Resources

Los Andes has given us access to a subset of data from the Vizcachitas porphyry Cu deposit. This is in the same belt and same age as Rio Blanco-Los Bronces, Los Pelambres and El Teniente. This data very clearly demonstrates the magmatic processes in a porphyry Cu system. The first exercise shows how to use immobile trace element geochemistry to chemically fingerprint different lithologies and then map fractionation in the porphyries. Rio Tinto has given us access to a subset of data from a porphyry Cu prospect in the western USA. This porphyry has almost the full spectrum of alteration types seen in porphyry Cu environments. Exercise 2 shows how to classify the alteration types using the major element analyses. Exercise 3 compares the classification of alteration from assays with SWIR data from Corescan. Exercise 4 is a demonstration of the CODES (Tas Uni) excel-based program that converts weight% of elements to weight% of minerals.

The exercise1 data is provided as an excel file. The data for exercises 2 to 4 are provided as ioGAS files in the zip folder.

This is a teach-yourself tutorial. I have provide tutorial notes in a powerpoint file. Be sure to open this in a mode where you can see the notes page, that is, not all the notes are on the slides. The data is provided in an ioGAS file. Most of this is aimed at a beginner level for ioGAS users.

This is a workshop that was run for the International Applied Geochemistry Symposium 2024 in Adelaide (October 2024).

The attached zip file contains an excel spreadsheet with assays from a drill hole cross section through a major porphyry Cu-Au deposit, merged with the logged rock types from the site geologists. It is designed as an exercise to complete in ioGAS to make a classification of the rock units combining both the analytical information and the logging. There is a powerpoint file containing the workshop notes, and also an ioGAS colour table and ioGAS "diagrams".

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I think this is one of the best geochemistry workshops I have ever put together.

This is a teach-yourself tutorial for ioGAS users. Northern Star Resources, owners of the Golden Mile, have provided 4 acid digest ICP-MS data and SWIR data through a cross section of one of the world's great gold mines. This tutorial will guide you through geochemically classifying rock types, creating an interpretation of the alteration mineralogy and then mapping the pathfinder element signature of the deposit.

There are signatures in this data that are relevant really just in Archean greenstone-hosted gold systems. In particular, the fractionation processes within the host dolerite are typical of in-situ fractionation of tholeiitic magmas in very shallow crustal environments.

The Geological Survey of Western Australia has been re-analysing its collection of rock powders with a new, consistent high quality analytical method. This is called the Barcode Project. I have used this data to create a self-guided tutorial on interpretation of lithogeochemical data from Archean rocks. The explanatory notes are in the following Word document, and the data is loaded into an ioGAS file.

This is a follow-on from the Lithogeochemistry of Archean Rocks tutorial. It is based on new analyses of rock powders collected by Dave Champion and Kevin Cassidy in their study of Yilgarn granite compositions; an AMIRA project completed in 2002. The format for this tutorial is a little different. It is not so much a hand-on ioGAS file, but more a discussion of the way that pressure, water content, degree of partial melting and extent of fractionation influences trace element contents of magmas.  The explanatory notes are in the following Word document, and the data is loaded into an ioGAS file.