

Less than one million years ago, during the Pleistocene Epoch of the Quaternary Period, the Prairie Dog Town Fork of the Red River began eroding headward into the Llano Estacado (Figure 6). The caprock escarpment is the result of differing resistance to erosion. The faster erosion of softer layers under the more resistant Ogallala and Trujillo formations forms the steep slopes of the escarpment.

The Prairie Dog Town Fork of the Red River is the small stream flowing in Palo Duro Canyon. Throughout the past million years it has been slowly excavating the canyon. The rate of change has been slow but continuous, carving the steep colorful walls of Palo Duro Canyon, an area of geologic interest and great scenic beauty.

PALEONTOLOGY

During the Permian Period the area that is now Palo Duro Canyon State Park, was a nearly-flat land surface along the edge of a restricted sea. The scarcity of fossils in the Quartermaster Formation indicates that plant and animal life was sparse. The environment was probably unsuited for plant life. It is thought that groundwater near the surface evaporated, leaving large amounts of salt as a residue. Since plants could not grow, animals would not have frequented the area either.

Fossils and rocks of the Tecovas Formation indicate that the sediments were deposited in a swamp and stream environment (Figure 7). As time went on and the land continued rising, the climate became drier and some of the earlier life forms disappeared.

Remains of Metoposaurus (‘Buettneria’), the last of a long line of giant amphibians, are found here. These animals lived in large ponds. Metoposaurus buried themselves in the bottom of a pond and waited for fish to pass. With the aid of a third eye in the middle of its head, the animal could direct its huge mouth to its prey. Metoposaurus was so bulky that it is thought that it did not leave the water because its weak legs could not support its weight on land.

Living in shallower areas of the swamp were a group of semiaquatic reptiles known as phytosaurs. Phytosaurs looked very much like giant crocodiles with a nostril on the top of their heads, which permitted them to lie submerged just below the surface of the water. They probably fed on fish and smaller reptiles. Phytosaurs reached a length of 50 feet.

A heavily armored aetosaur, Desmatosuchus also lived in the Park area during the Triassic. They attained a length of about 10 feet. These reptiles probably were herbivorous (plant eating). A unique feature of Desmatosuchus was a fringe of backward-pointing horns around their necks. These possibly served to protect them from the carnivorous (meat eating) phytosaurs.

Also found in the Tecovas and Trujillo formations are fossil lung-fish teeth. Lung-fish are a type of fish that can breathe air, enabling them to move from pond to pond. Footprints of a chicken-sized dinosaur have also been found. The Middle Triassic flora was dominated by giant palm-like trees. Also found are remains of a few large ferns and horsetails. As the climate became drier and the swamps began to disappear, coniferous (evergreen) trees such as Araucarioxylon became plentiful. These trees can be found in the canyon today as petrified wood.

The Ogallala in the park contains very few fossils. A giant tortoise was found near the bend where the road begins to descend into the canyon. Fossil seeds may be seen in the exposure of the Ogallala near the Coronado Lodge.