The oxide data, from SiO2 to P2O5 (or CO21) are first recalculated to 100 percent on an anhydrous basis, and then Fe oxidation ratio adjustment is done according to the recommendations of Middlemost (1989), or Le Maitre (1976), or else the measured Fe2O3/FeO ratios are maintained. Finally, the oxide data is recalculated to 100 percent on an anhydrous basis from Fe2O3/FeO ratios calculated.
a whole rock major and trace element chemical data. It is important to note that Fe2O3 or FeO could be Fe2O3T or FeOT if any of this values are NA or 0. On the other hands, the head format of CO2 column must be 'CO2.'
Volcanic
rock type, if is TRUE is shown the volcanic rock type after TASplot (Le Bas et al (1986)) in output, and combined with AdjTAS = FALSE, iron oxidation ratio is calculated following the equation of Le Maitre (1976) for Volcanic rocks, if is FALSE, then Plutonic adjusts are done.
AdjTAS
if is TRUE, iron oxidation ratio is calculated depending on rock type at TASplot.
Cancrinite
if is TRUE, CO2 will be used in whole rock adjust.
Calcite
if is TRUE, CO2 will be used in whole rock adjust.
digits
rounds the values to 'digits' after the decimal point. Default = 3, in order to keep their sum of rock oxides as close to 100 as possible.
Value
Returns a dataset of adjust oxide data on anhydrous basis.
References
Le Maitre, R.W. 1976. Some problems of the projection of chemical data into mineralogical classifications. Contribution Mineralogical Petrology. v. 56, pp. 181--189.
Middlemost, E.A.K. 1989. Iron oxidation ratios, norms and the classification of volcanic rocks. Chemical Geology. v. 77, pp. 19--26.
#create a dataframe with major elements indicating the appropriate parameters of rocksdata(TestTAS)#example of dataframeAdjRock(TestTAS)
##data(Andes)#example of dataframeAdjRock(Andes)
##