Articles | Volume 21, issue 11
https://doi.org/10.5194/cp-21-2115-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-21-2115-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Nov 2025
Research article |
| 11 Nov 2025
| 11 Nov 2025
Oligocene-early Miocene paradox of pCO2 inferred from alkenone carbon isotopic fractionation and sea surface temperature trends
José Guitián
CORRESPONDING AUTHOR
Department of Earth and Planetary Sciences, Geological Institute, ETH Zurich, 8092 Zurich, Switzerland
present address: Department of Oceanography, Instituto de Investigacións Mariñas, Consejo Superior de Investigaciones Científicas (CSIC), Vigo, Spain
Samuel Phelps
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
Reto S. Wijker
Department of Earth and Planetary Sciences, Geological Institute, ETH Zurich, 8092 Zurich, Switzerland
Pratigya J. Polissar
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
Ocean Sciences Department, University of California, Santa Cruz, CA, USA
Laura Arnold
Department of Earth and Planetary Sciences, Geological Institute, ETH Zurich, 8092 Zurich, Switzerland
Heather M. Stoll
CORRESPONDING AUTHOR
Department of Earth and Planetary Sciences, Geological Institute, ETH Zurich, 8092 Zurich, Switzerland
Related authors
No articles found.
Celia Campa-Bousoño, Miguel Iglesias, Iñaki Vadillo, Lucía Ojeda, Jorge Pisonero, Hai Cheng, R. Lawrence Edwards, and Heather Stoll
EGUsphere, https://doi.org/10.5194/egusphere-2026-3717, https://doi.org/10.5194/egusphere-2026-3717, 2026
This preprint is open for discussion and under review for Climate of the Past (CP).
Short summary
Short summary
To understand how rainfall changed in southern Iberia during the shift from the Medieval Climate Anomaly to the Little Ice Age, we studied yearly layers preserved in a stalagmite from Ardales Cave, southern Spain. The record shows repeated shifts between wetter and drier periods, including major droughts around 1125, 1250, 1500, and 1560 CE. It also reveals intervals of more variable rainfall, suggesting changing influence from Atlantic and Mediterranean weather patterns.
Thomas Tanner, Ivan Hernandez-Almeida, Reto Wijker, Andrea K. Manirajan, Madeleine Santos, Peter Bijl, Tim van Peer, and Heather Stoll
EGUsphere, https://doi.org/10.5194/egusphere-2026-3415, https://doi.org/10.5194/egusphere-2026-3415, 2026
This preprint is open for discussion and under review for Climate of the Past (CP).
Short summary
Short summary
In this study, we examined the relationship between surface ocean temperature in the midlatitudes in both the Northern and Southern Hemispheres over a period of major Antarctic ice expansion 24 to 22 million years ago, a period when Antarctica was the only polar ice sheet. We find consistent cooling of the surface ocean in both hemispheres as ice was expanding, indicating a close coupling of global climate and polar ice caps.
Laura Endres, Carlos Pérez-Mejías, Ruza Ivanovic, Lauren Gregoire, Anna L. C. Hughes, Hai Cheng, and Heather Stoll
Clim. Past, 22, 797–824, https://doi.org/10.5194/cp-22-797-2026, https://doi.org/10.5194/cp-22-797-2026, 2026
Short summary
Short summary
Stable isotope data of a precisely dated stalagmite from northwestern Iberia indicate gradual North Atlantic meltwater input during the last glacial maximum, followed by abrupt surges early in the last deglaciation. The first abrupt surge was decoupled from first cooling about 810 years later – unlike later events – which reveals that the Atlantic circulation’s sensitivity to meltwater is variable and related to the evolving background climate boundary conditions.
Reto S. Wijker, Pere Aguiló-Nicolau, Madalina Jaggi, Jeroni Galmés, and Heather M. Stoll
Biogeosciences, 23, 1591–1608, https://doi.org/10.5194/bg-23-1591-2026, https://doi.org/10.5194/bg-23-1591-2026, 2026
Short summary
Short summary
Photosynthetic organisms leave characteristic carbon isotope fingerprints that help scientists study Earth’s carbon cycle. We developed a simpler laboratory method to measure these isotope effects in Rubisco, the key enzyme fixing CO2. Applying this approach, we obtained the first measurement for Gephyrocapsa oceanica, a widespread marine alga that plays a major role in ocean carbon cycling.
Alexander J. Clark, Alba Gonzalez-Lanchas, Kyra Bachmakova, Madalina Jaggi, and Heather M. Stoll
J. Micropalaeontol., 44, 673–692, https://doi.org/10.5194/jm-44-673-2025, https://doi.org/10.5194/jm-44-673-2025, 2025
Short summary
Short summary
We quantified the thickness of early Eocene calcareous nannofossils and linked it to different depositional environment parameters. Discoasters and placoliths do not respond in the same manner. Carbonate content affects discoasters and induces overgrowth, but palaeowater depth affects placoliths and can induce dissolution. We also find that the ratio of non-overgrown to overgrown Discoaster multiradiatus is a potential quantitative placolith preservation indicator.
Nicolas Tapia, Laura Endres, Madalina Jaggi, and Heather Stoll
Biogeosciences, 22, 6861–6875, https://doi.org/10.5194/bg-22-6861-2025, https://doi.org/10.5194/bg-22-6861-2025, 2025
Short summary
Short summary
We use stalagmites to study past changes in the terrestrial P cycle. Our P records from multiple, coeval stalagmites from Northwest Spain show that the onsets of past abrupt cooling events are characterized by multi-century reproducible peaks in stalagmite P which reflect higher groundwater P/Ca concentrations and enhanced P export, potentially resulting from increased freeze-thaw frequency and more intense infiltration from snowmelt.
