Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9366
Location
Texel
Department
Ocean Systems (OCS)
Function
Senior Research Leader
Expertise
  • Marine geology
  • Marine palynology
  • Paleoceanography
  • Paleoecology
  • Stratigraphy
The Fluid Knowledge Podcast with Henk Brinkhuis

Palmtrees on Antarctica

What is the story of the Antarctic climate millions of years ago? Henk Brinkhuis took part in the drilling ship JOIDES Resolution that pulls drill cores from the ocean bottom up to 4 kilometers deep.

Bekijk ook de VPRO-aflevering van 'Beagle, in het kielzog van Darwin'.

50 miljoen jaar geleden was de Zuidpool subtropisch, met palmbomen en krokodillen. Het CO2-gehalte in de atmosfeer was toen zeven keer hoger dan nu en de gemiddelde temperatuur op aarde (van evenaar tot polen) was 34 graden. Nu is dat 15 graden. Het CO2-gehalte groeit sterk door het opstoken van fossiele brandstoffen als olie en kolen, en het kappen van regenwouden.

Als we de komende tweehonderd jaar op hetzelfde pad voortgaan, komen we op CO2-waarden uit die zo'n 40 miljoen jaar niet meer zijn voorgekomen op aarde. De gemiddelde jaartemperatuur zal dan kunnen verdubbelen en daarmee zal al het poolijs verdwijnen en de tropen onleefbaar heet worden voor mens en dier. De klimaatonderzoekers aan boord van de Beagle berekenen hoeveel tijd er nog is om in te grijpen.

Prof. Dr. Henk Brinkhuis

Senior Research Leader

‘Going back in time’

After completing the second of the two terms of five years leading the Institute as director, Henk Brinkhuis’ career comes full circle, turning back to his old loves: marine palynology and scientific ocean drilling.

Two-and-a-half billion years of climate information

“My scientific specialization is in the study of ancient ocean mud, especially its organic content” - In other words: marine palynology and organic biogeochemistry, combining marine geology with paleoecology, paleoclimate and paleoceanography’. Marine palynology entails the study of microscopic, acid-resistant organic remains of ancient plants and animals found in marine sediments. ‘My favourite group are the organic-walled dinoflagellate cysts” Typically, these are single celled algae inhabiting both fresh water and marine environments. One interesting thing is that some of them produce an organic-walled resting stage, called cyst. These may be considered as ‘bioplastic’, considering their resistance to degradation of organic material. By studying these cysts, and their Paleozoic and even older precursors, the so-called acritarchs, we can look back in time no less than two-and-a-half billion years. These microfossils are typically used for dating and assessing the paleoenvironment. Particularly when taken together with all the other palynological elements in each sample, including remains of other organisms, from sea and washed in from land, marine palynology becomes a powerful tool for recognizing and reconstructing ancient climate change. Moreover, such information, when tied to geochemical studies including stable isotope analysis from the same samples, can indeed be used to learn from the past, and predict the climatic future of our planet.

Scientific ocean drilling – the ’International ocean discovery program’ - IODP

“Earlier in 2021, I was appointed chair of the so-called Forum of the international Ocean Discovery Program, starting per October 1”. The IODP Forum is a venue for exchanging ideas and views on the scientific progress of the International Ocean Discovery Program. Specifically, the Forum is the custodian of the IODP Science Plan 2013-2023 and provides advice to the IODP Facility Boards on Platform Provider activity. The IODP Forum meets at least annually and membership is open to all countries, consortia, or entities that provide funds to IODP platform operations. Henk refers to this program as ‘the best international science program ever’ and compares it to the spirit of that famous classic TV series ‘StarTrek’ where all of mankind work together, even with beings from other worlds, to solve problems. With the present climate crisis in mind, we are particularly interested in reconstructing the warm periods in history. For example, the Paleocene-Eocene Thermal Maximum was a period, relatively ‘nearby’, only 56 million years ago, when the average temperature on Earth rapidly rose six degrees, in an already warmer world. There were even Palm trees growing on the continents around the North Pole! From a present point of view, with huge amounts of anthropogenic CO2 in the atmosphere, it is important to find out: how did the planet counter this warm period 56 million years ago, with its large amounts of CO2?” How did Mother Earth go from Hothouse to Icehouse. That is the main question on Henk’s mind.

