Dual clumped isotope thermometry of coral carbonate

Fingerprinting Kinetic Isotope Effects and Diagenetic Exchange Reactions Using Fluid Inclusion and Dual‐Clumped Isotope Analysis

“…Belemnites also exhibit ∆ 47 -∆ 48 values indistinguishable from equilibrium, yielding temperatures which are in agreement with the measured fluid inclusion temperatures (Table 1, Figure 5). Montastraea coral plots significantly above the equilibrium line (Figure 3), an observation made by previous workers for other warm-water coral species attributed to kinetics associated with the absorption of metabolic CO 2 into the calcifying fluid (Bajnai et al, 2020;Davies et al, 2022). Estimated paleotemperatures from α c-w and ∆ 47 /∆ 48 are compared with one another in Figure 5 in a α c-w ∆ 47 ∆ 48 (ADD) diagram, this is accomplished by subtracting the ∆ 47 (y-axis) and ∆ 48 (x-axis) values for Jurassic Wiltshire belemnites, results for each heating experiment (300°C-480°C) are shown with separate colors and symbols, the equilibrium ∆ 47 /∆ 48 value for each experimental temperature is shown as a star of the appropriate color on the dashed "equilibrium line" (Fiebig et al, 2021).…”

“…Recently, ∆ 47 data has also been reported on the I-CDES scale (Bernasconi et al, 2021), the I-CDES ∆ 47 data are reported in Table 1. However, note that the I-CDES is not available for ∆ 48 yet, and that our ∆ 47 -CDES 90 values are not identical to ∆ 47 -I-CDES values (Davies et al, 2022;Fiebig et al, 2021). We, therefore, consistently refer our ∆ 47 (CDES 90) and ∆ 48 (CDES 90) values to the polynomial best fits presented by Fiebig et al (2021), who rescaled the equilibrium calcite polynomials of Hill et al (2014)…”

Assessing the effects of embedding resins on carbonate stable and clumped isotope analyses

“…[11][12][13][14] For example, the application of clumped isotope thermometry to speleothem and coral carbonates could quantitatively reproduce their past formation temperature. 15,16 Furthermore, the reconstruction of absolute seasonal temperatures based on clumped isotopes of fossil bivalves has highlighted the crucial role of seasonal temperature differences in greenhouse climate dynamics. 17 Since the isotopologue with mass 47 occurs in relatively low abundance in natural CO 2 gasses ($45 ppm), 9 it has been demonstrated that Δ 47 measurements can be influenced by any contaminations in samples with organic or inorganic compounds that are able to fragment into compounds with the same masses as measured during clumped isotope analysis (masses 44-49).…”

“…The Δ 47 has evolved into a widely applied tool for the reconstruction of absolute temperatures that are independent from nonthermal effects on carbonate formation 11–14 . For example, the application of clumped isotope thermometry to speleothem and coral carbonates could quantitatively reproduce their past formation temperature 15,16 . Furthermore, the reconstruction of absolute seasonal temperatures based on clumped isotopes of fossil bivalves has highlighted the crucial role of seasonal temperature differences in greenhouse climate dynamics 17 .…”

δ13C and δ18O heterogeneities in carbonates: Nonlinear mixing in the application of dual‐carbonate‐clumped isotope thermometer

“…The dual-clumped isotope thermometer potentially can identify and quantify kinetic fractionations. 1,2,5,10 However, there is a danger that natural variability in sample isotopic values can be mistaken as kinetic disequilibrium. This variability can skew temperature reconstructions depending on differences in δ…”