THE ZALINGEI FOLD BELT IN DARFUR, SUDAN: IS IT A NEOPROTEROZOIC JUVENILE CRUSTAL STRIP WITHIN THE SAHARAN METACRATON?

We present preliminary geological results from the poorly known Zalingei fold belt in Darfur, Sudan, which crops out in the central part of the Saharan Metacraton. The metacraton covers an area of ~5,000,000 km² in northern Africa and extends within Algeria, Cameroon, Chad, Congo, Egypt, Niger, Nigeria, Sudan, and South Sudan. It represents an Archean – Paleoproterozoic craton that was partially and variably remobilized during the Neoproterozoic. The Zalingei fold belt is suspected to be one of few low-grade metamorphic terrains within the Saharan Metacraton, such as Jebel Rahib and Atmur-Delgo to the northeast, that are interpreted as Neoproterozoic juvenile crust hosting ophiolite-decorated sutures. However, no geochemical, isotopic or geochronological data are available to examine the nature of Zalingei fold belt crust. Southwest of the Zalingei fold belt, geochronological data from granitoids intruding the low- to medium-grade meta-sedimentary rocks of the Ouaddai massif in Chad gave Ediacaran ages, and the massif is interpreted as a continental back-arc basin formed in the southern margin of the Saharan Metacraton. However, xenoliths collected from the Cenozoic volcanic rocks of Jebel Marra, just to the northeast of the Zalingei fold belt, gave Archaean to Paleoproterozoic Nd T_DM model ages. Our preliminary results show that the eastern and southeastern parts of the outcropping region of Zalingei fold belt are dominated by gneisses that are intruded by undeformed granites. Differently, the western part of the fold belt is dominated by low-grade metasedimentary rocks in the form of micaschists, graphite schists and quartzites. These metasedimentary rocks are folded by ENE-plunging antiforms. Augen gneisses and deformed granites seem to occupy the core of the antiforms, raising the possible presence of metamorphic core complexes within the Zalingei fold belt. Our future plan is to acquire geochemical, isotopic and geochronological data to characterize the age and nature of the crust beneath Zalingei fold belt. For this, we have collected representative samples from the geological units of the Zalingei fold belt that are suitable for such analyses. We hope our completed work will contribute to understanding the processes by which the Saharan Metacraton was formed and how cratons are formed and destructed.