| Huab Formation | |
|---|---|
| Stratigraphic range: Artinskian-Kungurian typically Artinskian ~ | |
| Type | Geological formation |
| Unit of | "Ecca" Group |
| Underlies | Gai-As Formation |
| Overlies | Basement |
| Area | From Atlantic coast to Twyfelfontein |
| Thickness | 75–190 m (246–623 ft) |
| Lithology | |
| Primary | Shale, limestone |
| Other | Sandstone, conglomerate, stromatolite, coal |
| Location | |
| Location | Damaraland |
| Coordinates | 21°12′S 14°06′E / 21.2°S 14.1°E |
| Approximate paleocoordinates | 51°00′S 30°30′W / 51.0°S 30.5°W |
| Region | Kunene & Erongo Regions |
| Country |  Namibia |
| Extent | Huab Basin |
| Type section | |
| Named for | Huab River |
 Geologic map of Namibia with the Huab Formation partly cropping out in the northwestern area (orange) | |
The Huab Formation is an Early Permian (Artinskian to Kungurian) geologic formation correlated with the Ecca Group and designated "Ecca" Group, because it does not belong to the Karoo, in the southwestern Kunene Region and northern Erongo Region of northwestern Namibia. The Huab Formation represents the oldest sedimentary unit of the Huab Basin, overlying the basement. The oil shales within the formation were deposited in a shallow lacustrine environment, and the formation marks the transition from terrestrial deposits under glacial climatic circumstances towards a warmer fluvial and marine deltaic environment.
The Huab Formation is correlated with a series of formations in the Pelotas and Paraná Basins in southeastern Brazil, deposited in a larger basinal area, 150 million years before the break-up of Pangea. The abundance of Glossopteris and Mesosaurus fossils are characteristic of the Gondwanan correlation across present-day South America, Africa, Antarctica and Australia.