I am a palaeoceanographer and foraminiferal micropalaeontologist and have a particular interest in:
Much of my work has involved understanding the nature and causes of climatic change during the global warmth of the Eocene and mid-Cretaceous 'greenhouse' regimes. Another active research direction involves exploring the relationships between ocean circulation, ocean carbonate chemistry and atmospheric CO2 across a range of timescales. I am also investigating the role of climate change and switches in ocean circulation in structuring plankton biogeography, modulating inter-ocean exchanges of plankton populations and driving plankton extinctions.
Boulila, S., Vahlenkamp, M., De Vleeschouwer, D., Laskar, J., Yamamoto, Y., Pälike, H., Kirtland-Turner, S., Sexton, P.F., Westerhold, T. and Röhl, U. (2018), Towards a robust and consistent middle Eocene astronomical timescale, Earth and Planetary Science Letters, 486, 94–107.
Vahlenkamp, M., Niezgodzki, I., De Vleeschouwer, D., Bickert, T., Harper, D., Kirtland-Turner, S., Lohmann, G., Sexton, P.F., Zachos, J. and Pälike, H. (2018). Astronomically paced changes in overturning circulation in the Western North Atlantic during the middle Eocene, Earth and Planetary Science Letters, 484, 329-340.
Chalk, T.B., Hain, M.P., Foster, G.L., Rohling, E.J., Sexton, P.F., Badger, M.P.S., Cherry, S.G., Hasenfratz, A.P., Haug, G.H., Jaccard, S.L., Martínez-García, A., Pälike, H., Pancost, R.D. and Wilson, P.A. (2017), Causes of ice-age intensification across the Mid-Pleistocene Transition, Proceedings of the National Academy of Sciences, 114, 13114-13119.
Dyson, M. and Sexton, P.F. (2017). Blue Planet academic consultants: the message humanity cannot afford to ignore, The Conversation, https://theconversation.com/blue-planet-academic-consultants-the-message-humanity-cannot-afford-to-ignore-86157.
Gutjahr, M., Ridgwell, A., Sexton, P.F., Anagnostou, E., Pearson, P.N., Pälike, H., Norris, R.D., Thomas, E. and Foster, G.L. (2017), Very large release of mostly volcanic carbon during the Palaeocene-Eocene Thermal Maximum, Nature, 548, 573-577.
Gutjahr, M., Foster, G.L. and Sexton, P.F. (2017). Volcanic emissions caused the warmest period in past 56m years, The Conversation, https://theconversation.com/volcanic- emissions-caused-the-warmest-period-in-past-56m-years-new-study-82354.
Batenburg, S.J., Friedrich, O. Moriya, K., Voigt, S., Cournède, C., Möbius, I., Blum, P., Bornemann, A., Fiebig, J., Hasegawa, T., Hull, P., Norris, R., Röhl, U., Sexton, P.F., Westerhold, T., Wilson, P. and the IODP Expedition 342 Scientists (2017), Late Maastrichtian carbon isotope stratigraphy and cyclostratigraphy of the Newfoundland Margin (Site U1403, IODP Expedition 342), Newsletters on Stratigraphy, doi:10.1127/nos/2017/0398.
Boyle, P.R., Romans, B.W., Tucholke, B.E., Norris, R., Swift, S.A. & Sexton, P.F. (2017), Cenozoic North Atlantic deep circulation history recorded in contourite drifts, offshore Newfoundland, Canada, Marine Geology, 385, 185-203.
Hull, P.M., Bohaty, S.M., Cameron, A., Coxall, H.K., D’haenens, S., De Vleeschouwer, D., Elder, L.E., Friedrich, O., Kerr, K., Turner, S.K., Kordesch, W.E.C., Moriya, K., Norris, R.N., Opdyke, B.N., Penman, D.E., Pälike, H., Wilson, P.A., Sexton, P.F., Vahlenkamp, M., Wu, F., and Zachos, J.C. (2017). Data report: coarse fraction record for the Eocene megasplice at IODP Sites U1406, U1408, U1409, and U1411. In Norris, R.D., Wilson, P.A, Blum, P., and the Expedition 342 Scientists, Proceedings of the Integrated Ocean Drilling Program, 342: College Station, TX (Integrated Ocean Drilling Program), doi:10.2204/iodp.proc.342.203.2017.
