The geology of Chile is a characterized by processes linked to

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...

such as

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

s and

orogeny Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An '' orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted ...

. The buildings blocks of Chile's geology assembled during the

Paleozoic Era The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''z ...

. Chile was by then the southwestern margin of the supercontinent

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

. In the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

Gondwana began to split and the ongoing period of

crustal deformation Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

and

mountain building Mountain formation refers to the geological processes that underlie the formation of mountains. These processes are associated with large-scale movements of the Earth's crust (tectonic plates). Folding, faulting, volcanic activity, igneous intr ...

known as the

Andean orogeny The Andean orogeny ( es, Orogenia andina) is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system along ...

began. In the Late Cenozoic Chile definitely separated from Antarctica, the Andes experienced a great rise accomplained by a cooling climate and the onset of

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...

s. The subduction interactions shaped four main morphostructures of Chile: the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

; the Intermediate Depression, the Coast Range, and the

Peru–Chile Trench The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about off the coast of Peru and Chile. It reaches a maximum depth of below sea level in Richards Deep () and is approximately long; ...

off the coast. Since Chile is on an active

continental margin A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

, it has many

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...

es. Almost the entire country is subject to earthquakes arising from strains in the

Nazca Nazca (; sometimes spelled Nasca; qu, Naska) is a city and system of valleys on the southern coast of Peru. It is also the name of the largest existing town in the Nazca Province. The name is derived from the Nazca culture, which flourished in ...

and

Antarctic Plate The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...

s or shallow

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectoni ...

s. Northern Chilean mineral resources are a major economic resources, and the country is the leading producer of

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pink ...

lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense soli ...

and

molybdenum Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin ''molybdaenum'', which is based on Ancient Greek ', meaning lead, since its ores were confused with lead ...

. Most of these mineral deposits were created from

magmatic Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

activity. The water required to form those deposits derived from the subducted slab of the oceanic crust beneath the Andes. The Chilean

Easter Island Easter Island ( rap, Rapa Nui; es, Isla de Pascua) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is most famous for its nearl ...

and Juan Fernández Archipelago are volcanic hotspot islands in the eastward-moving Nazca plate. The geology of the

Chilean Antarctic Territory The Chilean Antarctic Territory or Chilean Antarctica (Spanish: ''Territorio Chileno Antártico'', ''Antártica Chilena'') is the territory in Antarctica claimed by Chile. The Chilean Antarctic Territory ranges from 53° West to 90° West and f ...

has various commonalities with that of mainland Chile.

General characteristics

The three primary morphological features derived from the Andes are the Andes Mountains proper, the Chilean Coast Range and the Chilean Central Valley, also known as the Intermediate Depression and the Longitudinal Valley. The mountains run parallel in a north-south direction from Morro de Arica to

Taitao Peninsula The Taitao Peninsula (Spanish: ''Península de Taitao'') is a westward projection of the mainland of Chile, with which it is connected by the narrow Isthmus of Ofqui, over which the natives and early missionaries were accustomed to carry their bo ...

, making up most of Chile's land surface. South of Taitao, only the Andes Mountains are present. North of the Taitao Peninsula, the Peru–Chile Trench

subduction zone Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

is the boundary between the South American and Nazca Plates. At Taitao, the

Chile Triple Junction The Chile Triple Junction (or Chile Margin Triple Junction) is a geologic triple junction located on the seafloor of the Pacific Ocean off Taitao and Tres Montes Peninsula on the southern coast of Chile. Here three tectonic plates meet: the South ...

and the

Nazca Plate The Nazca Plate or Nasca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the N ...

subduct the South American Plate.

The Andes

Miscanti Lagoon near San Pedro de Atacama Chile Luca Galuzzi 2006

In Norte Grande the mountains form a series of

plateaus In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ha ...

, such as

Puna de Atacama The Puna de Atacama or Atacama Plateau''Atacama Plateau''
article at the ''

Altiplano The Altiplano (Spanish for "high plain"), Collao (Quechua and Aymara: Qullaw, meaning "place of the Qulla") or Andean Plateau, in west-central South America, is the most extensive high plateau on Earth outside Tibet. The plateau is located at ...

