The imagery on this page is the basis for a paper entitled A 17-My-Old Whale Constrains Onset of Uplift and Climate Change in East Africa by H. Wichura, L.L. Jacobs, A. Lin, M.J. Polcyn, F.K. Manthi, D.A. Winkler, M.R. Strecker and M. Clemens (2015, Proceedings of the National Academy of Sciences, 112, 3910-3915). The abstract is as follows:

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 (EAP) 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 approximately 17 million years old and represents the oldest derived beaked whale known, consistent with molecular estimates of the emergence of modern strap-toothed whales (Mesoplodon). The whale travelled from the Indian Ocean inland along an eastward-directed drainage system controlled by the Cretaceous Anza Graben and 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.

See 'About the Scan' to download the original high-resolution X-ray CT data sets.

This specimen was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Louis Jacobs, Andrew Lin, and Mike Polcyn of Southern Methodist University. Funding was provided by the Institute for the Study of Earth and Man at Southern Methodist University, Dallas.

The specimen was scanned in three parts by Matthew Colbert on 9-10 February 2012. Scanning parameters were as follows: 1024x1024 16-bit TIFF images. P250D, 450 kV, 3 mA, large spot size, 1 brass filter, 190% offset, empty container wedge, integration time 64 ms, slice thickness = 1.5 mm, S.O.D. 747 mm, 1000 views, 1 ray per view, 1 sample per view, inter-slice spacing = 1.45 mm, field of reconstruction 299 mm, reconstruction offset 5000, reconstruction scale 6000.

Click here to download the original CT scan data for the right posterior portion of the skull.

Click here to download the original CT scan data for the left posterior portion of the skull.

Click here to download the original CT scan data for the snout portion of the skull.

Literature

Wichura, H., Jacobs, L.L., Lin, A., Polcyn, M.J., Manthi, F.K., Winkler, D.A., Strecker, M.R., and Clemens, M. In press. A 17 million year old whale constrains onset of uplift and climate change in East Africa. Proceedings of the National Academy of Sciences.

None available.