1
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Giuliani A, Kurz MD, Barry PH, Curtice JM, Stuart FM, Oesch S, Charbonnier Q, Peters BJ, Koornneef JM, Szilas K, Pearson DG. Primordial neon and the deep mantle origin of kimberlites. Nat Commun 2025; 16:3281. [PMID: 40188176 PMCID: PMC11972409 DOI: 10.1038/s41467-025-58625-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2024] [Accepted: 03/28/2025] [Indexed: 04/07/2025] Open
Abstract
The genesis of kimberlites is unclear despite the economic and scientific interest surrounding these diamond-bearing magmas. One critical question is whether they tap ancient, deep mantle domains or the shallow convecting mantle with partial melting triggered by plumes or plate tectonics. To address this question, we report the He-Ne-Ar isotopic compositions of magmatic fluids trapped in olivine from kimberlites worldwide. The kimberlites which have been least affected by addition of deeply subducted or metasomatic components have Ne isotopes less nucleogenic than the upper mantle, hence requiring a deep-mantle origin. This is corroborated by previous evidence of small negative W isotope anomalies and kimberlite location along age-progressive hot-spot tracks. The lack of strong primordial He isotope signatures indicates overprinting by lithospheric and crustal components, which suggests that Ne isotopes are more robust tracers of deep-mantle contributions in intraplate continental magmas. The most geochemically depleted kimberlites may preserve deep remnants of early-Earth heterogeneities.
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Affiliation(s)
- Andrea Giuliani
- Department of Earth and Planetary Sciences, ETH Zurich, Zurich, Switzerland.
- Earth and Planets Laboratory, Carnegie Institution of Science, Washington, DC, USA.
- Carnegie Institution of Science, Washington, DC, USA.
| | - Mark D Kurz
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Peter H Barry
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Finlay M Stuart
- Scottish Universities Environmental Research Centre, East Kilbride, UK
| | - Senan Oesch
- Department of Earth and Planetary Sciences, ETH Zurich, Zurich, Switzerland
| | | | - Bradley J Peters
- Department of Earth and Planetary Sciences, ETH Zurich, Zurich, Switzerland
| | | | - Kristoffer Szilas
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - D Graham Pearson
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada
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2
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Giuliani A, Phillips D, Pearson DG, Sarkar S, Müller AA, Weiss Y, Preston R, Seller M, Spetsius Z. Diamond preservation in the lithospheric mantle recorded by olivine in kimberlites. Nat Commun 2023; 14:6999. [PMID: 37919292 PMCID: PMC10622582 DOI: 10.1038/s41467-023-42888-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/24/2023] [Indexed: 11/04/2023] Open
Abstract
The diamond potential of kimberlites is difficult to assess due to several mantle and magmatic processes affecting diamond content. Traditionally, initial evaluations are based on the compositions of mantle-derived minerals (garnet, chromite, clinopyroxene), which allow an assessment of pressure-temperature conditions and lithologies suitable for diamond formation. Here we explore a complementary approach that considers the conditions of diamonds destruction by interaction with melts/fluids (metasomatism). We test the hypothesis that carbonate-rich metasomatism related to kimberlite melt infiltration into the deep lithosphere is detrimental to diamond preservation. Our results show that high diamond grades in kimberlites worldwide are exclusively associated with high-Mg/Fe olivine, which corresponds to mantle lithosphere minimally affected by kimberlite-related metasomatism. Diamond dissolution in strongly metasomatised lithosphere containing low-Mg/Fe olivine provides a causal link to the empirical associations between low diamond grades, abundant Ti-Zr-rich garnets and kimberlites with high Ti and low Mg contents. This finding show-cases olivine geochemistry as a viable tool in diamond exploration.
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Affiliation(s)
- Andrea Giuliani
- Institute for Geochemistry and Petrology, Department of Earth Sciences, ETH Zürich, Zürich, Switzerland.