Floating carbon-catcher

“There is increasing evidence that massive growth of the tiny free-floating freshwater fern Azolla has played a major role in taking carbon out of the atmosphere by the end of the very warm Early Eocene, some 50 million years ago. This phenomenon that lasted around 800,000 years, started right at the first, but definite, long term cooling trend, towards the modern ‘icehouse’. Azolla grows extremely fast, making it a pest to modern day ecologists, but back then, covering more than 30 million km2 of Nordic seas, it may have acted as the biggest floating carbon-catcher in history, its mats sinking in anoxic oblivion of the ancient oceans, bringing down all that Carbon to the (long term) geological Carbon cycle.”

Keep on Drilling

“I hope to further contribute to the detailed knowledge of the long-term carbon cycle, that can be understood through studies of dinoflagellates, isotopes and other tracers that we find in ocean sediments. This also means we must keep participating in international efforts of scientific ocean drilling in the future, also post 2024, when the current Ocean Discovery Program ends. The US is planning on renewing their scientific drilling vessel, while Europe is pushing for its Marine Science Program that Japan, China, Korea, India, Australia and New Zealand are part of as well.”

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Photos taken during the IODP 302 ACEX expedition on the North Pole.

Current positions (selection)

•    Professor in Marine Palynology and Paleoecology, Utrecht University
•    Chair IODP forum
•    Member of various scientific advisory boards, nationally and internationally
•    Member of the KNAW

Education

1985-1992 - University Utrecht, PhD Geology, Palaeoceanography, Marine Palynology, Micropaleontology
1978-1985 - University Utrecht, MSc, Geology

 

Linked news

Friday 03 June 2022
Former director of NIOZ Henk Brinkhuis receives an honorary medal from the Municipality of Texel
On Friday 3 June 2022, Prof. Dr. Henk Brinkhuis received the Medal of Honor from the Municipality of Texel during his formal retirement event as Director of the Royal Netherlands Institute for Sea Research (NIOZ). Mayor Michiel Uitdehaag presented…
Thursday 23 September 2021
New, innovative equipment for national marine research
Under the leadership of the Royal Netherlands Institute for Sea Research (NIOZ), a large consortium of national marine research and education institutes has been focusing, over the past few years, on the now necessary replacement of the national…
Thursday 30 April 2020
Large scale scientific infrastructure granted: a crucial contribution to investing in new, innovative equipment for national marine research
Under the leadership of the Royal Netherlands Institute for Sea Research (NIOZ), a large consortium of national marine research and education institutes has been focusing, over the past few years, on the now necessary replacement of the national…
Thursday 07 March 2019
Koninklijk Paar ontmoet NIOZ delegatie in Bremen
Op 6 maart 2019 spraken Koning Willem-Alexander en Koningin Maxima tijdens een werkbezoek aan Bremen met Nederlandse en Duitse pool- en marienonderzoekers over veranderingen in de poolgebieden en de wereldwijde directe of indirecte gevolgen daarvan.…

Linked blogs

Tuesday 21 December 2021
NIOZ Podcast Van Delta tot Diepzee aflevering 18 Waterplantje Azolla als grote klimaatkoeler met ex-NIOZ-directeur Henk Brinkhuis
Net afgezwaaid NIOZ-directeur en geoloog Prof Henk Brinkhuis over 10 jaar NIOZ, boren naar het verleden van het klimaat en de grote rol van het waterplantje Azolla bij het afkoelen van een warme wereld.
Wednesday 08 September 2021
International Ocean Discovery Program Expedition 396 | Mid-Norwegian Continental Margin Magmatism
IOPD Expedition 396 to the Mid-Norwegian margin investigates the role of volcanism in the rapid global warming of the Eocene and perturbations of the global Carbon cycle during the warmest climatic phase of the past ~85 million years, known as the…

