The Neoproterozoic Keraf Suture in NE Sudan: Sinistral transpression along the eastern margin of West Gondwana

The Keraf Suture, formed during the Neoproterozoic consolidation of Gondwana, is a similar to 500 km long, similar to 50 km wide, N-trending suture between the Neoproterozoic Arabian-Nubian Shield in the east and the older Nile Craton to the west. The Keraf Suture is superimposed on E- and NE-trending structures on both sides. The northern part of the suture is dominated by N-trending, upright folds, whereas the southern part is characterized by N- and NNW-trending, sinistral, strike-slip faults. A major antiform defines a structural divide between the northern and southern parts of the suture. 40Ar/39Ar ages on biotite and hornblendes separated from a deformed granitic body indicate that the sinistral movement along the N- and NNW-trending faults took place at similar to 580 Ma. The difference in structural styles along strike is due to formation of the Keraf Suture by sinistral transpression, which accompanied early NW-SE oblique collision between East and West Gondwana at similar to 650-600 Ma and terminal collision at similar to 580 Ma.