Geological Society of America

T219 130 Years of Research in the Turkana Basin, Kenya: Insights into Earth, Climate, and Life in Eastern Africa Topical Session

Tuesday, 24 September 2024
1:30 PM - 5:30 PM
207A

RECONSTRUCTING MIOCENE ECOLOGIES IN THE TURKANA BASIN: INSIGHTS FROM PLANT WAX N-ALKANES

Paper number: T219-7
Program: Technical Sessions
Time: 2:50 PM – 3:05 PM

Authors

Ruth Tweedy Presenting Author
Harvard University, Cambridge, MA
Ellen Miller
Wake Forest University, Winston-Salem, NC
Aggrey Minya
Turkana University College, Nairobi
Sara Shedroff
Hamilton College, Clinton, NY
Daniel R. Green
Harvard University, Cambridge, MA
Ashley House
Columbia University, New York, NY
Sneha Bapana
Barnard College, New York, NY
Kevin Uno
Harvard University, Cambridge, MA
Mae Saslaw
Stony Brook University, Stony Brook, NY
Gregory Henkes
Stony Brook University, Stony Brook, NY
Catherine Beck
Hamilton College, Clinton, NY
Craig Feibel
Rutgers University, New Brunswick, NJ
William E. Lukens
James Madison University, Harrisonburg, VA
Gary E. Stinchcomb
University of Memphis, Memphis, TN
Cynthia Liutkus-Pierce
Appalachian State University, Boone, NC

Abstract

This study advances understanding of the Turkana Basin's Miocene ecology through the analysis of plant wax n-alkanes – molecular remains of past vegetation. These biomarkers are analyzed for chain length distributions and their carbon (δ¹³C) and hydrogen (δD) isotopic signatures to elucidate past plant communities and hydrology.

We present δ¹³C and δD measurements from three key paleontological localities within the basin: Buluk (~16-17 Ma), Loperot (~17 Ma), and Locherangan (~17.5 Ma). Collectively, these sites have produced important cercopithecoid (e.g., Noropithecus bulukensis) and hominoid (e.g., Afropithecus turkanensis, Limnopithecus legetet, and Rangwapithecus gordoni) fossils. The close temporal relationship of these sites allows us to compare habitat ecology at the onset of the Middle Miocene Climatic Optimum within a narrow time frame.

All three sites yield δ¹³C data indicating ecosystems characterized wholly by C₃ plant biomass – traditionally interpreted as woody vegetation. These pure C₃ ecosystem reconstructions corroborate tooth enamel data from these sites which suggest C₃ diets, but the Buluk dataset provides a counterpoint to previously published paleosol carbonate δ¹³C data which demonstrated mixed C₃/C₄ environments.

Exceptional biomarker preservation at Buluk and Locherangan enables plant wax δD reconstructions of soil water availability. Results are forthcoming and will yield the first plant wax estimates of paleo-precipitation δD from the Turkana Basin, notably during the early Miocene.

These new biomarker records from Buluk, Loperot, and Locherangan offer insight into the region's paleoenvironmental conditions during the onset of the Miocene Climatic Optimum.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-401757

© Copyright 2024 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.