This archive contains the material needed to solve the geochemical mixing model and to produce some of the plots of the publication of Nevers et al. entitled "Landslides as geological hotspots of CO2 to the atmosphere: clues from the instrumented Séchilienne landslide, Western European Alps" published in E-surf Discussions (doi:10.5194/esurf-2020-42) and accepted for publication in E-surf with minor revisions as of Mar. 15, 2021. The archive contains: - A python code: "Nevers_et_al_2021_Esurf_code.py" - Data files that are used as inputs to the code: one for spring water composition ("Nevers_et_al_springs.csv") and six for the local rock compositional array ("Nevers_et_al_rocks_fcalc_X.csv", with X = 0,20,40,60,80,100), each corresponding to a particular scenario regarding the composition of the carbonate end member (role of calcite vs. dolomite).