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| Sossusvlei: 1. Sesriem Canyon 2. Dead Vlei 3. Dune 45 4&5. Dead Vlei 6. Big Mama dune. |
Namib Sand Sea is the only coastal desert in the world that includes extensive dune fields influenced by fog. It is composed of two dune systems, an ancient semi-consolidated one overlain by a younger active one. It features gravel plains, coastal flats, rocky hills, inselbergs within the sand sea, a coastal lagoon and ephemeral rivers, resulting in a landscape of exceptional beauty. Fog is the primary source of water, accounting for a unique environment in which endemic invertebrates, reptiles and mammals adapt to an ever-changing variety of microhabitats and ecological niches.
Because of its vast size, difficulty of access and current management within the protected Namib-Naukluft National Park, the Namib Sand Sea is well conserved and in an excellent, undamaged state. The most well-known area of the park is Sossusvlei, a salt and clay pan surrounded by high red dunes. Its name roughly means "dead-end marsh", and it owes them to the fact that is a drainage basin without outflows for the ephemeral Tsauchab River. Its dunes are among the highest in the world; many of them are above 200m, the highest being the one nicknamed Big Daddy, about 380m high.
Fauna in the Sossusvlei area is relatively rich, and much of it is endemic and highly adapted to the specific features of the Namib. Access to the Sossusvlei area is from the Sesriem gate, which is located in the surroundings of the eponymous canyon. From Sesriem, a 60km tarmac road leads to Sossusvlei proper. Sesriem Canyon was carved by the Tsauchab River in the local sedimentary rock, about a kilometre long and up to 30m deep.
Dead Vlei is a white clay pan located near the salt pan of Sossusvlei, formed after rainfall, when the Tsauchab River flooded, creating temporary shallow pools where the abundance of water allowed camel thorn trees to grow. The trees died, as there no longer was enough water to survive. Dune 45 is so called because it lies 45 km past Sesriem on the road to Sossusvlei. It is 80m high and it is composed of 5-million-year-old sands, which is detritus accumulated by the Orange River from the Kalahari Desert and then blown here.
Big Mama is a very high dune which faces Big Daddy, and is a favourite one for the climbers. It is easier to climb compared to Big Daddy and its crater is shallower allowing one to climb down the crater if you are adventurous enough. The slope of the dune changes with the wind. The vivid pink-to-orange color of the dunes is a consequence of a high percentage of iron in the sand and consequent oxidation processes.
About the stamp
The stamp is part of a large definitive series depicting birds, issued on February 15, 2012.
References
Sossusvlei - Wikipedia
Namib-Naukluft National Park - Wikipedia
Namib Sand Sea - UNESCO official website
Sender: Nadia
Sent from Nadia (Namibia), on ??.04.2015
Photo: Siggi Straube
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