Heather M. Stoll, Clara Bolton, Madalina Jaggi, Alfredo Martinez-Garcia, and Stefano M. Bernasconi
Clim. Past, 21, 2189–2203, https://doi.org/10.5194/cp-21-2189-2025, https://doi.org/10.5194/cp-21-2189-2025, 2025
Short summary
Short summary
In periods of high atmospheric CO2 many proxies suggest more extreme past polar warming than is simulated by current coupled climate models. Providing new data on high latitude temperatures in the South Atlantic over the last 15 million years using clumped isotope thermometry, we show that absolute temperatures may not have been as warm as indicated by some biomarker based proxy climate records.
Nikita Kaushal, Carlos Pérez-Mejías, and Heather M. Stoll
Clim. Past, 21, 1633–1660, https://doi.org/10.5194/cp-21-1633-2025, https://doi.org/10.5194/cp-21-1633-2025, 2025
Short summary
Short summary
Terminations are large-magnitude rapid events triggered in the North Atlantic region that manifest across the global climate system. They provide key examples of climatic teleconnections and dynamics. In this study, we use the SISAL global speleothem database and find that there are sufficient climatic records from key locations to make speleothems a valuable archive for studying terminations and provide instances for more targeted work on speleothem research.
Judit Torner, Isabel Cacho, Heather Stoll, Ana Moreno, Joan O. Grimalt, Francisco J. Sierro, Joan J. Fornós, Hai Cheng, and R. Lawrence Edwards
Clim. Past, 21, 465–487, https://doi.org/10.5194/cp-21-465-2025, https://doi.org/10.5194/cp-21-465-2025, 2025
Short summary
Short summary
We offer a clearer view of the timing of three relevant past glacial terminations. By analyzing the climatic signal recorded in stalagmite and linking it with marine records, we revealed differences in the intensity and duration of the ice melting associated with these three key deglaciations. This study shows that some deglaciations began earlier than previously thought; this improves our understanding of natural climate processes, helping us to contextualize current climate change.
Alexander J. Clark, Ismael Torres-Romero, Madalina Jaggi, Stefano M. Bernasconi, and Heather M. Stoll
Clim. Past, 20, 2081–2101, https://doi.org/10.5194/cp-20-2081-2024, https://doi.org/10.5194/cp-20-2081-2024, 2024
Short summary
Short summary
Coccoliths are abundant in sediments across the world’s oceans, yet it is difficult to apply traditional carbon or oxygen isotope methodologies for temperature reconstructions. We show that our coccolith clumped isotope temperature calibration with well-constrained temperatures systematically differs from inorganic carbonate calibrations. We suggest the use of our well-constrained calibration for future coccolith carbonate temperature reconstructions.
Nikita Kaushal, Franziska A. Lechleitner, Micah Wilhelm, Khalil Azennoud, Janica C. Bühler, Kerstin Braun, Yassine Ait Brahim, Andy Baker, Yuval Burstyn, Laia Comas-Bru, Jens Fohlmeister, Yonaton Goldsmith, Sandy P. Harrison, István G. Hatvani, Kira Rehfeld, Magdalena Ritzau, Vanessa Skiba, Heather M. Stoll, József G. Szűcs, Péter Tanos, Pauline C. Treble, Vitor Azevedo, Jonathan L. Baker, Andrea Borsato, Sakonvan Chawchai, Andrea Columbu, Laura Endres, Jun Hu, Zoltán Kern, Alena Kimbrough, Koray Koç, Monika Markowska, Belen Martrat, Syed Masood Ahmad, Carole Nehme, Valdir Felipe Novello, Carlos Pérez-Mejías, Jiaoyang Ruan, Natasha Sekhon, Nitesh Sinha, Carol V. Tadros, Benjamin H. Tiger, Sophie Warken, Annabel Wolf, Haiwei Zhang, and SISAL Working Group members
Earth Syst. Sci. Data, 16, 1933–1963, https://doi.org/10.5194/essd-16-1933-2024, https://doi.org/10.5194/essd-16-1933-2024, 2024
Short summary
Short summary
Speleothems are a popular, multi-proxy climate archive that provide regional to global insights into past hydroclimate trends with precise chronologies. We present an update to the SISAL (Speleothem Isotopes
Synthesis and AnaLysis) database, SISALv3, which, for the first time, contains speleothem trace element records, in addition to an update to the stable isotope records available in previous versions of the database, cumulatively providing data from 365 globally distributed sites.
Synthesis and AnaLysis) database, SISALv3, which, for the first time, contains speleothem trace element records, in addition to an update to the stable isotope records available in previous versions of the database, cumulatively providing data from 365 globally distributed sites.
Miguel Bartolomé, Ana Moreno, Carlos Sancho, Isabel Cacho, Heather Stoll, Negar Haghipour, Ánchel Belmonte, Christoph Spötl, John Hellstrom, R. Lawrence Edwards, and Hai Cheng
Clim. Past, 20, 467–494, https://doi.org/10.5194/cp-20-467-2024, https://doi.org/10.5194/cp-20-467-2024, 2024
Short summary
Short summary
Reconstructing past temperatures at regional scales during the Common Era is necessary to place the current warming in the context of natural climate variability. We present a climate reconstruction based on eight stalagmites from four caves in the Pyrenees, NE Spain. These stalagmites were dated precisely and analysed for their oxygen isotopes, which appear dominated by temperature changes. Solar variability and major volcanic eruptions are the two main drivers of observed climate variability.
