TAS {GCDkit} | R Documentation |
Assigns data for IUGS recommended TAS diagram into Figaro template
(list 'sheet
') and appropriate values into 'x.data
' and 'y.data
'
TAS(cutoff=95)
cutoff |
numeric; the minimal sum of the analysis to be considered for classification |
TAS diagram, as proposed by Le Bas et al. (1986), codified by Le Maitre
et al. (1989) and slightly modified by Le Bas (2000).
The diagram (in its basic form) defines following fields:
foidite
picrobasalt
basalt
basaltic andesite
andesite
dacite
rhyolite
trachybasalt
basaltic trachyandesite
trachyandesite
trachyte/trachydacite
tephrite/basanite
phonotephrite
tephriphonolite
phonolite
This primary division is further enhanced by
the 'TASadd
' routine
(called automatically by
'classify
').
Following actions are carried out:
Analyses with H2O > 2 and CO2 > 0.5 (weight percent) are filtered out
Trachybasalt is subdivided into hawaiite and potassic trachybasalt
Basaltic trachyandesite is subdivided into mugearite and shoshonite
Trachyandesite is subdivided into benmoreite and latite
High-Mg rocks are split into picrite, komatiite, meimechite and boninite
Note that systematics of high-Mg rocks follows revised IUGS Recommendations (Le Bas et al., 2000; Le Maitre et al. 2002) which differ from their 1st edition (Le Maitre et al, 1989). Further subdivisions recommended by Le Maitre et al. (1989) are not implemented in GCDkit, mainly for poorly defined CIPW version used by the Subcommission.
x.data |
SiO2 data recast to anhydrous sum (matrix 'WRanh') |
y.data |
Na2O+K2O data recast to anhydrous sum (matrix 'WRanh') |
sheet |
list with Figaro Style Sheet data |
results |
matrix with classification results |
groups |
vector with classification results |
grouping |
set to -1 |
Vojtech Erban, vojtech.erban@geology.cz
& Vojtech Janousek, vojtech.janousek@geology.cz
Le Bas M J, Le Maitre R W, Streckeisen A & Zanettin B (1986) A chemical classification of volcanic rocks based on the total alkali-silica diagram. J Petrology 27: 745-750 doi: 10.1093/petrology/27.3.745
Le Bas M J (2000) IUGS Reclassification of the High-Mg and Picritic Volcanic Rocks. J Petrology 41: 1467-1470 doi: 10.1093/petrology/41.10.1467
Le Maitre R W et al (1989) Igneous Rocks: A Classification and Glossary of Terms, 1st edition. Cambridge University Press
Le Maitre R W et al (2002) A Classification and Glossary of Terms, 1st edition. Cambridge University Press
#Within GCDkit, the plot is called using following auxiliary functions: #To Classify data stored in WR (Groups by diagram) classify("TAS") #To plot data stored in WR or its subset (menu Classification) plotDiagram("TAS", FALSE)