. At a south latitude of 27 degrees, Chile's highest mountain (

Ojos del Salado Nevado Ojos del Salado is a dormant complex volcano in the Andes on the Argentina–Chile border. It is the highest volcano on Earth and the highest peak in Chile. The upper reaches of Ojos del Salado consist of several overlapping lava domes, ...

) reaches a height of . Below 42 degrees south, the Andes split into a

fjord In physical geography, a fjord or fiord () is a long, narrow inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Alaska, Antarctica, British Columbia, Chile, Denmark, Germany, Greenland, the Faroe Islands, Icel ...

landscape and the highest mountain is

Monte San Valentin Monte may refer to: Places Argentina * Argentine Monte, an ecoregion * Monte Desert * Monte Partido, a ''partido'' in Buenos Aires Province Italy * Monte Bregagno * Monte Cassino * Montecorvino (disambiguation) * Montefalcione Portugal * Mont ...

at at north of

Northern Patagonian Ice Field The Northern Patagonian Ice Field, located in southern Chile, is the smaller of two remnant parts in which the Patagonian Ice Sheet in the Andes Mountains of southern South America can be divided. It is completely contained within the boundaries ...

. As the mountains ebb, the

snow line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

lowers; in the Llanquihue it is at , and in the Magallanes.

Intermediate Depression

The Intermediate Depression, a series of faults running north to south, separates the Andes from the Coast Range with a steady decrease in altitude as the latitude increases. In Norte Grande the Intermediate Depression is partially covered by a series of salt flats, and has the world's largest

potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and ...

deposits. In Norte Chico, the depression disappears briefly before reappearing in a narrow valley at

Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whos ...

. From the narrows southward the valley widens until it is interrupted near Loncoche by the Bahía Mansa Metamorphic Complex (part of the Coast Range), then widening at Los Llanos (near

Paillaco Paillaco is a city and commune in southern Chile. It is located in Valdivia Province of Los Ríos Region, and is about 48 km southeast of Valdivia. Demographics According to the 2002 census of the National Statistics Institute, Paillaco spans ...

). In central and southern Chile (33°–42° south), the landscape is partially covered with glacial

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

from the Andes. In Zona Austral (south of 42° south) the depression dips below

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

, appearing occasionally in islands such as Chiloé. Its southern end is the Isthmus of Ofqui.

Chilean Coast Range

The

Chilean Coast Range The Chilean Coastal Range ( es, Cordillera de la Costa) is a mountain range that runs from north to south along the Pacific coast of South America parallel to the Andean Mountains, extending from Morro de Arica in the north to Taitao Peninsula ...

runs southward along the coast (parallel to the Andes) from Morro de Arica to

, ending at the

. The range, a combined horst, forearc high and

accretionary wedge An accretionary wedge or accretionary prism forms from sediments accreted onto the non- subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the d ...

, was separated from the Andes during the

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

rise due to the

subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope mov ...

of the Intermediate Depression.

Geologic history

Paleozoic Era

The oldest rocks in Chile are

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

ceous

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...

phyllite Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily compo ...

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures a ...

es and

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

s, many examples of which are found in the Coast Range of south-central Chile. The schists of southern Chile were initially formed by sediment in the proto-Pacific Ocean, and later metamorphosed in the

forearc Forearc is a plate tectonic term referring to a region between an oceanic trench, also known as a subduction zone, and the associated volcanic arc. Forearc regions are present along a convergent margins and eponymously form 'in front of' the v ...

wedge of the Peru–Chile Trench.

Mesozoic Era

During the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

Period about 250 million years ago Chile was part of the

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...

Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...

, which concentrated the world's major land masses.

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

were near Chile. When Pangaea began to split apart during the

period, South America and the adjacent land masses formed

. Floral affinities among these now-distant landmasses date from the Gondwanaland period. South America separated from Antarctica and Australia 27 million years ago with the development of the

Drake Passage The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atla ...

. Across the -wide Drake Passage lie the mountains of the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

, south of the Scotia Plate, which appear to be a continuation of the Andes. In the extreme south, the Magallanes–Fagnano Fault separates

Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla ...

from the small

Scotia Plate The Scotia Plate () is a Plate tectonics, tectonic plate on the edge of the Atlantic Ocean, South Atlantic and Southern Ocean, Southern oceans. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates ...

