The Patagonian Desert, also known as the Patagonian Steppe, is the largest desert in Argentina and is the eighth-largest desert in the world by area, occupying approx. 673,000 square kilometres (260,000 mi²). It is located primarily in Argentina and is bounded by the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, to its west, and the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

to its east, in the region of

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

, southern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and areas of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. To the north the desert grades into the Cuyo Region and the Monte. The central parts of the steppe are dominated by

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

by and

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

plant species albeit to the west, where precipitation is higher, bushes are replaced by

grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...

es. Topographically the deserts consist of alternating tablelands and massifs dissected by river valleys and

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...

s. The more western parts of the steppe host lakes of glacial origin and grades into barren mountains or cold

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

forests along valleys. Inhabited by

hunter-gatherer A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived Lifestyle, lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources, esp ...

s since Pre-Hispanic times, the desert faced migration in the 19th century of

Argentines Argentines, Argentinians or Argentineans are people from Argentina. This connection may be residential, legal, historical, or cultural. For most Argentines, several (or all) of these connections exist and are collectively the source of their ...

, Welsh, and other European peoples, transforming it from a conflictive borderland zone to an integral part of Argentina, with cattle, sheep and horse

husbandry Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, management, production, nutrition, selective breeding, and the raising of livestock. ...

being the primary

land use Land use is an umbrella term to describe what happens on a parcel of land. It concerns the benefits derived from using the land, and also the land management actions that humans carry out there. The following categories are used for land use: fo ...

s. The Patagonian Desert has existed since the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

(14–12 million years ago) and came into existence as the Andes rose to the west.

Geography and climate

The Patagonian Desert is the largest desert south of the 40° parallel and is a large cold winter desert, where the temperature rarely exceeds 12 °C and averages just 3 °C. The region experiences about seven months of winter and five months of summer. Frost is not uncommon in the desert but, due to the very dry condition year round, snow is rare. The Andes, to the desert's west, are the primary reason for the Patagonian desert status as they inhibit the westerly flow of moisture from the southern Pacific from reaching inland. This creates a

rain shadow A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side. Evaporated moisture from body of water, bodies of water (such as oceans and larg ...

that accounts for the formation of the desert and is why, despite approximately half of the desert being only about 200 miles from the ocean, such a large desert is found in the region. The cold

Falkland Current The Falkland Current is a cold water current that flows northward along the Atlantic coast of Patagonia as far north as the mouth of the Río de la Plata. This current results from the movement of water from the West Wind Drift as it rounds Cape ...

off the Atlantic coast of South America also contributes to the area's aridity. Different climates can be distinguished: the coast north of the 45th parallel is much milder because of the warm currents from Brazil, and the entire northern half of the region is significantly warmer in the summer, when sunny weather predominates. Daily temperatures in the summer reach 31 °C in the Rio Colorado region, a general 26 °C to 29 °C in the northern coast, and 24 °C to 28 °C in the northern plain, with nights around 12 °C to 15 °C in the coast and between 7 °C and 10 °C in the steppe. In the south, summer temperatures decrease from 22 °C to only 16 °C along the coast, and from 24 °C to 17 °C along the steppes, while nights go from 8 °C to 11 °C on the coast, and from 6 °C to 10 °C in the steppe. During the winter, the proximity to the coast and the altitude are the main factors: while northern coastal areas have mild winters, from 2 °C at night to about 11 °C during the day, southern Santa Cruz ranges from -2 °C to 5 °C, and Tierra del Fuego, from -3 °C to 3 °C, for a mean of 0 °C. Inland, the northern areas range from 0 °C to 10 °C in low areas, and from -5 °C to 5 °C on the plateaus (again, mean around 0 °C), while in the south, low areas range from -3 °C to 4 °C, and higher areas are clearly below 0 °C. The coldest spots usually register temperatures between -20 °C and -25 °C during cold waves, and the official record is -33.9 °C in Chubut province. However, some towns claim to have had records of around -35 °C. Summer frost is common everywhere except for the northern coast, and even sleet and light snow can fall during the warm season. Winds are constant and very strong, from the west in most cases. Before the Andes were formed, the region was likely covered by

temperate forest A temperate forest is a forest found between the tropical and boreal regions, located in the temperate zone. It is the second largest terrestrial biome, covering 25% of the world's forest area, only behind the boreal forest, which covers about 3 ...

s. However, after the formation of the Andes, ash from nearby volcanoes covered the forests and mineral-saturated waters seeped into the logs, thus fossilizing the trees and creating one of the world's best preserved petrified forests in the desert's center. The Patagonian is mainly composed of

gravel Gravel () is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentation, sedimentary and erosion, erosive geological processes; it is also produced in large quantities commercially as crushed stone. Gr ...

plains and plateaus with

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

canyons and clay shapes dotting the landscape, sculpted by the desert wind. The region encompassing the desert, however, has many diverse features. Ephemeral rivers, lakes, and drainage deposits from the Andes' spring melt form annually, hosting a variety of

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

and aquatic grasses. A variety of glacial, fluvial, and volcanic deposits are also found in the region and have significantly affected the desert's climate over time, especially contributing to the gravel sediments covering parts of the Patagonian. The desert is quite windy as well, a result of the rain shadow effect and descending cool mountain air. This wind helps make the Patagonian one of the largest sources of dust over the South Atlantic Ocean. On the west, the Patagonian grasslands portion of the Patagonian Desert are bounded by

nothofagus ''Nothofagus'', also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere, found across southern South America (Chile, Argentina) and east and southeast Australia, New Zealand, New Guin ...

forests of the

Magellanic subpolar forests The Magellanic subpolar forests () are a terrestrial ecoregion of southernmost South America, covering parts of southern Chile and Argentina, and are part of the Neotropical realm. It is a temperate broadleaf and mixed forests ecoregion, and ...

