Rosablanca Formation


The Rosablanca Formation is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes and the Middle Magdalena Basin. The formation consists of grey limestones, dolomites and shales with at the upper part sandstones. The formation dates to the Early Cretaceous period; Valanginian epoch and has a thickness of in the valley of the Sogamoso River.

Definition

The formation was first defined by Wheeler in 1929.

Description

Lithologies

The Rosablanca Formation is characterised by a sequence of grey limestones, dolomites and shales with a maximum thickness of in the Sogamoso River valley. Fossils of Diaulax rosablanca have been found in and named after the Rosablanca Formation. In 2019, fossils of Sellithyris elizabetha were described from the formation.

Stratigraphy and depositional environment

The Rosablanca Formation overlies the Arcabuco Formation and is overlain by the Ritoque Formation. The age has been estimated to be Valanginian. Stratigraphically, the formation is time equivalent with the Macanal Formation.

Outcrops

The Rosablanca Formation is found, apart from its type locality on the Mesa de Los Santos, Santander, in Boyacá and the Middle Magdalena Basin.

Regional correlations

Maps

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