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Episodic denudation in east Africa: A legacy of intracontinental tectonism
Author(s) -
Foster David A.,
Gleadow Andrew J. W.
Publication year - 1993
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl02814
Subject(s) - geology , denudation , fission track dating , elevation (ballistics) , altitude (triangle) , lithosphere , apatite , geomorphology , paleontology , tectonics , physical geography , geochemistry , geometry , geography , mathematics
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 Madagascar from East Africa, opening of the South Atlantic Ocean, and changes in the geometry of plate spreading in the South Atlantic.