| | - David Phillips
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - D Graham Pearson
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AL, Canada
| | - Soumendu Sarkar
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Alex A Müller
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AL, Canada
| | - Yaakov Weiss
- Institute of Earth Sciences, The Hebrew University, Jerusalem, Israel
| | | | | | - Zdislav Spetsius
- Institute of Diamond and Precious Metal Geology, Siberian Branch of the Russian Academy of Science, Yakutsk, Russia
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3
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Gernon TM, Jones SM, Brune S, Hincks TK, Palmer MR, Schumacher JC, Primiceri RM, Field M, Griffin WL, O'Reilly SY, Keir D, Spencer CJ, Merdith AS, Glerum A. Rift-induced disruption of cratonic keels drives kimberlite volcanism. Nature 2023; 620:344-350. [PMID: 37495695 PMCID: PMC10727985 DOI: 10.1038/s41586-023-06193-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 05/10/2023] [Indexed: 07/28/2023]
Abstract
Kimberlites are volatile-rich, occasionally diamond-bearing magmas that have erupted explosively at Earth's surface in the geologic past1-3. These enigmatic magmas, originating from depths exceeding 150 km in Earth's mantle1, occur in stable cratons and in pulses broadly synchronous with supercontinent cyclicity4. Whether their mobilization is driven by mantle plumes5 or by mechanical weakening of cratonic lithosphere4,6 remains unclear. Here we show that most kimberlites spanning the past billion years erupted about 30 million years (Myr) after continental breakup, suggesting an association with rifting processes. Our dynamical and analytical models show that physically steep lithosphere-asthenosphere boundaries (LABs) formed during rifting generate convective instabilities in the asthenosphere that slowly migrate many hundreds to thousands of kilometres inboard of rift zones. These instabilities endure many tens of millions of years after continental breakup and destabilize the basal tens of kilometres of the cratonic lithosphere, or keel. Displaced keel is replaced by a hot, upwelling mixture of asthenosphere and recycled volatile-rich keel in the return flow, causing decompressional partial melting. Our calculations show that this process can generate small-volume, low-degree, volatile-rich melts, closely matching the characteristics expected of kimberlites1-3. Together, these results provide a quantitative and mechanistic link between kimberlite episodicity and supercontinent cycles through progressive disruption of cratonic keels.
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Affiliation(s)
- Thomas M Gernon
- School of Ocean and Earth Science, University of Southampton, Southampton, UK.
| | - Stephen M Jones
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Sascha Brune
- Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany
- University of Potsdam, Potsdam-Golm, Germany
| | - Thea K Hincks
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Martin R Palmer
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
| | | | - Rebecca M Primiceri
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
| | | | - William L Griffin
- GEMOC ARC National Key Centre, Department of Earth and Environmental Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Suzanne Y O'Reilly
- GEMOC ARC National Key Centre, Department of Earth and Environmental Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Derek Keir
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
- Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, Florence, Italy
| | - Christopher J Spencer
- Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario, Canada
| | | | - Anne Glerum
- Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany
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4
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Mather BR, Müller RD, Alfonso CP, Seton M, Wright NM. Kimberlite eruptions driven by slab flux and subduction angle. Sci Rep 2023; 13:9216. [PMID: 37280326 DOI: 10.1038/s41598-023-36250-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 05/30/2023] [Indexed: 06/08/2023] Open
Abstract
Kimberlites are sourced from thermochemical upwellings which can transport diamonds to the surface of the crust. The majority of kimberlites preserved at the Earth's surface erupted between 250 and 50 million years ago, and have been attributed to changes in plate velocity or mantle plumes. However, these mechanisms fail to explain the presence of strong subduction signatures observed in some Cretaceous kimberlites. This raises the question whether there is a subduction process that unifies our understanding of the timing of kimberlite eruptions. We develop a novel formulation for calculating subduction angle based on trench migration, convergence rate, slab thickness and density to connect the influx of slab material into the mantle with the timing of kimberlite eruptions. We find that subduction angles combined with peaks in slab flux predict pulses of kimberlite eruptions. High rates of subducting slab material trigger mantle return flow that stimulates fertile reservoirs in the mantle. These convective instabilities transport slab-influenced melt to the surface at a distance inbound from the trench corresponding to the subduction angle. Our deep-time slab dip formulation has numerous potential applications including modelling the deep carbon and water cycles, and an improved understanding of subduction-related mineral deposits.
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Affiliation(s)
- Ben R Mather
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, 2006, Australia.
