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Searching for life from the nm to the light year scale

Vendredi 9 mars 2018 11:00 - Duree : 1 heure
Lieu : Salle des séminaires de l’IBS - 71, avenue des Martyrs - Grenoble

Orateur : Alexandre SIMIONOVICI (Institut des Sciences de la Terre, Université Grenoble Alpes)

Using the non-destructive, penetrative and high-resolution properties of the ESRF X-ray beams we have developed a highly sensitive, hyperspectral methodology of analysis of solid samples on which we can identify present or past life traces. Our methodology associates fluorescence, tomography and speciation – and a brush-up of these techniques will be presented. We have designed and patented a quarantine extraterrestrial sample holder, aimed at analyzing Samples from Returned Missions, such as Hayabusa 2, Osiris Rex and Mars 2025. This was tested on several meteorites which contain potential life traces, and on bio-mineral analogs at the micron scale. Graduating to the current nanosized beams enforced a “measurement revolution”, implicating a re-evaluation of the sample preparation by revized FIB techniques for sectioning and polishing both samples and standards necessary for quantitative calibrations. The enhanced resolution/trace element goal was reached by analyzing samples down to several tens of nanometers, and quantifying intermediate Z (atomic number) elements in low Z (bio) matrices to the ultratrace levels (few tens of ppm). This is the level at which life appears on minerals and to identify it we will search for 100 nm to few μm closed-contour morphologies, encased in selectively permeable kerogenuous membranes protecting them from the medium and controlling their fluid exchanges. Speciation of these intermediate Z key elements, “camouflaged” in low Z matrices, will indicate the nature of local exchange chemistry, pinpointing the specific minuscule chemical actors finally converging to…LIFE.

Contact : ibs.seminaires@ibs.fr

Discipline évènement : (Biologie / Chimie)
Entité organisatrice : (IBS)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire IBS)
Site de l'évènement : Polygone scientifique

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