Cacho Formation

The Cacho Formation (Formación Cacho, E1C, Tpc, Tec) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly sandstone formation with thin intercalated beds of shales dates to the Paleogene period; Middle to Late Paleocene epochs, and has a maximum thickness of 400 m.

Definition
The formation was first described by Hubach in 1931 and 1957 and named by Campbell in 1962 and Julivert in 1963.

Lithologies
The Cacho Formation consists of white, yellow and reddish fine to coarse cross-bedded sandstones in thick banks intercalated with reddish and grey shales.

Stratigraphy and depositional environment
The 50 to 400 m thick Cacho Formation overlies the Guaduas Formation and is overlain by the Bogotá Formation. The age has been estimated to be Late Paleocene, based on paleoflora studied by Thomas van der Hammen in 1957. The formation is laterally equivalent to the Lower Socha and Barco Formations.

Outcrops
The Cacho Formation is apart from its type locality in Soacha, found in the Eastern Hills of Bogotá, and many other locations in the Eastern Ranges up until the south of Boyacá. The synclinals of the Río Frío, Checua-Lenguazaque, Sesquilé, Sisga, Subachoque, Teusacá, Siecha, and the anticlinal of Guatavita are composed of the Cacho Formation.