zrSaturation {GCDkit} | R Documentation |
Calculates zircon saturation temperatures for the observed major-element data and Zr concentrations. Returns also Zr saturation levels for the given major-element compositions and assumed magma temperature.
zrSaturation(cats = milli, T = 0, Zr = filterOut(WR, "Zr", 1))
cats |
numeric matrix; whole-rock data recast to millications |
T |
assumed temperature of the magma in C |
Zr |
numeric vector with Zr concentrations |
Calculates Zr saturation concentration at a given temperature. Given 'T
'
is the estimated absolute temperature (K) of the magma and 'M
' is a
cationic ratio:
M = 100(Na + K + 2Ca)/(Al*Si)
it can be written Watson & Harrison 1983):
DZr = exp(-3.8 - 0.85(M - 1) + 12900/T)
The Zr saturation level is then given by:
Zr.sat = 497644/DZr
On the other hand, the saturation temperature can be obtained from the observed Zr concentration and magma composition (assuming no zircon inheritance)
DZr = 497644/Zr
TZr.sat.C = 12900/(ln(DZr) + 3.8 + 0.85(M-1)) - 273.15
Returns a matrix 'results
' with the following columns:
M |
cationic ratios |
Zr |
observed Zr concentrations |
Zr.sat |
saturation levels of Zr for assumed temperature |
TZr.sat.C |
zircon saturation temperatures in C |
Saturation.r
Vojtech Janousek, vojtech.janousek@geology.cz
Watson E B & Harrison M (1983) Zircon saturation revisited: temperature and composition effects in a variety of crustal magma types. Earth Planet Sci Lett 64: 295-304 doi: 10.1016/0012-821X(83)90211-X