Silicate Analysis

Responsible for

Anne Alexandre, Research Director : alexandre@cerege.fr

David Au Yang, Research Engineer: auyang@cerege.fr

Tools

A line of fluorination-laser-IRMS of silicate oxygen, with BrF5 and CO2 infrared laser (CO2-laser 30W).
This line, connected to the mass spectrometer Delta V Plus (Thermo Fisher Scientific) is used to extract’oxygen from silicates and oxides and very accurate measurements of triple oxygen composition on silicate and oxide samples (silicates, biogenic silicates and (micro)meteorites) from 0.3 to 2 mg

A dehydration line with nitrogen flow and at very high temperatures (1100°C). It is used to dehydroxylate amorphous hydrated silica samples prior to fluorination-laser-IRMS analysis.

Fluorination line and gas extraction

MIR 10 laser

Delta V Plus

Nitrogen flow dehydration line

Applications

The compositions in δ¹⁸O, δ¹⁷O and ¹⁷O-excess biogenic silicates (phytoliths, diatoms), authigenic minerals and oxides, meteorites and micrometeorites are analyzed at CEREGE for :

The development of new paleoclimatic tracers (e.g. continental relative atmospheric humidity).
Reconstitution of the past dynamics of the continental water cycle: origin and quantity of precipitation, relative atmospheric humidity, water balance of lakes, evapo-transpiration fluxes at the soil-plant-atmosphere interface.
The study of weathering and pedogenesis processes.
The characterisation of the parent bodies of meteorites and micro-meteorites and the determination of extraterrestrial material flows.