NIOZ publications

  • 2023
    Berndt, Christian; Planke, Sverre; Alvarez Zarikian, Carlos A.; Frieling, Joost; Jones, Morgan T.; Millett, John M.; Brinkhuis, Henk; Bünz, Stefan; Svensen, Henrik H.; Longman, Jack; Scherer, Reed P.; Karstens, Jens; Manton, Ben; Nelissen, Mei; Reed, Brandon; Faleide, Jan Inge; Huismans, Ritske S.; Agarwal, Amar; Andrews, Graham D. M.; Betlem, Peter; Bhattacharya, Joyeeta; Chatterjee, Sayantani; Christopoulou, Marialena; Clementi, Vincent J.; Ferré, Eric C.; Filina, Irina Y.; Guo, Pengyuan; Harper, Dustin T.; Lambart, Sarah; Mohn, Geoffroy; Nakaoka, Reina; Tegner, Christian; Varela, Natalia; Wang, Mengyuan; Xu, Weimu; Yager, Stacy L. (2023). Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum. Nature Geoscience 16(9): 803-809. https://dx.doi.org/10.1038/s41561-023-01246-8
    Rush, W.; Self-Trail, J.M.; Zhang, Y.; Sluijs, A.; Brinkhuis, H.; Zachos, J.C.; Ogg, J.G.; Robinson, M.M. (2023). Assessing environmental change associated with early Eocene hyperthermals in the Atlantic Coastal Plain, USA. Clim. Past 19(8): 1677-1698. https://dx.doi.org/10.5194/cp-19-1677-2023
  • 2022
    Cramwinckel, M.J.; van der Ploeg, R.; van Helmond, N.A.G.M.; Waarlo, N.; Agnini, C.; Bijl, P.K.; van der Boon, A.; Brinkhuis, H.; Frieling, J.; Krijgsman, W.; Mather, T.A.; Middelburg, J.J.; Peterse, F.; Slomp, C.P.; Sluijs, A. (2023). Deoxygenation and organic carbon sequestration in the Tethyan realm associated with the middle Eocene climatic optimum. Geol. Soc. Am. Bull. 135(5-6): 1280-1296. https://dx.doi.org/10.1130/b36280.1
    Planke, S; Berndt, C.; Alvarez Zarikian, C.-A. and the Expedition 396 Scientists (2022). Expedition 396 preliminary report: Mid-Norwegian margin magmatism and paleoclimate implications. International Ocean Discovery Program : Texas. https://dx.doi.org/10.14379/iodp.pr.396.2022
  • 2021
    Hoem, F.S.; Sauermilch, I.; Hou, S.; Brinkhuis, H.; Sangiorgi, F.; Bijl, P.K. (2021). Late Eocene–early Miocene evolution of the southern Australian subtropical front: a marine palynological approach. J. Micropalaeontol. 40(2): 175-193. https://dx.doi.org/10.5194/jm-40-175-2021
    Hoem, F.S.; Valero, L.; Evangelinos, D.; Escutia, C.; Duncan, B.; McKay, R.M.; Brinkhuis, H.; Sangiorgi, F.; Bijl, P.K. (2021). Temperate Oligocene surface ocean conditions offshore of Cape Adare, Ross Sea, Antarctica. Clim. Past 17(4): 1423-1442. https://dx.doi.org/10.5194/cp-17-1423-2021
  • 2020
    Cramwinckel, M.J.; Coxall, H.K.; Sliwinska, K.K.; Polling, M.; Harper, D.P.; Bijl, P.K.; Brinkhuis, H.; Eldrett, J.S.; Houben, A.J.P.; Peterse, F; Schouten, S.; Reichart, G.-J.; Zachos, J.C.; Sluijs, A. (2020). A warm, stratified, and restricted Labrador Sea across the middle Eocene and its climatic optimum. Paleoceanography and Paleoclimatology 35(10): e2020PA003932. https://doi.org/10.1029/2020pa003932
    Cramwinckel, M.J.; Coxall, H.K.; Sliwinska, K.K.; Polling; Harper; Bijl, P.K.; Brinkhuis, H.; Eldrett, J.S.; Houben, A.J.P.; Peterse, F; Schouten, S.; Reichart, G.-J.; Zachos, J.C.; Sluijs, A. (2020). A warm, stratified, and restricted Labrador Sea across the middle Eocene and its climatic optimum. Paleoceanography and Paleoclimatology 35(10): e2020PA003932. https://doi.org/10.1029/2020pa003932
