Rovuma: the only large river of northern Mozambique?

The Rovuma River lays at the border between Tanzania and Mozambique and forms a large delta. There are gaps and inconsistencies in the geology maps of the border areas, making the drainage reconstruction more challenging. While attention has been fixed on the offshore Rovuma Basin, not much has been published on the drainage development in the hinterland. The Rovuma River as it is today is greatly influenced by Malawi rift tectonics, Quaternary incipient grabens, and reactivation of Karoo basin and Precambrian basement structures. 

The Rovuma Basin offshore also received a considerable amount of sediment from the adjacent rivers. While these are smaller today, they had a large impact and volumetric calculations lead to the recognition of progradational sequences. Moreover, tectonic and magmatic activity in northern Mozambique not only affected the sediment flux but also the mineralogy of some rivers of northern Mozambique. Last but not least, Late Cenozoic uplift of more than 1 km severely altered the distribution of drainage lines.

Rovuma palaedrainage: affected by three cycles of rifting. 

What else will you learn about the Rovuma River?

1. Our unpublished, complete Rovuma palaeodrainage history includes important drainage changes that lead to the assembly of the modern drainage. 

2. Through modelling of solid sediment volume and flux, we give an evolution of the progradation/transgression cycles of the Rovuma delta. 

3. Together with the other rivers of northern Mozambique, the filling of the Rovuma Basin is explained. 

4. The effect of the Madagascar transit and Davie Fracture Zone activity on sedimentation in the Rovuma Basin is explained.

5. We reconstruct the pre-Malawi drainage of the Rovuma River, as it was completely different then. 

6. We explain the interactions between the Rovuma and the adjacent smaller rivers of Mozambique (Lurio, Messalo, Liconha, Licungo), and consider the possibility of larger pre-Malawi drainage areas there. 

7. We show how Quaternary reactivation of faults, along pre-existing structures affect the geometry of drainage lines.

8. We explain the effects of Precambrian basement structures on geomorphologic and hydrologic processes in northern Mozambique.

9. We show how northern Mozambique paleodrainage developed in during and after Karoo Plume uplift and continental break-up, when an entirely new drainage geometry developed. 

10. We discuss the effect of magmatism in northern Mozambique, and geodynamic, far field effects, and their influence on the land forms, and hence drainage and erosion. 

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