Karoo Plume initial volume and erosion rates

30/04/2020

Karoo Large Igneous Province: a regional magmatic event preceding continental break-up, causing regional uplift, and a complete resetting of drainage systems

From incipient drainage systems until the development of large, mature drainage systems such as that of the Limpopo, the Karoo Plume controlled the sandstone mineralogy of the produced solid sediment load transported to the Mozambique Margins. 

The initial volume of the Karoo Large Igneous Province was calculated based distribution of existing outcrops, and data on LIP dynamics. Then, the PalaeoFlux Model was used to model erosion and denudation rates, timings of re-appearance of basement lithologies from underbeneath the basalts were estimated. 

Together with the reconstructed rivers, climate and topography variables, an evolution in offshore sandstone mineralogy was reconstructed. 

Basalt-derived sediments were produced at different rates and during different timespans, for palaeodrainage basins along the Mozambique Margins. The time-spans depended on the original thickness of the Karoo LIP volcanic emplacements and the denudation rates, in turn depending on tectonic setting, creation of slopes and climate. 

Understanding the dynamics of the Karoo LIP is vital for reconstruction Southern Africa and Mozambique source to sink patterns.