¹A.В. VERCHOVSKY,¹F. A. J. ABERNETHY,¹M. ANAND,¹S. J. BARBER,¹R. FINDLAY,¹I. A. FRANCHI,¹R. C. GREENWOOD,¹M. M. GRADY
Meteoritics & Planetary Science (in Press) Open Access Link to Article [doi: 10.1111/maps.13983]
¹School of Physical Sciences, The Open University, Milton Keynes, UK
Published by arrangement with John Wiley & Sons

Two bulk Winchcombe along with six other CM2 meteorite samples weresubjected to quantitative evolved gas analysis. The observed release patterns for almost allvolatile species demonstrate close similarity for all the samples and especially between thosefor Winchcombe. This can be considered as a fingerprint for this petrological type ofmeteorites. We identified several gases including H2,H2O, O2, CO, CO2, and SO2releasedin different temperature ranges. The sources and mechanisms of their release were alsoestablished. Some of the gases, H2, CO, and CO2, are released as a result of oxidation ofmacromolecular organic material from oxygen derived from oxygen-bearing minerals (a partof CO2is also released as a result of decomposition of carbonates). The others, O2andH2O, are associated with the phase transformation/decomposition of phyllosilicates and(oxy)hydrates, while a high-temperature release of SO2is associated mostly with thedecomposition of sulfides and in few cases also with sulfates. A low-temperature release ofSO2is due to evaporation and oxidation of elemental sulfur from the meteoritic matrix andorganic material. The total concentrations of H (mostly represented by H2O), C, and S,calculated according to calibration of the quadrupole mass spectrometer with referencegases and decomposition of solid samples (CaSO42H2O and NaHCO3) are in reasonableagreement with those determined by independent methods. Variations in the ratio of thecarbon amounts released as CO2and CO (CCO2/CCO) between the samples could be anindicator of their terrestrial weathering.