Carbon spherules in Ni-Cu-PGE sulphide deposits in the Sudbury impact structure, Canada

Alison Jane Wright, John Parnell, D. E. Ames

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The formation of Sudbury's economically important magmatic Ni-Cu-PGE sulphide deposits is attributed to superheating of crustal rocks, following meteorite impact at 1.85 Ga. Crustal contamination of magmatic sulphide deposits is thought to be important in the mineralization process and this paper documents the first occurrence of sedimentary carbon in the Sudbury Ni-Cu-PGE sulphides near the base of the Sudbury Igneous Complex (SIC). Spherules of graphitic and more disordered carbon inclusions were found in chalcopyrite crystals, suggesting that carbon has behaved as a chalcophilic element in the impact melt. Samples from the impact structure have been subjected to carbon isotopic analysis and Raman microspectroscopy in order to investigate the relationship between carbonaceous strata of the Huronian basement, the crater-fill impact breccias, and the mineral deposits associated with the Sudbury impact. Carbonaceous material occurs in the impact breccias of the Onaping Formation and this study presents stratigraphically constrained carbon isotopic analysis of the impact breccias. Sulphides from the hydrothermal Zn-Pb-Cu Vermilion-Errington deposits 1.5 km above the SIC were found to contain both carbon spherules and larger irregular carbonaceous flakes, suggesting a genetic link between the Ni-Cu-PGE deposits and the hydrothermal Zn-Pb-Cu mineralization. A shared source of carbon for the Vermilion-Errington mineralization and the cross-cutting anthraxolite veins 100m above the deposits in post-impact carbonaceous shales of the Onwatin Formation is indicated by the similarity in their Raman spectra. This is considered to be carbon remobilized by metamorphic hydrothermal fluids preferentially scavenging disordered carbon from within the Onaping Formation breccias. The occurrence of carbon in the Sudbury Ni-Cu-PGE massive sulphide deposits indicates that carbon from the target rocks played a role in the mineralization process, hitherto unrecognized. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)23-38
Number of pages16
JournalPrecambrian Research
Volume177
Issue number1-2
DOIs
Publication statusPublished - Feb 2010

Keywords

  • Carbon
  • Graphite
  • Ni-Cu mineralization
  • Raman microspectroscopy
  • Sudbury impact structure
  • Impact breccia
  • IGNEOUS COMPLEX
  • ISOTOPIC VARIATIONS
  • RAMAN-SPECTRA
  • MELT SHEET
  • GRAPHITE
  • ONTARIO
  • REDISTRIBUTION
  • GENESIS
  • GEOLOGY
  • SYSTEM
  • Impact breccia

Cite this

Carbon spherules in Ni-Cu-PGE sulphide deposits in the Sudbury impact structure, Canada. / Wright, Alison Jane; Parnell, John; Ames, D. E.

In: Precambrian Research, Vol. 177, No. 1-2, 02.2010, p. 23-38.

