New insights into peri-Gondwana paleogeography and the Gondwana super-fan system from detrital zircon U–Pb ages

Abstract

We present a synopsis of detrital zircon U–Pb ages of sandstones from North Africa and neighboring Israel and Jordan, which allows us to identify zones with characteristic sediment provenance along the northern Gondwana margin (in present-day coordinates) in Cambrian–Ordovician times, and helps us to unravel the peri-Gondwana jigsaw puzzle. A special feature of the early Paleozoic cover sequence of North Africa is the eastward increase of 1.1–0.95Ga detrital zircons, which become ubiquitous in the early Paleozoic sandstones of the Saharan Metacraton. Detrital zircons aged about 2.7–2.5, 2.15–1.75 and 0.75–0.53Ga are also present. Early Paleozoic sandstones with similar provenance are known from peri-Gondwana terranes in the Eastern and Western Mediterranean and from NW Iberia. These terranes need not be transported from western Gondwana (Amazonia) as suggested previously. They were likely located to the north of the Saharan Metacraton during the early Paleozoic before they rifted off from Gondwana. Furthermore, we recognize an increase, as stratigraphic ages get younger, of ca. 1.0Ga detrital zircons at some point between the Late Cambrian and late Middle Ordovician. We speculate that this might be linked to far-field tectonics and regional uplift in central Gondwana related to plate-tectonic reorganization along the Gondwana margin, leading to erosion of ca. 1.0Ga basement and country rocks of the Transgondwanan supermountain and fluvial dispersal of detritus toward the Gondwana margin.