Unpaired ophiolite belts in the Neoproterozoic Allaqi-Heiani Suture, the Arabian-Nubian Shield: Evidences from magnetic data

Under oblique convergence, the intraoceanic subduction zones tend to have a tectonically-escaped accretionary prism, incorporates exotic materials from different sources and oceanic crust fragments. The western part of the Allaqi-Heiani suture (AHS) is the type locality for a significant accretionary prism extends for similar to 200 km; this prism is mainly metavolcanic, and metasedimentary rocks have interwoven serpentinite, marble blocks and intruded with different phases of plutonism. Geologic studies of the western part of the AHS have suggested the allochthonous origin for this complex, and terrane accretion happened earlier than similar to 700 Ma and subsequently thrusted over Gabgaba terrane to the south. Magnetic data was applied to follow the deep-seated structures and the connectivity between ophiolite belts in the AHS. Magnetic data unravelled the presence of a deep-seated strike-slip faults aligned along N-S and NNE trends underneath the northern belt, and this fault zone was erased at the surface by a major zone of the post-accretionary left-lateral strike-slip faults. In the southern part, E-W and WNW-ESE faults are dominant at the edge of the autochthon Gabgaba terrane. At greater depths, thrusts related to the emplacement of the northern belt disappeared, while those to the south aligned with the suture zone becomes significant. In conclusion, there are two ophiolite belts are located in the western part of the AHS; the southern belt is extended along the edge of the Gabgaba terrane to the south and the Eastern Desert (ED) to the north. This south belt is the western extension of a major arc-arc suture zone that extends to the east into the Arabian shield. The northern ophiolite belt was emplaced onto the southern part of the ED similar to 70 km away from the arc-arc to the south.