Altiplano Basin
Cuenca del Altiplano
DEM, showing the approximate area of the basin
Coordinates	18°28′S67°20′W / 18.467°S 67.333°W /-18.467; -67.333
Etymology	Altiplano
Region	Central Andes
Country	Bolivia Peru
State(s)	La Paz,Oruro,Potosí Puno
Cities	La Paz,Oruro,Potosí,Uyuni
Characteristics
On/Offshore	Onshore
Boundaries	Pasani Fault,Cordillera Occidental,Ayaviri Fault,Cordillera Oriental,Coniri Fault
Part of	Intramontane Andean basins
Area	154,176 km2 (59,528 sq mi)
Hydrology
River(s)	Desaguadero River
Lake(s)	Titicaca,Poopó
Geology
Basin type	Piggy-back
Plate	South American
Orogeny	Andean
Age	Early Paleozoic-Holocene
Stratigraphy	Stratigraphy

TheAltiplano Basin (Spanish:Cuenca del Altiplano) is asedimentary basin within theAndes inBolivia andPeru. The basin is located on theAltiplano plateau between theCordillera Occidental and theCordillera Oriental. Over-all the basin has evolved through time in a context ofhorizontal shortening ofEarth's crust.^[1] The great thickness of thesediments accumulated in the basin is mostly the result of theerosion of Cordillera Oriental.^[2]

The Altiplano Basin has an approximate area of 154,176 square kilometres (59,528 sq mi).^[3] The northern part of the basin is overridden by the Cordillera Occidental along the Pasani Fault, athrust fault. To the east, the northern part of the basin was overridden by the Cordillera Oriental along the Ayaviri Fault, another thrust fault albeit the fault is now buried under more recent sediments.^[1] Further south nearOruro andSica Sica the boundary of the basin with the Cordillera Oriental block is made up by the largely buried Coniri Fault. The fault contact is not reflected in surface topography since Cordillera Oriental rises more than 10 kilometers to the east of Coniri Fault.^[2]

The sedimentation rate in the basin has varied strongly overgeological time. In the time from the middlePaleocene to the middleEocene on average less than 10 metres (33 ft) of sediments accumulated in the basin every million years. In theLate Eocene andOligocene, sediments accumulated in the basin at a rate of up to 500 metres (1,600 ft) every million years.^[4] Similarly in theMiocene and Oligocene (15 to 30 million years ago) the Ayaviri Sub-basin in the north accumulated 110 to 660 metres (360 to 2,170 ft) of sediments every million years.^[1]

The basin contains three large successions of sediments. The sedimentary sequence in the basin started in theEarly Paleozoic.^[5] Frombottom to top these are:^[4]

• Maastrichtian–Paleocene aged marine and non-marine sediments of theSanta Lucía andEl Molino Formations. Their thickness is about 250 to 900 metres (820 to 2,950 ft).
• The 3,000-to-6,500-metre (9,800 to 21,300 ft) thick non-marinePotoco Formation. Most of the formation is ofEocene–Oligocene age.
• Sedimentary and volcanic rocks ofOligocene toQuaternary age making of a 1,000-to-4,000-metre (3,300 to 13,100 ft) thick pile.

It has been suggested that the northern part of the Altiplano Basin experienced a significantreverse fault movement in theOligocene andEarly Miocene (c. 28 to 16million years ago).^[1]

• Jiménez, Néstor; López Velásquez, Shirley; Santiváñez, Reynaldo (2009),"Evolución tectonomagmática de los Andes bolivianos"(PDF),Revista de la Asociación Geológica Argentina,65:36–67, retrieved2017-08-21

• Altiplano
• Sedimentary basins of Bolivia
• Sedimentary basins of Peru
• Geology of La Paz Department (Bolivia)
• Geology of Oruro Department
• Geology of Potosí Department
• Geography of the Department of Puno

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