Experimental calibration of clumped isotopes in siderite between 8.5 and 62 °C and its application as paleo-thermometer in paleosols

Effects of Improved 17O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral‐Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation

“…We must note, however, that none of the data that initially suggested large mineralogical differences in Δ* 25-X was included in this reprocessing effort. This data set is not able to interrogate Δ* mineralogyX values (difference between Δ 47 of CO 2 and Δ 63 of solid carbonate), which some have suggested shows mineralogical differences as well (van Dijk et al, 2019;Müller et al, 2017).…”

“…Without applying any acid fractionation correction, Δ 47 values for samples reacted at the same temperature can be directly compared, but a choice of Δ* 25-X (or Δ* T1-T2 between any two reaction temperatures) is necessary to compare samples reacted at different acid temperatures. A variety of theoretical (Guo et al, 2009) and experimental (Bonifacie et al, 2017;Defliese et al, 2015;van Dijk et al, 2019;Guo et al, 2009;Henkes et al, 2013;Kelson et al, 2017;Müller et al, 2017;Murray et al, 2016;Passey et al, 2010;Tripati et al, 2015;Wacker et al, 2013;Winkelstern et al, 2016) values for Δ* 17ineralogy and Δ* 25-X have been put forward. Many of these experimental studies have found similar behavior across differing mineralogies (Bonifacie et al, 2017;Defliese et al, 2015;Kelson et al, 2017;Wacker et al, 2013;Winkelstern et al, 2016), with nondistinguishable values (Δ* dolomite90 values within error of theoretical Δ* calcite90 values, Bonifacie et al, 2017), overlapping calibration data (Bonifacie et al, 2017;Defliese et al, 2015;Kelson et al, 2017;Wacker et al, 2013;Winkelstern et al, 2016), or identical Δ* 25-X values across multiple mineralogies (Defliese et al, 2015).…”

Clumped isotope temperature calibration for calcite: Bridging theory and experimentation

“…We choose to work solely on calcites to avoid potential biases due to specific acid fractionation factors (AFF) when using different carbonates (i.e. aragonite, dolomite, siderite) as theoretically predicted (Guo et al, 2009) and shown by recent experimental work (Müller et al, 2017a;van Dijk et al, 2019) at the temperature of acid digestion used in this study (70°C). We also took advantage of the growing number of laboratories that adopted a fully carbonate-based standardisation of Δ 47 measurementsidentical to the treatment used hereto evaluate further the improvement brought by this standardisation scheme to interlaboratory comparison.…”

Effects of different constants and standards on the reproducibility of carbonate clumped isotope (Δ47) measurements: Insights from a long‐term dataset

“…Since the initial proposal of this proxy, a number of different Δ 47 -T calibrations have been published, leading to reconstructed temperature discrepancies of up to 10-15 C based on the same Δ 47 value. 1,17,[20][21][22][23][24][25][26][27][28][29][30][31][32][33] Several hypotheses exist as to the origin of calibration differences, including different gas preparation procedures, different mass spectrometric corrections, and potentially different acid fractionation factors [34][35][36] 20,25,30,34 or use of temperature calibrations for different carbonate minerals (e.g. dolomite in Bonifacie et al, 37 calcite in Kele et al 31 and Kelson et al, 32 and siderite in van Dijk et al 36 ).…”