The Central African Shear Zone (CASZ) (or Shear System) is a wrench fault system extending in an ENE direction from the Gulf of Guinea by way of Cameroon into Sudan. The construction just isn't effectively understood. The shear zone dates to not less than 640 Ma (million years in the past). Motion occurred alongside the zone during the break-up of Gondwanaland in the Jurassic and Cretaceous intervals. Some of the faults within the zone were rejuvenated greater than once earlier than and in the course of the opening of the South Atlantic within the Cretaceous period. It has been proposed that the Pernambuco fault in Brazil is a continuation of the shear zone to the west. In Cameroon, the CASZ cuts throughout the Adamawa uplift, a submit-Cretaeous formation. The Benue Trough lies to the north, and the Foumban Shear Zone to the south. Volcanic activity has occurred along many of the size of the Cameroon line from 130 Ma to the current, and could also be related to re-activation of the CASZ.
The lithosphere beneath the CASZ in this space is thinned in a relatively narrow belt, with the asthenosphere upwelling from a depth of about 190 km to about one hundred twenty km. The Mesozoic and Tertiary movements have produced elongated rift basins in central Cameroon, northern Central African Republic and southern Chad. The CASZ was formerly thought to extend eastward solely to the Darfur region of western Sudan. It's now interpreted to extend into central and japanese Sudan, with a complete size of 4,000 km. In the Sudan, outdoor trimming tool the shear zone could have acted as a structural barrier to improvement of deep Cretaceous-Tertiary sedimentary basins in the north of the area. Objections to this principle are that the Bahr el Arab and Blue Nile rifts lengthen northwest past one proposed line for the shear zone. However, the alignment of the northwestern ends of the rifts on this areas supports the speculation. Ibrahim, Ebinger & Fairhead 1996, pp.
Dorbath et al. 1986, pp. Schlüter & Trauth 2008, pp. Foulger & Jurdy 2007, pp. Plomerova et al. 1993, pp. Bowen & Jux 1987, pp. Bowen, Robert