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Exploration targeting in porphyry Cu systems using propylitic mineral chemistry: a case study of the El Teniente deposit, Chile

journal contribution
posted on 2023-05-20, 15:01 authored by Jamie Wilkinson, Michael BakerMichael Baker, David CookeDavid Cooke, Wilkinson, CC
The mineral chemistry of epidote and chlorite from the propylitic halo at El Teniente, in samples collected at distances up to 6.6 km from the deposit center, was determined by microprobe and laser ablation-inductively coupled plasma-mass spectrometry. Results show that both minerals systematically incorporated a range of trace elements that define a much larger footprint to the system than is easily recognized using conventional means such as whole-rock geochemistry. Apart from Fe and Mg in chlorite, there is no significant control of mineral chemistry by bulk-rock composition. For chlorite, geothermometry temperatures and Ti and V concentrations are high proximal, whereas Li, As, Co, Sr, Ca, and Y are low proximal and elevated in distal positions. Ratios of these elements define gradients toward ore varying over three to five orders of magnitude. The proximal-high Ti content is thought to reflect crystallization temperature, whereas proximal-low signatures are believed to characterize elements that are relatively fluid mobile in the inner parts of the propylitic halo in the presence of mildly alkaline to mildly acidic and oxidized fluids so that they are not incorporated into crystallizing chlorite, despite being generally compatible within the mineral structure. These elements begin to substitute into chlorite in the distal parts of the propylitic halo where fluids are largely rock buffered in terms of major element chemistry. In epidote, As defines a broad proximal low and is generally elevated at distances of at least 3 km from the edge of the ore shell. Zinc, La, Yb, Y, and Zr in epidote, among others, appear to define a geochemical shoulder that surrounds the deposit. These patterns are broadly similar to those observed in previous work at Batu Hijau and in the Baguio district, suggesting that these minerals behave consistently in porphyry systems and can therefore provide useful exploration tools within propylitic green rocks.


Australian Research Council

AMIRA International Ltd

ARC C of E Industry Partner $ to be allocated

Anglo American Exploration Philippines Inc

AngloGold Ashanti Australia Limited

Australian National University

BHP Billiton Ltd

Barrick (Australia Pacific) PTY Limited

CSIRO Earth Science & Resource Engineering

Mineral Resources Tasmania

Minerals Council of Australia

Newcrest Mining Limited

Newmont Australia Ltd

Oz Minerals Australia Limited

Rio Tinto Exploration

St Barbara Limited

Teck Cominco Limited

University of Melbourne

University of Queensland

Zinifex Australia Ltd


Publication title

Economic Geology










School of Natural Sciences


Society of Economic Geologists, Inc

Place of publication

United States

Repository Status

  • Restricted

Socio-economic Objectives

Copper ore exploration; Precious (noble) metal ore exploration

Usage metrics

    University Of Tasmania