Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile

Baker, R. G. A.; Rehkämper, Mark; Ihlenfeld, Christian; Oates, Christopher J.; Coggon, Rosalind M.

doi:10.1016/j.gca.2010.04.068

Cited by 33 publications

(32 citation statements)

References 26 publications

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“…5) lies in the range previously determined for Cu porphyry deposits (Baker et al 2010). This supports the interpretation of the magmatic origin of the Pizzo Cervandone mineralization as previously suggested by Graeser and Roggiani (1976).…”

Section: Evidence From Tl Isotope Composition On the Origin And Mobilsupporting

confidence: 76%

Thallium geochemistry in the metamorphic Lengenbach sulfide deposit, Switzerland: Thallium-isotope fractionation in a sulfide melt

Hettmann

Kreissig

Rehkämper

et al. 2014

American Mineralogist

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The Lengenbach (Switzerland) Pb-As-Tl-Zn deposit was formed from a sulfide melt at about 500 °C during Alpine metamorphism, but details on its formation and especially the source of the metals are still under debate. In this study we present two sample sets to address these questions:(1) MC-ICP-MS analyses of thallium isotopes in sulfides, sulfosalts, and melt inclusions from the Alpine metamorphic Lengenbach deposit in the Binn Valley of Switzerland, the non-metamorphic Wiesloch Mississippi Valley-type deposit in Southern Germany, and the Cu-and As-rich mineralization at Pizzo Cervandone about 2 km SW of the Lengenbach deposit, which has been discussed as potential source of the Lengenbach metals.(2) LA-ICP-MS analyses of micas from the Lengenbach deposit and surrounding country rocks between the deposit and the Pizzo Cervandone to trace potential metal-bearing fluid pathways.We found that Tl isotope compositions expressed as e 205 Tl values in all investigated samples range from -4.1 ± 0.5 to +1.9 ± 0.5. The whole variation can be seen in the Lengenbach deposit alone, which hence records considerable fractionation even during high-temperature processes involving a sulfide melt. This large range of e 205 Tl is thought to be caused by nuclear volume-dependent fractionation. Interestingly, the common fahlores at Lengenbach behave differently from all other investigated sulfosalts: based on their heavy isotopic composition together with a low As/S-ratio, they do not seem to be crystallized from the sulfide melt, but are interpreted to have formed from hydrothermal fluids enriched in the heavy Tl isotopes. Although As mobilization in the gneisses and dolomites surrounding the Lengenbach deposit is evident based on secondary arsenites, no traces of such a country rock fluid could be found in fissure micas at Lengenbach. Hence, considerations involving K/Rb, Rb/Tl, As/S, and Pb/Tl ratios in the sulfides and micas imply that the element enrichment in the Lengenbach deposit is either pre-Alpine or related to peak metamorphism, but occurred definitely before mica growth at Lengenbach.

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Section: Evidence From Tl Isotope Composition On the Origin And Mobilsupporting

confidence: 76%

Thallium geochemistry in the metamorphic Lengenbach sulfide deposit, Switzerland: Thallium-isotope fractionation in a sulfide melt

Hettmann

Kreissig

Rehkämper

et al. 2014

American Mineralogist

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“…Two previous studies are of particular relevance (Baker et al, 2010;Hettmann et al, 2014). This study presents two suites of lavas from tectonically distinct locations (Hekla, Iceland, and Anatahan, Mariana intra-oceanic arc) to assess:…”

Section: Accepted Manuscriptmentioning

confidence: 89%

“…McGoldrick et al (1979) suggests that Tl displays chalcophile behavior and follows sulphur in sulphur-saturated magmas. However, study of sulphur-rich ore deposits (Baker et al 2010) Most recently, Nielsen et al (2014) have shown that the only phase housing significant Tl in the lherz massif are interstitial sulphides, which yielded variable concentrations from 23 to 430 ng/g. Noll et al (1996) assumed that Tl behaved as a chalcophile element and used chalcophile/lithophile element ratios in subductionrelated lavas to determine relative fluid mobility of trace elements.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Since the initial work of Rehkämper and Halliday (1999), study of Tl stable isotopes includes diverse applications such as the tracing of pollutants (Kersten et al, 2014), ore genesis (Baker et al, 2010;Hettmann et al 2014), cosmochemistry (Nielsen et al, 2006a), paleoceanography (Nielsen et al, 2011), hydrothermal alteration (Coggon et al, 2014Nielsen et al, 2006b), and seawater chemistry (Baker Nielsen et al, 2004). Previous work relevant to magmatic systems includes investigation of volcanic aerosols, a peralkaline intrusive complex, eclogites, MORB, Icelandic and Hawaiian picrites, Azorean and arc lavas (Baker et al, 2009;Hettmann et al, 2013;Nielsen et al 2006cNielsen et al , 2007Nielsen et al , 2009aNielsen et al , 2016aPrytulak et al 2013b).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

