A new protocol for oxygen isotope analysis of authigenic and biogenic fine silica grains using laser-extraction technique

J. Crespin (1) , Anne Alexandre (1) , C. Sonzogni (1) , F. Sylvestre (2)

1 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
2 BIAF - Bio-Indicateurs Actuels et Fossiles

We report here a 30 W CO 2 laser heating protocol for analyzing oxygen isotope composition (d 18 O in x vs. V-SMOW) of quartz and amorphous silica grains lower than 50 and 2 Am with a good external precision (1r b 0.15x). This technique is used to investigate d 18 O composition of macro-, micro-and crypto-crystalline quartz cements of quartzite levels occurring in a sand sequence from the South of France (Apt Series), after a physical separation of the quartz cements. d 18 O data obtained from this technique are compared with d 18 O data obtained from in situ ion microprobe analyses. This study also presents promising results on d 18 O analysis of phytoliths obtained with the laser heating protocol (1r b 0.1x).

Mots clés: Oxygen isotope analysis; Laser-extraction technique; Silica grain; Oxygen isotope analysis

Domaines: Sciences de l'environnement

J. Crespin, Anne Alexandre, C. Sonzogni, F. Sylvestre. A new protocol for oxygen isotope analysis of authigenic and biogenic fine silica grains using laser-extraction technique. Journal of Geochemical Exploration, 2006, 88 (1-3), pp.423 - 426. ⟨10.1016/j.gexplo.2005.08.090⟩. ⟨hal-01909582⟩