Implications for sedimentary transport processes in southwestern Africa: a combined zircon morphology and age study including extensive geochronology databases

Extensive morphological and age studies on more than 4600 detrital zircon grains recovered from modern sands of Namibia reveal complex mechanisms of sediment transport. These data are further supplemented by a zircon age database containing more than 100,000 single grain analyses from the entire southern Africa and allow for hypothesising of a large Southern Namibian Sediment Vortex located between the Damara Orogen and the Orange River in southern Namibia. The results of this study also allow assuming a modified model of the Orange River sand highway, whose origin is likely located further south than previously expected. Moreover, studied samples from other parts of Namibia give first insights into sediment movements towards the interior of the continent and highlight the potential impact of very little spatial variations of erosion rates. Finally, this study points out the huge potential of detrital zircon morphology and large geo-databases as an easy-to-use additional tool for provenance analysis.

Automated summary

Extensive morphological and age studies on detrital zircon grains from modern sands of Namibia reveal complex mechanisms of sediment transport. A large Southern Namibian Sediment Vortex and a modified model of the Orange River sand highway are hypothesized based on the results of this study. The potential impact of spatial variations of erosion rates on sediment movements towards the interior of the continent is also highlighted. Additionally, detrital zircon morphology and large geo-databases are identified as valuable tools for provenance analysis.