Llano Estacado

Llano Estacado (Sp. IPA|/ˈʎano ˌestəˈkado/, " [http://en.wiktionary.org/wiki/palisade Palisaded] Plains") is a region in the southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas, including the South Plains and parts of the Texas Panhandle. One of the largest mesas or tablelands on the North American continent,cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood] the elevation rises from 3000 ft in the southeast to over 5000 ft in the northwest, sloping almost uniformly at about 10 feet per mile [Wendorf, F., 1961. Paleoecology of the Llano Estacado, Vol. 1. The Museum of New Mexico Press, Santa Fe, Fort Burgwin Research Center Publication, 144 pp.] . However, at such a gradual slope, the elevation change is imperceptible to the observer, making the landscape appear almost completely flat.

Geography and climate

The Llano Estacado lies at the southern end of the High Plains section of the Great Plains of North America and is part of what was once called the Great American Desert. The Canadian River forms the Llano's northern boundary, separating it from the rest of the High Plains. To the east, the Caprock Escarpment, a precipitous cliff about 300 ft high, lies between the Llano and the red Permian plains of Texas, while to the west, the Mescalero Escarpment demarcates the edge of the Pecos River valley. The Llano has no natural southern boundary, instead blending into the Edwards Plateau near Big Spring, Texas. This geographic area stretches about 250 mi north to south, and 150 mi east to west, a total area of some 37,500 sq mi, larger than all of New England, and covering all or part of thirty-three Texas counties and four New Mexico counties.

Spanish conquistador Francisco Coronado, the first European to traverse this "sea of grass" in 1541, described it as follows: "I reached some plains so vast, that I did not find their limit anywhere I went, although I travelled over them for more than 300 leagues ... with no more land marks than if we had been swallowed up by the sea ... there was not a stone, nor bit of rising ground, nor a tree, nor a shrub, nor anything to go by."cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood] General Randolph Marcy, after his expedition to explore the headwaters of the Red and Colorado rivers in 1852, agreed: " [not] a tree, shrub, or any other herbage to intercept the vision... the almost total absence of water causes all animals to shun it: even the Indians do not venture to cross it except at two or three places."cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood] The landscape is, however, dotted by numerous small playa lakes, seasonal depressions that fill with water, making an important habitat for waterfowl.

The Llano Estacado has a semi-arid climate (Köppen "Bsk"), characterized by long hot summers and cold winters. Rainfall is extremely low; the entire region receives less than 23" of rainfall annually, and the western part receives as little as 14". High summer temperatures (average July temperature above 85°F) mean that most of this already-small amount of precipitation is lost to evaporation, making dry-land farming extremely difficult.cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood]

The Llano Estacado is one of the largest cotton-producing regions of the United States.

All the agriculture-enabling water visible on the Llano today is brought to the surface by electrical pumps. Before electricity, grazing was possible and large ranches existed. However, grazing soon destroyed the fragile grass. The scanty rainfall simply evaporates or disappears into the porous soil, and cannot refill the parched aquifer at the rate it is being depleted. There are no nearby sources of abundant water, and the Pecos runs nearly dry from irrigation diversions. When the store of water is gone, there will be no more to support the large cities of Lubbock and Amarillo.Fact|date=October 2007 There was a permanent oasis, Monument Spring, not far from Hobbs, New Mexico, that was one of the rare watering places. The "monument" was a pile of caliche raised by the Native Americans to guide people to the spot.

_Shaded_Relief_Image_of_the_Llano_EstacadoImage:Hill_1900_LlanoEstacado.jpg|_The_level_surface_of_the_Llano_Estacado_with_natural_grass_cover_as_seen_in_1900Image:Llano_Estacado_Northern_Escarpment_2003.jpg|_Escarpment_that_defines_the_northern_edge_of_Llano_EstacadoImage:Palo_Duro_Canyon_2002.jpg|_Palo Duro Canyon along the eastern edge of Llano Estacado

History and name

The region's name was given to the region by Coronado himself, when he saw the cliffs of the Caprock Escarpment from the north on his way east from Cíbola, appearing to him as an impenetrable defense for the land and leading him to dub it the "Llano Estacado", Spanish for " [http://en.wiktionary.org/wiki/palisade Palisaded] Plains." The name is often mistranslated as "staked" plain," and fanciful stories have been created to explain this title. Some allude to yucca stems, others to actual stakes driven into the ground as landmarks, and still others to similar, even less plausible objects. None of these have ever been evident enough to be responsible for the name, especially not to Coronado riding along the Canadian.cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood]

The horses of the conquistadors were the first to return to the Great Plains since their extinction in North America eons earlier. Some horses would escape, thus giving horses to some of the Native American tribes in the succeeding centuries. Before this, the dog was their largest domesticated animal.

