Abstract
Environmental and biotic responses to early Eocene hyperthermal events in the southwest Pacific are critical for global paleoclimate reconstructions during Cenozoic greenhouse intervals, but detailed multidisciplinary studies are generally missing from this time and location. Eocene carbonate sediments were recovered during International Ocean Discovery Program Expedition 371 at Site U1510 on southern Lord Howe Rise in the Tasman Sea. Part of the Early Eocene Climatic Optimum (EECO; 53.26–49.14 Ma) and superimposed hyperthermal events have been identified based on refined calcareous nannofossil biostratigraphic data and carbon stable isotope records on bulk sediment and benthic foraminifera. Four negative carbon isotope excursions (CIEs) associated with negative oxygen isotope excursions are recognized within the EECO. Comparison with a global compilation of sites indicates these CIEs correlate to the K event (Eocene Thermal Maximum 3), and tentatively to the S, T, and U events. Sediments with a high carbonate content throughout the EECO provide an excellent opportunity to examine these CIEs, as carbonate dissolution often impacts correlative records elsewhere. Benthic foraminifera and calcareous nannoplankton taxa indicative of warm waters are most abundant during the K event, the most prominent hyperthermal of the EECO. Eutrophication of surface waters during the K event did not lead to increased trophic conditions at the seafloor, whereas a coupled response is observed during smaller hyperthermals. The biotic turnover sheds new light on the paleoenvironmental consequences of hyperthermal events.
| Original language | English |
|---|---|
| Article number | e2020PA004179 |
| Pages (from-to) | 1-23 |
| Journal | Paleoceanography and Paleoclimatology |
| Volume | 36 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Aug 2021 |
Bibliographical note
Funding Information:L. Alegret acknowledges funding from project PID2019‐105537RB‐I00 (Spanish Ministry of Science and Innovation and FEDER funds), and a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. E. Dallanave is supported by Deutsche Forschungsgemeinschaft (DFG) Projektnummer 408178503. C. Newsam was funded by a UKIODP Moratorium Award. The authors are grateful to the Integrated Ocean Discovery Program (IODP) for providing samples and data used in this study. The IODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under the management of Joint Oceanographic Institutions, Inc. The authors thank Ellen Thomas for thoughtful discussions on the manuscript, Colin Carney for analytical support, and IODP Expedition 371 Scientists and all personnel aboard the R/V JOIDES Resolution on IODP Expedition 371. Map generated with Gplates.
Publisher Copyright:
© 2021. The Authors.
Funding
L. Alegret acknowledges funding from project PID2019‐105537RB‐I00 (Spanish Ministry of Science and Innovation and FEDER funds), and a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. E. Dallanave is supported by Deutsche Forschungsgemeinschaft (DFG) Projektnummer 408178503. C. Newsam was funded by a UKIODP Moratorium Award. The authors are grateful to the Integrated Ocean Discovery Program (IODP) for providing samples and data used in this study. The IODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under the management of Joint Oceanographic Institutions, Inc. The authors thank Ellen Thomas for thoughtful discussions on the manuscript, Colin Carney for analytical support, and IODP Expedition 371 Scientists and all personnel aboard the R/V JOIDES Resolution on IODP Expedition 371. Map generated with Gplates.
Keywords
- benthic foraminifera
- calcareous nannofossils
- Eocene
- isotope excursions
- SW Pacific
- warming