Volcano Type: Scoria cones
Volcano Status: Holocene
Last Known Eruption: 2950 BC ± 500 years
Summit Elevation: 2000? m    6,562 feet
Latitude: 15.32°N *    15°19’0″N
Longitude: 26.47°E   26°28’0″E

The alkaline Meidob volcanic field in western Sudan, at the NE end of the Dafur volcanic province, covers an area of 5000 sq km with nearly 700 Pliocene-to-Holocene vents. The volcanic field was constructed over an uplifted Precambrian igneous and metamorphic basement and is elongated in an E-W direction. Basaltic scoria cones and associated lava flows dominate, but trachytic-phonolitic lava domes, tuff rings, and maars are among the youngest volcanic products. Basaltic scoria cones are scattered throughout the field; their lavas have produced a broad lava plateau. The central part of the field consists of younger phonolitic lava flows, trachytic pumice-fall deposits, ignimbrites, and maars.

The volcano contains 316 scoria cones, lava flows, lava domes, tuff rings, and maars. Meidob volcanic field contains 700 eruptive vents. The total volume of erupted material at the volcano is 1400 cubic km, which forms a 400-m-thick plateau.

The Meidob Hills are divided into an elevated central area, topped by phonolitic mesa flows up to 2000 m above sea level, and a low elevation outer area (1000-1500 m) formed mostly from basaltic lava flows and scoria cones.

Scoria cones
Many cones at Meidob Volcano follow an east-west alignment. The average height of the cones above the surrounding plateau is 80 m (range: 20-300 m), and the basal diameter ranges from 500-1500 m. The internal, well-stratified structure of some
scoria cones has been exposed by later phreatomagmatic activity or erosion.

Mesa flow units
Forty mesa flows have been identified from aerial photographs. They are mostly located in the central volcanic field. The mesa flow units have a circular to slightly oval shape, and are about 200 m in height above the surrounding area (range: 40-420 m) with diameters from 300-4000 m. All have steep slopes, and bases which are mostly covered with talus.

Malha Crater
Malha Crater is the best known feature of Meidob volcano. The crater is situated at 220 km NNE of El Fasher, at an altitude of 905 m above sea level. It is a maar 150 m deep and 1050 m wide. The crater rim is between 105 and 130 m above the lake, is nearly circular in outline. The alkaline lake water has a pH of 9.5 to 10.3.

Eruption 5000 years ago
An eruption 5000 years ago produced a tuff ring and a lava flow.

Originally posted 2010-10-28 04:22:56.