Heather M. Stoll, Leopoldo D. Pena, Ivan Hernandez-Almeida, José Guitián, Thomas Tanner, and Heiko Pälike
Clim. Past, 20, 25–36, https://doi.org/10.5194/cp-20-25-2024, https://doi.org/10.5194/cp-20-25-2024, 2024
Short summary
Short summary
The Oligocene and early Miocene periods featured dynamic glacial cycles on Antarctica. In this paper, we use Sr isotopes in marine carbonate sediments to document a change in the location and intensity of continental weathering during short periods of very intense Antarctic glaciation. Potentially, the weathering intensity of old continental rocks on Antarctica was reduced during glaciation. We also show improved age models for correlation of Southern Ocean and North Atlantic sediments.
Heather M. Stoll, Chris Day, Franziska Lechleitner, Oliver Kost, Laura Endres, Jakub Sliwinski, Carlos Pérez-Mejías, Hai Cheng, and Denis Scholz
Clim. Past, 19, 2423–2444, https://doi.org/10.5194/cp-19-2423-2023, https://doi.org/10.5194/cp-19-2423-2023, 2023
Short summary
Short summary
Stalagmites formed in caves provide valuable information about past changes in climate and vegetation conditions. In this contribution, we present a new method to better estimate past changes in soil and vegetation productivity using carbon isotopes and trace elements measured in stalagmites. Applying this method to other stalagmites should provide a better indication of past vegetation feedbacks to climate change.
Oliver Kost, Saúl González-Lemos, Laura Rodríguez-Rodríguez, Jakub Sliwinski, Laura Endres, Negar Haghipour, and Heather Stoll
Hydrol. Earth Syst. Sci., 27, 2227–2255, https://doi.org/10.5194/hess-27-2227-2023, https://doi.org/10.5194/hess-27-2227-2023, 2023
Short summary
Short summary
Cave monitoring studies including cave drip water are unique opportunities to sample water which has percolated through the soil and rock. The change in drip water chemistry is resolved over the course of 16 months, inferring seasonal and hydrological variations in soil and karst processes at the water–air and water–rock interface. Such data sets improve the understanding of hydrological and hydrochemical processes and ultimately advance the interpretation of geochemical stalagmite records.
Amanda Gerotto, Hongrui Zhang, Renata Hanae Nagai, Heather M. Stoll, Rubens César Lopes Figueira, Chuanlian Liu, and Iván Hernández-Almeida
Biogeosciences, 20, 1725–1739, https://doi.org/10.5194/bg-20-1725-2023, https://doi.org/10.5194/bg-20-1725-2023, 2023
Short summary
Short summary
Based on the analysis of the response of coccolithophores’ morphological attributes in a laboratory dissolution experiment and surface sediment samples from the South China Sea, we proposed that the thickness shape (ks) factor of fossil coccoliths together with the normalized ks variation, which is the ratio of the standard deviation of ks (σ) over the mean ks (σ/ks), is a robust and novel proxy to reconstruct past changes in deep ocean carbon chemistry.
Jessica G. M. Crumpton-Banks, Thomas Tanner, Ivan Hernández Almeida, James W. B. Rae, and Heather Stoll
Biogeosciences, 19, 5633–5644, https://doi.org/10.5194/bg-19-5633-2022, https://doi.org/10.5194/bg-19-5633-2022, 2022
Short summary
Short summary
Past ocean carbon is reconstructed using proxies, but it is unknown whether preparing ocean sediment for one proxy might damage the data given by another. We have tested whether the extraction of an organic proxy archive from sediment samples impacts the geochemistry of tiny shells also within the sediment. We find no difference in shell geochemistry between samples which come from treated and untreated sediment. This will help us to maximize scientific return from valuable sediment samples.
José Guitián, Miguel Ángel Fuertes, José-Abel Flores, Iván Hernández-Almeida, and Heather Stoll
Biogeosciences, 19, 5007–5019, https://doi.org/10.5194/bg-19-5007-2022, https://doi.org/10.5194/bg-19-5007-2022, 2022
Short summary
Short summary
The effect of environmental conditions on the degree of calcification of marine phytoplankton remains unclear. This study implements a new microscopic approach to quantify the calcification of ancient coccolithophores, using North Atlantic sediments. Results show significant differences in the thickness and shape factor of coccoliths for samples with minimum dissolution, providing the first evaluation of phytoplankton physiology adaptation to million-year-scale variable environmental conditions.
Franziska A. Lechleitner, Christopher C. Day, Oliver Kost, Micah Wilhelm, Negar Haghipour, Gideon M. Henderson, and Heather M. Stoll
Clim. Past, 17, 1903–1918, https://doi.org/10.5194/cp-17-1903-2021, https://doi.org/10.5194/cp-17-1903-2021, 2021
Short summary
Short summary
Soil respiration is a critical but poorly constrained component of the global carbon cycle. We analyse the effect of changing soil respiration rates on the stable carbon isotope ratio of speleothems from northern Spain covering the last deglaciation. Using geochemical analysis and forward modelling we quantify the processes affecting speleothem stable carbon isotope ratios and extract a signature of increasing soil respiration synchronous with deglacial warming.
Cited articles
Auderset, A., Moretti, S., Taphorn, B., Ebner, P.-R., Kast, E., Wang, X. T., Schiebel, R., Sigman, D. M., Haug, G. H., and Martínez-García, A.: Enhanced ocean oxygenation during Cenozoic warm periods, Nature, 609, 77–82, 2022.
