My research focuses on understanding modern human origins through archaeological excavation of Stone Age sites as well as the studies of volcanic glass (obsidian) and volcanic ash layers (tephra) from the last 500,000 years in East Africa. This work entails: 1) Establishing the geographic scale of prehistoric human interactions via stone raw material sourcing and 2) Refining the stratigraphy and chronology of correspondingly vast landscape-scale archaeological, paleontological and geological deposits through correlation and dating of volcanic ashes.
Long-distance transport of stone materials is a feature of prehistoric human behavior that is important for determining the geographic scale of human interactions with their physical environments as well as with one another. Using modern digital techniques of archaeological excavation and geochemical sourcing of obsidian artifacts at sites from equatorial East Africa my work is showing that prehistoric hunter-gatherer populations for the last 400,000 years before present regularly transported obsidian distances between 55–250 km. This behavior was not previously documented at sites dating to more than ~60,000 years ago.
To establish a chronology of geographic scale matching the large range over which our early modern human ancestors traversed, I combine geological survey and chemical analysis of volcanic ashes dispersed across equatorial East Africa. Such work has documented many widespread ash layers, some found across an area of over 115,000 km2 and correlating across several East African rift basins. All these rift basins contain rich archaeological, fossil and paleoenvironmental archives. These tephras thus provide the context with which to characterize past landscapes and environments relating to human behavior and interactions on large geographic scales commensurate with the scope of human interactions documented by raw material sourcing.
Peer-reviewed Journal Publications:
Under Review & Under Revision
Blegen, N., Jicha, B., McBrearty, S. (In Revision). A New Tephrochronology for Early Diverse Stone Tool
Technologies and Long Transport in the Middle to Late Pleistocene Kapthurin Formation, Kenya: The
Journal of Human Evolution.
Blegen, N., Faith, J.T., Mant-Melville, A., Peppe, D.J., Tryon, C.A., (In Press).The East African Middle
Stone Age after 50,000 years ago: New evidence from the Late Pleistocene sediments of the
eastern Lake Victoria Basin, Nyanza Province, western Kenya. PaleoAnthropology.
Beverly, E.J., Peppe, D.J., Driese, S.G., Blegen, N., Faith, J.T., Tryon, C.A., & Stinchcomb, G.E. (In Press).
Reconstructions of Late Pleistocene Paleoenvironments using bulk geochemistry of paleosols from
the Lake Victoria Region. Frontiers.
Blegen, N. 2017. The earliest evidence for long-distance obsidian transport at the ~200 ka Middle Stone
Age Sibilo School Road Site, Baringo, Kenya. Journal of Human Evolution. 103, 1-19.
Blegen, N. Brown, F.H., Jicha, B., Binetti, K.M., Faith, J.T., Ferraro, J.V,. Gathogo, P.N., Richardson, J.L.,
Tryon, C.A. (2016). The Menengai Tuff: A 36 ka widespread tephra and its chronological relevance
to Late Pleistocene human evolution in East Africa. Quaternary Science Reviews. 152, 152-168.
Faith, J. T., Patterson, D.B., Blegen, N., O'Neill, C.J., Marean, C.W., Peppe, D.J., & Tryon, C.A. (2016).
Size variation in Tachyoryctes splendens (East African mole-rat) and its implications for late
Quaternary temperature change in equatorial East Africa. Quaternary Science Reviews, 140, 39-48.
Tryon, C.A., Faith, J.T., Peppe, D.J., Beverly, E.J., Blegen, N., Blumenthal, S.A., Chritz, K.L., Driese, S.G.,
Patterson, D., Sharp, W.D. (2016). The Pleistocene prehistory of the Lake Victoria basin. Quaternary
International, 404, 100-114.
Blegen, N., Tryon, C.A., Faith, J.T., Peppe, D.J., Beverly, E.J., Li, B., Jacobs, Z., (2015). Distal tephras of
the eastern Lake Victoria basin, equatorial East Africa: correlations, chronology and a context for
early modern humans. Quaternary Science Reviews, 122, 89-111.
Beverly, E.J., Driese, S.G., Peppe, D.J., Arellano, L.N., Blegen, N., Faith, J.T., & Tryon, C.A. (2015).
Reconstruction of a semi-arid late Pleistocene paleocatena from the Lake Victoria region, Kenya.
Quaternary Research, 84, 368-381.
Faith, J.T., Tryon, C.A., Peppe, D.J., Beverly, E.J., Blegen, N., Blumenthal, S., Chritz, K.L., Driese, S.G.
and Patterson, D. (2015). Paleoenvironmental context of the Middle Stone Age record from
Karungu, Lake Victoria Basin, Kenya, and its implications for human and faunal dispersals in East
Africa. Journal of Human Evolution, 83, 28-45.
Faith, J.T., Tryon, C.A., Peppe, D.J., Beverly, E.J., & Blegen, N. (2014). Biogeographic and Evolutionary
Implications of an Extinct Late Pleistocene Impala from the Lake Victoria Basin, Kenya. Journal of
Mammalian Evolution, 21, 213-222.