Platinum-group element geochemistry of the Forest Reef Volcanics, southeastern Australia: Implications for porphyry Au-Cu mineralisation

Lowczak, Jessica N.; Campbell, Ian H.; Cocker, Helen A.; Park, Jung‐Woo; Cooke, David R.

doi:10.1016/j.gca.2017.09.052

Cited by 26 publications

(34 citation statements)

References 83 publications

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“…One of the unique characteristics of the PGE is that their extreme partition coefficients make them sensitive indicators of sulphide saturation. (Lowczak, Campbell, Cocker, Park, & Cooke, ; Park, Campbell, Ickert, & Allen, ). Sulphur behaves as an incompatible element during the process of magmatic differentiation.…”

Section: Discussionmentioning

confidence: 99%

Platinum group element geochemistry and whole‐rock systematics of the Vempalle sills, Cuddapah Basin, India: Implications on sulphur saturation history, mantle processes, and tectonic setting

Singh

Manikyamba

2019

Geological Journal

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The intracratonic Cuddapah Basin of southern peninsular India has multiple phases of magmatism exposed as mafic intrusives and extrusives in the Vempalle and Tadpatri formations. We report platinum group element geochemistry along with whole‐rock systematics of the mafic sills from the Vempalle Formation to understand their sulphur saturation history, source characteristics, and tectonic setting. These sills are medium‐ to fine‐grained dolerites with plagioclase and pyroxenes as essential minerals exhibiting sub‐ophitic to intergranular texture. Geochemically, they are characterized by moderate MgO (6.3–8.5 wt.%), Ni (55–105 ppm), Cr (20–130 ppm), and ∑PGE (22–61 ppb) contents and exhibit transitional to calc‐alkaline in nature. Primitive mantle‐ and chondrite‐normalized trace and rare earth element patterns display relative enrichment of LILE–LREE over HFSE, suggesting plume‐related intraplate magmatism with contributions from subcontinental lithospheric mantle (SCLM), lithosphere–asthenosphere interaction, crustal contamination, and fractional crystallization. Their REE relationship indicates the generation of parent magma from a heterogeneous source marked by 10–25% polybaric partial melting within spinel and garnet lherzolite domain. Platinum group elements (PGE) geochemistry reveals their sulphur‐undersaturated nature, and sulphide fractionation played a key role in the distribution of PGEs, which is evidenced by their enriched character, moderate degrees of partial melting, and crustal contamination. Further, the negative platinum anomalies in these sills indicate its removal during fractional crystallization, and the enrichment of Pd over Pt endorses the decoupling nature of these elements prior to their emplacement. Diagnostic trace element signatures and their relationship corroborate a riftogenic intraplate tectonic regime for the emplacement of the Vempalle sills through an ocean–continent transition zone.

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Section: Discussionmentioning

confidence: 99%

Platinum group element geochemistry and whole‐rock systematics of the Vempalle sills, Cuddapah Basin, India: Implications on sulphur saturation history, mantle processes, and tectonic setting

Singh

Manikyamba

2019

Geological Journal

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“…PGE geochemistry has been used to identify sulfide saturation in several evolving magmatic systems (Barnes and Picard, 1993;Barnes et al, 2008Barnes et al, , 2015Keays, 1995;Keays and Lightfoot, 2010;Keays et al, 2012;Maier and Barnes, 1999;Maier et al, 2012;Park et al, 2013aPark et al, , 2013bPark et al, , 2015Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018). The Pd, Pt and Ir concentrations in the highest MgO (4.72 wt.%) samples analysed from the regional diorites are at least 10 times lower than sulfide undersaturated samples from geochemically similar suites at the same MgO content from previous studies (Park et al, 2013a(Park et al, , b, 2015Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018), and decrease with decreasing MgO (Fig. 12).…”

Section: Sulfide Saturation In the Regional Dioritesmentioning

confidence: 94%

“…It has been suggested that the time interval between sulfide and volatile saturation plays a critical role in determining the fertility of felsic magma systems (Park et al, 2013b(Park et al, , 2015Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018). If ore-associated porphyries were derived by fractional crystallization of the magmatic system that gave rise to the regional diorites, the system reached sulfide saturation early in its evolution, before the magma had fractionated to 4.72 wt.% MgO, and the percentage of sulfide melt to precipitate is estimated to have been about 0.12 wt.% of the crystallizing phases.…”