Baczynski, A. A., Polissar, P. J., Juchelka, D., Schwieters, J., Hilkert, A., Summons, R. E., and Freeman, K. H.: Picomolar-scale compound-specific isotope analyses, Rapid Communications in Mass Spectrometry, 32, 730–738, 2018.
Behrenfeld, M. J., Boss, E., Siegel, D. A., and Shea, D. M.: Carbon-based ocean productivity and phytoplankton physiology from space, Global Biogeochemical Cycles, 19, https://doi.org/10.1029/2004GB002299, 2005.
Blaauw, M. and Christen, J. A.: Flexible paleoclimate age-depth models using an autoregressive gamma process, Bayesian Analysis, 6, 457–474, 2011.
Boller, A. J., Thomas, P. J., Cavanaugh, C. M., and Scott, K. M.: Low stable carbon isotope fractionation by coccolithophore RubisCO, Geochimica et Cosmochimica Acta, 75, 7200–7207, 2011.
Bolton, C. T. and Stoll, H. M.: Late Miocene threshold response of marine algae to carbon dioxide limitation, Nature, 500, 558–562, 2013.
Bolton, C. T., Hernandez-Sanchez, M. T., Fuertes, M. A., Gonzalez-Lemos, S., Abrevaya, L., Mendez-Vicente, A., Flores, J. A., Probert, I., Giosan, L., Johnson, J., and Stoll, H. M.: Decrease in coccolithophore calcification and CO2 since the middle Miocene, Nat. Commun., 7, 10284, https://doi.org/10.1038/ncomms10284, 2016.
Bradshaw, C. D., Langebroek, P. M., Lear, C. H., Lunt, D. J., Coxall, H. K., Sosdian, S. M., and de Boer, A. M.: Hydrological impact of Middle Miocene Antarctic ice-free areas coupled to deep ocean temperatures, Nature Geoscience, 14, 429–436, 2021.
Breitenbach, S. F. and Bernasconi, S. M.: Carbon and oxygen isotope analysis of small carbonate samples (20 to 100 µg) with a GasBench II preparation device, Rapid Communications in Mass Spectrometry, 25, 1910–1914, 2011.
Consortium, C. P.: Toward a Cenozoic history of atmospheric CO2, Science, 382, eadi5177, https://doi.org/10.1126/science.adi5177, 2023.
Cramer, B., Miller, K., Barrett, P., and Wright, J.: Late Cretaceous–Neogene trends in deep ocean temperature and continental ice volume: Reconciling records of benthic foraminiferal geochemistry (δ18O and
Curry, W., Shackleton, N., and Richter, C.: Leg 154, Synthesis. Proceedings ODP, Initial Reports, 154, 421–442, 1995.
Deconto, R. M., Pollard, D., Wilson, P. A., Palike, H., Lear, C. H., and Pagani, M.: Thresholds for Cenozoic bipolar glaciation, Nature, 455, 652–656, https://doi.org/10.1038/nature07337, 2008.
Erdei, B., Utescher, T., Hably, L., Tamas, J., Roth-Nebelsick, A., and Grein, M.: Early Oligocene continental climate of the Palaeogene Basin (Hungary and Slovenia) and the surrounding area, Turkish Journal of Earth Sciences, 21, 153–186, 2012.
Evangelinos, D., Etourneau, J., van de Flierdt, T., Crosta, X., Jeandel, C., Flores, J.-A., Harwood, D. M., Valero, L., Ducassou, E., and Sauermilch, I.: Late Miocene onset of the modern Antarctic circumpolar current, Nature Geoscience, 17, 165–170, 2024.
Evans, D., Brugger, J., Inglis, G. N., and Valdes, P.: The Temperature of the Deep Ocean Is a Robust Proxy for Global Mean Surface Temperature During the Cenozoic, Paleoceanography and Paleoclimatology, 39, e2023PA004788, https://doi.org/10.1029/2023PA004788, 2024.
Exon, N. F., Kennett, J. P., and Malone, M. J., et al.: Proceedings of the Ocean Drilling Program, Initial Reports Volume 189, https://doi.org/10.2973/odp.proc.ir.189.101.2001, 2001.
Fielding, S. R.: Emiliania huxleyi specific growth rate dependence on temperature, Limnology and Oceanography, 58, 663–666, 2013.
Forster, P. M., Storelvmo, T., Armour, K., Collins, W., Dufresne, J.-L., Frame, D., Lunt, D., Mauritsen, T., Palmer, M., Watanabe, M., Wild, M., and Zhang, H.: The Earth's Energy Budget, Climate Feedbacks and Climate Sensitivity, In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., 923–1054, https://doi.org/10.1017/9781009157896.009, 2021.
Foster, G. L., Royer, D. L., and Lunt, D. J.: Future climate forcing potentially without precedent in the last 420 million years, Nature Communications, 8, 14845, https://doi.org/10.1038/ncomms14845, 2017.
Freeman, K. H. and Hayes, J.: Fractionation of carbon isotopes by phytoplankton and estimates of ancient CO2 levels, Global Biogeochemical Cycles, 6, 185–198, 1992.
Golledge, N. R.: Long-term projections of sea-level rise from ice sheets, Wiley Interdisciplinary Reviews: Climate Change, 11, e634, https://doi.org/10.1002/wcc.634 2020.