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Thallium elemental behavior and stable isotope fractionation during magmatic processes

et al. 2017

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Please cite this article as: Prytulak, J., Brett, A., Webb, M., Plank, T., Rehkämper, M., Savage, P.S., Woodhead, J., Thallium elemental behavior and stable isotope fractionation during magmatic processes, Chemical Geology (2016), doi: 10.1016/j.chemgeo. 2016.11.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractStable thallium (Tl) isotopes are an extremely sensitive tracer for the addition of small amounts of sediments or materials altered at low temperatures to the source(s) of mantle-derived melts. The ability of Tl to trace such materials is due to the large concentration contrast between the mantle (Tl < 2ng/g) and possible exotic inputs (Tl ~100ng/g to >g/g), which also often display fractionated Tl isotope compositions.However, the magnitude of Tl isotope fractionation induced by igneous processes alone has not been systematically assessed. Here, two suites of co-genetic magmas, spanning a large range of differentiation, from Hekla, Iceland, and Anatahan, in the Mariana arc, are used to assess the behavior of thallium and its stable isotope variations during magmatic processes. Thallium behaves as a near-perfectly incompatible lithophile element throughout magmatic evolution, mirroring elements such as Rb, Cs, and K. Lavas from Hekla have restricted Cs/Tl ratios and stable Tl isotope compositions, which overlap with mantle estimates. Lavas from subductionrelated Anatahan volcano also have a restricted range in Tl isotope composition, which overlaps with Hekla and MORB, demonstrating that fractional crystallisation and partial melting does not fractionate stable Tl isotopes. Subduction environments display variable Cs/Tl, indicating that the subduction process commonly fractionates these two elements. The immunity of thallium stable isotopes to fractionation by magmatic processes coupled with its extreme sensitivity for tracing pelagic sediments, FeMn crusts and low temperature altered oceanic crust highlight its value in elucidating the nature of mantle sources of both oceanic basalts and arc lavas.Critically, meaningful interpretation of thallium isotope compositions need not be restricted to primitive lavas.

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“…Tl [149] and references therein, [150][151][152][153] Significant isotopic variability in natural samples points to the potential of Tl-isotopes for understanding formation of hydrothermal deposits; more baseline data are needed. …”

Section: Non-traditional Stable Isotopesmentioning

confidence: 99%

Advances and Opportunities in Ore Mineralogy

et al. 2017

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Abstract:The study of ore minerals is rapidly transforming due to an explosion of new microand nano-analytical technologies. These advanced microbeam techniques can expose the physical and chemical character of ore minerals at ever-better spatial resolution and analytical precision. The insights that can be obtained from ten of today's most important, or emerging, techniques and methodologies are reviewed: laser-ablation inductively-coupled plasma mass spectrometry; focussed ion beam-scanning electron microscopy; high-angle annular dark field scanning transmission electron microscopy; electron back-scatter diffraction; synchrotron X-ray fluorescence mapping; automated mineral analysis (Quantitative Evaluation of Mineralogy via Scanning Electron Microscopy and Mineral Liberation Analysis); nanoscale secondary ion mass spectrometry; atom probe tomography; radioisotope geochronology using ore minerals; and, non-traditional stable isotopes. Many of these technical advances cut across conceptual boundaries between mineralogy and geochemistry and require an in-depth knowledge of the material that is being analysed. These technological advances are accompanied by changing approaches to ore mineralogy: the increased focus on trace element distributions; the challenges offered by nanoscale characterisation; and the recognition of the critical petrogenetic information in gangue minerals, and, thus the need to for a holistic approach to the characterization of mineral assemblages. Using original examples, with an emphasis on iron oxide-copper-gold deposits, we show how increased analytical capabilities, particularly imaging and chemical mapping at the nanoscale, offer the potential to resolve outstanding questions in ore mineralogy. Broad regional or deposit-scale genetic models can be validated or refuted by careful analysis at the smallest scales of observation. As the volume of information at different scales of observation expands, the level of complexity that is revealed will increase, in turn generating additional research questions. Topics that are likely to be a focus of breakthrough research over the coming decades include, understanding atomic-scale distributions of metals and the role of nanoparticles, as well how minerals adapt, at the lattice-scale, to changing physicochemical conditions. Most importantly, the complementary use of advanced microbeam techniques allows for information of different types and levels of quantification on the same materials to be correlated.

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Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile

Cited by 33 publications

References 26 publications

Thallium geochemistry in the metamorphic Lengenbach sulfide deposit, Switzerland: Thallium-isotope fractionation in a sulfide melt

Thallium geochemistry in the metamorphic Lengenbach sulfide deposit, Switzerland: Thallium-isotope fractionation in a sulfide melt

Thallium elemental behavior and stable isotope fractionation during magmatic processes

Advances and Opportunities in Ore Mineralogy

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