Johan Vellekoop

Johan Vellekoop is a micropaleontologist and geochemist studying ecological and paleoenvironmental changes associated with major climatological and biological perturbations in the Cretaceous and Paleogene greenhouse world, in order to understand the challenges that modern biota face in our rapidly changing world.

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Function

Johan is employed under the BELSPO FED-tWIN mandate MicroPAST, between the Belgian Institute of Natural Sciences (50%) and KU Leuven (50%), where he is assistant professor at the Biogeology & Paleoclimatology research group.

Research team: Paleobiosphere Evolution Research Unit
Research theme: Ecosystems over time

Current Project(s)

Since 2021, Johan works as a micropaleontologist and geochemist, employed under the BELSPO FED-tWIN mandate MicroPAST (Micropaleontology of PAleogene marine Shelves and correlation with the Terrestrial domain), between the Belgian Institute of Natural Sciences (50%) and KU Leuven (50%). His expertise is on stratigraphy, paleoecology and paleoclimatology of the Cretaceous and Paleogene, a geological time period between 243 and 66 million years ago that was characterized by major climate perturbations, biodiversity changes and evolutionary radiations.

Area of Expertise

Johan has expertise in a variety of micro- and macrofossil groups, such as organic-walled dinoflagellate cysts, foraminifera, gastropods and fish otoliths, and a range of geochemical techniques, including stable isotopes (IRMS), trace- and major elemental analyses (ICP-MS, ICP-OES, LA-ICP-MS, uXRF) and organic biomarkers (GC-MS, HPLC-MS). His research interests comprise stratigraphy, paleoecology, paleo-ecosystems and seasonal- to millennial scale paleoclimatology, including high-resolution proxy-based records and sclerochronology on fossil mollusks, providing a glimpse into climate and biota of past worlds.

External activities

• Assistant professor (tenure track) at the Biogeology & Paleoclimatology Research Group, KU Leuven
• Member of the Subcommission for Paleogene and Neogene Stratigraphy of the National Commission for Stratigraphy of Belgium
• Member of the Subcommission for Cretaceous Stratigraphy of the National Commission for Stratigraphy of Belgium
• PhD committees:
  • Chair of Examination committee of Sander Molendijk (KU Leuven) - Differentiation processes of the Nyiragongo volcano, DR Congo: a natural and experimental study – (3 July 2024)
  • Examination committee Nicolas Pige (Université Claude Bernard Lyon 1)- Assessing the impact of variable calcareous nannoplankton productivity on oceanic carbon cycle dynamics during the Paleogene – (6 June 2024)
  • Examination committee of Monika Doubrawa (KU Leuven) - Shelf ecosystems of the U.S. Atlantic Coastal Plains prior to and during the PETM (Paleocene-Eocene Thermal Maximum) - (30 may 2023)
  • Examination committee Asefeh Golreihan (KU Leuven) - Stimulated Raman spectroscopy as a complementary research technique in sedimentology and diagenetic studies - (preliminary defense 3 May 2023, not completed)

Dissemination activities

Johan has passion for public outreach, in particular on the subjects of paleontology and paleobiology, for example highlighted by his involvement in a variety of organizations that focus on science communication on paleontology. He is founder of the Paleontica Foundation, a non-profit organization that aims to create bridges between fossil collectors and professional paleontologists, chief coordinator of PaleoTime-NL, the largest paleontological event in the Netherlands, and board member of the Paleobiological Circle, which focusses on the contacts between scientists and students involved in paleobiological research. In addition, during the past few years, he has been involved in a variety of citizen science projects on paleontological topics, and have initiated a the “Maastrichtian Geoheritage Project”, a geoheritage project focusing the original type-locality of the Maastrichtian in the Netherlands and Belgium.

