Frost_2008 {GCDkit}R Documentation

Frost + Frost (2008)

Description

Classification of feldspathic igneous rocks proposed by Frost and Frost (2008).

Usage

    Frost_2008(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 originally proposed by Frost et al. (2001) for (subalkaline) granitic rocks. It was modified and expanded for alkaline and/or mafic rocks by Frost and Frost (2008). It consists of four diagrams:

The following associations are distinguished:

ferroan, magnesian

alkalic, alkali-calcic, calc-alkalic, calcic

peralkaline, metaluminous, peraluminous

silica-undersaturated, silica-saturated

Frost2008.png

Value

results

The function returns table of calculated coefficients (Fe-number, MALI, ASI, FSSI).

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.

Due to the specific design of this scheme (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_2008(clssf = TRUE).

Warning

Note that the Fe-number is calculated as weight proportion of FeOtot/(FeOtot+MgO). The approach used here should not be confused with the more common usage of the term "Fe-number" (as well as "Mg-number") for molecular proportions.

The equation for ASI in both original works of Frost et al. (2001) and Frost and Frost (2008) was stated erroneously as molecular proportions of elements, instead of oxides.

The equation for FSSI in Frost and Frost (2008) has apparently misplaced the outermost brackets, having been originally stated as: Q-[Lc+2(Ne+Kp)]/100.

Author(s)

Vojtěch Janoušek vojtech.janousek@geology.cz

& Vojtěch Erban, erban@sopky.cz

References

Frost BR, Frost CD (2008) A geochemical classification for feldspathic igneous rocks. J Petrol 49:1955-1969. doi: 10.1093/petrology/egn054

Frost BR, Barnes CG, Collins WJ, Arculus RJ, Ellis DJ, Frost CD (2001) A geochemical classification for granitic rocks. J Petrol 42: 2033-2048. doi: 10.1093/petrology/42.11.2033

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

See Also

Frost Shand CIPW classify Plate Plate editing plotPlate figaro

Examples

    data(sazava)
    accessVar("sazava")
    
    # Plot the diagrams
    plotPlate("Frost_2008")

    # Classify the samples, suppress the graphical output
    Frost_2008(clssf = TRUE, GUI=TRUE)

[Package GCDkit version 6.1 Index]