The biogeochemistry of copper metallophytes in the Roseby Corridor (North-West Queensland, Australia)

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CHEMOECOLOGY

ORIGINAL ARTICLE

The biogeochemistry of copper metallophytes in the Roseby Corridor (North‑West Queensland, Australia) Roger H. Tang1 · Peter D. Erskine1 · Richard Lilly2 · Antony van der Ent1  Received: 20 May 2020 / Accepted: 12 September 2020 © Springer Nature Switzerland AG 2020

Abstract The ability of Australian native metallophytes to tolerate extreme metal concentrations in the soil and other difficult edaphic conditions is still not well understood. Copper is an essential micronutrient for plants to survive, but at high concentrations (> 20 µg g−1) in plant tissues, it can cause foliar chlorosis, stunted growth, and ultimately plant death. The Roseby Corridor in Central Queensland (near Cloncurry) is host to copper metallophytes (Polycarpaea spirostylis, Bulbostylis barbata, Tephrosia virens, Eriachne mucronata) which are able to tolerate soils with total copper concentrations up to 12,700 µg g−1. Even with these high levels of copper in the rhizosphere, the maximum copper in all species is relatively low when compared to Cu concentrations in the soil (leaf/stem: Bulbostylis barbata: 40.9 µg g−1, Eriachne mucronata: 12.3 µg g−1, Polycarpaea spirostylis: 10.9 µg g−1, Tephrosia virens: 128 µg g−1). Therefore, all of these species can be classified as copper Excludertype metallophytes. Their affinity to copper makes these metallophytes useful indicators of copper surface mineralisation within the Roseby Corridor. Keywords  Copper · Excluder · Metal tolerance

Introduction Gossans are heavily weathered surface outcrop expressions of metal sulphide minerals that can indicate the presence of potentially economic ore systems (Salama et al. 2016). The recognition of gossanous outcrops has been used since antiquity to aid exploration for mineral resources, and the presence of associated plant species has spurred the development of biogeochemical prospecting using indicator species  (Brooks 1972; Cole 1980). Gossans developed above copper (Cu)-bearing systems, in particular, can be found in Australia, subtropical Africa, Arizona (United States), Chile, Communicated by Marko Rohlfs. Electronic supplementary material  The online version of this article (https​://doi.org/10.1007/s0004​9-020-00325​-1) contains supplementary material, which is available to authorized users. * Antony van der Ent [email protected] 1



Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, Australia



Department of Earth Sciences, The University of Adelaide, Adelaide, Australia

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and Peru (Saad et al. 2012). Apart from mineralisation, gossans generally have poor water retention and are nutrientdepauperate, which creates a hostile environment for most plant species (Cole and Smith 1984). Gossanous surface expressions are often very limited in size and are composed of a heterogeneous mineral mosaic of contrasting metal concentrations forming distinctive micro-habitats for  a few metal-tolerant plant species (Faucon et al. 2016). The metaltolerant plants which can