Lago Colhué Huapí Formation
The Lago Colhué Huapí Formation is a Late Cretaceous geologic formation of the Chubut Group in the Golfo San Jorge Basin in Patagonia, Argentina. The formation, named after Lake Colhué Huapí, is overlain by the Salamanca Formation of the Río Chico Group and in some areas by the Laguna Palacios Formation.
The strata of the Lago Colhué Huapé Formation were thought to pertain to the Bajo Barreal Formation, but are now recognized as a distinct stratigraphic unit in their own right. The upper part of the Lago Colhué Huapí Formation has been dated to the upper Maastrichtian age of the late Cretaceous period. A basalt flow in the formation has been dated to, reinforcing the Late Maastrichtian age.