Foumban Shear Zone

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The Foumban Shear Zone, or Central Cameroon Shear Zone (CCSZ), is a fault zone in Cameroon that has been identified with the Pernambuco fault in northeastern Brazil, which splays from the Trans-Brazilian Lineament.[1] It is part of the Central African Shear Zone (CASZ) and dates to at least 640 million years ago. The zone was rejuvenated several times, usually with a dextral movement, before and during the opening of the South Atlantic in the Cretaceous period.[2]

The Foumban shear zone is a series of faults associated with major mylonite zones, a segment of the CASZ. The CASZ can be traced from the Sudan to the Adamawa plateau, after which its path is obscured by volcanoes. Based on reconstruction of the configuration of South America before it separated from Africa, the zone can be identified with the Pernambuco fault.[3] The shear zone underlies a chain of extinct volcanoes, called the Cameroon Volcanic Line. In August 1986 a magnitude 5 earthquake with epicenter near Lake Nyos indicated that the shear zone may be again reactivating.[4]

References[edit]

  1. ^ J D Fairhead, Nasreddine Bournas and M Chaker Raddadi (2007). "The Role of Gravity and Aeromagnetic Data in Mapping Mega Gondwana Crustal Lineaments: the Argentina - Brazil – Algeria (ABA) Lineament". SEG. Retrieved 2011-01-30. 
  2. ^ C. Dorbath, L. Dorbath, D. Fairhead and G. W. Stuart (1986). "A teleseismic delay time study across the Central African Shear Zone in the Adamawa region of Cameroon, West Africa". Geophys. J. R. astr. Soc. pp. 751–766. Retrieved 2011-01-31. 
  3. ^ G. W. STUART, J.D. FAIRHEAD, L. DORBATH, C. DORBATH (1985). "CRUSTAL STRUCTURE OF THE ADAMAWA PLATEAU CAMEROON". Rev. Sci. et Tech. Sér Sci. Terre. Retrieved 2011-01-31. 
  4. ^ "Quake may have triggered Nyos disaster". New Scientist. 12 Feb 1987. Retrieved 2011-01-31. 

Coordinates: 6°37′0″N 12°52′0″E / 6.61667°N 12.86667°E / 6.61667; 12.86667