Cesar-Ranchería Basin

Cesar-Ranchería Basin
Cuenca Cesar-Ranchería
View of Valledupar in the basin
Location of the basin in Colombia
Outline of the Cesar-Ranchería Basin
Etymology	Cesar & Ranchería Rivers
Region	Caribbean  Guajira-Barranquilla xeric scrub ecoregion
Country	Colombia
State(s)	Cesar, La Guajira
Cities	Valledupar
Characteristics
On/Offshore	Onshore
Boundaries	Sierra Nevada de Santa Marta, Oca Fault, Venezuela, Bucaramanga-Santa Marta Fault
Part of	Andean foreland basins
Area	11,668 km2 (4,505 sq mi)
Hydrology
River(s)	Cesar, Ranchería, Guatapurí
Geology
Basin type	Intermontane foreland basin
Plate	South American
Orogeny	Andean
Age	Jurassic-Holocene
Stratigraphy	Stratigraphy
Field(s)	Marracas

The Cesar-Ranchería Basin (Spanish: Cuenca Cesar-Ranchería) is a sedimentary basin in northeastern Colombia. It is located in the southeastern part of the department of La Guajira and eastern portion of Cesar. The basin is bound by the Oca Fault in the northeast and the Bucaramanga-Santa Marta Fault in the west. The mountain ranges Sierra Nevada de Santa Marta and the Serranía del Perijá enclose the narrow triangular intermontane basin, that covers an area of 11,668 square kilometres (4,505 sq mi).

The basin is of importance for hosting the worldwide tenth biggest and largest coal mine of Latin America, Cerrejón. The coals are mined from the Paleocene Cerrejón Formation, that also has provided several important paleontological finds, among others Titanoboa cerrejonensis, with an estimated length of 14 metres (46 ft) and a weight of 1,135 kilograms (2,502 lb), the biggest snake discovered to date, the giant crocodylians Cerrejonisuchus improcerus, Anthracosuchus balrogus and Acherontisuchus guajiraensis, and the large turtles Carbonemys cofrinii, Puentemys mushaisaensis and Cerrejonemys wayuunaiki. Various genera of flora, as Aerofructus dillhoffi, Menispermites cerrejonensis, M. guajiraensis, Montrichardia aquatica, Petrocardium cerrejonense and P. wayuuorum, Stephania palaeosudamericana and Ulmoidicarpum tupperi among others, have been found in the Cerrejón Formation, the sediments of which are interpreted as representing the first Neotropic forest in the world. Mean annual temperature has been estimated to have been between 28.5 and 33 °C (83.3 and 91.4 °F) and yearly precipitation ranging from 2,260 to 4,640 millimetres (89 to 183 in) per year.