Brigitte Zanda

Biography

Brigitte Zanda is a lecturer and researcher at the Institute of Mineralogy, Materials Physics and Cosmochemistry (IMPMC) of the Muséum national d’Histoire naturelle and Alliance Sorbonne Université, specializing in meteorites. These fragments of asteroids, the Moon, Mars and perhaps cometary nuclei, detached from their parent bodies by impacts, arrive on Earth loaded with information about the genesis and evolution of planetary bodies. Brigitte Zanda studies the early solar system and the geology of asteroids through primitive meteorites, as well as the geology of Mars through Martian meteorites. She is one of the leaders of the FRIPON (Fireball recovery inter planetary observation network) and Vigie-Ciel programs, whose main aims are to monitor the sky for the arrival of new meteorites and to involve the public in their field research. She is vice-president of the Meteoritical Society, the international learned society of meteorite experts and enthusiasts.

Conference: How to establish a chronology on a planetary scale?

The solar system is over 4.5 billion years old. How has the study of meteorites enabled us to determine this age and understand the first stages in the genesis of planetary bodies? How can we reconstruct the long succession of events that shaped the surfaces of rocky bodies, giving them the appearance we know today? Since the 17th century, geologists have been able to establish relative chronologies for the Earth. These were based on the principle that sedimentary deposits were superimposed over time, and that these deposits corresponded from one site to another – notably by observing the fossils found there. It was only with the discovery of radioactivity in the early 20th century that the absolute ages of some of these successive stages could be assessed. The same principles apply to the dating of rocky planetary surfaces: the abundance and size of impact craters can be used to determine a relative age for these surfaces. These ages can then be calibrated using the crater/absolute age correspondence established with the dating of Apollo samples brought back from the Moon exactly 50 years ago.