The upper reaches of the massif is a small area of temperate climate with high rainfall and permanent springs of water amidst the dry savanna and scrub of the Sahel below.

They were described as being located within a vast amphitheatre, approximately 4.8 to 6.4 km (3 to 4 miles) in diameter, formed by a continuous circular (or slightly oval) range of steeply sloping heights, varying from about 244 to 610 m (800 to 2,000 feet) above the surrounding area.

Rising nearly vertically from the water's edge, the crater walls reached heights of around 120–210 metres (390–690 ft), except for the northern rim, which sloped gently.

[10] The hydrobiological importance of Jebel Marra stems from the isolation of these waters near the geographical centre of the African continent, coupled with the known chemical differences between the various streams and lakes (Hunting Technical Services, 1958[11]).

Further investigation, including depth checks using a variety of methods, revealed evidence of significant water level rises in both lakes in relatively recent times.

Isolated hills and ridges, such as the 1,413 metres (4,636 ft) Tebella Massif, possibly remnants of an older erosional surface, dot the peneplain.

[13] To the southeast and south of Jebel Marra, the plateau maintains an elevation of 600–700 metres (2,000–2,300 ft), revealing Archaean rocks beneath sand and clay deposits at distances of 24–113 kilometres (15–70 mi) from the base of the mountain.

About 160 kilometres (100 mi) east of Jebel Marra, the Archaean rocks are covered by Nubian sandstones, with evidence of a westward extension near El Geneina.

Recent geological surveys suggest the extensive presence of Nubian sandstones southwest of El Fasher under wind-borne sands, challenging previous beliefs.

A large silt or clay plain north-east of Kutum is thought to be a playa, while a former erg, the qoz, retains dune relief, immobilised by the prevailing savannah.

The W. Ibra conveys river runoff south of Jebel Marra, and the Qoz Dango continues the extension of the erg, with no western counterpart on the volcanic highlands.