Triplot Templates

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

  1. 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.
  2. 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.
  3. 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

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

  • [2] 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).

  • [3] 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.

  • [4] 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.

  • [5] 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.

  • [6] 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.

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

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