EPR of radicals in primitive organic matter : a tool for the search of biosignatures of the most ancient traces of life - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Applied Magnetic Resonance Année : 2008

EPR of radicals in primitive organic matter : a tool for the search of biosignatures of the most ancient traces of life

Résumé

In this paper we report on electron paramagnetic resonance (EPR) of paramagnetic centers in the carbonaceous matter of primitive siliceous rocks, known to contain the most ancient traces of life. The EPR lines observed are attributed to π-radicals stabilized by the aromatic structure of this matter. It is found that the line widths and the line shapes vary continuously during geological periods and show a progressive pattern evolution from Gaussian–Lorentzian (recent) to purely Lorentzian (ca. 2000 million years [Myr]), and to supra-Lorentzian (ca. 3500 Myr). Artificial ageing experiments allowed us to define four stages of maturation of the organic matter according to the evolution of g-factors, EPR intensity, peak-to-peak line width and line shape. We suggest that the peculiar supra-Lorentzian line shape observed for organic matter older than 2000 Myr should be related to a low-dimensional (two- or one-dimensional) spatial distribution of electron spins. From these results, we derive a relationship between the line shape and the age of the organic matter, valid for ages ranging from about 600 Myr to about 3500 Myr.

Domaines

Chimie organique

Dates et versions

bioemco-00393589 , version 1 (09-06-2009)

Identifiants

Citer

Audrey Skrzypczack, Laurent Binet, O. Delpoux, Hervé Vezin, Sylvie Derenne, et al.. EPR of radicals in primitive organic matter : a tool for the search of biosignatures of the most ancient traces of life. Applied Magnetic Resonance, 2008, 33, pp.371-397. ⟨10.1007/s00723-008-0083-y⟩. ⟨bioemco-00393589⟩
109 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More