QAPF {GCDkit}R Documentation

QAPF diagram (Streckeisen 1974, 1978)

Description

Assigns data for Streckeisen's diagram into Figaro template (list 'sheet') and appropriate values into 'x.data' and 'y.data'. The Q, A, P and F coordinates are assigned into matrix 'results'.

Usage

QAPFVolc()
QAPFPlut()

Details

Following the IUGS recommendation (Le Maitre et al 2002), the QAPF diagram should be the prime classification scheme for holocrystalline plutonic and volcanic rocks containing at least 10% of felsic minerals. The apices are defined as follows:

Q = Quartz modal %

A = Alkali feldspar modal %

P = Plagioclase modal %

F = feldspathoid modal %

Q + A + P + F = 100 %

As the whole QAPF diagram is rather complicated, GCDkit plots just the appropriate triangle if the dataset contains only Si-oversaturated or only Si-undersaturated rock samples. If both kinds of rock samples are present, the whole double triangle is shown. This behaviour may be changed in the source code of the diagram (in file 'QAPFPlut.r' or 'QAPFVolc.r', stored in the subdirectory GCDkit\Diagrams\Classification, change the 'triangle<-"auto"' to 'triangle<-"both"' and complete double triangle will be always plotted).

Value

sheet

list with Figaro Style Sheet data

x.data, y.data

Q, A, P and F data (see details) transformed to orthogonal coordinates

Author(s)

Vojtech Erban, vojtech.erban@geology.cz

References

Streckeisen A (1974) Classification and nomenclature of plutonic rocks. Geol Rundsch 63: 773-786 doi: 10.1007/BF01820841

Streckeisen A (1978) IUGS Subcommission on the Systematics of Igneous Rocks: Classification and nomenclature of volcanic rocks, lamprophyres, carbonatites and melilitic rocks; recommendation and suggestions. Neu Jb Min, Abh 134: 1-14.

Le Maitre R. W. et al. (2002) Igneous Rocks. A Classification and Glossary of Terms. 2nd edition. Cambridge University Press.

See Also

classify figaro plotDiagram

Examples

#plots the QAPF diagram for current dataset

plotDiagram("QAPFVolc", FALSE)

plotDiagram("QAPFPlut", FALSE)

#classifies the current dataset using the QAPF diagram

classify("QAPFVolc")

classify("QAPFPlut")


[Package GCDkit version 3.00 Index]