In the latter part of the 19th century, the Llano was then a refuge for the bands of Kiowas and Comanches who did not wish to be cooped up in Oklahoma. One of the last battles was fought in bitter cold on 2 December 1874 in Palo Duro Canyon. The waterless surface was very difficult for the U.S. Cavalry to cope with, and it was easy to disappear into the slight draws of its featureless expanse, or into the labyrinths of canyons like Palo Duro.

Because of the lack of surface water, low rainfall, and the harsher climate, the Llano was one of the last areas to be settled and farmed in contemporary Texas. Better well-drilling technology by the late 1910s to 1920s was responsible for the maintenance and growth of many caprock towns. However, over-utilization of the underground aquifer has led to a major move back towards dryland crops since the 1970s.

Human population

The Llano Estacado has an extremely low population density, as can be seen in the map; most of the area's population is localized in the principal cities of Amarillo, Lubbock, and Midland/Odessa, Texas. The vast majority of the area is rural, covered by large ranches and irrigated farms. Several small- to medium-sized towns do exist, however, including Plainview, Levelland, and Lamesa, Texas and Clovis and Hobbs, New Mexico.

Lubbock, TX, the largest city on the Llano
Amarillo, Texas
Midland the "The Tall City" of West Texas

Geology

The Ogallala Group is a late Tertiary (Pliocene) sheet of sediments spread over the area east of the Rocky Mountains from Wyoming to Texas, rather recently in a geological sense, when the Colorado Plateau and Rocky Mountain regions were elevated from near sea level to about their current elevations, and the eroded sediments (mainly earlier Tertiary rocks) spread over the low plains to the east. The Rocky Mountains had been formed much earlier, at the end of the Cretaceous and the beginning of the Tertiary eras, and had been worn down to near flatness before the late Tertiary uplift. In the northern areas, the Ogallala was spread over earlier Tertiary and Cretaceous rocks, but in the Llano Estacado area erosion had removed everything down to the Triassic, and even to the Permian redbeds. At the southern end, some Cretaceous limestone remained, however. The Ogallala was laid down over all of this by lazy, sandy streams near sea level, which produced the flatness of its surface. Subsequently, the uplift to the west progressed to the east, raising and tilting the Ogallala surface to its present position, and changing the environment from depositional to erosional. Some major rivers, such as the Pecos and Canadian, incised their courses deeply as the region was elevated, while others, such as the Red, Brazos, and Colorado, arose on the dip slope. The erosion of these rivers has now defined the area of the Llano Estacado, separating it from its Rocky Mountain sources and from other parts of the High Plains.

Other areas of the Ogallala surface, or High Plains, have the same history. In Wyoming, it is still in contact with the mountains west of Cheyenne (the "Gangplank"), but elsewhere it is separated from the mountains by valleys of Cretaceous and earlier rocks due to active erosion at these higher levels. Only in the Llano Estacado area has the formation of the Caprock given rise to a prominent, distinctive, palisade-like escarpment, as well as to a remarkably flat surface; further north, rivers such as the Platte, Arkansas, and Cimarron have sliced it into segments.

Another distinctive characteristic is that the surrounding rocks are often red, as in Palo Duro Canyon, making a striking contrast with the light-colored rocks of the plateau. In some other places, the erosional edge of the High Plains is marked by "breaks" or other abrupt changes of scenery, as in eastern Wyoming and western Nebraska. In these areas, the High Plains are usually sandy, rolling plains with normal, branching drainage, not flat surfaces without continuous streams.

Hydrogeology

The "bedrock" of the plain is the indurated top of the Ogallala Group, a hard caliche layer called the Caprock. This was formed when surface drying caused mineral-laden water to rise by capillary action to the surface. Evaporating, the minerals were left behind to cement the otherwise fairly loose sandy sediments of the Ogallala Group. The Caprock is generally covered by sands and soils. Where soils predominate, the land is fertile when irrigated, and is devoted to field crops, including grain and cotton. Irrigation water is mined from the deeper parts of the Ogallala Group by electric pumps, since there is almost no usable surface water. The pumped water is used much more rapidly than it is replenished,cite web|url=http://www.tsha.utexas.edu/handbook/online/articles/LL/ryl2.html|title=Handbook of Texas Online|accessdate=2007-10-28|Art Leatherwood] so eventually Llano farmers will be forced to employ dryland cropping systems or return the area to its natural state of sparse grasslandFact|date=October 2007.

Other meanings

Llano Estacado Winery is a winery located near Lubbock, Texas."El Llano Estacado" is a traditional folk song adapted by Tom Russell, which, according to Brian Burns (who has recorded a version of the song with Russell), is a tale in which the "subject falls victim to the whim of a sadistic señorita and decides to take on the West Texas desert to win her hand in marriage."

ee also

* List of geographical regions in Texas
* Palo Duro Canyon
* Caprock Canyons State Park and Trailway
* Mount Blanco
* Caprock Escarpment
* Butte
* Blowouts

References