EPISODIC DENUDATION IN EAST-AFRICA - A LEGACY OF INTRACONTINENTAL TECTONISM

Abstract

Apatite fission‐track data from samples collected over an altitude range of >2.5 km in western and central Kenya reveal three elevation intervals where the apparent apatite age varies linearly with elevation. The mean ages of these intervals are 64 ± 1 Ma, 112 ± 2 Ma, and 180 ± 6 Ma and they result from cooling of rocks below 110° ± 10°C by erosional denudation. The form of the apatite age ‐ elevation profile and forward modeling of the fission‐track length distributions suggests that discrete periods of exhumation commenced at 70–75 Ma, 120–130 Ma, and ≥220 Ma. These times correspond with periods of intracontinental deformation of the African lithosphere, including: the separation of Madaga..