Drilling in an impact structure: a first in France at Rochechouart!

“Summary :

Humanity funds an average of one or two scientific drilling campaigns in an Earth impact crater every 10 years. The present decade will have two, the first in Chicxulub in Mexico carried out in 2016 (that of the extinction of the dinosaurs), with a budget of around 10 M€, the second around Rochechouart this year, with a budget close to 100 times lower, and yet objectives and scientific benefits of the same order. The equivalent of Curiosity on Mars has just started to drill and for the first time, the only impact crater in France. The campaign began on September 5, 2017 and will last approximately 3 months. Distributed in Charente and Haute Vienne, around twenty boreholes up to 150 m deep will be carried out in 8 of the sites of the National Natural Reserve of the Astroblème de Rochechouart-Chassenon. Their purpose is to find and read the past traces produced by the impact of an asteroid 1 to 3 km away, 200 million years ago and beyond, to provide answers to the fundamental questions that scientists and humanity arise: how the planets were formed, and why and how Life can appear and disappear, on Earth and “elsewhere”, questions which also motivate the sending of probes to explore the surface of the Moon, Mars and other planetary objects … Moreover, these are partly the same teams that we find today on Earth in Rochechouart, associated with the CIRIR (International Research Center on Impacts and on Rochechouart). Created in 2016, the CIRIR designed the program and leads the explorations for the benefit of national and international research. About sixty researchers of a dozen nationalities are currently associated with the CIRIR for the exploitation of this data, including researchers from about ten French institutions. The challenge is to establish the Astroblème site as a natural laboratory for the benefit of national and international research. »

Core from the survey near Valette in the center of the structure sampling a melting breccia produced by the impact and formed after cooling of the “lava lake” which filled the bottom of the crater 200 million years ago (Credits: CIRIR /Philip Lambert)

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