Penman, D.E., Kirtland-Turner, S., Sexton, P.F., Norris, R., Dickson, A., Boulila, S., Ridgwell, A., Zeebe, R., Zachos, J., Cameron, A., Westerhold, T. and Röhl, U. (2016), A carbonate compensation depth overshoot in the aftermath of the Palaeocene-Eocene Thermal Maximum, Nature Geoscience, 9, 575–580.
Salmon, K.H., Anand, P., Sexton, P.F. & Conte, M. (2016), Calcification and growth processes in planktonic foraminifera complicate the use of B/Ca and U/Ca as carbonate chemistry proxies, Earth and Planetary Science Letters, 449, 372-381.
Möbius, I., Friedrich, O., Edgar, K.M. & Sexton, P.F. (2015), Episodes of intensified biological productivity in the subtropical Atlantic Ocean during the termination of the Middle Eocene Climatic Optimum, Paleoceanography, 30, 1041-1058.
Martinez-Botí, M.A., Foster, G.L., Chalk, T. B., Rohling, E.J., Sexton, P.F., Lunt, D.J., Pancost, R.D., Badger, M.P.S. & Schmidt, D.N. (2015), Plio-Pleistocene climate sensitivity evaluated using high-resolution CO2 records, Nature, 518, 49–54.
Salmon, K.H., Anand, P., Sexton, P.F. & Conte, M. (2015), Upper ocean mixing controls the seasonality of planktonic foraminifer fluxes and associated strength of the carbonate pump in the oligotrophic North Atlantic, Biogeosciences, 12, 223-235.
Friedrich, O., Norris, R. D., Wilson, P. A., Opdyke, B. N., Badger, M., Bailey, I., Beddow-Twigg, H., Bohaty, S., Bolton, C., Bornemann, A., Crocker, A., Grützner, J., Herbert, T., Holbourn, A., Hull, P., Liebrand, D., Lippert, P., Lourens, L., Lyle, M., Pross, J., Rosenthal, Y., Sexton, P.F., Stärz, M., & Westerhold, T. (2015). Newfoundland Neogene sediment drifts - Transition from the Paleogene greenhouse to the modern icehouse, Scientific Drilling, 19, 39-42.
Foster, G.L. and Sexton, P.F. (2014), Enhanced carbon dioxide outgassing from the equatorial Atlantic during the last glacial, Geology, 42, 1003–1006.
Kirtland-Turner, S., Sexton, P.F., Charles, C. & Norris, R. (2014), Persistence of carbon release events through the peak of early Eocene global warmth, Nature Geoscience, 7, 748–751.
Kemp, D.B. and Sexton, P.F. (2014), Timescale uncertainty of abrupt events in the geologic record arising from unsteady sedimentation, Geology, 42, 891–894.
Expedition 342 Scientists (incl. Sexton, P.F.) (2014). Paleogene Newfoundland Sediment Drifts, Proc. IODP, 342: College Station, TX (Integrated Ocean Drilling Program), doi:10.2204/iodp.proc.342.2014.
Hohbein, M., Sexton, P.F. and Cartwright, J. (2013), Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend: Reply, Geology, 41, p. e292, doi:10.1130/G34655Y.1.
Edgar, K.M., Bohaty, S.M., Gibbs, S.J., Sexton, P.F., Norris, R.D. and Wilson, P.A. (2013), Symbiont ‘bleaching’ in planktic foraminifera during the Middle Eocene Climatic Optimum, Geology, 41, 15-18.
Sexton, P.F., Wilson, P.A., Bown, P.R. and Liebrand, D. (2013) Expedition 342: Paleogene Newfoundland Sediment Drifts, Integrated Ocean Drilling Program UK Newsletter, 38, 2-7.
Sexton, P.F. and Barker, S. (2012), Onset of 'Pacific-style' deep-sea sedimentary carbonate cycles at the mid-Pleistocene transition, Earth and Planetary Science Letters, 321, 81-94.