| | - R Dietmar Müller
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, 2006, Australia
| | - Christopher P Alfonso
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, 2006, Australia
| | - Maria Seton
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, 2006, Australia
| | - Nicky M Wright
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, 2006, Australia
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Giuliani A, Drysdale RN, Woodhead JD, Planavsky NJ, Phillips D, Hergt J, Griffin WL, Oesch S, Dalton H, Davies GR. Perturbation of the deep-Earth carbon cycle in response to the Cambrian Explosion. SCIENCE ADVANCES 2022; 8:eabj1325. [PMID: 35245120 PMCID: PMC8896790 DOI: 10.1126/sciadv.abj1325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 01/11/2022] [Indexed: 05/26/2023]
Abstract
Earth's carbon cycle is strongly influenced by subduction of sedimentary material into the mantle. The composition of the sedimentary subduction flux has changed considerably over Earth's history, but the impact of these changes on the mantle carbon cycle is unclear. Here, we show that the carbon isotopes of kimberlite magmas record a fundamental change in their deep-mantle source compositions during the Phanerozoic Eon. The 13C/12C of kimberlites before ~250 Ma preserves typical mantle values, whereas younger kimberlites exhibit lower and more variable ratios-a switch coincident with a recognized surge in kimberlite magmatism. We attribute these changes to increased deep subduction of organic carbon with low 13C/12C following the Cambrian Explosion when organic carbon deposition in marine sediments increased significantly. These observations demonstrate that biogeochemical processes at Earth's surface have a profound influence on the deep mantle, revealing an integral link between the deep and shallow carbon cycles.
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Affiliation(s)
- Andrea Giuliani
- Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Clausiusstrasse 25, Zurich 8092, Switzerland
| | - Russell N. Drysdale
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Jon D. Woodhead
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Noah J. Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - David Phillips
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Janet Hergt
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - William L. Griffin
- Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC, Department of Earth and Environmental Sciences, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Senan Oesch
- Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Clausiusstrasse 25, Zurich 8092, Switzerland
| | - Hayden Dalton
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Gareth R. Davies
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands
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Xu JY, Giuliani A, Li QL, Lu K, Melgarejo JC, Griffin WL. Light oxygen isotopes in mantle-derived magmas reflect assimilation of sub-continental lithospheric mantle material. Nat Commun 2021; 12:6295. [PMID: 34728640 PMCID: PMC8563987 DOI: 10.1038/s41467-021-26668-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 10/05/2021] [Indexed: 11/09/2022] Open
Abstract
Oxygen isotope ratios in mantle-derived magmas that differ from typical mantle values are generally attributed to crustal contamination, deeply subducted crustal material in the mantle source or primordial heterogeneities. Here we provide an alternative view for the origin of light oxygen-isotope signatures in mantle-derived magmas using kimberlites, carbonate-rich magmas that assimilate mantle debris during ascent. Olivine grains in kimberlites are commonly zoned between a mantle-derived core and a magmatic rim, thus constraining the compositions of both mantle wall-rocks and melt phase. Secondary ion mass spectrometry (SIMS) analyses of olivine in worldwide kimberlites show a remarkable correlation between mean oxygen-isotope compositions of cores and rims from mantle-like 18O/16O to lower 'crustal' values. This observation indicates that kimberlites entraining low-18O/16O olivine xenocrysts are modified by assimilation of low-18O/16O sub-continental lithospheric mantle material. Interaction with geochemically-enriched domains of the sub-continental lithospheric mantle can therefore be an important source of apparently 'crustal' signatures in mantle-derived magmas.
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Affiliation(s)
- Jing-Yao Xu
- grid.9227.e0000000119573309State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China ,grid.9227.e0000000119573309Innovation Academy for Earth Science, Chinese Academy of Sciences, 100029 Beijing, China
| | - Andrea Giuliani
- grid.5801.c0000 0001 2156 2780Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Qiu-Li Li
- grid.9227.e0000000119573309State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China ,grid.9227.e0000000119573309Innovation Academy for Earth Science, Chinese Academy of Sciences, 100029 Beijing, China ,grid.410726.60000 0004 1797 8419College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Kai Lu
- grid.9227.e0000000119573309State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China ,grid.410726.60000 0004 1797 8419College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Joan Carles Melgarejo
- grid.5841.80000 0004 1937 0247Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona, 08028 Barcelona, Spain
| | - William L. Griffin
- grid.1004.50000 0001 2158 5405ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC, Earth and Environmental Sciences, Macquarie University, Sydney, NSW 2109 Australia
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7
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Abstract
Globally distributed kimberlites with broadly chondritic initial 143Nd-176Hf isotopic systematics may be derived from a chemically homogenous, relatively primitive mantle source that remained isolated from the convecting mantle for much of the Earth's history. To assess whether this putative reservoir may have preserved remnants of an early Earth process, we report 182W/184W and 142Nd/144Nd data for "primitive" kimberlites from 10 localities worldwide, ranging in age from 1,153 to 89 Ma. Most are characterized by homogeneous μ182W and μ142Nd values averaging -5.9 ± 3.6 ppm (2SD, n = 13) and +2.7 ± 2.9 ppm (2SD, n = 6), respectively. The remarkably uniform yet modestly negative μ182W values, coupled with chondritic to slightly suprachondritic initial 143Nd/144Nd and 176Hf/177Hf ratios over a span of nearly 1,000 Mya, provides permissive evidence that these kimberlites were derived from one or more long-lived, early formed mantle reservoirs. Possible causes for negative μ182W values among these kimberlites include the transfer of W with low μ182W from the core to the mantle source reservoir(s), creation of the source reservoir(s) as a result of early silicate fractionation, or an overabundance of late-accreted materials in the source reservoir(s). By contrast, two younger kimberlites emplaced at 72 and 52 Ma and characterized by distinctly subchondritic initial 176Hf/177Hf and 143Nd/144Nd have μ182W values consistent with the modern upper mantle. These isotopic compositions may reflect contamination of the ancient kimberlite source by recycled crustal components with μ182W ≥ 0.