He considers is his duty to society to translate the implications of his research to the general public in understandable messages. He regularly publishes in popular scientific journals:

• Jelu, I., Vellekoop, J. (2023). Het Paleogeen: een cruciaal tijdperk voor de evolutie van zoogdieren. Afzettingen WTKG, 44 (2), 48-55.
• Vellekoop, J. (2023). Een tijdelijke ontsluiting bij Euverem: nieuwe inzichten in de Campanien/Maastrichtien overgang in het type-Maastrichtien. Sprekende Bodem 67 (2), 47-52.
• Vellekoop, J., Bil, M. (2021). Een zeldzame Otodus obliquus Agassiz, 1843 uit een zand-suppletie op het strand van Dishoek (Walcheren, Nederland). Afzettingen WTKG, 42 (4), 122-132.
• Vellekoop, J. (2020). Het Maastrichtian Geoheritage Project: een introductie, eerste resultaten en toekomstplannen. Sprekende Bodem, 64 (4), 88-92.

He also regularly gives lectures at schools, museums and geological societies in the Netherlands and Belgium, and had given interviews and contributions for national and international media (radio, television, newspapers and magazines).

GEOLOGIE: Onderzoekers brengen miljoenen jaren oude kalksteengroeve in kaart

Professional Experience

Johan holds a Master of Science in Biogeology from Utrecht University, the Netherlands. In 2015, he obtained a PhD degree in geology at the same university, on the bolide impact and long- and short term environmental change across the Cretaceous-Paleogene boundary. Since then, he has acquired over 6 years of experience as a postdoctoral researcher, through 4 different postdoctoral research positions (from 15/01/2015 to 14/01/2017 at KU Leuven; from 01/04/2017 to 30/09/2017 at VUB, a FWO junior postdoctoral fellowship at KU Leuven from 01/10/2017 to 30/09/2020 and FWO senior postdoctoral fellowship at VUB from 01/10/2020 to 30/09/2021).

From 01/10/2021-present, he hold a 50% position as assistant professor (tenure track) at KU Leuven, and 50% position as senior researcher at the Belgian Institute of Natural Sciences, in the context of the BELSPO FEDtWIN research profile “Micropaleontology of PAleogene marine Shelves and correlation with the Terrestrial domain – MicroPAST”.

Publication highlights

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, PNAS 111 (21), 7537-7541, doi: 10.1073/pnas.1319253111. Impact factor: 9.423 · 161 citations

Vellekoop, J., Woelders, L., van Helmond, N.A.G.M., Galeotti, S., Smit, J., Slomp, C.P., Brinkhuis, H., Claeys, P., Speijer, R.P., (2018). Shelf hypoxia in response to global warming after the Cretaceous-Paleogene boundary impact. Geology, 46 (8), p. 683-686. doi:10.1130/G45000.1. Impact factor: 4.635 · 34 citations

Vellekoop, J., Woelders, L., Sluijs, A., Miller, K.G., Speijer, R.P. (2019). Phytoplankton community disruption caused by latest Cretaceous global warming. Biogeosciences 16, 4201–4210. doi:10.5194/bg-16-4201-2019 · Impact factor: 3.951 · 17 citations

Vellekoop, J., Kaskes, P., Sinnesael, M., Huygh, J., Déhais, T., Jagt, J.W.M., Speijer, R.P., Claeys, P. (2022) A new age model and chemostratigraphic framework for the Maastrichtian type area (southeastern Netherlands, northeastern Belgium). Newsletters on Stratigraphy 55 (4), p. 479 - 501 doi:10.1127/nos/2022/0703 · Impact factor: 2.974 · 22 citations

Vellekoop, J., Vanhove, D., Jelu, I., Claeys, P., Ivany, L.C., de Winter, N.J., Speijer, R.P., Steurbaut, E. (2025) Making sense of variation in sclerochronological stable isotope profiles of mollusks and fish otoliths from the early Eocene southern North Sea Basin. Palaeogeography, Palaeoclimatology, Palaeoecology 659, 112627. doi:10.1016/j.palaeo.2024.112627 · Impact factor: 2.6 · 0 citations