https://github.com/alexlipp/crustal-comp

Supplementary code and data for the publication: 'The Composition and Weathering of the Continents over Geologic Time'

https://github.com/alexlipp/crustal-comp

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Supplementary code and data for the publication: 'The Composition and Weathering of the Continents over Geologic Time'

https://github.com/AlexLipp/crustal-comp/blob/master/

# Code and data for 'The composition and weathering of the continents over geologic time' 

This repository contains the code and data required to reproduce the results in the paper [*'The composition and weathering of the continents over geologic time'.*](https://eartharxiv.org/qhtb6/). It is archived at the point of submission at [![DOI](https://zenodo.org/badge/279322730.svg)](https://zenodo.org/badge/latestdoi/279322730)


## Code 

The document `data_analysis.html` is an [R-markdown document](https://rmarkdown.rstudio.com/) which performs all data analysis described in the paper. This file can be viewed in any browser. 
The same document is also given in the raw `.Rmd` form, which can be opened in [R-studio](https://www.rstudio.com/). This was written in `R` v3.4.4

The script `invert_coeffs_grad.py` is a `python` script which calculates the weathering and provenance coefficients for a given set of major-element compositions, incorporating a cation exchange correction. This was written in `python` v3.6.9.

The script `SGP_query.sql` is the `SQL` command used to query the Sedimentary Geochemistry and Paleoenvironments project database.

`macrostrat_mafic.json` and `macrostrat_felsic.json` are the [MacroStrat](https://macrostrat.org/) API calls to extract the igneous rock data used to generate Figure S5 in the manuscript.

## Data 

### Main input data files 

The Sedimentary Geochemistry and Paleoenvironments Project sedimentary major-element data is given in `SGP_final.csv`. Data from [Lipp et al. 2020](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GC008758) is given in `sedimentary_rocks_PCA_paper.csv`. 

References for SGP data are given in `SGP_references.csv`. See [`github.com/alexLipp/weathering-and-provenance`](github.com/alexLipp/weathering-and-provenance) for references for data from Lipp et al. 2020.

### Intermediate results

The cleaned data, calculated  and  coefficients, as well as the fitted compositions are given in: `SGP_data_cleaned_comps.csv`,`SGP_data_cleaned_coeffs.csv` & `SGP_data_cleaned_fit.csv`. Composite samples and their coefficients/fitted compositions are given in:  `mixture_comps.csv`,`mixture_coeffs.csv` & `mixture_fit.csv`

### Output Data

The smoothed weathering time series and the bootstrap uncertainty bounds is given in the file `weathering_time_series.csv`. The $\psi$ and $\omega$ coefficients for every sample, with their SGP sample ID, interpreted Age and stratigraphic formation is given in the file `omega_psi_metadata.csv`. 

### Additional data

Additional data `.csv` files for igneous rocks are used to calculate the pristine omega value for recreating protolith compositions as well as identifying a suitable cutoff value of CaO wt% to exclude carbonate contamination. See [Lipp et al. 2020](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GC008758) and [`github.com/alexLipp/weathering-and-provenance`](github.com/alexLipp/weathering-and-provenance) for details. 

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