The Blue Nile rift is a major geological formation in the Sudan, a

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

with a NW trend that terminates on the

Central African Shear Zone The Central African Shear Zone (CASZ) (or Shear System) is a wrench fault system extending in an ENE direction from the Gulf of Guinea through Cameroon into Sudan. The structure is not well understood. , there was still no general agreement about ...

. It was formed through crustal extension during the break-up of

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final st ...

. The rift, and other rifts in the area such as the Bahr El Arab rift and

White Nile rift The White Nile rift is one of several rifts in central Sudan running in a NW direction and terminating in the Central African Shear Zone. The rift is a Cretaceous/ Tertiary structure that has similar tectonic characteristics to the Southern Sud ...

, appears to have been activated several times since the

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

era, which ended about 250 Ma.Ma = Million years ago During periods of rapid uplift and subsidence, the rifts accumulated sediments of different ages, origins and methods of deposition. Late

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

rifting occurred in the Blue Nile rift, with east-west

half-graben A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults. Rift and fault structure A rift is a region where the lithosphe ...

extension connected by large-scale shear zones and pull-apart basins, and early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

rifting re-activated the Jurassic basin. The Blue Nile Basin in

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the Er ...

may be a southeastern extension of the rift. Further to the southeast, the late Palaeozoic-Mesozoic Ogaden Rift is aligned with the Blue Nile rift.

Explanatory notes

References

Geology of Africa Paleozoic rifts and grabens Paleozoic Africa {{tectonics-stub