Tarso Toh

Tarso Toh (also known as Tarso Toon[1] or Tarson Tôh[2]) is a volcanic field located in Chad, north of Tarso Toussidé volcano. It fills valleys and plains over an area of 80 km in east-west direction and 20–30 km in north-south direction. It contains 150 scoria cones and two maars.

Tarso Toh
Satellite image of the Tarso Toh volcanic field.
Highest point
Elevation2,000 m (6,600 ft)
Coordinates21.33°0′0″N 16.33°0′0″E 
Geography
Tarso Toh
Location in Chad
LocationChad
Parent rangeTibesti Mountains
Geology
Mountain typeVolcanic field
Last eruptionUnknown

Tarso Toh is a volcanic plateau and has lateral dimensions of 43 by 23 kilometres (27 mi × 14 mi), resulting in a surface area of about 490 square kilometres (190 sq mi). It rises to elevations of 2,065 metres (6,775 ft) above sea level and 1,150 metres (3,770 ft) above the surrounding terrain.[3] The plateau encompasses about 150 separate volcanoes, some of which are found in remnants.[4] Some lava flows at Tarso Toh have reached large distances.[5]

Part of the field is the Begour crater.[6] It is about 800 metres (0.5 mi) wide and is mostly dry with the exception of several small ponds and a ring of diatom- and mollusc-containing sediments which forms a ring terrace inside the crater.[7] Radiocarbon dating has yielded ages of 8,300 ± 300 years ago on sediments within Begour, and Tarso Toh is considered to be a Holocene volcano.[8]

The Tibesti features several different rock formations. A crystalline basement cis covered by Mesozoic sandstones. These were subject to deformation and later overprinted by volcanic rocks.[9] This basement is about 500-600 million years old.[10] The recent volcanism has been explained with the existence of a mantle plume beneath Tibesti.[11]

Climate and biota

The climate of the region is arid but in general there is more precipitation than in the surrounding desert, which results in the formation of wadis. Temperatures at Zouar (730 metres (2,400 ft) elevation) range from −1–10 °C (30–50 °F) in winter to 24–41 °C (75–105 °F) in summer; at high altitudes freezing temperatures may be common.[12]

Vegetation is scarce; in the proximity of waters some acacias and grasses can be found.[13] A number of mollusc shells have been found in the Begour sediments, such as Anisus costulatus, Anisus dallonii, Biomphalaria pfeifferi, Bulinus truncatus, Gastrocopta klunzingeri, Lymnaea natalensis, Melanoides tuberculata, Pisidium sp. Segmentina angusta, Succinea sp., Thapsia vesti and Zootecus insularis,[14] although their identification is now always clear.[15]

See also

References
  1. Thesiger, Wilfred (1939). "A Camel Journey to Tibesti". The Geographical Journal. 94 (6): 433–446. doi:10.2307/1787293. JSTOR 1787293.
  2. Permenter and Oppenheimer 2007, p.619
  3. Permenter and Oppenheimer 2007, p.615
  4. Deniel, C.; Vincent, P. M.; Beauvilain, A.; Gourgaud, A. (1 September 2015). "The Cenozoic volcanic province of Tibesti (Sahara of Chad): major units, chronology, and structural features". Bulletin of Volcanology. 77 (9): 150. doi:10.1007/s00445-015-0955-6. ISSN 0258-8900.
  5. Permenter and Oppenheimer 2007, p.618
  6. Permenter and Oppenheimer 2007, p.619
  7. Sparks and Grove 1961, p.355
  8. Permenter and Oppenheimer 2007, p.619
  9. Grove 1960, p.26
  10. Permenter and Oppenheimer 2007, p.611
  11. Permenter and Oppenheimer 2007, p.619
  12. Grove 1960, p.21
  13. Sparks and Grove 1961, p.355
  14. Sparks and Grove 1961, p.356
  15. Sparks and Grove 1961, p.360

Sources
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