Section: Implications For Ore-forming Processmentioning

confidence: 99%

“…Porphyry deposits, the world's most important source of Cu, Au and Mo, are generally associated with continental or oceanic arc magmas of intermediate to felsic composition (Burnham, 1979;Richards, 2003;Cooke et al, 2005;Sillitoe, 2010). Processes that control the formation of porphyry mineralization include: the metal endowment of the primitive magma (McInnes et al, 1999;Mungall, 2002;Richards, 2011a;Audétat and Simon, 2012); the oxidation state during magmatic evolution (Candela, 1992;Richards, 2003Richards, , 2015Sillitoe, 2010); the water content of the magma (Burnham, 1979;Candela, 1992;Richards, 2003Richards, , 2011bRichards, , 2012; the timing of sulfide saturation relative to volatile exsolution (Richards, 2003;Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018); the metal content of the magma at the time of volatile exsolution (Jenner et al, 2010;Park et al, 2015); and the efficiency of the hydrothermal fluid, released by the magma, to dissolve, transport, and precipitate ore metals (Cline and Bodnar, 1991;Candela and Piccoli, 2005;Wilkinson, 2013). In this paper, we focus on the petrogenesis and evolution of porphyry magma systems, emphasizing the relative timing of sulfide and volatile saturation and their roles in determining magma fertility.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we focus on the petrogenesis and evolution of porphyry magma systems, emphasizing the relative timing of sulfide and volatile saturation and their roles in determining magma fertility. Recent studies (Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018) have used platinum-group element (PGE) geochemistry to argue that the relationship between sulfide and volatile saturation plays a critical role in determining magma fertility (i.e., the potential of a given magma system to produce a hydrothermal ore deposit). The results of initial studies (Cocker et al, 2015;Hao et al, 2017) are consistent with the hypothesis that if fluid exsolution occurs before, or shortly after sulfide saturation, Cu and/or Au will be available to enter the hydrothermal fluid, potentially resulting in the formation of a porphyry Cu ± Au deposit (Spooner, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Platinum-Group Element Geochemistry of the Escondida Igneous Suites, Northern Chile: Implications for Ore Formation

Hao

Campbell

Richards

et al. 2019

Journal of Petrology

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Platinum-group element (PGE) geochemistry may be used to constrain the timing of sulfide saturation in magmas, which influences Cu and Au fertility of evolving magmatic systems. We report new geochronological and geochemical analyses, with emphasis on PGE geochemistry, for a suite of regional hornblende-porphyritic diorite intrusions and ore-bearing porphyries from the super-giant Escondida and smaller Zaldivar Cu deposits of Northern Chile. The regional dioritic intrusions have zircon U-Pb ages between 39.6 to 37.1 Ma, which overlap with ages of ore-bearing Escondida and Zaldivar porphyries (38.1 to 35.0 Ma). Whole rock major and trace element, Sr-Nd-Pb and zircon O-Hf isotope geochemistry indicates that the regional diorites and ore-bearing porphyries are co-magmatic and originated from the same mantle-derived magma by fractional crystallization, with minor contamination by Paleozoic crust (~10%). The low concentrations of PGE in the regional diorites show that they reached sulfide saturation before the MgO content of the melt fell to 4.7 wt.%, the MgO state of the melt, and the magma volume are critical factors in determining the potential to form a porphyry Cu deposit. Plots of Pd/MgO against Y can be used as empirical indicators of magma fertility for porphyry mineralization, and to discriminate between Cu-Au and Cudominated systems, but cannot predict the size of the deposit. The super-giant status of the Escondida deposit is attributed to it being underlain by a large batholith with a calculated minimum mass of 10 12 tonnes (~400 km 3).

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Platinum group elements in gabbroic intrusions from the Valerianov‐Beltau‐Kurama arc: Implications for genesis of the Kalmakyr porphyry Cu–Au deposit

et al. 2020

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Porphyry Cu–Au ores areamong the important types of porphyry deposits. Some of these are enriched in Pd and Pt, which in some cases have economic potential for PGE (platinum group element) recovery. The behaviour of PGE and S‐saturation in mafic intrusions associated with porphyry deposits are, however, poorly constrained. Here we investigate the PGE concentrations of gabbroic intrusions from Akcha, Beleuti, and Kalmakyr in the Almalyk porphyry Cu–Au ore field in Uzbekistan through Ni–S analyses employing fire assay‐isotope dilution method. The results reveal extremely high Pd/Ir ratio and a negative Ru anomaly for the Beleuti and Akcha gabbro which we attribute to fractional crystallization of olivine and Ru–Os–Ir alloys. The extremely high Cu/Pd ratio (2.56 × 105–2.98 × 106) and depleted PGE contents of the Kalmakyr gabbro possibly represent immiscible separation of sulphide. During the emplacement of the parental magma of Kalmakyr gabbro, crustal contamination might have resulted in S‐saturation and sulphide segregation. Sulphide‐bearing crust was remobilized during the increasing maturity of the island and long‐lived arc magmatism, which released the sulphide into the hydrothermal system of the porphyry deposit. We propose that this process favoured the enrichment of Pt–Pd and sulphide in the Kalmakyr porphyry Cu–Au deposit.

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Platinum-group element geochemistry of the Forest Reef Volcanics, southeastern Australia: Implications for porphyry Au-Cu mineralisation

Cited by 26 publications

References 83 publications

Platinum group element geochemistry and whole‐rock systematics of the Vempalle sills, Cuddapah Basin, India: Implications on sulphur saturation history, mantle processes, and tectonic setting

Platinum group element geochemistry and whole‐rock systematics of the Vempalle sills, Cuddapah Basin, India: Implications on sulphur saturation history, mantle processes, and tectonic setting

Platinum-Group Element Geochemistry of the Escondida Igneous Suites, Northern Chile: Implications for Ore Formation

Platinum group elements in gabbroic intrusions from the Valerianov‐Beltau‐Kurama arc: Implications for genesis of the Kalmakyr porphyry Cu–Au deposit

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