Extension, detachments, and sedimentation in continental rifts (with particular reference to East Africa)

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Abstract
Plots of extension versus maximum synrift sediment thickness for rifts display a wide range of values. Some rifts display almost equal amounts of vertical displacement and horizontal extension, while others display considerably more extension than vertical displacement. The former appear to be associated with deep depths to detachment and/or steeply dipping boundary faults, while the latter tend to correspond with shallower depths to detachment and/or more gently dipping boundary faults. Boundary fault shape is inferred to exert an important control on relative amounts of extension and maximum sediment thickness and in sedimentation style. The deep anoxic lakes of the Western Branch, East African Rift system are associated with relatively steeply (40°–70°) dipping faults and depths to detachment ranging between 15 and 30 km. The more coarse clastic‐dominated Miocene half grabens in Northern Kenya are associated with relatively gently dipping boundary faults (50°–20°) and shallower depths to detachment (less than 15 km).