González-Lanchas, A., Hernández-Alméida, I., Flores, J. A., Sierro, F. J., Guitian, J., and Stoll, H. M.: Carbon Isotopic Fractionation of Alkenones and Gephyrocapsa Coccoliths Over the Late Quaternary (Marine Isotope Stages 12–9) Glacial-Interglacial Cycles at the Western Tropical Atlantic, Paleoceanography and Paleoclimatology, 36, e2020PA004175, https://doi.org/10.1029/2020PA004175, 2021.
Gradstein, F. M., Ogg, J. G., Schmitz, M., and Ogg, G.: The geologic time scale 2012, Elsevier, ISBN 978-0-44-459390-0, 2012.
Greenop, R., Sosdian, S. M., Henehan, M. J., Wilson, P. A., Lear, C. H., and Foster, G. L.: Orbital forcing, ice-volume and CO2 across the Oligocene-Miocene Transition, Paleoceanography and Paleoclimatology, https://doi.org/10.1029/2018PA003420, 2019.
Guitián, J. and Stoll, H. M.: Evolution of Sea Surface Temperature in the Southern Mid-latitudes from Late Oligocene through Early Miocene, Paleoceanography and Paleoclimatology, 36, e2020PA004199, https://doi.org/10.1029/2020PA004199, 2021.
Guitián, J., Phelps, S., Polissar, P. J., Ausín, B., Eglinton, T. I., and Stoll, H. M.: Midlatitude Temperature Variations in the Oligocene to Early Miocene, Paleoceanography and Paleoclimatology, 34, 1328–1343, 2019.
Guitián, J., Dunkley Jones, T., Hernández-Almeida, I., Löffel, T., and Stoll, H. M.: Adaptations of coccolithophore size to selective pressures during the Oligocene to Early Miocene high CO2 world, Paleoceanography and Paleoclimatology, 35, e2020PA003918, https://doi.org/10.1029/2020PA003918, 2020.
Guitián, J., Phelps, S., Wijker, R., Polissar, P., Arnold, L., and Stoll, H.: Alkenone carbon isotopic fractionation and sea surface temperature trends from 30 to 16 Ma. Sites IODP 1406, ODP 1168 and ODP 925, Zenodo [data set], https://doi.org/10.5281/zenodo.13908061, 2025.
Hansen, J., Sato, M., Russell, G., and Kharecha, P.: Climate sensitivity, sea level and atmospheric carbon dioxide, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 371, 20120294, https://doi.org/10.1098/rsta.2012.0294, 2013.
Hay, W. W., DeConto, R. M., Wold, C. N., Wilson, K. M., Voigt, S., Schulz, M., Wold, A. R., Dullo, W.-C., Ronov, A. B., and Balukhovsky, A. N.: Alternative global Cretaceous paleogeography, edited by: Barrera, E., and Johnson, C., 332, 1–47, https://doi.org/10.1130/0-8137-2332-9.1, 1999.
Henderiks, J. and Pagani, M.: Refining ancient carbon dioxide estimates: Significance of coccolithophore cell size for alkenone-based pCO2 records, Paleoceanography, 22, https://doi.org/10.1029/2006PA001399, 2007.
Henderiks, J. and Pagani, M.: Coccolithophore cell size and the Paleogene decline in atmospheric CO2, Earth and Planetary Science Letters, 269, 576–584, 2008.
Hernández-Almeida, I., Guitián, J., Tanner, T., Zhang, H., and Stoll, H. M.: Hydrographic control on carbon isotope fractionation in coccolithophores in the North Atlantic during the Mid-Pleistocene, Quaternary Science Reviews, 309, 108081, https://doi.org/10.1016/j.quascirev.2023.108081, 2023.
Hernández-Almeida, I., Krumhardt, K. M., Zhang, H., and Stoll, H. M.: Estimation of physiological factors controlling carbon isotope fractionation in coccolithophores in photic zone and core-top samples, Geochemistry, Geophysics, Geosystems, 21, e2020GC009272, https://doi.org/10.1029/2020GC009272, 2020.
Hou, S., Lamprou, F., Hoem, F. S., Hadju, M. R. N., Sangiorgi, F., Peterse, F., and Bijl, P. K.: Lipid-biomarker-based sea surface temperature record offshore Tasmania over the last 23 million years, Clim. Past, 19, 787–802, https://doi.org/10.5194/cp-19-787-2023, 2023a.
Hou, S., Stap, L. B., Paul, R., Nelissen, M., Hoem, F. S., Ziegler, M., Sluijs, A., Sangiorgi, F., and Bijl, P. K.: Reconciling Southern Ocean fronts equatorward migration with minor Antarctic ice volume change during Miocene cooling, Nature Communications, 14, 7230, https://doi.org/10.1038/s41467-023-43106-4, 2023b.
Jasper J. P., Hayes, J. M., Mix, A. C., and Prahl, F. G.: Photosynthetic fractionation of 13C and concentrations of dissolved CO2 in the central equatorial Pacific during the last 255,000 years, Paleoceanography, 9, 781–798, https://doi.org/10.1029/94PA02116, 1994.
Krumhardt, K. M., Lovenduski, N. S., Iglesias-Rodriguez, M. D., and Kleypas, J. A.: Coccolithophore growth and calcification in a changing ocean, Progress in Oceanography, 159, 276–295, 2017.
LaRiviere, J. P., Ravelo, A. C., Crimmins, A., Dekens, P. S., Ford, H. L., Lyle, M., and Wara, M. W.: Late Miocene decoupling of oceanic warmth and atmospheric carbon dioxide forcing, Nature, 486, 97–100, 2012.