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8
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Remnants of early Earth differentiation in the deepest mantle-derived lavas. Proc Natl Acad Sci U S A 2020; 118:2015211118. [PMID: 33443165 DOI: 10.1073/pnas.2015211118] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites-volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically depleted component (where geochemical depletion refers to ancient melt extraction) common to most oceanic island basalts, previously called PREMA (prevalent mantle) or FOZO (focal zone). Extrapolation of the Nd and Hf isotopic compositions of the kimberlite source to the age of Earth formation yields a 143Nd/144Nd-176Hf/177Hf composition within error of chondrite meteorites, which include the likely parent bodies of Earth. This supports a hypothesis where the source of kimberlites and ocean island basalts contains a long-lived component that formed by melt extraction from a domain with chondritic 143Nd/144Nd and 176Hf/177Hf shortly after Earth accretion. The geographic distribution of kimberlites containing the PREMA component suggests that these remnants of early Earth differentiation are located in large seismically anomalous regions corresponding to thermochemical piles above the core-mantle boundary. PREMA could have been stored in these structures for most of Earth's history, partially shielded from convective homogenization.
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Blanks DE, Holwell DA, Fiorentini ML, Moroni M, Giuliani A, Tassara S, González-Jiménez JM, Boyce AJ, Ferrari E. Fluxing of mantle carbon as a physical agent for metallogenic fertilization of the crust. Nat Commun 2020; 11:4342. [PMID: 32859892 PMCID: PMC7455710 DOI: 10.1038/s41467-020-18157-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 08/04/2020] [Indexed: 11/09/2022] Open
Abstract
Magmatic systems play a crucial role in enriching the crust with volatiles and elements that reside primarily within the Earth's mantle, including economically important metals like nickel, copper and platinum-group elements. However, transport of these metals within silicate magmas primarily occurs within dense sulfide liquids, which tend to coalesce, settle and not be efficiently transported in ascending magmas. Here we show textural observations, backed up with carbon and oxygen isotope data, which indicate an intimate association between mantle-derived carbonates and sulfides in some mafic-ultramafic magmatic systems emplaced at the base of the continental crust. We propose that carbon, as a buoyant supercritical CO2 fluid, might be a covert agent aiding and promoting the physical transport of sulfides across the mantle-crust transition. This may be a common but cryptic mechanism that facilitates cycling of volatiles and metals from the mantle to the lower-to-mid continental crust, which leaves little footprint behind by the time magmas reach the Earth's surface.
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Affiliation(s)
- Daryl E Blanks
- Centre for Sustainable Resource Extraction, School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester, LE1 7RH, UK.
| | - David A Holwell
- Centre for Sustainable Resource Extraction, School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Marco L Fiorentini
- Centre for Exploration Targeting, School of Earth Sciences, ARC Centre of Excellence for Core to Crust Fluid Systems, University of Western Australia, Perth, WA, 6009, Australia
| | - Marilena Moroni
- Earth Science Department, Milan State University, Milan, Italy
| | - Andrea Giuliani
- Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Clausiusstrasse 25, Zurich, 8092, Switzerland
- Kimberlites and Diamonds (KiDs), School of Earth Sciences, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Santiago Tassara
- Earth and Planetary Sciences, Yale University, PO Box 208109, New Haven, CT, 06520-8109, USA
- Millennium Nucleus for Metal Tracing Along Subduction, FCFM, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile
| | - José M González-Jiménez
- Departmento de Mineralogía y Petrología, Universidad de Granada, Facultad de Ciencias, Fuentenueva s/n, 180002, Granada, Spain
| | - Adrian J Boyce
- Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, UK
| | - Elena Ferrari
- Earth Science Department, Milan State University, Milan, Italy
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