Hohbein, M., Sexton, P.F. and Cartwright, J. (2012), Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend, Geology, 40, 255-258.
Expedition 342 Scientists (incl. Sexton, P.F.) (2012). Paleogene Newfoundland sediment drifts. IODP Prel. Rept., 342. doi:10.2204/iodp.pr.342.2012.
Sexton, P.F. and Norris, R.D. (2011), High latitude regulation of low latitude thermocline ventilation and planktic foraminifer populations across glacial-interglacial cycles, Earth and Planetary Science Letters, 311, 69-81.
Sexton, P.F., Norris, R.D., Wilson, P.A., Pälike, H., Westerhold, T., Röhl, U., Bolton, C. and Gibbs, S. (2011), Eocene global warming events driven by ventilation of oceanic dissolved organic carbon, Nature, 471, 349-352.
Edgar, K.M., Wilson, P.A., Sexton, P.F., Gibbs, S.J., Roberts, A.P. and Norris, R.D. (2010), New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes, Palaeogeography, Palaeoclimatology, Palaeoecology, 297, 670-682.
Sexton, P.F. and Wilson, P.A. (2009), Preservation of benthic foraminifera and reliability of deep-sea temperature records: The importance of sedimentation rates, lithology and the need to examine test wall structure, Paleoceanography, 24, PA2208, doi:10.1029/2008PA001650.
Sexton, P.F. and Norris, R.D. (2008), Dispersal and biogeography of marine plankton: Long-distance dispersal of the foraminifer Truncorotalia truncatulinoides, Geology, 36, 899-902.
Edgar, K.M., Wilson, P.A., Sexton, P.F. and Suganuma, Y. (2007), No extreme bipolar glaciation during the main Eocene calcite compensation shift, Nature, 448, 908-911.
Coxall, H.K., Wilson, P.A., Pearson, P.N. and Sexton, P.F. (2007), Iterative evolution of digitate planktonic foraminifera, Paleobiology, 33(4), 495-516.
Sexton, P.F., Wilson, P.A. and Pearson, P.N. (2006), Microstructural and geochemical perspectives on planktic foraminiferal preservation: 'Glassy' versus 'Frosty', Geochem. Geophys. Geosyst., 7, Q12P19, doi:10.1029/2006GC001291.
Sexton, P.F., Wilson, P.A. and Norris, R.D. (2006), Testing the Cenozoic multi-site composite d18O and d13C curves: New mono-specific Eocene records from a single locality, Demerara Rise (Ocean Drilling Program Leg 207), Paleoceanography, 21, PA2019, doi:10.1029/2005PA001253.
Sexton, P.F., Wilson, P.A. and Pearson, P.N. (2006), Palaeoecology of late middle Eocene planktic foraminifera and evolutionary implications, Marine Micropaleontology, 60, 1-16.
Danelian T, Le Callonnec L, Erbacher J et al. (incl. Sexton P.F.), (2005), Preliminary results on Cretaceous-Cenozoic tropical Atlantic pelagic sedimentation (Demerara Rise, ODP Leg 207), Comptes Rendus Geoscience, 337 (6), 609-616.
Erbacher, J., Mosher, D., Malone, M. and ODP Leg 207 Scientific Party (incl. Sexton, P.F.) (2004), Drilling probes past carbon cycle perturbations on Demerara Rise, Eos (Trans. AGU), 85, 57-63.
Sexton, P.F., Thurow, J. and Wilson, P.A. (2003), ODP Leg 207: Demerara Rise - Equatorial Cretaceous and Palaeogene palaeoceanographic transect, UK ODP Newsletter, 29, 18-21.
Sexton, P.F. and Norris, R.D. (2002), Orbital control of late Pliocene planktic foraminiferal biogeography, Newsletter of Micropalaeontology, 66, 18-19.