Lear, C. H., Elderfield, H., and Wilson, P.: Cenozoic deep-sea temperatures and global ice volumes from
Lear, C. H., Rosenthal, Y., Coxall, H. K., and Wilson, P.: Late Eocene to early Miocene ice sheet dynamics and the global carbon cycle, Paleoceanography, 19, https://doi.org/10.1029/2004PA001039, 2004.
Levy, R., Meyers, S., Naish, T., Golledge, N., McKay, R., Crampton, J., DeConto, R., De Santis, L., Florindo, F., and Gasson, E.: Antarctic ice-sheet sensitivity to obliquity forcing enhanced through ocean connections, Nature Geoscience, 1, https://doi.org/10.1038/s41561-018-0284-4, 2019.
Liang, J.-Q., Leng, Q., Xiao, L., Höfig, D. F., Royer, D. L., Zhang, Y. G., and Yang, H.: Early Miocene redwood fossils from Inner Mongolia: CO2 reconstructions and paleoclimate effects of a low Mongolian plateau, Review of Palaeobotany and Palynology, 70 305, 104743, https://doi.org/10.1016/j.revpalbo.2022.104743, 2022a.
Liang, J.-Q., Leng, Q., Höfig, D. F., Niu, G., Wang, L., Royer, D. L., Burke, K., Xiao, L., Zhang, Y. G., and Yang, H.: Constraining conifer physiological parameters in leaf gas-exchange models for ancient CO2 reconstruction, Global and Planetary Change, 209, 103737, https://doi.org/10.1016/j.gloplacha.2022.103737, 2022b.
Liebrand, D., de Bakker, A. T., Beddow, H. M., Wilson, P. A., Bohaty, S. M., Ruessink, G., Palike, H., Batenburg, S. J., Hilgen, F. J., Hodell, D. A., Huck, C. E., Kroon, D., Raffi, I., Saes, M. J., van Dijk, A. E., and Lourens, L. J.: Evolution of the early Antarctic ice ages, P. Natl. Acad. Sci. USA, 114, 3867–3872, https://doi.org/10.1073/pnas.1615440114, 2017.
Lisiecki, L. E. and Raymo, M. E.: A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records, Paleoceanography, 20, https://doi.org/10.1029/2004PA001071, 2005.
Liu, Z., He, Y., Jiang, Y., Wang, H., Liu, W., Bohaty, S. M., and Wilson, P. A.: Transient temperature asymmetry between hemispheres in the Palaeogene Atlantic Ocean, Nature Geoscience, 11, 656, https://doi.org/10.1038/s41561-018-0182-9, 2018.
Liu, Z., Pagani, M., Zinniker, D., Deconto, R., Huber, M., Brinkhuis, H., Shah, S. R., Leckie, R. M., and Pearson, A.: Global cooling during the eocene-oligocene climate transition, Science, 323, 1187-1190, https://doi.org/10.1126/science.1166368, 2009.
Londoño, L., Royer, D. L., Jaramillo, C., Escobar, J., Foster, D. A., Cárdenas-Rozo, A. L., and Wood, A.: Early Miocene CO2 estimates from a Neotropical fossil leaf assemblage exceed 400 ppm, American Journal of Botany, 105, 1929–1937, 2018.
Miller, K. G., Wright, J. D., and Fairbanks, R. G.: Unlocking the ice house: Oligocene-Miocene oxygen isotopes, eustasy, and margin erosion, Journal of Geophysical Research: Solid Earth, 96, 6829–6848, 1991.
Miller, K. G., Browning, J. V., Schmelz, W. J., Kopp, R. E., Mountain, G. S., and Wright, J. D.: Cenozoic sea-level and cryospheric evolution from deep-sea geochemical and continental margin records, Science Advances, 6, eaaz1346, https://doi.org/10.1126/sciadv.aaz1346, 2020.
Misra, S. and Froelich, P. N.: Lithium isotope history of Cenozoic seawater: changes in silicate weathering and reverse weathering, Science, 335, 818–823, 2012.
Mook, W., Bommerson, J., and Staverman, W.: Carbon isotope fractionation between dissolved bicarbonate and gaseous carbon dioxide, Earth and Planetary Science Letters, 22, 169–176, 1974.
Moraweck, K., Grein, M., Konrad, W., Kvaček, J., Kova-Eder, J., Neinhuis, C., Traiser, C., and Kunzmann, L.: Leaf traits of long-ranging Paleogene species and their relationship with depositional facies, climate and atmospheric CO2 level; Leaf traits of long-ranging Paleogene species and their relationship with depositional facies, climate and atmospheric CO2 level, Palaeontographica Abteilung B: Palaeophytologie, 298, 93–172, 2019.
Novak, J., McGrath, S. M., Wang, K. J., Liao, S., Clemens, S. C., Kuhnt, W., and Huang, Y.: U38MEK′ Expands the linear dynamic range of the alkenone sea surface temperature proxy, Geochimica et Cosmochimica Acta, 328, 207–220, 2022.
O'Brien, C. L., Huber, M., Thomas, E., Pagani, M., Super, J. R., Elder, L. E., and Hull, P. M.: The enigma of Oligocene climate and global surface temperature evolution, Proceedings of the National Academy of Sciences, 117, 25302–25309, 2020.
Pagani, M., Arthur, M. A., and Freeman, K. H.: Miocene evolution of atmospheric carbon dioxide, Paleoceanography, 14, 273–292, 1999.
