Oxygen three-isotope diagram

Oxygen isotopic compositions of minerals in CAIs on an oxygen three-isotope diagram. Axes are given in delta notation 81S0 =[((180/160)sampie/(180/160)s,andard)-1] x 1000, and similarly for S170. After Clayton et al. (1977). 

Figure 1. Oxygen three-isotope diagram showing isotopic compositions of minerals from Allende CAIs (CCAM = carbonaceous chondrite anhydrous minerals). The other line, labelled TF (terrestrial fractionation) is the locus of data points for terrestrial rocks and waters (data not shown). The bulk oxygen isotopic composition of the Earth is indicated by point E the expected oxygen isotopic composition of the Sun is indicated by point S. The S-notation on the...

Figure 3 Oxygen-isotopic compositions of CM2 carbonaceous chondrites plotted in a three-isotope diagram. The CM2s form a linear array with a slope of 0.7, with enrichments in the heavy isotopes that show a general increase as a function of increasing alteration. Nogoya (NG) and Cold Bokkeveld (CB) are the most heavily altered CMs and Murchison (MC) is one of the least altered. Chondrites with intermediate degrees of alteration are not well resolved in this diagram (after Browning et al., 1996 source Clayton, 1993).

Figure 6 Oxygen-isotopic compositions of CV chondrites and their dark inclusions plotted on a three-isotope diagram. Bulk CVS chondrites plot close to the CCAM line defined by the isotopic composition of anhydrous minerals from CAIs in Allende. The reduced CV chondrites are isotopically lighter than the oxidized CV chondrites such as Allende. Dark inclusions from Allende also plot on the CCAM line, whereas inclusions from the reduced CV chondrites, Vigarano, Leoville, and Efremovka have oxygen-isotopic compositions that show significant heavy isotope enrichments, indicative of aqueous alteration (source Krot et al., 1999).

Figure 4.9 Schematic illustration displaying the observed oxygen isotopic composition of silicate and that expected via reaction with ozone in a three-isotope plot. Oxidation was postulated as a two-step fractionation process (Kimura et al. 2007) as shown in the diagram.

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