DIETARY AND ENVIRONMENTAL RECONSTRUCTION WITH STABLE-ISOTOPE ANALYSESOF HERBIVORE TOOTH ENAMEL FROM THE MIOCENE LOCALITY OF FORT TERNAN, KENYA

Tooth enamel of nine Middle Miocene mammalian herbivores from Fort Ter nan, Kenya, was analyzed for delta(13)C and delta(18)O. Th, delta(18)O values of the tooth enamel compared with pedogenic and diagenetic car bonate confirm the use of stable isotope analysis of fossil tooth enam el as a paleoenvironmental indicator. Furthermore, the delta(18)O of t ooth enamel indicates differences in water sources between some of the mammals. The delta(13)C Values of tooth enamel ranged from -8.6--13.0 parts per thousand which is compatible with a pure C-3 diet, though t he possibility of a small C-4 fraction in the diet of a few of the spe cimens sampled is not precluded. The carbon isotopic data do not suppo rt environmental reconstructions of a Serengeti-typed wooded grassland with a significant proportion of C-4 grasses. This study does not pre clude the presence of C-3 grasses at Fort Ternan; it is possible that C-3 grasses could have had a wider geographic range if atmospheric CO2 levels were higher than the present values. (C) 1997 Academic Press L imited.