Supprimer la page de wiki "Central African Shear Zone" ne peut être annulé. Continuer ?
Central African Shear Zone
Alan Wirtz a édité cette page il y a 4 jours
The Central African Shear Zone (CASZ) (or Shear System) is a wrench fault system extending in an ENE route from the Gulf of Guinea by way of Cameroon into Sudan. The construction is just not properly understood. The shear zone dates to at least 640 Ma (million years in the past). Motion occurred alongside the zone in the course of the break-up of Gondwanaland within the Jurassic and Cretaceous intervals. A few of the faults within the zone had been rejuvenated greater than once before and through the opening of the South Atlantic within the Cretaceous interval. 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 put up-Cretaeous formation. The Benue Trough lies to the north, and the Foumban Shear Zone to the south. Volcanic exercise has occurred alongside 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 on this space is thinned in a comparatively slim belt, with the asthenosphere upwelling from a depth of about 190 km to about 120 km. The Mesozoic and Tertiary movements have produced elongated rift basins in central Cameroon, northern Central African Republic and southern Chad. The CASZ was previously thought to increase eastward only to the Darfur region of western Sudan. It’s now interpreted to increase into central and japanese Sudan, with a total size of 4,000 km. Within the Sudan, the shear zone may have acted as a structural barrier to growth of deep Cretaceous-Tertiary sedimentary basins in the north of the world. Objections to this principle are that the Bahr el Arab and Blue Nile rifts prolong northwest beyond one proposed line for the shear zone. However, the alignment of the northwestern ends of the rifts on this areas supports the theory. Ibrahim, Ebinger & Fairhead 1996, Wood Ranger Power Shears coupon 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
Supprimer la page