OConnor {GCDkit} | R Documentation |
Assigns data for O'Connor's triangular diagram into Figaro template
(list 'sheet
') and appropriate values into 'x.data
' and 'y.data
'.
OConnorVolc() OConnorPlut(ab=NULL,an=NULL,or=NULL,calc.cipw=TRUE)
ab,an,or |
character; specification of the plotting variables. |
calc.cipw |
logical; should be the CIPW norm calculated automatically? |
The O'Connor's triangular diagram is based on combination of Albite, Anorthite and
K-feldspar modal or normative data. While the function 'OConnorPlut
' can
plot either modal or normative diagrams for plutonic rocks, 'OConnorVolc
'
is to be used exclusively with normative data computed from chemical compositions
of volcanic rocks.
In fact, the triangle represents projection of the Quartz - K-feldspar - Albite - Anorthite tetrahedron. All three diagrams are designed for quartz-rich rocks, i.e. those with quartz contents higher than 10 such silica-rich samples, the rock type can be determined purely on the basis of the feldspars' proportions.
As the specific version of the normative calculation is not mentioned in the
original paper by 'O'Connor (1965)', the function 'CIPW
',
designed after 'Hutchison (1974, 1975)' was implemented as a default calculation
scheme.
Alternatively, the plotting variables can be present already in the dataset (variable
WR
). The variables to be plotted can be then specified upon call or can be
selected using the function 'selectColumnLabel
'.
The samples can be selected based on combination of three searching
mechanisms (by sample name/label, range or a Boolean condition) - see
selectSubset
for details.
sheet |
list with Figaro Style Sheet data |
x.data, y.data |
An, Ab and Or data (see details) transformed to orthogonal coordinates |
Vojtěch Erban, erban@sopky.cz
Vojtěch Janoušek, vojtech.janousek@geology.cz
Jean-Francois Moyen, jfmoyen@gmail.com
O'Connor JT (1965) A classification for Quartz-rich igneous rocks based on feldspar ratios. U.S. Geol. Survey Prof Paper 525-B: B79-B84
Hutchison CS (1974) Laboratory Handbook of Petrographic Techniques. John Wiley & Sons, New York, p. 1-527
Hutchison CS (1975) The norm, its variations, their calculation and relationships. Schweiz Mineral Petrogr Mitt 55: 243-256
classify figaro CIPW plotDiagram
data(blatna) accessVar("blatna") # Volcanic plotDiagram("OConnorVolc",FALSE) classify("OConnorVolc") # Plutonic selectSubset("SiO2>60") results<-Mesonorm(WR) addResults() plotDiagram("OConnorPlut",FALSE,ab="Albite",an="Anorthite",or="Orthoclase")