Sulfate: A time capsule for Earth's O2, O3, and H2O

Triple Oxygen Isotopes: Fundamental Relationships and Applications

“…Greenland (Farquhar et al 1998(Farquhar et al , 1999 • λ = 0.52 (Miller 2002) • C = 0.525 for water (Angert et al 2004) • β = 0.5305, 0.5288 ± 0.0031 (Wiechert et al 2004) • β = 0.5250 ± 0.0007 (Gehler et • λ RL ≡ 0.5305 , 2015 • λ = 0.524-0.526 (Miller et al 2015, Starkey et al 2015 • λ 0 = 0.516 for atmospheric CO 2 (Boering et al 2004, Liang & Mahata 2015 • λ = 0.522∼0.531 for terrestrial silicates and oxides (Levin et al 2014) (Ahn et al 2012, Kusakabe & Matsuhisa 2008, Miller et al 2015). This adoption of a compound-specific S as C appears to be practical.…”

“…This has resulted in only a slight change in the value of C, with most change reflected at the third or fourth decimal places. Another option for an arbitrary C value is 0.5305, the upper temperature limit for intrinsic equilibrium θ values for oxygen (Cao & Liu 2011, Matsuhisa et al 1978, which is a number unbiased by the paradigms of any research community , 2015. Whatever C value we pick, it is important that everyone use the same reference frame so that comparison of the 17 O values among different oxygen-bearing compounds or across different laboratories can be made.…”

“…One such derivative, sulfate (SO 4 2− ), is particularly interesting because it carries not only the signature of O 3 but the signature of O 2 as well. For atmospheric O 3 and O 2 signatures of the geological past, sulfate currently seems to be our only safe bet (Bao 2015).…”

“…A subset of the triple oxygen isotope studies on Earth systems is focused on distinctly 17 O-anomalous atmospheric O 3 and its derivative gas and solid compounds. Thiemens' group and others have published thorough reviews on these observations, experiments, and mechanistic interpretations (Bao 2015;Brenninkmeijer et al 2003;Thiemens , 2006Thiemens et al 2001Thiemens et al , 2012. Therefore, this review touches only lightly upon triple oxygen isotope studies pertinent to atmospheric chemistry.…”

Variations of Stable Isotope Ratios in Nature

“…Thus by analysing terrestrial sulfates, a record of 17 O anomalies through geological history may be obtained (Bao et al 2000(Bao et al , 2001Bao 2015).…”