Lake Mataro is an ancient lake in the Andes. It formed over the northern
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 the ...
at an altitude of and extended over the central Altiplano. It is one of the ancient lakes of the Altiplano like Lake Minchin, Lake Ballivian and Lake Cabana. It existed between 2.8 and 1.8 million years ago.
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 the ...
is a highland in
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
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 most important lacustrine bodies of today are
Lake Titicaca
Lake Titicaca (; es, Lago Titicaca ; qu, Titiqaqa Qucha) is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. By volume of water and by surface area, i ...
ITCZ
The Intertropical Convergence Zone (ITCZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal ...
moves south and brings precipitation to the Altiplano, with the amount decreasing from north to south. In the past, several large lakes formed in the Altiplano, including Lake Minchin, Lake Ballivian, Lake Cabana and Lake Mataro. Additional ancient lakes have been identified. A tectonic event resulting into a relative uplift of the Eastern Cordillera with respect to the Altiplano may have triggered a lowering of the terrain and facilitated the formation of Mataro and Cabana.
River sediments consisting of thick deposits of clay, gravel and sand have been left by Lake Mataro. Deposits of the lake have been found mostly in the northeastern part of its basin and the lake is named after an outcrop in the Mataro Chico locality. The erosion surface of Lake Mataro and Lake Cabana is found in both the northern and central Altiplano, implying that the Ulloma-Capalla pass did not exist back then.
Lake Mataro has been identified in the northern Altiplano, where deposits from this stage are found at an altitude of . For comparison, Lake Cabana deposits are found at altitudes of and Lake Ballivian at an altitude of . Both Mataro and Cabana were named by Lavenu and others in 1984. The height of Lake Mataro was above that of Lake Titicaca. It formed a single large lake over the central and northern Altiplano. Progressive erosion of the outlet of Lake Titicaca may be responsible for the observed reduction of the levels of the northern paleolakes during time, as it allowed water from the northern lakes to spill into the southern ones.
Lake Mataro along with Lake Cabana and Lake Ballivian was first debatably dated to be late
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Quaternary in age. Proposed ages include 1.8 and 2.8 million years ago, lake deposits lie on top of a 2.8 ± 0.4 million years old
volcanic ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...
layer. The Mataro formation has been dated at 1.6 million years ago.
The lake existed at the same time as the Calvario glaciation over 2.8 million years ago, when the glaciation was ending. The Ayo Ayo and Purapurani
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondar ...
s are coeval with the existence of Lake Mataro, as is the differentiation of '' Hyalella'' amphipods; these are freshwater animals.