ATMUR-DELGO SUTURE - A NEOPROTEROZOIC OCEANIC BASIN EXTENDING INTO THE INTERIOR OF NORTHEAST AFRICA

Field and remote-sensing data have enabled identification of a previou sly unrecognized discontinuous belt of ophiolitic nappe remnants in no rtheastern Sudan. The belt crops out for 200 km in a west-southwest to southwest direction from the western margin of the Arabian-Nubian shi eld into the gneissic terrane previously accepted as part of the Arche an to Paleoproterozoic Nile craton. Although highly dismembered and me tamorphosed, the belt contains all the components of a Phanerozoic-typ e ophiolite. The ophiolite belt is interpreted as a suture zone (Atmur -Delgo suture), manifesting collision (approximately 700 Ma) between a passive-margin terrane in the south with an island-arc terrane in the north, following the consumption of an oceanic basin along a north-di pping subduction zone. Our results indicate that previously recognized crustal provinces in northeastern Africa must be reassessed criticall y.