Determination of hydrogen content in geological. samples using elastic recoil detection analysis (ERDA) | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Determination of hydrogen content in geological. samples using elastic recoil detection analysis (ERDA)

Type de publication:

Journal Article

Source:

Geochimica Et Cosmochimica Acta, Volume 73, Ticket 11, p.3311-3322 (2009)

ISBN:

0016-7037

Numéro d'accès:

WOS:000266059700014

URL:

http://www.sciencedirect.com/science/article/pii/S0016703709001513

Mots-clés:

UMR 7154 ; Physico-chimie des Fluides Géologiques

Résumé:

The present study illustrates the interest of using the elastic recoil detection analysis (ERDA) method to characterize any geological sample matrix with respect to hydrogen. ERDA is combined with Rutherford back scattering (RBS) and particle induced X-ray emission (PIXE), allowing the simultaneous characterization of the matrix with respect to major and trace elements (Z > 15). Analyses are performed by mapping of a 4 x 16 mu m(2) incident beam of He-4(+) on hirge areas (50 x 200 mu m(2)). The method is almost not destructive and requires no calibration with respect to well known hydrous samples. Hydrous and nominally anhydrous phases in contact with each other in the same sample may both be characterized. The depth of the analyses is limited to several mu m beneath the surface, allowing tiny samples to be investigated, provided their sizes are larger than the incident beam. Our setup has been improved in order to allow H determination on a micrometric scale with a 5-15% relative uncertainty and a detection limit of 94 wt ppm H2O. We present multi-elemental mappings on a large panel of samples: (1) natural and analogue synthetic glasses from Stromboli volcano (0.44-4.59 wt% H2O), natural rhyolitic glasses (1466-1616 wt ppm H2O); (2) magmatic rhyolitic melt inclusions from Guadeloupe Island (4.37-5.47 wt% H2O) and their quartz host crystal (2020 +/- 230 wt ppm H2O); (3) nominally anhydrous natural (82-260 wt ppm H2O) and experimentally hydrated (240-790 wt ppm H2O) olivines; natural clinopyroxenes (159-716 wt ppm H2O); natural orthopyroxenes (201-452 wt ppm H2O); a natural garnet (90 wt ppm H2O). Results show that ERDA is a strong and accurate reference method that can be used to characterize geological sample from various matrix compositions from high to low water contents. It can be used to calibrate other methods of microanalysis such as Fourier Transform Infrared Spectroscopy (FTIR) or secondary ion mass spectrometry (SIMS). (C) 2009 Elsevier Ltd. All rights reserved.