Arequipa-Antofalla is a

basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...

unit underlying the central

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 ...

in northwestern Argentina, western

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, northern Chile and southern

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

. Geologically, it corresponds to a

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 ...

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its own ...

or block of

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...

. Arequipa-Antofalla collided and

amalgamated Amalgamation is the process of combining or uniting multiple entities into one form. Amalgamation, amalgam, and other derivatives may refer to: Mathematics and science * Amalgam (chemistry), the combination of mercury with another metal **Pan ama ...

with the

Amazonian craton The Amazonian Craton is a geologic province located in South America. It occupies a large portion of the central, north and eastern part of the continent and represents one of Earth's largest cratonic regions. The Guiana Shield and Central Brazi ...

about 1000 Ma ago during the

Sunsás orogeny The Sunsás orogeny was an ancient orogeny active during the Late Paleoproterozoic and Mesoproterozoic and currently preserved as the Sunsás orogen in the Amazonian Craton in South America. About 85% of the belt is covered by Phanerozoic sediments ...

. As a terrane Arequipa-Antofalla was ribbon-shaped during the

Paleozoic 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 ' ...

, a time when it was bounded by the west by the

Iapetus Ocean The Iapetus Ocean (; ) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). The Iapetus Ocean was situated in the southern hemisphere, between the paleoco ...

and by the east by the Puncoviscana Ocean.

References

Cratons Geology of Argentina Geology of Bolivia Geology of Chile Geology of Peru Terranes Precambrian South America Geology of the Andes {{regional-geology-stub