About Triplot Templates

A Template is a predefined Triplot diagram with set axes and graphical categorization elements. Each Template consists of three files:

The Template file, "*.geosoft_template", which is a text file that contains information on the channels, scales, titles, etc., as well as the name of the associated overlay file.
The Overlay file, "*.geosoft_overlay", which is a text file that contains either i) line/text commands to draw an overlay or ii) the name of a map file to use as the overlay. In this case, it refers to a map file.
The Map file, "*_Overlay.map", which is a Geosoft map containing the overlay map items.

These files are stored in the "…/Geosoft/resourcefiles/etc" directory. New or modified Templates and Overlays are stored in the "…/Geosoft/user/etc" directory.

Nine Ternary Diagram (Triplot) Templates are included in montaj Geochemistry. They are divided into three categories: Lithological Discrimination, Diamond Exploration, and Uncategorized.

Lithological Discrimination Diagrams

The lithological discrimination diagrams include a combination of major and trace element diagrams, as well as some that are useful for volcanic and some that are useful for plutonic rock types.

10P2O5 vs 10MnO vs TiO2 - Ternary discrimination diagram for basalts and basaltic andesites (45-54 wt% SiO2). After Mullen, 1983.

3Y vs Zr vs Ti_100 - Discrimination diagram for basalts. (After Pearce and Cann, 1973).

Al2O3 v MgO v FeO - Shows the discriminant boundaries for a range of tectonic settings, based on the compositional range of recent volcanic rocks. This diagram should only be used with subalkaline rocks in the silica range SiO2 = 51-56 wt% (calculated dry). (After Pearce et al., 1977)

Mg vs Al vs Fe+Ti - For the classification of volcanic rocks according to their cation percentages of Al, (FeTOT + Ti) and Mg, showing the tholeiite, calc-alkaline and komatiite fields. Known as the Jenson Cation Plot, it is particularly useful for Archean meta-volcanics because it has a separate field for komatiites. (After Rickwood, 1989; Jensen, 1976).

Diamond Exploration Diagrams

The diamond exploration ternary diagrams are aimed at classifying indicator minerals in to groupings that help to distinguish between diamondiferous and barren kimberlites.

Garnet_MgO-FeO-CaO - For Garnet classification. This diagram classifies garnets on the basis of MgO, FeO and CaO content. Garnets are grouped by G-number, where G9 & G10 garnets are within the diamond-bearing facies.

Spinel_Xenolith - For discriminating various types of spinel.

Uncategorized

10Hf vs La vs TiO2_1000 - For potassic igneous rocks; discrimination between samples from oceanic arcs (top) and those from continental or postcollisional arc settings. (After Muller and Groves, 1993).

Ce_P2O5 vs 50Nb vs 3Zr - For potassic igneous rocks; for discrimination between samples from continental vs postcollisional arc settings. (After Muller and Groves, 1993).

MgO vs Na2O+K2O vs FeO - AFM diagram, for differentiating between calc-alkaline and tholeiitic volcanic rocks. (After Kuno, 1968).

References

Jensen, L. S., 1976. A New Cation Plot for Classifying Subalkalic Volcanic Rocks. Ontario Geological Survey Miscellaneous Paper 66.

Kuno, H., 1968. "Differentiation of basaltic magmas". p. 623-688. In H. Hess and Arie Poldervaart, eds. (1967–68) "Basalts. The Poldervaart Treatise on Rocks of Basaltic Composition". Vol. 1, pp. 495 and vol. 2, pp. 400. New York: Interscience (Wiley).

Mullen, E. D., 1983. MnO/TiO2/P2O5: a minor element discriminant for basaltic rocks of oceanic environments and its implications for petrogenesis. Earth and Planetary Science Letters 62, 53–62.

Muller, D., Groves, D.I., 1993. 'Direct and indirect associations between potassic igneous rocks, shoshonites and gold-copper deposits', Ore Geology Reviews, 28, pp. 469-481.

Pearce, J. A. & Cann, J. R., 1973. Tectonic setting of basic volcanic rocks determined using trace element analyses. Earth and Planetary Science Letters 19, 290–300.

Pearce, T. H., Gorman, B. E. & Birkett, T. C., 1977. The relationship between major element geochemistry and tectonic environment of basic and intermediate volcanic rocks. Earth and Planetary Science Letters 36, 121–132.

Rickwood, P.C., 1989. Boundary lines within petrologic diagrams which use oxides of major and minor elements. Lithos, 22, 247-263.