Etosha Pan

The Etosha Pan was a Neogene, saline palaeolake at the endpoint of Angolan-sourced Cubango Megafan (Hipondoka, 2005; Buch and Rose, 1996; Miller et al., 2010) and the Cuvelai-Ekuma River System. Alternate flooding and desiccation occurred under semi-arid climatic conditions. Green, analcime-bearing clays of the Etosha Pan Clay Member formed the palaeolake bed. Fossils in interfingering sandstones include 4 – 6 million-year-old plants, invertebrates, birds, bovids, mammoth, white rhinoceros, crocodiles, hippopotamae, carnivores, turtles and fish. The fresh-water aquatic and riparian fossils were washed down the Ekuma River. The saline conditions supported flamingo populations. Arid conditions set in at about 4 Ma. Both river systems ceased to flow but palygorskite-bearing calcrete started to spread northwards over the lake bed clays. This calcrete was deposited by hard water sourced from highly karsted Neoproterozoic mountains south of the pan. Arid conditions prevailed for about 3 million years after which the cycle of flooding and desiccation resumed. Salt fragmented the calcrete. Deflation by easterly winds inverted the palaeolake stratigraphy in lunette dunes that accumulated along the western margin of the pan by first excavating the palygorskite-bearing calcrete then the analcime-bearing clays. Groundwater seeps support vibrant wildlife that is Namibia’s main tourist attraction.