Preferential formation of 13C–18O bonds in carbonate minerals, estimated using first-principles lattice dynamics

Temperatures of aqueous alteration and evidence for methane generation on the parent bodies of the CM chondrites

“…13 C and 18 O in thermodynamically equilibrated carbonate minerals preferentially group or 'clump' together into the same carbonate ion group to form 13 Schauble et al, 2006). The extent of 13 C-18 O clumping in a carbonate mineral is determined through the measurements of anomalous enrichment of mass 47 CO 2 (mainly 13 C 18 O 16 O) in the CO 2 derived from phosphoric acid digestion of that mineral Eiler and Schauble, 2004;Affek and Eiler, 2006).…”

“…We used the 'carbonate clumped-isotope thermometer' Schauble et al, 2006) to determine the temperatures of carbonate precipitation in the CM chondrites. The carbonate clumped-isotope thermometer is based on a thermodynamic equilibrium that orders 13 C and 18 O into bonds with each other within the carbonate lattice, and is independent of the isotopic composition of any co-existing phase.…”

Fe isotope exchange between Fe(II)aq and nanoparticulate mackinawite (FeSm) during nanoparticle growth

“…In order to interpret natural data measured in pyrite, they assumed that the β-factors for mackinawite would be similar to those for troilite, since both are Fe(II) monosulphides. Blanchard et al (2009) used first principle calculations (Schauble et al, 2001(Schauble et al, ,2006 to discuss the pyrite β-factors given by the technique from Polyakov and co-workers. Fig.…”

Experimental calibration of clumped isotope reordering in dolomite

“…Regardless of calibration choice, dolomite ∆47 rate constants determined using both models are resolvably slower than those of calcite and apatite, and predict that high-grade dolomite crystals should preserve apparent equilibrium blocking temperatures of between ~210 and 300 °C during cooling on geologic timescales. Best agreement between model predictions and natural dolomite marbles was found when using the exchangediffusion model and the ab initio ∆63-T calibration of Schauble et al (2006), projected into the ∆47 reference frame by Bonifacie et al (2017). Therefore, we recommend modeling dolomite ∆47 reordering using the exchange-diffusion model and this parameter set.…”