In Situ Multiple Sulfur Isotope and S/Se Composition of Magmatic Sulfide Occurrences in the Labrador Trough, Northern Quebec
| Autor: | W. D. Smith, Wolfgang D. Maier, Laure Martin, Ian Bliss |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
In situ
010504 meteorology & atmospheric sciences Isotope Trough (geology) Geochemistry chemistry.chemical_element Geology 010502 geochemistry & geophysics 01 natural sciences Sulfur Geophysics chemistry Geochemistry and Petrology Economic Geology Composition (visual arts) Magmatic sulfide 0105 earth and related environmental sciences |
| Zdroj: | Economic Geology. 116:1669-1686 |
| ISSN: | 1554-0774 0361-0128 |
| DOI: | 10.5382/econgeo.4843 |
| Popis: | The interaction between mafic-ultramafic magma and crustal sulfide is considered a key process in the formation of magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Integrated S/Se and multiple sulfur isotope studies are the most robust in constraining the role of crustal sulfur during ore genesis. In the present study, we report the first integrated S/Se and multiple sulfur isotope study of magmatic sulfide occurrences in the Labrador Trough, namely, on the recently discovered Idefix PGE-Cu and Huckleberry Cu-Ni-(PGE) prospects.Whole-rock and in situ S/Se values (~810–3115) of magmatic sulfides and their host rocks are consistent with S loss during postmagmatic hydrothermal alteration, negating their use in interpreting the origin of S. Values of ∆33S ~0 indicate no record of the assimilation of Archaean sulfur. Disseminated (–0.5 to +2.5‰) and globular (3.0–4.5‰) sulfides at Idefix as well as globular sulfides (2.1–9.6‰) at Huckleberry have δ34S values greater than the accepted mantle range, suggesting that crustal S played a role in the formation of these sulfides. In contrast, disseminated and net-textured sulfides at Huckleberry have variable δ34S values (–4.6 to +3.2‰) that are mostly within the accepted mantle range, excluding one anomalous sample that records relatively higher δ34S values (11.9–15.0‰). It is proposed that sulfide melt segregated in response to the addition of small proportions of crustal S prior to the final emplacement of the host intrusions, i.e., in a feeder conduit or staging chamber. Isotopic exchange between the sulfide melt and silicate magma has diluted and, in places, eradicated a crustal δ34S signature. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|