Pagani, M., Arthur, M. A., and Freeman, K. H.: Variations in Miocene phytoplankton growth rates in the southwest Atlantic: Evidence for changes in ocean circulation, Paleoceanography, 15, 486–496, 2000.
Pagani, M., Zachos, J. C., Freeman, K. H., Tipple, B., and Bohaty, S.: Marked decline in atmospheric carbon dioxide concentrations during the Paleogene, Science, 309, 600–603, 2005.
Pagani, M., Huber, M., Liu, Z., Bohaty, S. M., Henderiks, J., Sijp, W., Krishnan, S., and DeConto, R. M.: The role of carbon dioxide during the onset of Antarctic glaciation, Science, 334, 1261–1264, 2011.
Pagani, M.: 12.13 – Biomarker-Based Inferences of Past Climate: The Alkenone pCO2 Proxy, edited by: Holland, H. D. and Turekian, K. K., Treatise on Geochemistry, 2nd Edn., Elsevier, 361–378, ISBN 9780080983004, https://doi.org/10.1016/B978-0-08-095975-7.01027-5, 2014.
Pfuhl, H. A. and McCave, I. N.: Integrated age models for the early Oligocene-early Miocene, edited by: Exon, N. F., Kennett, J. P., and Malone, M. J., sites 1168 and 1170–1172, Proc. ODP, Sci. Results, 189, https://doi.org/10.2973/odp.proc.sr.189.108.2003, 2003.
Popp, B. N., Kenig, F., Wakeham, S. G., Laws, E. A., and Bidigare, R. R.: Does growth rate affect ketone unsaturation and intracellular carbon isotopic variability in Emiliania huxleyi?, Paleoceanography, 13, 35–41, 1998.
Rae, J. W., Zhang, Y. G., Liu, X., Foster, G. L., Stoll, H. M., and Whiteford, R. D.: Atmospheric CO2 over the past 66 million years from marine archives, Annual Review of Earth and Planetary Sciences, 49, 609–641, 2021.
Ragueneau, O., Tréguer, P., Leynaert, A., Anderson, R., Brzezinski, M., DeMaster, D., Dugdale, R., Dymond, J., Fischer, G., and Francois, R.: A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy, Global and Planetary Change, 26, 317–365, 2000.
Rama-Corredor, O., Cortina, A., Martrat, B., Lopez, J. F., and Grimalt, J. O.: Removal of bias in C37 alkenone-based sea surface temperature measurements by high-performance liquid chromatography fractionation, Journal of Chromatography A, 1567, 90–98, 2018.
Rau, G. H., Riebesell, U., and Wolf-Gladrow, D.: A model of photosynthetic 13C fractionation by marine phytoplankton based on diffusive molecular CO2 uptake, Marine Ecology Progress Series, 133, 275–285, 1996.
Raymo, M. E. and Ruddiman, W. F.: Tectonic forcing of late Cenozoic climate, Nature, 359, 117–122, 1992.
Reichgelt, T., D'Andrea, W. J., Valdivia-McCarthy, A. C., Fox, B. R. S., Bannister, J. M., Conran, J. G., Lee, W. G., and Lee, D. E.: Elevated CO2, increased leaf-level productivity, and water-use efficiency during the early Miocene, Clim. Past, 16, 1509–1521, https://doi.org/10.5194/cp-16-1509-2020, 2020.
Reilly, T. J., Miller, K. G., and Feigenson, M. D.: Latest Eocene-earliest Miocene Sr isotopic reference section, Site 522, eastern South Atlantic, Paleoceanography, 17, 18-11–18-19, 2002.
Roth-Nebelsick, A., Oehm, C., Grein, M., Utescher, T., Kunzmann, L., Friedrich, J.-P., and Konrad, W.: Stomatal density and index data of Platanus neptuni leaf fossils and their evaluation as a CO2 proxy for the Oligocene, Review of Palaeobotany and Palynology, 206, 1–9, 2014.
Rugenstein, J. K. C., Ibarra, D. E., and von Blanckenburg, F.: Neogene cooling driven by land surface reactivity rather than increased weathering fluxes, Nature, 571, 99–102, 2019.
Salabarnada, A., Escutia, C., Röhl, U., Nelson, C. H., McKay, R., Jiménez-Espejo, F. J., Bijl, P. K., Hartman, J. D., Strother, S. L., Salzmann, U., Evangelinos, D., López-Quirós, A., Flores, J. A., Sangiorgi, F., Ikehara, M., and Brinkhuis, H.: Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation, Clim. Past, 14, 991–1014, https://doi.org/10.5194/cp-14-991-2018, 2018.
Shackleton, N.: Oxygen isotopes, ice volume and sea level, Quaternary Science Reviews, 6, 183–190, 1987.
Sherman, E., Moore, J. K., Primeau, F., and Tanouye, D.: Temperature influence on phytoplankton community growth rates, Global Biogeochemical Cycles, 30, 550–559, 2016.
Sosdian, S. M., Greenop, R., Hain, M., Foster, G. L., Pearson, P. N., and Lear, C. H.: Constraining the evolution of Neogene ocean carbonate chemistry using the boron isotope pH proxy, Earth and Planetary Science Letters, 498, 362–376, 2018.
Stoll, H. M., Pena, L. D., Hernandez-Almeida, I., Guitián, J., Tanner, T., and Pälike, H.: Nonlinear increase in seawater
Stoll, H. M., Guitian, J., Hernandez-Almeida, I., Mejia, L. M., Phelps, S., Polissar, P., Rosenthal, Y., Zhang, H., and Ziveri, P.: Upregulation of phytoplankton carbon concentrating mechanisms during low CO2 glacial periods and implications for the phytoplankton pCO2 proxy, Quaternary Science Reviews, 208, 1–20, 2019.
