Transfer zones with en echelon faulting at the northern end of the Suez Rift

Abstract

Detailed field mapping of the central part of the area between the northern end of the Suez rift to the Nile Valley (Cairo‐Suez area) shows that the Eocene to Miocene rocks are affected by E‐W elongated belts of left‐stepped en echelon normal faults. These belts act as transfer zones between NW oriented normal faults synchronous with faults of the same trend in the Suez rift. Individual faults within the en echelon fault belts are oriented E‐W to WNW and dip in the same direction as the linked NW faults. Step faulting or horsts and grabens are two possible fault arrangements in the transfer zones depending on the geometry of the linked faults. The linked faults and the transfer zones are joined together in zigzag fault belts that extend northwest‐ward from the northern part of the Suez rift into the Cairo‐Suez area and possibly further northwestward. A substantial amount of the throw of the NW faults of the Suez rift is transferred northwestward by these zigzag fault belts. The throw generally decreases northwestward away from the rift. The en echelon fault belts were probably formed by right‐lateral divergent wrenching on E‐W oriented, deep‐seated, preexisting faults. This right‐lateral divergent wrenching is kinematically related to the dip‐slip movement on the linked, NW oriented, normal faults. Copyright 1992 by the American Geophysical Union.