TITLE:
13C-18O Bonds in Precipitated Calcite and Aragonite: An ab Initio Study
AUTHORS:
Jie Yuan, Zhigang Zhang, Yigang Zhang
KEYWORDS:
13C-18O Bonds, Clumped Isotope, Calcite and Aragonite, ab Initio Calculation
JOURNAL NAME:
Open Journal of Geology,
Vol.4 No.9,
September
26,
2014
ABSTRACT: The 13C-18O bonds in
carbonates are potential single-phase geo-thermometers. However, their
theoretical distributions (noted as Δ47s) in CO2 degassed from calcite and aragonite
with phosphoric acid are unclear. Thus, the isotope reactions of 13C-18O bonds on
the growing surfaces of calcite (0001) and aragonite (001) planes were
investigated using ab initio techniques. It was found that these
reactions determined 13C-18O
clumped isotope signatures in bulk calcite and aragonite minerals with novel Δ47 polynomials:
and
for temperatures ranging from 260 to 1500 K.
These theoretical results were in good agreement with the
experimental data. In addition, the influence of phosphoric acid on these
polynomials was at the level of 0.01‰.