The 5 MV cosmogenic rock star

Professor Didier Bourlès

26th April 1955 – 1st March 2021

Before becoming a geochronologist, Didier Bourlès studied physics, completing a doctorate in experimental physics (1981) in Paris. He was a pioneer in performing the first measurements of 10Be using a low-energy ( < 3 MV) accelerator mass spectrometer, working with Grant Raisbeck and Françoise Yiou in the CSNSM group at the Tandetron in Gif-sur-Yvette.

In 1982, he became a CNRS researcher at CSNSM. After completing his habilitation in 1988, he spent 2 years as a postdoctoral fellow at the Massachusetts Institute of Technology, in John Edmond ’ s Marine Geochemistry Lab. Collaborations initiated at MIT and at WHOI expanded his research horizons, using 10Be as a tool to explore systems ranging from submarine hydrothermal vents to tropical rivers and landscapes. Didier measured 10Be in all sorts of things, from sediments to ice cores, to corals, starfish and mussels.

Didier’s pioneering contributions during the eighties ranged from discovery of increased 10Be production during geomagnetic reversals and excursions to the development of sequential leaching experiments to extract the authigenic phase from marine sediments, which represents the 10Be/9Be ratio of soluble Be in the ocean at the time of deposition. Authigenic 10Be/9Be ratios remain an effective method for reconstructing paleo-denudation rates and variation in meteoric 10Be production from sedimentary records. In these articles, Didier demonstrated the potential of 10Be/9Be for dating, but he also suggested that the accepted 10Be half-life was likely about 7% too long, an assertion that was confirmed some 20 years. In 1994, Didier received the prestigious CNRS Bronze Medal and in 1998 he moved to CEREGE with a professorship at Aix-Marseille University.

Now in South of France, he was totally dedicated to his teaching duties but also to the development of the ASTER project at CEREGE, struggling with complex time-consuming French bureaucratic constraints, but ultimately establishing a research unit devoted to the measurement of cosmogenic radionuclides. In 2006, the National Cosmogenic Nuclide Laboratory (LN2C, composed of the ASTER AMS facility and the ASCHIM preparation laboratory) was launched, setting the state for innovative and fruitful collaborations worldwide.

To increase accessibility to ASTER he worked to develop a French network of sample preparation laboratories. Didier never stopped improving analytical techniques and developing innovative applications of cosmogenic nuclides in geosciences; in 2018, to ensure that the ASTER AMS will remain a top-quality facility, he managed to convince the CNRS as well as local and regional institutions to fund a new magnet to improve 26Al detection limits.

Besides his passion for sciences, Didier had a contagious enthusiasm and always worked in a great and noisy atmosphere (Didier laugh was unique!). Didier’s door was always opened and everybody was treated as his equal.

Since 1995, Didier rained a generation of students and scientist with ~20 PhD students, most of them being now involved in research and managing new cosmogenic preparation lab in France or applying “cosmo” in many environmental studies.

Didier in 2006 at the Tandétron (Gif sur Yvette).

Ref:  Quaternary Geochronology 65 (2021) 101186 :


Nov 19 2021


11:45 am - 12:15 pm

Local Time

  • Timezone: America/New_York
  • Date: Nov 18 2021
  • Time: 7:45 pm - 8:15 pm