Geochemical Data Toolkit
(GCDkit)
PC software for interpretation of whole-rock geochemical 
data from igneous rocks using R language

V. JANOUSEK1,3, C. M. FARROW2, V. ERBAN3. and J. SMID3
1 Institut für Mineralogie, Universität Salzburg, Austria
(vojtech.janousek@sbg.ac.at)
2 Computing Service, University of Glasgow, Scotland
(c.farrow@compserv.gla.ac.uk)
3 Czech Geological Survey, Prague, Czech Republic (erban@cgu.cz)


ABSTRACT

The dearth of truly potent and flexible software for recalculation and plotting of whole-rock analyses is often a limiting factor to a creative scientific work in igneous geochemistry. An ideal package should include a variety of calculation schemes, produce publication quality diagrams, be readily available, easy to use and expand. The Geochemical Data Toolkit (GCDkit) is being developed to meet this requirement, with facilities for handling and recalculation of whole-rock major- and trace-element as well as Sr-Nd isotopic data. It is built using the freeware R language, version for Windows (http://www.r-project.org) which in itself provides a rich environment for data analysis, graphics and software development.
   Data management includes loading and saving of free form text files, data editing, searching and generation of subsets using regular expressions and Boolean logic. Analyses may be grouped for subsequent statistical processing or plotting on the basis of particular attributes (locality, rock type…), ranges of a numerical variable, by cluster analysis or using a selected classification diagram (TAS, R1-R2…). Statistical functions include simple descriptive statistics, histograms, box-and-whiskers diagrams, correlation plots, coplots, or multivariate methods such as principal components analysis. Also implemented are recalculation and normative algorithms, for instance CIPW, Catanorm, Granite Mesonorm, Niggli's values, as are the common geochemical plots (e.g. Harker diagrams, AFM, spider diagrams, REE plots). A wide palette of classification and geotectonic diagrams are available, and new templates can be added. All plots are publication ready but can be further retouched (editing axes labels, adding comments or legend, identifying data points).
   With the current version are plugin modules to calculate saturation temperatures of various accessories (apatite, zircon and monazite) and for interpretation of the Sr-Nd isotopic data (initial isotopic ratios, Nd model ages, isochron plots and plots involving the isotopic data). Modules for petrogenetic modelling are under development. Users with an understanding of the R language will readily be able to enhance the functionality.

WWW pages of the GCDkit

R language

Reprint of the article 
Janousek, V., Farrow, C. M. & Erban, V. (2003): GCDkit: new PC software for interpretation of whole-rock geochemical data from igneous rocks.
Geochimica et Cosmochimica Acta 67, A186. (PDF)


Norman v. 2
Simple petrochemical calculator
for PC compatibles


ABSTRACT

NORMAN is a Microsoft QuickBasic 4.5 package designed for handling and recalculation of whole-rock major-element data on PC compatible computers. It is capable of computing parameters of the most common normative calculation schemes, including CIPW and Catanorm. The core of the system consists of modules to handle the import, editing and saving of the major-element analyses, as well as browsing, saving and exporting the computed results. The calculation algorithms are: (1) nearly independent QuickBasic programmes (”standard modules”), and (2) plain text calculation scripts (”user-defined functions”) that may contain variables referring to the original data, to constants as well as to parameters calculated by other standard modules and user-defined functions.

The advantage of the chosen approach is the simplicity, availability and open architecture that enables an average user not only to follow, but also, if need be, to modify the algorithms applied to his data.

On line version of the manual

Download (all files are zipped):

Executables - 184 kB
Sources - 11 kB
Manual (HTML - 211 kB)
Manual (old version, Word 6 - 205 kB)
Manual (new version, Word 97 - 163 kB)


Reprint of the article 
Janousek V.(2000): Norman, a QuickBasic programme for petrochemical re-calculation of whole-rock major-element analyses on IBM PC. J. Czech Geol. Soc., 46, 9-13.
(PDF)


 © 1999-2003 Vojtech Janousek