Meseta Central

Meseta Central

 

(also Mexican Highland), a highland in the southern part of North America, occupying most of Mexico. It consists of a vast plateau and the mountain ranges rimming it on the east, south, and west. In the north, near the US border, the highland gradually gives way to the Great Plains and the Colorado Plateau, divided by ranges and basins. It covers an area of about 1.2 million sq km, and prevailing elevations range from 1,000 m to 2,000 m.

The eastern rim of the highland is formed by the Sierra Madre Oriental (4,054 m), which descends abruptly to the lowlands along the Gulf of Mexico. The western rim, the Sierra Madre Occidental (3,150 m), is broken by faults running parallel to the Pacific coast, to which it descends by stages. A chain of extinct and active volcanos, known as the Transverse Volcanic Axis, marks the southern edge of the highland. The principal volcanoes are Orizaba (5,700 m, the highest peak in the highland and all of Mexico), Colima, Popocatépetl, and Ixtacihuatl. The Jorullo volcano first erupted in the 18th century, and the currently active volcano Paricutin, in February 1943. The interior of the highland comprises two regions, the northern and central mesas. The northern mesa consists of relatively flat areas, called bolsons, with elevations of 900–1,200 m, divided by low short ranges. The central mesa to the south comprises volcanic plateaus (2,000–2,400 m), separated by mountain uplifts and depressions. The highland is composed chiefly of limestone, sandstone, and marl. Lava sheets cover a large part of the highland, and alluvialtalus deposits are found on the plateau. The Meseta Central has deposits of silver, lead, antimony, zinc, mercury, iron and manganese ores, gold, copper, and other minerals.

The climate is tropical, but it varies considerably from one region to another depending on the relief and on proximity to the Atlantic and Pacific oceans and to the vast continent to the north. Influenced by the summer trade wind from the Gulf of Mexico, the south has a mild and humid climate. In the north the climate is dry and continental. Average January temperatures range from 9°C to 14°C. In the north cold northern winds may lower the temperature to — 20°C. Average July temperatures range from 15°C to 20°C. Annual precipitation ranges from 200–400 mm in the north and interior regions to 2,000–3,000 mm on the outer mountain slopes. In the south there are three climatic zones, depending on elevation: tierra caliente, tierra templada, and tierra fría. The tierra caliente, occurring at elevations up to 1,400 m, has continually hot weather, with sunny skies and alternately dry and wet phases in winter and very humid and rainy summers. The tierra templada, rising to elevations of 3,000 m, has moderately warm weather throughout the year. In winter and spring the skies are clear, and in the autumn cloudy and rainy weather prevails. The tierra fría is the cold zone of the upper slopes of high mountains. The snow line is at 4,500 m, and the highest peaks are snow-capped.

There is no surface runoff in the dry northern part of the Meseta Central. Streams are temporary and generally flow into the bolsons, resulting in the accumulation of a thick layer of sediments in the bolsons and in the formation of a number of temporary interior-drainage salt lakes. An exception is Rio Conchos, a tributary of the Rio Grande (Mexican name, Rio Bravo del Norte), flowing along the northern border. In the south the rivers are deeper, with steep descents. In regions of active volcanism and frequent earthquakes there are many lakes dammed up by lava and tectonic lakes (Chapala, Cuitzeo).

In the arid north soils are primitive, frequently consisting of slightly altered gypsum and carbonaceous weathering crusts. In the south these soils gradually give way to mountain sierozems and to the gray-cinnamonic, cinnamonic, and red soils of the tall-grass tropical savannas. Mountain cinnamonic soils predominate over large areas in the southern part of the highland and on the mountain slopes.