Research output: Contribution to journalArticle

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abstract = "The formation of Sudbury's economically important magmatic Ni-Cu-PGE sulphide deposits is attributed to superheating of crustal rocks, following meteorite impact at 1.85 Ga. Crustal contamination of magmatic sulphide deposits is thought to be important in the mineralization process and this paper documents the first occurrence of sedimentary carbon in the Sudbury Ni-Cu-PGE sulphides near the base of the Sudbury Igneous Complex (SIC). Spherules of graphitic and more disordered carbon inclusions were found in chalcopyrite crystals, suggesting that carbon has behaved as a chalcophilic element in the impact melt. Samples from the impact structure have been subjected to carbon isotopic analysis and Raman microspectroscopy in order to investigate the relationship between carbonaceous strata of the Huronian basement, the crater-fill impact breccias, and the mineral deposits associated with the Sudbury impact. Carbonaceous material occurs in the impact breccias of the Onaping Formation and this study presents stratigraphically constrained carbon isotopic analysis of the impact breccias. Sulphides from the hydrothermal Zn-Pb-Cu Vermilion-Errington deposits 1.5 km above the SIC were found to contain both carbon spherules and larger irregular carbonaceous flakes, suggesting a genetic link between the Ni-Cu-PGE deposits and the hydrothermal Zn-Pb-Cu mineralization. A shared source of carbon for the Vermilion-Errington mineralization and the cross-cutting anthraxolite veins 100m above the deposits in post-impact carbonaceous shales of the Onwatin Formation is indicated by the similarity in their Raman spectra. This is considered to be carbon remobilized by metamorphic hydrothermal fluids preferentially scavenging disordered carbon from within the Onaping Formation breccias. The occurrence of carbon in the Sudbury Ni-Cu-PGE massive sulphide deposits indicates that carbon from the target rocks played a role in the mineralization process, hitherto unrecognized. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.",
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N2 - The formation of Sudbury's economically important magmatic Ni-Cu-PGE sulphide deposits is attributed to superheating of crustal rocks, following meteorite impact at 1.85 Ga. Crustal contamination of magmatic sulphide deposits is thought to be important in the mineralization process and this paper documents the first occurrence of sedimentary carbon in the Sudbury Ni-Cu-PGE sulphides near the base of the Sudbury Igneous Complex (SIC). Spherules of graphitic and more disordered carbon inclusions were found in chalcopyrite crystals, suggesting that carbon has behaved as a chalcophilic element in the impact melt. Samples from the impact structure have been subjected to carbon isotopic analysis and Raman microspectroscopy in order to investigate the relationship between carbonaceous strata of the Huronian basement, the crater-fill impact breccias, and the mineral deposits associated with the Sudbury impact. Carbonaceous material occurs in the impact breccias of the Onaping Formation and this study presents stratigraphically constrained carbon isotopic analysis of the impact breccias. Sulphides from the hydrothermal Zn-Pb-Cu Vermilion-Errington deposits 1.5 km above the SIC were found to contain both carbon spherules and larger irregular carbonaceous flakes, suggesting a genetic link between the Ni-Cu-PGE deposits and the hydrothermal Zn-Pb-Cu mineralization. A shared source of carbon for the Vermilion-Errington mineralization and the cross-cutting anthraxolite veins 100m above the deposits in post-impact carbonaceous shales of the Onwatin Formation is indicated by the similarity in their Raman spectra. This is considered to be carbon remobilized by metamorphic hydrothermal fluids preferentially scavenging disordered carbon from within the Onaping Formation breccias. The occurrence of carbon in the Sudbury Ni-Cu-PGE massive sulphide deposits indicates that carbon from the target rocks played a role in the mineralization process, hitherto unrecognized. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

AB - The formation of Sudbury's economically important magmatic Ni-Cu-PGE sulphide deposits is attributed to superheating of crustal rocks, following meteorite impact at 1.85 Ga. Crustal contamination of magmatic sulphide deposits is thought to be important in the mineralization process and this paper documents the first occurrence of sedimentary carbon in the Sudbury Ni-Cu-PGE sulphides near the base of the Sudbury Igneous Complex (SIC). Spherules of graphitic and more disordered carbon inclusions were found in chalcopyrite crystals, suggesting that carbon has behaved as a chalcophilic element in the impact melt. Samples from the impact structure have been subjected to carbon isotopic analysis and Raman microspectroscopy in order to investigate the relationship between carbonaceous strata of the Huronian basement, the crater-fill impact breccias, and the mineral deposits associated with the Sudbury impact. Carbonaceous material occurs in the impact breccias of the Onaping Formation and this study presents stratigraphically constrained carbon isotopic analysis of the impact breccias. Sulphides from the hydrothermal Zn-Pb-Cu Vermilion-Errington deposits 1.5 km above the SIC were found to contain both carbon spherules and larger irregular carbonaceous flakes, suggesting a genetic link between the Ni-Cu-PGE deposits and the hydrothermal Zn-Pb-Cu mineralization. A shared source of carbon for the Vermilion-Errington mineralization and the cross-cutting anthraxolite veins 100m above the deposits in post-impact carbonaceous shales of the Onwatin Formation is indicated by the similarity in their Raman spectra. This is considered to be carbon remobilized by metamorphic hydrothermal fluids preferentially scavenging disordered carbon from within the Onaping Formation breccias. The occurrence of carbon in the Sudbury Ni-Cu-PGE massive sulphide deposits indicates that carbon from the target rocks played a role in the mineralization process, hitherto unrecognized. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

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KW - Graphite

KW - Ni-Cu mineralization

KW - Raman microspectroscopy

KW - Sudbury impact structure

KW - Impact breccia

KW - IGNEOUS COMPLEX

KW - ISOTOPIC VARIATIONS

KW - RAMAN-SPECTRA

KW - MELT SHEET

KW - GRAPHITE

KW - ONTARIO

KW - REDISTRIBUTION

KW - GENESIS

KW - GEOLOGY

KW - SYSTEM

KW - Impact breccia

U2 - 10.1016/j.precamres.2009.11.002

DO - 10.1016/j.precamres.2009.11.002

M3 - Article

VL - 177

SP - 23

EP - 38

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

IS - 1-2

ER -