. Volcanic rocks covers more than 120,000 km² of the Patagonian Desert, mainly in the Somún Cura Massif (i.e. North Patagonian Massif) and the Deseado Massif. Some other volcanic areas include the Pali-Aike Volcanic Field near the

Strait of Magellan The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and the Tierra del Fuego archipelago to the south. Considered the most important natura ...

. The volcanic rocks are the result of back-arc volcanism distributed mainly in two episodes: one in the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

and the other from Late Miocene to

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Fauna and flora

Despite the harsh desert environment, a number of animals venture into and live in the Patagonian. Some only live on the more habitable and geographically-varied outskirts of the desert, where food is more abundant and the environment less hostile, but all are found within the region encompassing the Patagonian. The

burrowing owl The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged, primarily terrestrial—though not flightless—species of owl native to the open landscapes of North and South America. They are typically found in gra ...

, lesser rhea,

guanaco The guanaco ( ; ''Lama guanicoe'') is a camelid native to South America, closely related to the llama. Guanacos are one of two wild South American camelids; the other species is the vicuña, which lives at higher elevations. Etymology The gua ...

, tuco-tuco, mara, pygmy armadillo, Patagonian weasel, puma, Patagonian gray fox, desert iguana, western ribbon snake, and various species of eagle and hawk are a few of the variety of animals living in the region. The flora of the region is quite common for its climate and includes several species of desert shrubs like '' Acantholippia'' and '' Benthamiella'' and tuft grasses like ''

Stipa ''Stipa'' is a genus of 141 species of large Perennial plant, perennial hermaphrodite, hermaphroditic grasses collectively known as feather grass, needle grass, and spear grass. They are placed in the subfamily Pooideae and the tribe Stipeae, w ...

'' and ''

Poa ''Poa'' is a genus of about 570 species of Poaceae, grasses, native to the temperate regions of both hemispheres. Common names include meadow-grass (mainly in Europe and Asia), bluegrass (mainly in North America), tussock (some New Zealand spe ...

''. Aquatic grasses and larger flora exist on the outskirts of the desert and around the ephemeral lakes that form from the Andes' runoff.World Wildlife Fund.

Human land use

The desert has hosted various

indigenous peoples There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...

in its past, as evidenced by

cave painting In archaeology, cave paintings are a type of parietal art (which category also includes petroglyphs, or engravings), found on the wall or ceilings of caves. The term usually implies prehistoric art, prehistoric origin. These paintings were often c ...

s in the area. The earliest inhabitants of the desert known by name are those of the Tehuelche complex. Tehuelches lived as

s and did not practise agriculture in lush valleys found in the desert. In the 18th and 19th centuries the northern part of the desert came under

Mapuche The Mapuche ( , ) also known as Araucanians are a group of Indigenous peoples of the Americas, Indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging e ...

influence during a process of Araucanization. Mapuches came to practise horse husbandry in the northern part of the Patagonian steppe. Mapuche tribes came to control trade across the desert and traded with the cities of southern Chile as well as

Buenos Aires Buenos Aires, controlled by the government of the Autonomous City of Buenos Aires, is the Capital city, capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− glob ...

and the Cuyo Region. From the mid-19th century onwards several Argentine and European settlements, some of them sporadic, appeared at the edges of the desert. The most important was established at Chubut River's outflow by Welsh immigrants in 1860. Perito Moreno explored the desert in the 1870s. In the 1870s the Argentine army undertook the Conquest of the Desert campaign, massively defeating Mapuche warlords. The Conquest of the Desert was followed by a sharp decline in the indigenous population of the desert; some were chased into Chile and peripheral areas in the Andes. It is estimated that the Conquest of the Desert caused the death of about 1,000 Native Americans. Additionally 10,000 Native Americans were taken prisoner of whom 3,000 ended up in Buenos Aires separated by sexes to avoid their procreation. The boundary treaty of 1881 between Chile and Argentina bought most of the desert under definitive Argentine sovereignty; previously Chile had claimed varying now Argentine areas under claims of inherited colonial titles. In the few decades before and after 1900 the less dry parts of the Patagonian steppe experienced a sheep farming boom, transforming the region into one of the world's greatest exporters of ovine products. The area is sparsely populated today and those that do live here survive mainly by the raising of livestock such as sheep and goats. Resource mining, especially of oil, gas, and coal in parts of the region, is another way humans interact with and influence the desert environment.

Protected areas

A 2017 assessment found that 70,970 km², or 12%, of the ecoregion is in protected areas. Protected areas include:"Patagonian steppe". DOPA Explorer. Accessed 16 April 2022
/ref> * Bernardo O'Higgins National Park * Cerro Castillo National Park * Bosques Petrificados de Jaramillo National Park * El Rincón Wilderness Nature Reserve * Kawésqar National Park * La Ascensión Wilderness Nature Reserve * Laguna Blanca National Park * Laguna del Diamante Nature Reserve * Laguna San Rafael National Park * Lanín National Park * Leicester Falls Nature Reserve * Los Glaciares National Park * Monte León National Park * Pali Aike National Park * Patagonia National Park (Argentina) * Patagonia National Park (Chile) * Patagonia Wilderness Nature Reserve * Perito Moreno National Park * Sea Lion Island Nature Reserve * Valdes Biosphere Reserve

External links

References