Usme Formation

The Usme Formation (Formación Usme, Tsu, Teu) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of a lower part with predominantly shales with intercalated sandstone beds and an upper sequence with sandstones and conglomerates. The Usme Formation dates to the Neogene and Paleogene periods; Late Eocene to Early Oligocene epochs, and has a maximum thickness of 300 m.

Etymology
The formation was defined by Hubach in 1957 and named after the locality of Usme, Bogotá.

Lithologies
The Usme Formation is subdivided into a lower sequence of shales with intercalated sandstones and an upper part of sandstones and conglomerates.

Stratigraphy and depositional environment
The Usme Formation unconformably overlies the Regadera Formation and is overlain by the Tilatá Formation. The age has been estimated, based on palynological data, to be Late Eocene to Early Oligocene. The depositional environment has been interpreted as marine with the upper part deposited in a deltaic setting.

Outcrops
The Usme Formation is found in its type locality in the synclinal of Usme, the valley of the Tunjuelo River.