tetrad {GCDkit} | R Documentation |
Calculates lanthanide tetrad effect following the method of Irber (1999).
tetrad(method=NULL)
method |
Normalization scheme. |
The method
indicates which normalization scheme is to be used. It can be
either 'Boynton' or 'Nakamura'. If not specified, the user is prompted to choose it interactively
by the function spider
.
The anomalies of individual elements are calculated as follows for the first tetrad:
Ce/Cet = CeN/(La^(2/3)*Nd^(1/3))
Pr/Prt = PrN/(La^(1/3)*Nd^(2/3))
sqrt(Ce/Cet*Pr/Prt)
By analogy, one can define for the third tetrad:
Tb/Tbt = TbN/(Gd^(2/3)*Ho^(1/3))
Dy/Dyt = DyN/(Gd^(1/3)*Ho^(2/3))
sqrt(Tb/Tbt*Dy/Dyt)
The magnitude of the tetrad effect is then calculated as a geometric mean:
sqrt(t1*t3)
Returns a matrix 'results
' with the following columns:
Ce/Cet |
Ce anomaly |
Pr/Prt |
Pr anomaly |
t1 |
first tetrad |
Tb/Tbt |
Tb anomaly |
Dy/Dyt |
Dy anomaly |
t3 |
third tetrad |
TE1-3 |
degree of lanthanide tetrad effect, geometric mean of t1 and t3 |
tetrad.r
Vojtech Janousek, vojtech.janousek@geology.cz
Irber W (1999) The lanthanide tetrad effect and its correlation with K/Rb, Eu/Eu*, Sr/Eu, Y/Ho, and Zr/Hf of evolving peraluminous granite suites. Geochim Cosmochim Acta 63: 489-508
tetrad("Boynton")