KArMars: A Breadboard Model for In Situ Absolute Geochronology Based on the K–Ar Method Using UV‐Laser‐Induced Breakdown Spectroscopy and Quadrupole Mass Spectrometry |
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| Authors: | Damien Devismes Pierre‐Yves Gillot Jean‐Claude Lefèvre Claire Boukari Francis Rocard Florence Chiavassa |
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| Institution: | 1. UMR GEOPS‐CNRS 8148, Université Paris Sud, Orsay, France;2. Laboratoire Archéométrie et Archéologie, UMR 5138, Université Lyon 1, Villeurbanne, France;3. CNES, Paris, France |
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| Abstract: | We present a breadboard prototype to perform in situ dating applicable to planetary exploration. Based on the K–Ar dating method and using instruments inspired by flight‐proven analytical components, ‘KArMars’ ablated a geological sample under high vacuum with a quadrupled ultraviolet (UV at 266 nm) Nd:YAG laser. During ablation, the K content of the target material was given by laser‐induced breakdown spectroscopy and the released 40Ar was measured with a quadrupole mass spectrometer. Because K was measured as a concentration and 40Ar as a count of atoms, these values were converted using the ablated mass given by the product of the density and the ablated volume. The uncertainties of the age measurement were < 15%. The quality of the K–Ar measurements was enhanced by the advantages of UV laser ablation such as the minimisation of thermal effects on argon diffusion. This work demonstrates that a specialised instrument inspired by this set‐up could provide in situ absolute geochronology with sufficient precision for scientific investigations, particularly where the crater density counting provides higher uncertainties on Mars. |
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| Keywords: | geochronology K– Ar laser ablation laser‐induced breakdown spectroscopy mass spectrometry in situ analysis gé ochronologie K– Ar ablation laser LIBS spectromé trie de masse analyse in situ |
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