A Leaf Wax Biomarker Record of Plio-Pleistocene Environmental Change from the Baringo Basin (Tugen Hills), Kenya
Abstract
The Plio-Pleistocene encompasses key global climate transitions around 2.7 Ma such as the intensification of Northern Hemispheric glaciation and the onset of 41-kyr glacial-interglacial cycles. These are thought to be contemporaneous with continuous rifting and diversification of hominins in East Africa, yet the relationship between early hominin evolution and environmental conditions remains unclear. In order to provide such context, the fossiliferous and hominin-bearing upper Pliocene strata of the Baringo Basin (central Kenyan Rift) was drilled by the Hominin Sites and Paleolakes Drilling Project (HSPDP). The recovered core represents a near-continuous sedimentary record spanning ~3.3-2.6 Ma.
Here, we present a suite of geochemical data from this core, including leaf wax n-alkane hydrogen isotopes (δDwax), n-alkane average carbon chain length, and selected x-ray fluorescence (XRF) elemental ratios in order to characterize precipitation amount, vegetation type, and weathering intensity / lake depth on sub-orbital timescales. Of particular interest is whether the onset of Northern Hemisphere glaciation at ~2.7 Ma forced a transition in African climate variability from precessional- to obliquity-dominated timescales, and to assess synchronicity between East African climate and global trends. This multi-proxy approach enables a better separation of hydrologic and tectonic influences on climate and a significant advance in our understanding of sub-Saharan conditions during a key geologic transition.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP43B1603M
- Keywords:
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- 1620 Climate dynamics;
- GLOBAL CHANGE;
- 1627 Coupled models of the climate system;
- GLOBAL CHANGE;
- 4901 Abrupt/rapid climate change;
- PALEOCEANOGRAPHY;
- 4910 Astronomical forcing;
- PALEOCEANOGRAPHY