ClumpyCrunch
v1.0

(1) Short version

This is an web application intended for basic processing of Δ47 data, based on the algorithms described by Daëron et al. (2016, in review). In the "crunching" step, it converts working-gas delta values to δ13C, δ18O and raw Δ47 values. In the "scaling" step, it converts raw Δ47 into "absolute" values based on a scaling model contrained by equilibrated gases or carbonate standards. More details in section (4) below.

(2) Isotopic parameters used in the "crunching" step

By default, the Brand et al. (2010) parameters are used in the "crunching" step, but you may enter different values below:

(13C/12C) in PDB
(18O/16O) in PDB-CO2
(17O/16O) in PDB-CO2
Triple oxygen isotope exponent (λ)

(3a) Input: raw working-gas data

Paste your raw data here in tab-delimited or comma-separated values format, as shown in the example below.


(3b) Input / output: crunched data


(4) Detailed instructions

Raw working-gas data in section (3a) must include the following fields (columns), in no particular order: The crunching step then computes δ13C, δ18O and raw Δ47 values, based on the isotopic parameters defined in section (2). Bulk isotope composition is determined using a second-order Taylor polynomial equation as described by Daëron et al. (in review). The output is printed to the "crunched data" text area in section (3b). The "crunched data" in section (3b) must include the following fields (columns), in no particular order: The scaling step then computes a scaling model, defined by the equation below:

rawD47 = a × absD47 + b × d47 + c

Although the above equation uses a different formalism, the underlying corrections are strictly equivalent to those described by Dennis et al. (2011), with parameters a, b and c being respectively related to scrambling effects, compositional nonlinearity, and non-stochasticity of the working gas. Numerical values for (a, b, c) are determined by least-squares fitting of measurements with a non-empty value for TeqCO2 and/or D47nominal ("scaling standards"). This scaling model is then used to compute absolute Δ47 values for all measurements. Model-resulting standard errors (sD47_model) are explicitly separated from internal measurement errors (sD47_internal), and are added quadratically to compute the combined standard error for a single measurement (sD47_total). The output is printed to the "Scaled data" text area in section (3c).

Source code released under an Academic Free License (3.0). Any comments / bug reports / requests for the source code should be addressed to mathieu@daeron.fr.

(5) Clear data

For technical reasons the plots and data generated here are not erased immediately. If you wish to remove them from the server, you can use the "clear all data" button below, but you must do so before leaving the page. As far as I am aware, no other copy of your data exists server-side.