6533b7d0fe1ef96bd125a2c0

RESEARCH PRODUCT

Evolution of Pan-African island arc assemblages in the southern Red Sea Hills, Sudan, and in southwestern Arabia as exemplified by geochemistry and geochronology

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Kr6ner, A., Linnebacher, P., Stern, R.J., Reischmann, T., Manton, W. and Hussein, I.M., 1991. Evolution of Pan-African island arc assemblages in the southern Red Sea Hills, Sudan, and in southwestern Arabia as exemplified by geochemistry and geochronology. In: R.J. Stern and W.R. van Schmus (Editors), Proterozoic Crustal Evolution in the Late Proterozoic. Precambrian Res., 53:99-117. We report Rb-Sr whole-rock and zircon ages for metavolcanic and plutonic associations in the southeastern part of the Red Sea Hills, Sudan, and show that these rocks constitute one of the earliest Pan-African arc assemblages within the Arabian-Nubian shield. The remarkable similarity in geochemistry and age between these and comparable rocks in southwestern Arabia suggests that the southeastern Red Sea Hills and the Al-Lith area of Arabia probably formed part of one large arc complex that was probably accreted to the African continent about 720 Ma ago. The Erkowit and nearby Dahand plutons SW of Suakin yield ages of 850-870 Ma and intrude older metavolcanic suites; one of these, exposed in Khor Ashat, provides an imprecise Rb-Sr age of 860+ 101 Ma. Several rhyolite suites from the hills SE of Tokar and near the border with Ethiopia yield variable Rb-Sr ages between ~ 670 and 770 Ma that we relate to partial resetting, whereas single zircons from these rocks gave 2°7pb/2°rpb ages of ~ 840-855 Ma. An early syn-tectonic granite infolded with the Tokar metavolcanic assemblage has a 2°7pb/2°6pb age of 827 + 33 Ma, while a post-tectonic granite, probably resulting from intracrustal melting after arc/continent collision, was dated at 652 + 14 Ma.