Analysis of carbonate clumped isotopes compositions ∆47 | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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Stable isotope geochemistry

  Analysis of carbonate clumped isotopes compositions ∆47



The analysis of the ∆47 of carbonates consists in the measurement of the overabundance of the 13C–18O chemical bounds (relative to a stochastic distribution) in gaseous CO2 produced via acid digestion of carbonates. The abundance of the 13C–18O bounds inside the carbonate lattice increases at low temperature and only depends on their temperature of crystallization or equilibration, thus providing a reliable paleo-thermometer.

 

Since 2013, we are routinely analyzing any type of carbonate (calcite, aragonite, dolomite…) with a precision better than ±0.015‰ (1 SD for 3 replicates). Each analysis requires 5 mg of carbonate powder. The measurement of ∆47 is performed using a Thermo MAT 253 mass spectrometer after CO2 extraction via H3PO4 digestion of carbonates, and purification of CO2 on vacuum line.

 

47 data allow estimating both the temperature of crystallization (from 1 to 200°C) and the oxygen isotope composition (δ18O) of the fluid from which the carbonate precipitated. See our recent paper presenting an up to date presentation of the accuracy and precision of the D47 thermometry and of the high performance of the IPGP’s lab.  DOI : 10.1016/j.gca.2016.11.028

 

In 2016, we received a Thermo 253 Ultra for measuring clumped isotope compositions in other molecules  (e.g., CH4, 02, N2, contact Pierre Cartigny for more details).

 

In 2017, we are organizing the 6th International Clumped Isotope Workshop at IPGP. More details can be found here:  http://www.ipgp.fr/en/iciw

 

 

 

For further informations, please contact Magali Bonifacie