Photons and electrons for the study of a white veil covering some walls in prehistoric caves

Rémy Chapoulie, Léna Bassel, Guilhem Mauran, Catherine Ferrier, Alain Queffelec, Delphine Lacanette, Philippe Malaurent, Bruno Bousquet, Vincent Motto-Ros, Florian Trichard, Frédéric Pelascini, Vincent Rodriguez


Our research deals with the evolution of wall surfaces in prehistoric caves. The focus of this paper is dedicated to the structural and chemical characterization of a white concretion partially covering some walls in caves. In one of the caves, a non-ornate one which became a laboratory-cave (the Leye cave at Marquay, Dordogne, France) located in the Vézère valley, a set of physical methods has been proposed and tested on the first samples taken: SEM-EDXS, cathodoluminescence and laser-based techniques such as Raman spectroscopy and Laser Induced Breakdown Spectroscopy and LIBS. Thus two facies mainly composed of calcium carbonate crystals have been determined: moonmilk and coralloids. The identification of theses crystalline phases is the first step of an ambitious research project that plans to understand the development of unexpected layers on the cave walls of the famous ornate caves listed as part of the UNESCO cultural heritage sites. This first set of data provides good insight to the structure  and the physico-chemical composition of the involved materials. Future works will be dedicated to bring knowledge about the facies chronology, the climatic conditions of environment (temperature, CO2 rate and air velocities) over a long period.

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