Function that implements the M3 mixing model. This model is based on the projection of the chemical information in a low-dimensional space defined using Principal Component Analysis (PCA). The compositions of pre-defined end-members are also projected and from these coordinates, the mixing ratios of each end-member are calculated using a constrained least-squares procedure (mixing ratios add up to 1).
m3_mixing_model(gdata, end.members = NULL)
| gdata | A geochemical_dataset object with the major ions only. |
|---|---|
| end.members | If provided, this is a numeric vector with the indices of the end members to be used in the mixing calculations. If it is not specified then the end members are defined using the convex hull of the first two principal components. |
This function returns a list with the following entries:
mixing.ratios: Matrix with the mixing ratios estimated using constrained least-squares.
res.pca: Object returned by the princomp function. This object contains the eigenvectors, eigenvalues, scores and other results of the PCA.
res.lm: List with the results of the multiple linear regression applied on each ion included in the gdata geochemical_dataset object. Each entry of this list is a lm object for each ion.
names.lm: Character vector with the names of the ions used in the mixing analysis.
X:
dataset:
Laaksoharju, M., Skarrman, C., \& Skarrman, E. (1999). Multivariate mixing and mass balance (M3) calculations, a new tool for decoding hydrogeochemical information. Applied Geochemistry, 14(7), 861–871. http://doi.org/10.1016/S0883-2927(99)00024-4
Other mixing functions: constrained_lm,
mix_model,
plot_m3_mixing_results,
select_end_members,
uncertainty_m3_mixing_model