  • 2019
    Houben, A.J.P.; Bijl, P.K.; Sluijs, A.; Schouten, S.; Brinkhuis, H. (2019). Late Eocene Southern Ocean Cooling and invigoration of circulation preconditioned Antarctica for full‐scale glaciation. Geochem. Geophys. Geosyst. 20(5): 2214-2234. https://dx.doi.org/10.1029/2019gc008182
    Houben, A.J.P.; Quaijtaal, W.; Wade, B.S.; Schouten, S.; Brinkhuis, H. (2019). Quantitative organic-walled dinoflagellate cyst stratigraphy across the Eocene-Oligocene Transition in the Gulf of Mexico: A record of climate- and sea level change during the onset of Antarctic glaciation. Newsl. Stratigr. 52(2): 131-154. https://dx.doi.org/10.1127/nos/2018/0455
  • 2018
    Donders, T.H.; van Helmond, N.A.G.M.; Verreussel, R.; Munsterman, D.; ten Veen, J.; Speijer, R.P.; Weijers, J.W.H.; Sangiorgi, F.; Peterse, F.; Reichart, G.-J.; Sinninghe Damsté, J.S.; Lourens, L.; Kuhlmann, G.; Brinkhuis, H. (2018). Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing. Clim. Past 14(3): 397-411. https://doi.org/10.5194/cp-14-397-2018
    Grothe, A.; Sangiorgi, F.; Brinkhuis, H.; Stoica, M.; Krijgsman, W. (2018). Migration of the dinoflagellate Galeacysta etrusca and its implications for the Messinian Salinity Crisis. Newsl. Stratigr. 51(1): 73-91. https://doi.org/10.1127/nos/2016/0340
    Hartman, J.D.; Sangiorgi, F.; Salabarnada, A.; Peterse, F; Houben, A.J.P.; Schouten, S.; Brinkhuis, H.; Escutia, C.; Bijl, P.K. (2018). Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 3: Insights from Oligocene–Miocene TEX86-based sea surface temperature reconstructions. Clim. Past 14(9): 1275-1297. https://doi.org/10.5194/cp-14-1275-2018
    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.; Brinkhuis, H. (2018). Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica - Part 1: Insights from late Oligocene astronomically paced contourite sedimentation. Clim. Past 14(7): 991-1014. https://doi.org/10.5194/cp-14-991-2018
    Sangiorgi, F.; Bijl, P.K.; Passchier, S.; Salzmann, U.; Schouten, S.; McKay, R.M.; Cody, R.D.; Pross, J.; van de Flierdt, T.; Bohaty, S.M.; Levy, R.; Williams, T.; Escutia, C.; Brinkhuis, H. (2018). Southern Ocean warming and Wilkes Land ice sheet retreat during the mid-Miocene. Nature Comm. 9(1): 317. https://dx.doi.org/10.1038/s41467-017-02609-7
  • 2017
    Bijl, P.K.; Brinkhuis, H.; Egger, L.M.; Eldrett, J.S.; Frieling, J.; Grothe, A.; Houben, A.J.P.; Pross, J.; Sliwinska, K.K.; Sluijs, A. (2017). Comment on ‘Wetzeliella and its allies – the ‘hole’ story: a taxonomic revision of thePaleogene dinoflagellate subfamily Wetzelielloideae’ by Williams et al. (2015). Palynology 41(3): 423-429. https://dx.doi.org/10.1080/01916122.2016.1235056
    Vellekoop, J.; Holwerda, F.; Prámparo, M.B.; Willmott, V.; Schouten, S.; Cúneo, N.R.; Scasso, R.A.; Brinkhuis, H. (2017). Climate and sea-level changes across a shallow marine Cretaceous-Palaeogene boundary succession in Patagonia, Argentina. Palaeontology 60(4): 519-534. https://dx.doi.org/10.1111/pala.12297
