An Improved Method for Carbonates Evaluating from Carbonaceous Chondrites

We have updated the standard method for estimating the amount of carbonates in carbonaceous chondrites on the example of the Murchison meteorite (CM2). In contrast to the existing technique (passing carbon dioxide released from carbonates through brine and weighing the remainder of the substance, when a small volume of gas may be too small for analysis using a mass spectrometer, our method is more reliable because all carbonates are collected in the form of a precipitate and then decompose at once at high temperature to carbon dioxide CO2 and divalent metal oxides. This required the creation of a laboratory setup and development of the technique to calibrate mixtures of (Volcano Tolbachik, Kamchatka, Russia) with pure calcium carbonate CaCO3 for analysis (from 0.1 to 1.0 wt.% with an interval of 0.1). The error estimation method was made on the basis of physicochemical calculations of the content of carbon dioxide gas in the installation air. Results are tested and confirmed using gas chromatograph.