Date of Completion
Stable Isotopes, Middle Stone Age, Acheulean, Pedogenic Carbonates, Landscape Archaeology, Soil Organic Matter, Biomass Productivity
Daniel S. Adler
Field of Study
Doctor of Philosophy
Global, regional, and local changes in environments are critically important to understanding the selective pressures that affected the hominin lineage. Shifts in regional environments of East Africa, driven by solar insolation, have been associated with adaptive niches of hominins during the Pleistocene epoch, a time period that spans the inception of the genus Homo and the emergence of own species, Homo sapiens. Several hypotheses link the influence of changing environments and the evolution of the genus Homo, based on global drying trends during the Pleistocene, but also the increased variability of dry and wet cycles near the equator, driven by Milankovitch cycles. These hypotheses are buttressed by continental and global environmental data from ice and ocean cores, but lack high-resolution, regional environmental data for support.
The distribution of archaeological material across a paleolandscape is best understood, in the context of modern foragers’ daily activities, as a continuum of large, highly concentrated to small, highly diffuse archaeological sites. Landscape archaeology offers researchers a way to address this larger foraging context by reconstructing regional paleolandscapes and collecting representative samples of archaeological material. The Middle Pleistocene (781 – 126 ka) of East Africa records many significant events in human evolution; it encompasses the emergence of our own species, Homo sapiens, the development of technologies that are “modern”, and a shift to resource extraction from a diverse range of environments. Paleoanthropologists regularly use stable isotope ratios of several proxies (paleosols, pedogenic carbonates, mammalian teeth, tufa composition) to reconstruct environments associated with hominin evolution, but these are rarely applied to the Middle Pleistocene of East Africa. The application of stable isotope analyses to Middle Pleistocene sedimentary sequences may be useful for discerning the local environments associated with hominins who used Acheulean and Middle Stone Age technologies.
In this dissertation, I combine a landscape perspective with paleoenvironmental reconstructions, primarily using stable isotope analyses of paleosols, mammalian tooth enamel, and pedogenic carbonates. This technique is applied to two paleolandscapes preserved in the Kapthurin Formation, a well-documented Middle Pleistocene sedimentary sequence containing Acheulean and Middle Stone Age technology, hominin remains identified to Homo erectus and Homo sp., and chimpanzee fossils. I also develop a novel technique for correlating modern primary biomass productivity with stable carbon isotope values of bulk soil organic matter, and provide a method for extrapolating primary biomass productivity from well preserved paleosols. The high-resolution landscape environmental reconstructions presented in this dissertation provide the first evidence for hominin site choice in two well-documented landscapes of the Middle Pleistocene, indicating that both Terminal Acheulean and MSA foragers regularly occupied wooded grassland ecosystems.
Leslie, David E., "Stable Isotopic Evidence for Landscape Environmental Reconstructions, Kapthurin Formation, Kenya" (2016). Doctoral Dissertations. 1108.