Start |Author Index | View Uploaded Presentations | Meeting Information

GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 111-13
Presentation Time: 11:25 AM

THE MENENGAI TUFF: A 36 KA WIDESPREAD TEPHRA AND ITS CHRONOLOGICAL RELEVANCE TO LATE PLEISTOCENE HUMAN EVOLUTION IN EAST AFRICA


BLEGEN, Nick1, BROWN, Francis H.2, JICHA, Brian R.3, BINETTI, Katie M.4, FAITH, J. Tyler5, FERRARO, Joseph V.4, RICHARDSON, Jonathan L.6, TRYON, Christian A.7 and GATHOGO, Patrick2, (1)Anthropology, Harvard University, 11 Divinity Ave, Cambridge, MA 02138, (2)Geology and Geophysics, University of Utah, 115 S 1460 E Room 383, Salt Lake City, UT 84112, (3)Department of Geoscience, University of Wisconsin, 1215 W. Dayton St., Madison, WI 53706, (4)Department of Anthropology and Institute of Archaeology, Baylor University, Baylor University, 1214 S. 4th Street, Waco, TX 76798, (5)School of Social Science, University of Queensland, Michie Building (#9), Brisbane, 4072, Australia, (6)Department of Biology, Franklin & Marshall College, P.O. BOX 3003, Lancaster, PA 17604, (7)Department of Anthropology, Harvard University, Cambridge, MA 02138, nick_blegen@fas.harvard.edu

The East African Rift preserves the world’s richest Middle and Late Pleistocene (~780 –12 ka) geological, archaeological and paleontological archives relevant to the emergence of Homo sapiens. This region also provides unparalleled chronological control for many important sites though tephrostratigraphy, the dating and correlation of volcanic ashes as widespread isochronous markers in the geological record. There are many well-characterized Pliocene-Early Pleistocene tephras that are widespread across East Africa. A comparable framework is lacking for the Middle and Late Pleistocene; a period characterized by spatially and temporally complex patterns of climate change, as well as the emergence of modern Homo sapiens and the dispersal this species across and out of Africa. Unraveling relationships among these spatial and temporally complex phenomena requires a precise chronology. To this end we report the Menengai Tuff, a widespread volcanic ash produced by the large-scale caldera forming eruption of Menengai Crater in Kenya and 40Ar/39Ar dated to 35.62 ± 0.26 ka. Geochemical characterization of 585 glass shards from 39 samples by wavelength-dispersive electron probe microanalysis show the Menengai Tuff was deposited over > 115,000 km2 and is found in the Baringo, Chalbi, Elmenteita, Nakuru, Olorgesailie, Turkana, and Victoria basins, all of which preserve rich Late Pleistocene paleoenvironmental and archaeological archives. Correlation and dating of the Menengai Tuff demonstrate that it is the most widespread tephra and largest eruption currently known from the Late Pleistocene of East Africa. As such, it is a valuable marker for resolving Late Pleistocene chronology relevant to paleoclimatic, archaeological and paleontological records of human evolution.

Session No. 111

T194. The Context of Our Origins: Geological Studies of Old World Fossil Primate and Hominin Sites
Monday, 26 September 2016: 8:00 AM-12:00 PM
Room 401 (Colorado Convention Center)
Geological Society of America Abstracts with Programs. Vol. 48, No. 7
doi: 10.1130/abs/2016AM-278770
© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
Back to: T194. The Context of Our Origins: Geological Studies of Old World Fossil Primate and Hominin Sites
<< Previous Abstract | Next Abstract >>