Dr Philip Sexton

Lecturer

The Open University Faculty of Science Department of Environment, Earth & Ecosystems

philip.sexton@open.ac.uk

Profile

I joined the Dept in 2010 and am a palaeoceanographer and foraminiferal micropalaeontologist. I have a particular interest in:

palaeoceanography & carbon cycling of past warm 'greenhouse' climate regimes
interactions between ocean circulation, ocean carbonate chemistry & atmospheric CO2
the role of climatic change in structuring ocean ecosystems and evolution
the geochemical utility of fossil foraminifera shells preserved in deep-sea sediments
stable isotope mass spectrometry
the development of novel 'bio-proxies' for palaeoenvironmental reconstruction

Professional Experience:

Aug 10 - Leverhulme Trust Research Fellow & Lecturer, Open University

Nov 09 - Aug 10 Leverhulme Trust Research Fellow, Cardiff University

Feb 09 - Nov 09 EC Marie Curie Research Fellow, Cardiff University

Nov 06 - Feb 09 EC Marie Curie Research Fellow, Scripps Institution of Oceanography, USA

Mar 05 - Oct 06 Postdoctoral Research Scientist, National Oceanography Centre, Southampton

Jun 01 - Sep 01 Visiting Scholar, Woods Hole Oceanographic Institution, USA

Oct 00 - Mar 05 Postgraduate Research Student, National Oceanography Centre, Southampton

Qualifications

Oct 00 - Mar 05 Ph.D., Palaeoceanography, National Oceanography Centre, Southampton "Foraminiferal taphonomy, geochemistry and palaeoceanography of the Eocene"

Oct 95 - Jul 98 B.Sc. (Hons), University of Liverpool

Research Interests

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 research theme is aimed at improving knowledge of the scale and intensity of diagenetic alteration in planktic and benthic foraminifera (the 'workhorses' of palaeoceanography) and its impact on geochemical signals incorporated within their calcite shells. More recently, I have begun to investigate 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. I am also exploring the relationships between ocean circulation, ocean carbonate chemistry and atmospheric CO2 across a range of timescales.

Publications (for pdf files, see my 'Publications' tab):

Edgar, K.M., Bohaty, S.M., Gibbs, S.J., Sexton, P.F., Norris, R.D. and Wilson, P.A. (in press), Symbiont ‘bleaching’ in planktic foraminifera during the Middle Eocene Climatic Optimum, Geology.

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.

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.

Publications

Conference Item

Dixon, Sophie; Parkinson, Ian; Sexton, Philip; Fehr, Manuela; Peacock, Caroline and James, Rachael (2013). Ocean redox across the PETM: stable Cr isotopes in planktic foraminifera. In: Geochemistry Group RiP meeting 2013, 14 March 2013, Milton Keynes.

Dixon, Sophie K.; Parkinson, Ian J.; Sexton, Philip; Fehr, Manuela; James, Rachael Helen and Peacock, Caroline (2012). Tracking changes in ocean redox during the PETM using stable chromium isotopes. In: AGU Fall Meeting, 3-7 December 2012, San Francisco, CA, USA.

Journal Article

Edgar, K. M.; Bohaty, S. M.; Gibbs, S. J.; Sexton, P. F.; Norris, R. D. and Wilson, P. A. (2012). Symbiont ‘bleaching’ in planktic foraminifera during the Middle Eocene Climatic Optimum. Geology (in press).

Sexton, Philip F. and Barker, Stephen (2012). Onset of ‘Pacific-style’ deep-sea sedimentary carbonate cycles at the mid-Pleistocene transition. Earth and Planetary Science Letters, 321 pp. 81–94.

Hohbein, Michael W.; Sexton, Philip F. and Cartwright, Joseph A. (2012). Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend. Geology, 40(3), pp. 255–258.

Sexton, Philip F. and Norris, Richard D. (2011). High latitude regulation of low latitude thermocline ventilation and planktic foraminifer populations across glacial-interglacial cycles. Earth and Planetary Science Letters, 311(1-2), pp. 69–81.

Sexton, Philip F.; Norris, Richard D.; Wilson, Paul A.; Pälike, Heiko; Westerhold, Thomas; Röhl, Ursula; Bolton, Clara T. and Gibbs, Samantha (2011). Eocene global warming events driven by ventilation of oceanic dissolved organic carbon. Nature, 471 pp. 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(3-4), pp. 670–682.

Sexton, Philip F. and Wilson, Paul A. (2009). Preservation of benthic foraminifera and reliability of deep-sea temperature records: Importance of sedimentation rates, lithology, and the need to examine test wall structure. Paleoceanography, 24 PA2208.

Sexton, Philip F. and Norris, Richard D. (2008). Dispersal and biogeography of marine plankton: Long-distance dispersal of the foraminifer Truncorotalia truncatulinoides. Geology, 36(11), pp. 899–902.

Coxall, Helen K.; Wilson, Paul A.; Pearson, Paul N. and Sexton, Philip F. (2007). Iterative evolution of digitate planktonic foraminifera. Paleobiology, 33(4), pp. 495–516.

Edgar, Kirsty M.; Wilson, Paul A.; Sexton, Philip F. and Suganuma, Yusuke (2007). No extreme bipolar glaciation during the main Eocene calcite compensation shift. Nature, 448 pp. 908–911.

Sexton, Philip F.; Wilson, Paul A. and Pearson, Paul N. (2006). Microstructural and geochemical perspectives on planktic foraminiferal preservation: “Glassy” versus “Frosty”. Geochemistry Geophysics Geosystems, 7(12), Q12P19.

Sexton, Philip F.; Wilson, Paul A. and Pearson, Paul N. (2006). Palaeoecology of late middle Eocene planktic foraminifera and evolutionary implications. Marine Micropaleontology, 60(1), pp. 1–16.

Sexton, Philip F; Wilson, Paul A. and Norris, Richard D. (2006). Testing the Cenozoic multisite composite δ18O and δ13C curves: new monospecific Eocene records from a single locality, Demerara Rise (Ocean Drilling Program Leg 207). Paleoceanography, 21 PA2019.

Danelian, Taniel; Le Callonec, Laurence; Erbacher, Jochen; Mosher, David C.; Malone, Mitchell J.; Berti, Debora; Bice, Karen L.; Bostock, Helen; Brumsack, Hans-Jurgen; Forster, Astrid; Heidersdorf, Felix; Henderiks, Jorijntje; Janecek, Thomas J.; Junium, Christopher; Macleod, Ken; Meyers, Philip A.; Mutterlose, Jorg H.; Nishi, Hiroshi; Norris, Richard D.; Ogg, James G.; O’Regan, Matthew A.; Rea, Brice; Sexton, Philip; Sturt-Fredricks, Helen; Suganuma, Yusuke; Thurow, Jurgen W.; Wilson, Paul A.; Wise, Sherwood W. and Glatz, Catherine (2005). Preliminary results on Cretaceous-Tertiary tropical Atlantic pelagic sedimentation (Demerara Rise, ODP Leg 207). Comptes Rendus Geosciences, 337(6), pp. 609–616.

last updated 05-Oct-2012