. The formation of the Andes began during the Jurassic. During the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

, the Andes began to assume their present form by the uplifting,

faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

and folding of

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

and

metamorphic rocks Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

of ancient

craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and ...

s. Tectonic forces along the

along the west coast of South America continue to their

orogenesis Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumpl ...

, resulting in earthquakes and volcanic eruptions to this day.

Cenozoic Era

The

plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ...

was formed during the

, with several mechanisms proposed; all attempt to explain why the topography of the Andes incorporates a large area of low relief at high altitude (high plateau): # Existence of weaknesses in the Earth's crust prior to tectonic shortening. Such weaknesses would cause the partition of tectonic deformation and uplift into eastern and western cordillera, leaving the necessary space for the formation of the Altiplano basin. # Magmatic processes rooted in the asthenosphere might have contributed to uplift the plateau. # Climate controlled the spatial distribution of erosion and sediment deposition, creating the lubrication along the Nazca Plate subduction and hence influencing the transmission of tectonic forces into South America. # Climate also determined the formation of internal drainage (endorheism) and sediment trapping within the Andes, potentially blocking tectonic deformation in the area between the two cordilleras.

Quaternary

The

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million year ...

s left visible marks in most parts of Chile, particularly

Zona Sur Zona Sur (''Southern Zone'') is one of the five natural regions on which CORFO divided continental Chile in 1950. Its northern border is formed by the Bío-Bío River, which separates it from the Central Chile Zone. The Southern Zone borders t ...

and Zona Austral. These include

ice field An ice field (also spelled icefield) is a mass of interconnected valley glaciers (also called mountain glaciers or alpine glaciers) on a mountain mass with protruding rock ridges or summits. They are often found in the colder climates and highe ...

glacial lake A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10, ...

s and u-shaped valleys. During the

Santa María glaciation The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period c.191,000 to c.130,000 years ago, during the middle Pleistocene, when sediments comprising the Illinoian Glacial Lobe were deposited. It prec ...

glaciers extended into the Pacific Ocean at 42° south, dividing the

and creating what is now

Chacao Channel The Chacao Channel ( es, Canal de Chacao) is located in Los Lagos Region, Chile and separates Chiloé Island from mainland Chile. The channel was created during the Quaternary glaciations by successive glaciers that flowed down from the Andes ...

. Chiloé, part of the Chilean Coast Range, became an island. South of Chacao Channel, Chile's coast is split by fjords, islands and channels; these glaciers created

moraine A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...

s at the edges of the Patagonian lakes, changing their outlets to the Pacific and shifting the

continental divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not c ...

. The remnants of the

Patagonian Ice Sheet upright=1.4, Map showing the extent of the Patagonian Ice Sheet in the Strait of Magellan area during the last glacial period. Selected modern settlements are shown with yellow dots. Sea level was much lower than shown here. The Patagonian Ice S ...

which covered large parts of Chile and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

are the

Northern Northern may refer to the following: Geography * North, a point in direction * Northern Europe, the northern part or region of Europe * Northern Highland, a region of Wisconsin, United States * Northern Province, Sri Lanka * Northern Range, a r ...

and the

Southern Patagonian Ice Field The Southern Patagonian Ice Field ( es, Hielo Continental or '), located at the Southern Patagonic Andes between Chile and Argentina, is the world's second largest contiguous extrapolar ice field. It is the bigger of two remnant parts of the P ...

s. It has been suggested that from 1675 to 1850 the

San Rafael Glacier The San Rafael Glacier is one of the major outlet glaciers of the Northern Patagonian Ice Field in southern Chile and is the tidewater glacier nearest the equator. It calves into the Laguna San Rafael and is contained within Laguna San Rafael Na ...

advanced during the

Little Ice Age The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Ma ...

. The first documented visit to the area was made in 1675 by the Spanish explorer

Antonio de Vea Antonio de Vea was a 17th-century Spanish sailor best known for leading the Antonio de Vea expedition to the fjords and channels of Patagonia in 1675–1676. The map of the archipelagoes of southern Chile made by Antonio de Vea was a milestone in ...

, who entered San Rafael Lagoon through Río Témpanos ("Ice Floe River") without mentioning the many ice floes for which the river is named. De Vea also wrote that the

did not reach far into the lagoon. In 1766 another expedition noticed that the glacier did reach the lagoon and had

calved {{Short pages monitor