Frost {GCDkit}R Documentation

Frost et al. (2001)

Description

Classification of granitic rocks proposed by Frost et al (2001).

Usage

Frost(plot.txt = getOption("gcd.plot.text"), 
clssf = FALSE, GUI = FALSE)

Arguments

plot.txt

logical, annotate fields by their names?

clssf

logical, should the samples be classified?

GUI

logical, is the function called from a GUI?

Details

Classification scheme proposed by Frost et al. (2001). It consists of three diagrams:

The classification is designed to work both with analyses distinguishing between ferrous and ferric iron (preferred) and those with total iron only. The dialogue box lets the user decide, whether to use the ferrous iron value or the total iron.

Similarly, if some P2O5 concentration are missing in the dataset, the user is prompted whether the missing values should be replaced with zero. If not, the problematic analyses are not plotted/classified.

Value

The function returns table of calculated coefficients (Fe-Number, MALI, ASI). There are two values for the ASI: one labeled 'ASI' is calculated from molecular proportions of oxides, and is used for plotting and classification. The other one is labeled 'ASI_orig', and is calculated exactly as stated in the original paper (i.e. Al/(Ca-1.67P+Na+K).

The following associations are distinguished:

ferroan

magnesian

alkalic

alkali-calcic

calc-alkalic

calcic

peralkaline

metaluminous

peraluminous

The geologically reasonable combinations, together with examples, are listed in the ../Diagrams/Geotectonic/FrostTable.htm, modified from the original article.

Note

Due to the specific design of this classification (combination of multiple diagrams), the classification option is not available via the pull-down menus. Currently, the only way to apply Frost's classification in GCDkit on individual samples is to call the function manually from the Console (Frost(clssf = TRUE)).

Note

This function uses the plates concept. The individual plots can be selected and their properties/appearance changed as if they were stand alone Figaro-compatible plots. See Plate, Plate editing and figaro for details.

Author(s)

Vojtech Erban, vojtech.erban@geology.cz

& Vojtech Janousek vojtech.janousek@geology.cz

References

Frost B R, Barnes C G, Collins W J, Arculus R J, Ellis D J, Frost C D (2001) A geochemical classification for granitic rocks. J Petrol 42: 2033-2048. doi: 10.1093/petrology/42.11.2033

Shand, S J (1943) Eruptive rocks, 2nd ed. John Wiley, New York, pp 1-444

See Also

classify Shand Plate Plate editing plotPlate figaro

Examples

#plot the diagrams
plotPlate("Frost")

#classify the samples, suppress the graphical output
Frost(clssf = TRUE)

[Package GCDkit version 3.00 Index]