As one of the regions where American flora developed, the Meseta Central has a rich vegetation, with 8,000 endemic species. In the north sparse vegetation predominates, represented by some 500 species of cacti, ranging from tiny round plants to giant species up to 4 m high, agaves (140 species), yuccas, dasylirions, and thorny shrubs. To the south this vegetation gives way to savannas with sparse stands of acacias, species of Amaranthaceae, and indigos. Wet tropical forests grow on windward slopes in the south. Broadleaf varieties, such as evergreen oaks and plane trees, predominate to elevations of 1,000 m; here also grow trees of the Myrtaceae family, laurels, and species of Annonaceae, with magnolias and ligneous ferns in the underbrush. Between 1,000 m and 2,000 m the tropical forests are supplanted by mixed forests, and at higher elevations, by coniferous forests of pines and, at the upper limits, firs. A zone of subalpine and alpine meadows lies between 4,000 m and 4,500. Most of the animals belong to the Nearctic zoogeographic region. Animals found throughout most of the Meseta Central include white-tailed and other species of deer, prong-horn antelopes, and various rodents (squirrels, gophers). Among predators are red lynxes, pumas, wolves, foxes, skunks, otters, and raccoons. Various birds of the order Passeriformes are common, and there are many reptiles. In the south the jaguar, ocelot, kinkajou, peccary, armadillo, and anteater are encountered.

Although most of the highland is sparsely populated, about half the population of Mexico lives in the fertile valleys and basins in the south.

REFERENCES

James, P. Latinskaia Amerika. Moscow, 1949. (Translated from English.)
Vivó, J. A. Geografiia Meksiki. Moscow, 1951. (Translated from Spanish.)
Garfias, V., and T. Chapin. Geologiia Meksiki. Moscow, 1956. (Translated from Spanish.)

G. M. IGNAT’EV

References in periodicals archive ?
Se deben hacer dos salvedades, la region bajo analisis en este trabajo es la region septentrional del Chubut, es decir, noroeste (y su comarca andina), la meseta central y el noreste del Chubut, considerando que este conjunto regional es clave para abordar el origen y desarrollo del movimiento ambiental provincial.
Hace ya algun tiempo cambio el estudio de los pueblos y el tributo andinos por el de los pueblos de la meseta central y las leyes mexicanas.
De tal forma que, no era casual visualizar que las companias agricolas y agrocomerciales se ubicaban en la Meseta Central. Asi, en la provincia de San Jose, entre 1830 y 1850:
Produccion de forraje y calidad nutricional de variedades de Pennisetum purpureum en la meseta central de Costa Rica, Agronomia Mesoamericana 16(1) 37-43.
Manuel Cueto y colaboradores analizan las estrategias de aprovisionamiento, produccion y consumo realizadas con obsidiana para sitios de la Meseta Central de la provincia de Santa Cruz.
Esta dominada por cadenas montanosas con una meseta central de llanuras, colinas y grandes lagos.
Esta disposicion corresponde con los castra-oppida de la II Edad del Hierro de mayor extension de la Meseta central, que presentan varios recintos amurallados, el mas interior de los cuales suele ser el que sirve de acropolis al conjunto (Curchin, 1991: 18; Davila, 2014: 59-65).
El siguiente cuadro evidencia la correlacion entre el despoblamiento de la meseta central de la provincia, la migracion hacia las ciudades de la costa y la concentracion del producto bruto geografico en la zona urbanizada, proceso que ya estaba en curso hacia 1960 y se profundizo a partir de 1970 con la puesta en practica de las orientaciones generales contenidas en este informe.
Se cultiva en la region andaluza y en la meseta central de donde procede el de Fuentesauco.
1999), ubicado en el Macizo del Deseado (o Meseta Central), en la provincia de Santa Cruz (figuras 1 y 2a).
En la franja occidental de la Meseta central, entre las provincias de Leon y Badajoz, se distingue un subestilo de la alfareria Protocogotas -1800-1450 cal AC- caracterizado por los punteados impresos con marquilla (Fabian, 2012).
Por otra parte, en las provincias de Guanacaste (34, 8 %), Puntarenas (41, 7 %) y Limon (42, 0 %), la abstencion resulto mayor a la obtenida en la meseta central. En este sentido, Puntarenas y Limon tienen los valores medianos mas altos --superiores del 40 %--; en otras palabras, en los distritos ubicados en estas dos provincias, la abstencion supero el 50%.