Chapter 6. Albertine Rift marginal lacustrine environments

Marginal lacustrine depositional environments in the Albertine Rift are highly sensitive to short-term, climatically controlled lake level fluctuations. As such, they act as one of the prime recorders of palaeoshoreline transgression or regression in rift-fill stratigraphy. In both Lakes Edward and Albert, modern-day seasonal winds blow parallel with the long axis of the rift basin, developing wave-dominated shorelines at the end of a lake, but sheltered rift flanks display coastal features associated with longshore drift. The different types of shorelines around Albertine Rift lakes today produce characteristic geomorphological features and associated lithofacies, with key sedimentary structures and fauna and flora which can include hippopotamus, elephant, crocodile and fish remains. These can be identified in Pleistocene–Holocene onshore sedimentary successions around the Lake Edward and Lake Albert rift basins, providing a record of glacial–interglacial climatic cyclicity in the Equatorial Tropics of East Africa. Northern Hemisphere interglacials result in a wet phase and lake level rise in the Albertine Rift, with marginal lacustrine shorelines back-stepping landward. Whereas high-latitude glacials cause corresponding periods of aridification and rift lake level fall, with palaeoshorelines prograding out towards the centre of the basin.