    Vellekoop, J.; Woelders, L.; Açikalin, S.; Smit, J.; van de Schootbrugge, B.; Yilmaz, I.Ö.; Brinkhuis, H.; Speijer, R.P. (2017). Ecological response to collapse of the biological pump following the mass extinction at the Cretaceous–Paleogene boundary. Biogeosciences 14(4): 885-900. https://dx.doi.org/10.5194/bg-14-885-2017
  • 2016
    van Helmond, N.A.G.M.; Sluijs, A.; Papadomanolaki, N.M.; Plint, A.G.; Gröcke, D.R.; Pearce, A.; Eldrett, J.S.; Trabucho-Alexandre, J.; Walaszczyk, I.; van de Schootbrugge, B.; Brinkhuis, H. (2016). Equatorward phytoplankton migration during a cold spell within the Late Cretaceous super-greenhouse. Biogeosciences 13: 2859–2872. dx.doi.org/10.5194/bg-13-2859-2016
    Vellekoop, J.; Esmeray-Senlet, S.; Miller, K.G.; Browning, J.V.; Sluijs, A.; van de Schootbrugge, B.; Sinninghe Damsté, J.S.; Brinkhuis, H. (2016). Evidence for Cretaceous-Paleogene boundary bolide “impact winter” conditions from New Jersey, USA. Geology (Boulder Colo.) 44(8): 619-622. https://dx.doi.org/10.1130/G37961.1
  • 2015
    Bijl, P.K.; Brinkhuis, H. (2015). A new genus and two new species of dinoflagellate cysts from lower Eocene marine sediments of the Wilkes Land Margin, Antarctica. Rev. Palaeobot. Palynol. 220: 88-97. dx.doi.org/10.1016/j.revpalbo.2015.05.004
    van Helmond, N.A.G.M.; Hennekam, R.; Donders, T.H.; Bunnik, F.P.M.; de Lange, G.J.; Brinkhuis, H.; Sangiorgi, F. (2015). Marine productivity leads organic matter preservation in sapropel S1: palynological evidence from a core east of the Nile River outflow. Quat. Sci. Rev. 108: 130–138. dx.doi.org/10.1016/j.quascirev.2014.11.014
    van Helmond, N.A.G.M.; Sluijs, A.; Sinninghe Damsté, J.S.; Reichart, G.-J.; Voigt, S.; Erbacher, J.; Pross, J.; Brinkhuis, H. (2015). Freshwater discharge controlled deposition of Cenomanian–Turonian black shales on the NW European epicontinental shelf (Wunstorf, northern Germany). Clim. Past 11: 495-508. dx.doi.org/10.5194/cp-11-495-2015
    Van Hinsbergen, D.J.J.; De Groot, L.V.; Van Schaik, S.J.; Spakman, W.; Bijl, P.K.; Sluijs, A.; Langereis, C.G.; Brinkhuis, H. (2015). A Paleolatitude Calculator for Paleoclimate Studies. PLoS One 10(6): e0126946. dx.doi.org/10.1371/journal.pone.0126946
    Vellekoop, J.; Smit, J.; van de Schootbrugge, B.; Weijers, J.W.; Galeotti, S.; Sinninghe Damsté, J.S.; Brinkhuis, H. (2015). Palynological evidence for prolonged cooling along the Tunisian continental shelf following the K–Pg boundary impact. Palaeogeogr. Palaeoclimatol. Palaeoecol. 426: 216-228. dx.doi.org/10.1016/j.palaeo.2015.03.021
  • 2014
    Baroni, I.R.; Topper, R.P.M.; van Helmond, N.A.G.M.; Brinkhuis, H.; Slomp, C.P. (2014). Biogeochemistry of the North Atlantic during oceanic anoxic event 2: role of changes in ocean circulation and phosphorus input. Biogeosciences 11(4): 977-993. dx.doi.org/10.5194/bg-11-977-2014
    Bosboom, R.; Dupont-Nivet, G.; Grothe, A.; Brinkhuis, H.; Villa, G.; Mandic, O.; Stoica, M.; Huang, W.; Yang, W.; Guo, Z.; Krijgsman, W. (2014). Linking Tarim Basin sea retreat (west China) and Asian aridification in the late Eocene. Basin Res. 26(5): 621–640. dx.doi.org/10.1111/bre.12054