Sun, B.-N., Wang, Q.-J., Konrad, W., Ma, F.-J., Dong, J.-L., and Wang, Z.-X.: Reconstruction of atmospheric CO2 during the Oligocene based on leaf fossils from the Ningming Formation in Guangxi, China, Palaeogeography, Palaeoclimatology, Palaeoecology, 467, 5–15, 2017.
Super, J. R., Thomas, E., Pagani, M., Huber, M., O'Brien, C., and Hull, P. M.: North Atlantic temperature and pCO2 coupling in the early-middle Miocene, Geology, 46, 519–522, 2018.
Sutton, R. T., Dong, B., and Gregory, J. M.:
Tanner, T., Hernández-Almeida, I., Drury, A. J., Guitián, J., and Stoll, H.: Decreasing atmospheric CO2 during the late Miocene cooling, Paleoceanography and Paleoclimatology, 35, e2020PA003925, https://doi.org/10.1029/2020PA003925, 2020.
Tesfamichael, T., Jacobs, B., Tabor, N., Michel, L., Currano, E., Feseha, M., Barclay, R., Kappelman, J., and Schmitz, M.: Settling the issue of “decoupling” between atmospheric carbon dioxide and global temperature:[CO2] atm reconstructions across the warming Paleogene-Neogene divide, Geology, 45, 999–1002, 2017.
Tierney, J. E. and Tingley, M. P.: A TEX(8)(6) surface sediment database and extended Bayesian calibration, Sci. Data, 2, 150029, https://doi.org/10.1038/sdata.2015.29, 2015.
Tierney, J. E. and Tingley, M. P.: BAYSPLINE: A new calibration for the alkenone paleothermometer, Paleoceanography and Paleoclimatology, 33, 281–301, 2018.
Torres Romero, I., Clark, A. J., Wijker, R. S., Jaggi, M., Zhang, H., and Stoll, H. M.: Temperature-dependent carbon isotope fractionation in coccolithophores, Frontiers in Earth Science, 12, 1331179, https://doi.org/10.3389/feart.2024.1331179, 2024.
Torsvik, T. H., Van der Voo, R., Preeden, U., Mac Niocaill, C., Steinberger, B., Doubrovine, P. V., Van Hinsbergen, D. J., Domeier, M., Gaina, C., and Tohver, E.: Phanerozoic polar wander, palaeogeography and dynamics, Earth-Science Reviews, 114, 325–368, 2012.
van Hinsbergen, D. J., de Groot, L. V., van Schaik, S. J., Spakman, W., Bijl, P. K., Sluijs, A., Langereis, C. G., and Brinkhuis, H.: A paleolatitude calculator for paleoclimate studies, PloS one, 10, https://doi.org/10.1371/journal.pone.0126946, 2015.
Van Peer, T. E., Xuan, C., Lippert, P. C., Liebrand, D., Agnini, C., and Wilson, P. A.: Extracting a detailed magnetostratigraphy from weakly magnetized, Oligocene to early Miocene sediment drifts recovered at IODP Site U1406 (Newfoundland margin, northwest Atlantic Ocean), Geochemistry, Geophysics, Geosystems, 18, 3910–3928, 2017.
Westerhold, T., Marwan, N., Drury, A. J., Liebrand, D., Agnini, C., Anagnostou, E., Barnet, J. S., Bohaty, S. M., De Vleeschouwer, D., and Florindo, F.: An astronomically dated record of Earth's climate and its predictability over the last 66 million years, Science, 369, 1383–1387, 2020.
Wilkes, E. B., Lee, R. B., McClelland, H. L., Rickaby, R. E., and Pearson, A.: Carbon isotope ratios of coccolith–associated polysaccharides of Emiliania huxleyi as a function of growth rate and CO2 concentration, Organic Geochemistry, 119, 1–10, 2018.
Zachos, J., Pagani, M., Sloan, L., Thomas, E., and Billups, K.: Trends, rhythms, and aberrations in global climate 65 Ma to present, Science, 292, 686–693, https://doi.org/10.1126/science.1059412, 2001.
Zachos, J. C., Dickens, G. R., and Zeebe, R. E.: An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics, Nature, 451, 279–283, https://doi.org/10.1038/nature06588, 2008.
Zeebe, R. E. and Wolf-Gladrow, D.: CO2 in seawater: equilibrium, kinetics, isotopes, Gulf Professional Publishing, ISBN 9780444509468, 2001.
Zhang, Y. G., Pagani, M., Liu, Z., Bohaty, S. M., and Deconto, R.: A 40-million-year history of atmospheric CO2, Philos. Trans. A Math. Phys. Eng. Sci., 371, 20130096, https://doi.org/10.1098/rsta.2013.0096, 2013.
Short summary
We reconstructed from sediments of different ocean sites phytoplankton carbon isotopic fractionation (εp), mainly linked to CO2 variations, during the Oligocene to early Miocene. Data confirm Cenozoic long-term CO2 record but show contrasting relationships with the sea surface temperatures evolution. We evaluate the role of non-CO2 environmental factors such as temperature and nutrients at each site εp, highlighting the complexity of interpreting climate dynamics and CO2 reconstructions.
We reconstructed from sediments of different ocean sites phytoplankton carbon isotopic...
