BayClump: Bayesian Calibration and Temperature Reconstructions for
Clumped Isotope Thermometry
Abstract
Carbonate clumped isotope thermometry (Δ47) is a temperature proxy that
is becoming more widely used in the geosciences. Most calibration
studies have used ordinary least squares linear regressions or York
models to describe the relationship between Δ47 and temperature.
However, Bayesian models have not yet been explored for clumped
isotopes. There also has not yet been a comprehensive study assessing
the performance of commonly used regression models in the field. Here,
we use simulated datasets to compare the performance of seven regression
models, three of which are new and fit using a Bayesian framework. All
models recover regression parameters within error of true values.
Ordinary least squares linear and Bayesian models have the highest
precision and accuracy. Congruently, for temperature reconstructions
where the fitted model is used to predict temperature from Δ47, Bayesian
models generally outperform other regression models in both precision
and accuracy. Our analyses suggest that depending on the structure of
the examined dataset and relative to classical models, Bayesian
regressions could improve the accuracy and precision of (i) calibration
parameter estimates and (ii) temperature reconstructions by at least a
factor of two. We implement our comparative framework into a new
web-based interface, BayClump. This tool should increase reproducibility
by enabling access to the different Bayesian and non-Bayesian regression
models examined here. We utilize this tool with a published data
synthesis to assess regression parameters and show that while both yield
similarly accurate results, uncertainty in estimates of the slope and
regression are reduced.