    Contreras, L.; Pross, J.; Bijl, P.K.; O'Hara, R.B.; Raine, J.I.; Sluijs, A.; Brinkhuis, H. (2014). Southern high-latitude terrestrial climate change during the Palaeocene–Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau). Clim. Past 10: 1401-1420. hdl.handle.net/10.5194/cp-10-1401-2014
    Grothe, A.; Sangiorgi, F; Mulders, Y.; Vasiliev, I.; Brinkhuis, H.; Stoica, M.; Krijgsman, W.; Reichart, G.-J. (2014). Black Sea desiccation during the Messinian Salinity Crisis: Fact or fiction? Geology (Boulder Colo.) 42(7): 563-566. hdl.handle.net/10.1130/G35503.1
    Rugenstein, M.; Stocchi, P.; van der Heydt, A.; Brinkhuis, H. (2014). Emplacement of Antarctic ice sheet mass affects circumpolar ocean flow. Global Planet. Change 118: 16-24. hdl.handle.net/10.1016/j.gloplacha.2014.03.011
    Timmermans, K.R.; Brinkhuis, H. (2014). Zeewier, in: Het beste idee van 2014. pp. 69-71
    van Helmond, N.A.G.M.; Sluijs, A.; Reichart, G.J; Sinninghe Damsté, J.S.; Slomp, C.P.; Brinkhuis, H. (2014). A perturbed hydrological cycle during Oceanic Anoxic Event 2. Geology (Boulder Colo.) 42(2): 123-126. dx.doi.org/10.1130/G34929.1
    Vellekoop, J.; Sluijs, A.; Smit, J.; Schouten, S.; Weijers, J.W.H.; Sinninghe Damsté, J.S.; Brinkhuis, H. (2014). Rapid short-term cooling following the Chicxulub impact at the Cretaceous-Paleogene boundary. Proc. Natl. Acad. Sci. U.S.A. 111(21): 7537-7541. dx.doi.org/10.1073/pnas.1319253111
  • 2013
    Bijl, P.K.; Bendle, J.A.P.; Bohaty, S.M.; Pross, J.; Schouten, S.; Tauxe, L.; Stickley, C.E.; McKay, R.M.; Röhl, U.; Olney, M.; Sluijs, A.; Escutia, C.; Brinkhuis, H.; Expedition 318 Scientists (2013). Eocene cooling linked to early flow across the Tasmanian Gateway. Proc. Natl. Acad. Sci. U.S.A. 110(24): 9645-9650. dx.doi.org/10.1073/pnas.1220872110
    Contreras, L.; Pross, J.; Bijl, P.K.; Koutsodendris, A.; Raine, J.I.; van de Schootbrugge, B.; Brinkhuis, H. (2013). Early to Middle Eocene vegetation dynamics at the Wilkes Land Margin (Antarctica). Rev. Palaeobot. Palynol. 197: 119-142. dx.doi.org/10.1016/j.revpalbo.2013.05.009
    Stocchi, P.; Escutia, C.; Houben, A.J.P.; Vermeersen, B.L.A.; Bijl, P.K.; Brinkhuis, H.; DeConto , R.M.; Galeotti, S.; Passchier, S.; Pollard, D.; IODP Expedition 318 Scientists; Houben, A.J.P. (2013). Relative sea-level rise around East Antarctica during Oligocene glaciation. Nature Geoscience 6(5): 380-384. dx.doi.org/10.1038/NGEO1783
  • 2012
    Pross, J.; Contreras, L.; Bijl, P.K.; Greenwood, D.R.; Bohaty, S.M.; Schouten, S.; Bendle, J.A.; Röhl, U.; Tauxe, L.; Raine, J.I.; Huck, C.E.; van de Flierdt, T.; Jamieson, S.S.R.; Stickley, C.E.; van de Schootbrugge, B.; Escutia, C.; Escutia, C.; Brinkhuis, H. (2012). Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch. Nature (Lond.) 488(7409): 73-77. dx.doi.org/10.1038/nature11300
    Wade, B.S.; Houben, A.J.P.; Quaijtaal, W.; Schouten, S.; Rosenthal, Y.; Miller, K.G.; Katz, M.E.; Wright, J.D.; Brinkhuis, H. (2012). Multiproxy record of abrupt sea-surface cooling across the Eocene-Oligocene transition in the Gulf of Mexico. Geology (Boulder Colo.) 40(2): 159-162. hdl.handle.net/10.1130/G32577.1