CIPW.trace: CIPW Norm (major and trace elements)

Description

Computed from the chemical composition, the normative mineralogy is an alternative approach for mineralogical classification and useful for set up the naming of igneous rocks (as parts of the TAS classification, TASplot). The CIPW Norm (acronym from the surnames of the authors: Cross, Iddings, Pirrson and Washington, Cross et al., 1902) is the most commonly used calculation algorithm to estimate the standard mineral assemblages for igneous rocks, generated over more than a hundred years ago and thereafter modified by some authors to the passage of the years (e.g., Verma et al., 2002). It is based upon assumptions about the order of mineral formation and known phase relationships of rocks and minerals, using simplified mineral formulas.

In this option, the trace elements that can be used are Ba, Cl, Co, Cr Cs, F, Li, Ni, Rb, S, Sr, V and Zr. Additionally, the oxides concentrations of Cr2O3, NiO and SO3 (expressed as wt. percent) are handled like trace elements as well. However Cr2O3 are preferable to Cr and NiO to Ni. Sulfur concentration when available is reported as either SO3 or S, in which case their separate identity should be maintained.

Usage

CIPW.trace(filename, Volcanic= TRUE, AdjTAS= TRUE, Cancrinite= FALSE, 
Calcite= FALSE, digits=3)

Arguments

filename

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 format of CO2 and F column must be 'CO2.' and 'F.', respectively.

Volcanic

rock type, if is TRUE is shown the volcanic rock type after TASplot 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. If the concentration of CO2 is more than 0, and the modal cancrinite is present then Sodium carbonate is calculated.

Calcite

if is TRUE, CO2 will be used in whole rock adjust. If the concentration of CO2 is more than 0, and the modal calcite is present then Calcite is calculated.

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

Calculate the CIPW Norm and others geochemical parameters.

References

Cross, W., Iddings, J.P., Pirsson, L. V., Washington, Henry S. 1902, A quantitative chemico-mineralogical classification and nomenclature of igneous rocks: The Journal of Geology, v. 10, no. 6, pp. 555--690.

Verma, S.P., Torres-Alvarado, I.S., and Velasco-Tapia, F., 2003, A revised CIPW norm: Schweizerische Mineralogische und Petrographische Mitteilungen, v. 83, no. 2, pp. 197--216.

Examples

Run this code

#create a dataframe with major elements indicating the appropriate parameters of rocks
data(Andes)#example of dataframe
CIPW.trace(Andes)
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