Central African Shear Zone

The Central African Shear Zone (CASZ) (or Shear System) is a wrench fault system extending in an ENE path from the Gulf of Guinea by Cameroon into Sudan. The structure is not properly understood. The shear zone dates to at the very least 640 Ma (million years ago). Motion occurred along the zone in the course of the break-up of Gondwanaland within the Jurassic and Cretaceous periods. A number of the faults within the zone were rejuvenated greater than once before and during 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 across the Adamawa uplift, a post-Cretaeous formation. The Benue Trough lies to the north, and the Foumban Shear Zone to the south. Volcanic exercise has occurred alongside most of the size of the Cameroon line from 130 Ma to the current, and may be associated to re-activation of the CASZ.



The lithosphere beneath the CASZ in 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 formerly thought to extend eastward solely to the Darfur region of western Sudan. It is now interpreted to extend into central and eastern Sudan, with a complete length of 4,000 km. Within the Sudan, the shear zone could have acted as a structural barrier to improvement of deep Cretaceous-Tertiary sedimentary basins in the north of the realm. Objections to this theory 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 helps 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; Jux, Ulrich (1987). Afro-Arabian geology: a kinematic view. Dorbath, C.; Dorbath, L.; Fairhead, J. D.; Stuart, G. W. (1986). "A teleseismic delay time study throughout the Central African Shear Zone within the Adamawa region of Cameroon, West Africa". Foulger, Gillian R.; Jurdy, Donna M. (2007). Plates, plumes, and planetary processes. Geological Society of America. Ibrahim, A. E.; Ebinger, C. J.; Fairhead, J. D. (20 April 1996). "Lithospheric extension northwest of the Central African Shear Zone in Sudan from potential subject research". Pankhurst, Robert J. (2008). West Gondwana: pre-Cenozoic correlations across the South Atlantic Region. Plomerova, J; Babuska, V; Dorbath, C.; Dorbath, L.; Lillie, R. J. (1993). "Deep lithospheric structure throughout the Central African Shear Zone in Cameroon". Geophysical Journal International. One hundred fifteen (2): 381-390. Bibcode:1993GeoJI.115..381P. Selley, Richard C. (1997). African basins. Schlüter, Thomas; Trauth, Martin H. (2008). Geological atlas of Africa: with notes on stratigraphy, tectonics, financial geology, geohazards, geosites and geoscientific education of every country. シュプリンガー・ジャパン株式会社.



Viscosity is a measure of a fluid's rate-dependent resistance to a change in form or to motion of its neighboring parts relative to each other. For liquids, it corresponds to the informal concept of thickness; for example, syrup has a higher viscosity than water. Viscosity is outlined scientifically as a Wood Ranger Power Shears website multiplied by a time divided by an space. Thus its SI models are newton-seconds per metre squared, or pascal-seconds. Viscosity quantifies the inner frictional Wood Ranger Power Shears review between adjacent layers of fluid that are in relative movement. As an illustration, when a viscous fluid is compelled by way of a tube, Wood Ranger Power Shears website it flows more quickly near the tube's middle line than near its partitions. Experiments present that some stress (reminiscent of a strain distinction between the two ends of the tube) is needed to maintain the circulation. This is because a Wood Ranger Power Shears website is required to overcome the friction between the layers of the fluid that are in relative motion. For a tube with a constant Wood Ranger Power Shears price of stream, the Wood Ranger Power Shears manual of the compensating force is proportional to the fluid's viscosity.



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