Plio-Pleistocene Continental Hydroclimate and Indian Ocean Sea Surface Temperatures at the Southeast African Margin

Audrey K. Taylor, Melissa A. Berke, Isla S. Castañeda, Andreas Koutsodendris, Hernan Campos, Ian R. Hall, Sidney R. Hemming, Leah J. LeVay, Alejandra Cartagena Sierra, Keith O'Connor, Expedition 361 Scientists

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Abstract Efforts to understand long-term Indian Ocean dynamics and land-sea linkages in southeast Africa during periods of significant global and regional climate change have been inhibited by a lack of high-resolution climate records, particularly during the Plio-Pleistocene. Here we present new biomarker and pollen records from International Ocean Discovery Program (IODP) Site U1478, located at the Upper Agulhas Confluence near the Limpopo River mouth, to establish environmental conditions at the southeast African margin between 4 and 1.8 Ma and address this spatiotemporal gap. Compound-specific hydrogen isotopes of terrestrial leaf waxes (δDwax) and TEX86, using marine archaeal lipids, document hydroclimate variability and sea surface temperature (SST), respectively, permitting an onshore-offshore climate comparison. The U1478 records establish the Limpopo catchment response to the switch in Indonesian Throughflow source waters, the mid-Pliocene Warm Period, and intensification of Northern Hemisphere glaciations at ?2.7 Ma. Broad coherence between the δDwax and SST records supports a linkage between Indian Ocean temperatures and southeast African hydroclimate. We hypothesize that additional mechanisms including Indian Ocean cross-basin SST gradients (?SST) and high latitude glaciation acted as hydroclimate controls during the Plio-Pleistocene. We use ?SST to evaluate ocean-atmosphere patterns similar to the Indian Ocean Dipole (IOD) and establish generally wetter conditions in the region associated with positive IOD-like phases. Additionally, an obliquity signal evident in the δDwax record indicates that glacial-interglacial variability likely influenced the tropical rain belt position and also controlled rainfall. Hydroclimate and environmental conditions across the Plio-Pleistocene in southeast Africa may have important implications for regional hominin evolution.
Original languageEnglish
Article numbere2020PA004186
Pages (from-to)e2020PA004186
JournalPaleoceanography and Paleoclimatology
Volume36
Issue number3
DOIs
Publication statusPublished - 2021
Externally publishedYes

Bibliographical note

https://doi.org/10.1029/2020PA004186

Funding

The authors would like to thank Drs. Dana Biasatti and Jeffrey Salacup for laboratory assistance. Thank you to the Center for Environmental Science and Technology (CEST) at the University of Notre Dame and the captain and crew of the Joides Resolution. This research was supported by a Clare Boothe Luce Fellowship (to MAB and AKT), the National Science Foundation Graduate Research Funding Program (GRFP) (to AKT), a Geological Society of America (GSA) Charles A. and June R.P. Ross Research Fund grant (to AKT), a U.S. Science Support Program Post‐Expedition Award (to MAB), and the Deutsche Forschungsgemeinschaft within the IODP Special Priority Program (grant KO4960/8 to AK). The authors appreciate the helpful comments and suggestions provided by two anonymous reviewers and the Associate Editor, Dr. Sarah Feakins, that improved this manuscript. The authors would like to thank Drs. Dana Biasatti and Jeffrey Salacup for laboratory assistance. Thank you to the Center for Environmental Science and Technology (CEST) at the University of Notre Dame and the captain and crew of the Joides Resolution. This research was supported by a Clare Boothe Luce Fellowship (to MAB and AKT), the National Science Foundation Graduate Research Funding Program (GRFP) (to AKT), a Geological Society of America (GSA) Charles A. and June R.P. Ross Research Fund grant (to AKT), a U.S. Science Support Program Post-Expedition Award (to MAB), and the Deutsche Forschungsgemeinschaft within the IODP Special Priority Program (grant KO4960/8 to AK). The authors appreciate the helpful comments and suggestions provided by two anonymous reviewers and the Associate Editor, Dr. Sarah Feakins, that improved this manuscript.

FundersFunder number
Clare Boothe Luce Fellowship
IODPKO4960/8
National Science Foundation
Geological Society of America
University of Notre Dame
United States Science Support Program
Center for Environmental Science and Technology, University of Notre Dame
Deutsche Forschungsgemeinschaft

    Keywords

    • East Africa
    • hydroclimate
    • Indian Ocean
    • organic geochemistry
    • Plio-Pleistocene
    • sea surface temperature

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