Bamba NIANG, PhD student at Cheikh Anta Diop University (Dakar, Senegal) shares his experience in the field during the drilling of Rochechouart impact structure

I am a student at Cheikh Anta Diop University, in Dakar. I started in 2017 a PhD thesis on impact craters (https://bambaniang.wordpress.com/). I am probably one of the first doctoral students in West African geology departments trained in this field. I benefit from the advice of a supervising team composed of specialists in the field (including David Baratoux, Uwe Reimold, and Sylvain Bouley) as well as the momentum generate by the Africa Initiative for Planetary and Space Sciences (http://africapss.org).

As part of this thesis, I had the opportunity to participate in the drilling campaign of the Rochechouart impact structure, in France. The impact structure has been known for more than 50 years but has remained relatively unexplored compared to comparable objects in other parts of Europe or North Africa.

All our current knowledge is based on the investigations of Professor François Kraut and to a large part of Dr. Philippe Lambert, who defended his thesis in 1977, on the study of this impact structure, and who is also at the origin of the CIRIR and of the drilling campaign funded by the Reserve Naturelle de l’Astroblème de Rochechouart Chassenon. Thus, the drilling campaign marks the beginning of a new era of scientific research on this unique impact structure in France and opens exciting new perspectives for the international scientific community. It has been successfully conducted and has produced unrivalled sampling of the impactites formed during a 200 Ma cataclysm. These samples will soon be made available to scientists in France and internationally, which will allow both to elucidate the outstanding scientific questions related to the impact of Rochechouart, but also to better understand impact processes in general and their fundamental consequences on the evolution of the planets and on life. I also hope to work soon on these samples!

Personally, my best memory has been an encounter by chance. As I was walking in the field using my handheld spectroradiometer, and near a site being drilled, a remote site deep in the woods, I met an 85-year-old lady, Mrs. Solange Boulesteix. Attracted by the sound of the machine, she asked me if it was related to “the history of the meteorite”. I answered that it was a drilling campaign to better understand the impact structure. I was astonished when she told me that she had met 50 years earlier Pr. François Kraut, which allowed his team to discover in the Pré du Roc at Fontceverrane a rock of microgranite with shatter cones, considered to be an undisputable evidence of the meteoritic origin of the Rochechouart structure. A sign of destiny? I hope to be back soon at CIRIR to carry out my measurements of potassium, thorium and uranium concentrations in the Rochechouart impactites and thus contribute to the understanding of the consequences of such phenomenon on the Earth’s crust.

It was a great experience and I learned a lot on the field. Today, the drilling is complete and the samples are stored at the CIRIR. I congratulate and thank the people who participated in this project and made my stay really enjoyable and fruitful: Philippe, David, Jerry, Manu, Patrice, Crystyl, Pierre, Jean Luc…