Wichura et al. 2015; PNAS
A 17-MY-OLD WHALE CONSTRAINS ONSET OF UPLIFT AND CLIMATE CHANGE IN EAST AFRICA
Henry Wichura, Louis L. Jacobs, Andrew Lin, Michael J. Polcyn, Fredrick K. Manthi, Dale A. Winkler, Manfred R. Strecker, Matthew Clemens
Timing and magnitude of surface uplift are key to understanding the impact of crustal deformation and topographic growth on atmospheric circulation, environmental conditions, and surface processes. Uplift of the East African Plateau is linked to mantle processes, but paleoaltimetry data are too scarce to constrain plateau evolution and subsequent vertical motions associated with rifting. Here, we assess the paleotopographic implications of a beaked whale fossil (Ziphiidae) from the Turkana region of Kenya found 740 km inland from the present-day coastline of the Indian Ocean at an elevation of 620 m. The specimen is ~17 My old and represents the oldest derived beaked whale known, consistent with molecular estimates of the emergence of modern straptoothed whales (Mesoplodon). The whale traveled from the Indian Ocean inland along an eastward-directed drainage system controlled by the Cretaceous Anza Graben and was stranded slightly above sea level. Surface uplift from near sea level coincides with paleoclimatic change from a humid environment to highly variable and much drier conditions, which altered biotic communities and drove evolution in east Africa, including that of primates.
Copyright © 2015 National Academy of Science. All rights reserved.
3D rendered movies of the Turkana ziphiid can be seen at digimorph.
A full online version and .pdf of this article can you find and order here.