Creator: Goudie, A Date: 1972 Language: English Subjects: Climate Abstract: The central Namib Desert inland from Walvis Bay, South West Africa, has a rainfa ll of 23 mm and a fog precipitation of 31 mm per annum at Gobabeb. The temperature range is only 6,5 °C in a year. The basic rock types of the area are Damaran schists, marbles, quartzites and Salem granites. The rocks, particularly the granites, have been intensely wea thered by the various arid weathering processes into tafonis, honeycombs, exfoliated scales, and constituent grains. Marbles show minor solution forms, including 'rillen '. The processes responsible for the weathering are discussed , <1nd reference is made to the role of salt crystallisation, fog, lichens, and insolation. Data on soil and rock I.emperature fluctuations are presented . The central Namib i~ also covered by gypsum crusts, calcrete and desert pavemenL In a calcareo-gypsiferous crust at Gobabeb some 20 m diameter polygons have developed , but their origin is uncertain . They are situated on a terrace at 42 m above the Kuiseb River. The Kuiseb also has two lower terraces, at 20 and 6 m above its present bed, and a marked convex long profile. It forms the northern limit of the Namib dune- field, which consists of I inear ridges, largely unvcgetated, and having a height of 80-100 m. Some wind data are presented which show that strong, infrequent easterly winds are a major factor in their north to south orientation . The paper ends with a discussion of erosion surfaces and the evidence for Quaternary climatic change in the area. |
Climate, weathering, crust fonnation, dunes, and fluvial features of the Central Namib Desert, near Gobabeh, South West Africa