Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa - GéoHydrosystèmes COntinentaux - EA6293 Accéder directement au contenu
Article Dans Une Revue Geochimica et Cosmochimica Acta Année : 2019

Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa

Résumé

Electron paramagnetic resonance (EPR) analysis of carbonaceous, volcanic, tidal sediments from the 3.33 Ga-old Josefsdal Chert (Kromberg Formation, Barberton Greenstone Belt), documents the presence of two types of insoluble organic matter (IOM): (1) IOM similar to that previously found in Archean cherts from numerous other sedimentary rocks in the world and of purported biogenic origin; (2) anomalous IOM localized in a 2 mm-thick sedimentary horizon. Detailed analysis by continuous-wave-EPR and pulse-EPR reveals that IOM in this layer is similar to the insoluble component of the hydrogenated organic matter in carbonaceous chondrites, suggesting that this narrow sedimentary horizon has preserved organic matter of extraterrestrial origin. This conclusion is supported by the presence in this thin layer of another anomalous EPR signal at g = 3 attributed to Ni-Cr-Al ferrite spinel nanoparticles, which are known to form during atmospheric entry of cosmic objects. From this EPR analysis, it was deduced that the anomalous sedimentary layer originates from deposition, in a nearshore environment, of a cloud of tiny dust particles originating from a flux of micrometeorites falling through the oxygen-poor Archean atmosphere.
Fichier principal
Vignette du fichier
1-s2.0-S0016703719302662-main.pdf (3.29 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

insu-02139075 , version 1 (10-07-2019)

Identifiants

Citer

Didier Gourier, Laurent Binet, Thomas Calligaro, Serena Cappelli, Hervé Vezin, et al.. Extraterrestrial organic matter preserved in 3.33 Ga sediments from Barberton, South Africa. Geochimica et Cosmochimica Acta, 2019, 258, pp.207-225. ⟨10.1016/j.gca.2019.05.009⟩. ⟨insu-02139075⟩
271 Consultations
178 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More