University Of Tasmania
150744 - Assessing copper fertility of intrusive rocks - Author version.pdf (2.61 MB)
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Assessing copper fertility of intrusive rocks using field portable X-Ray fluorescence (pXRF) data

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journal contribution
posted on 2023-05-21, 08:57 authored by Ahmed, A, Anthony CrawfordAnthony Crawford, Leslie, C, Joshua Phillips, Wells, T, Garay, A, Shawn Hood, David CookeDavid Cooke

Based on a global compilation of whole-rock geochemical data, Sr/Y and Sr/MnO are identified as effective discriminators between ore-forming and unprospective intrusions in the porphyry Cu setting. Intrusive rocks are classified into three fertility groups – prospective, unprospective and mixed-signal – designed to assist explorers as a discrimination tool, narrowing the exploration search space in porphyry Cu districts.

Portable X-ray fluorescence (pXRF) data of Sr, Y and MnO were collected on pulp powders and rock slabs from six porphyry Cu (±Mo ± Au) districts. Pre- and post-mineralization intrusions from porphyry Cu districts have lower Sr/Y and Sr/MnO values than syn-mineralization intrusions from the same districts, although absolute values are variable between districts.

pXRF data were compared to conventional whole-rock data to determine if pXRF data were appropriate substitutes for conventional whole-rock methods of evaluating the ore-forming potential of intrusive rocks. pXRF data collected on pulp material were found to be more accurate (within 16% of conventional methods) and more precise (<5% relative standard deviation (RSD)) than those collected on intact rock slabs (within 37% of conventional methods and <24% RSD). These differences are attributed to the grain size and mineral homogeneity of samples. Despite the low precision of pXRF analyses on individual rock slabs (mean RSD of 24% Sr/Y and 32% Sr/MnO), the mean values for each sample plot in the expected fertility field on the Sr/Y and Sr/MnO diagram. Our results demonstrate that in situ pXRF data collection provides an effective discriminator of Cu fertility, and represents a powerful field exploration tool.


Publication title

Geochemistry: Exploration, Environment, Analysis










School of Natural Sciences


Geological Society Publishing House

Place of publication

United Kingdom

Rights statement

Copyright © 2019 The Author(s). Published by The Geological Society of London for GSL and AAG. All rights reserved.

Repository Status

  • Open

Socio-economic Objectives

Copper ore exploration; Precious (noble) metal ore exploration