2016 - Senior Lecturer, The Open University
2012 - 2016 Lecturer, The Open University
2010 - 2012 Leverhulme Trust Research Fellow, The Open University
2009 - 2010 EC Marie Curie Research Fellow, Cardiff University
2006 - 2009 EC Marie Curie Research Fellow, Scripps Institution of Oceanography, USA
2005 - 2006 Postdoctoral Research Scientist, National Oceanography Centre, Southampton
2001 - 2001 Visiting Scholar, Woods Hole Oceanographic Institution, USA
2000 - 2005 Postgraduate Research Student, National Oceanography Centre, Southampton
At The Open University (the world-leader in distance teaching):
S330 Oceanography (30 credits) 2014-present, module team Chair. 2010-2014, module team member.
S366 Evolution (30 credits) 2010-2015, module team member, responsible for Macroevolution and Palaeontology (~ one third of module)
S175 Frozen Planet (10 credits) 2013-present, module team Chair
SXG288 Practical Science: Earth and Environment (30 credits) 2013-2014, module team Chair
S104 Exploring Science (60 credits) 2013-2014, module team member, responsible for Earth Science
S209 Earth Science (60 credits) 2014-present, module team member, responsible for Palaeontology, and Sedimentary Processes/Environments (~40% of module)
S309 Earth System Processes (60 credits) 2014-present, production module team member, responsible for the Oceans block (3 of 6)
|Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)||Centre||Faculty of Science|
|Role||Start date||End date||Funding source|
|Lead||01/Oct/2017||30/Sep/2022||NERC (Natural Environment Research Council)|
The Earth’s climate is currently changing rapidly, primarily due to emissions of greenhouse gases caused by human industrialisation. These emissions are projected to increase through this century, and under some scenarios atmospheric carbon dioxide (CO2) concentrations could reach more than 1000 parts per million (ppm) by the year 2100, compared with 280 ppm prior to industrialisation. In order to predict the sociological, environmental, and economic impacts of such scenarios, and thus to better prepare for them, the only tool at our disposal is climate modelling. In order to assess our confidence in predictions from climate models, they are routinely tested under conditions of known climate. However, this testing (and associated tuning of the models) is almost exclusively carried out under modern climate conditions, and relative to recently observed climate change, for which CO2 concentrations are less than 400 ppmv. As such, our state-of-the-art climate models have never been tested under the high CO2, super-warm climate conditions to which they are primarily applied, and upon which major policy decisions are made. However, there exist time periods in Earth’s deeper past (for example the Eocene, about 50 million years ago) when CO2 concentrations were similar to those expected by the end of this century; but climatological information from these time periods is currently sparse and is associated with large uncertainties, and the exact concentrations of CO2 are only poorly known. Recent changes in our understanding of how the geological record preserves climate signals, and developments in laboratory techniques, mean that for the first time there exists a new and exciting opportunity to remedy this situation and provide a much-needed evaluation of our very latest climate models in a super-warm world. In SWEET, we will apply these emerging techniques, and develop new methodologies and tools, to produce a global dataset of Eocene temperatures. Coupled with new and high-fidelity reconstructions of Eocene CO2 concentrations, and state-of-the-art maps of the ‘palaeogeograpy’ (continental positions, mountain ranges, ocean depths etc.), we will use this dataset to test a state-of-the art climate model under high atmospheric CO2, Eocene conditions. The model, UKESM, is identical to that being used by the UK Met Office in the international ‘CMIP6’ project, which itself will be the primary input to the next Intergovernmental Panel on Climate Change (IPCC) assessment report. We will also use our data and additional model simulations (running at high spatial resolution) to investigate the relative importance of the various mechanisms which determine the response of the Earth system to high CO2 and to changes in palaeogeography. A characteristic of SWEET is that we will take full account of uncertainties in the geological data and the modelling, and our model-data comparisons will be underpinned by a statistical framework which incorporates these uncertainties. We will also adopt a ‘multi-proxy’ approach by using several independent geological archives to reconstruct temperature. For one of these archives, namely the oxygen isotopic composition of the fossilised shells of microscopic marine creatures from the Eocene, we will apply a particularly innovative approach which will enable us to ‘resurrect’ previously discredited data, by using an extremely fine-scale ‘ion probe’ to investigate how these isotopic signatures of past climate change are recorded in individual fossils.
In addition to teaching on Open University modules our academics are engaged in ground breaking research that benefits individuals and society.
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