Tracking mineralisation with in situ multiple sulphur isotopes: a case study from the Fraser Zone, Western Australia

A. T. Walker, K. A. Evans, C. L. Kirkland, L. Martin, O. C. Kiddie, C. V. Spaggiari

Research output: Contribution to journalArticle

Abstract

Sulphur isotopes have become a widely deployed tool to address the sources of fluids in ore systems, given the widespread interaction of H2S, HS and S2 - with metals. However, the sensitivity of sulphur isotopes to magma source composition relative to other radiogenic isotopes and the nature of processes differentially affecting isotopic systems have not been extensively explored in magmatic mineral systems. In this work we present a case study of sulphide bearing magmas within the Fraser Zone of the Albany-Fraser Orogen in Western Australia that seeks to evaluate the sensitivity of sulphur isotopes to track magma source composition in space and time. New δ34S data from mineralised NRM, Plato and Octagonal localities of the Fraser Zone indicate variable degrees of assimilation of local sediments of the Snowys Dam Formation. Despite an Archean heritage in the Fraser Zone magmas being indicated by radiogenic isotopes, sparse xenocrystic zircon, and whole rock geochemical modelling, Δ33S data from these localities reveal Archean sulphur is absent; implying decoupling of the sulphur component from other geochemical and isotopic systems. This is consistent with a mechanism by which Archean sulphur was removed from detrital material incorporated in the Fraser Zone. We conclude that sulphides were stripped from sediments during uplift, erosion and transport to the Fraser Zone, with these Archean-sulphur depleted sediments then assimilated by the Fraser Zone parental magmas. Our results indicate a coupling between variable assimilation of external sulphur by Fraser Zone magmas and the mineralisation present at the prospects studied. However assimilated sulphur cannot account for all of the sulphur within mineralised samples, indicating the involvement of additional processes such as tenor upgrading.

Original languageEnglish
Article number105379
JournalPrecambrian Research
Volume332
DOIs
Publication statusPublished - 15 Sep 2019

Fingerprint

Sulfur Isotopes
sulfur isotope
Sulfur
sulfur
mineralization
Archean
Sediments
Sulfides
Isotopes
Bearings (structural)
magma
sulfide
isotope
sediment
in situ
Chemical analysis
Dams
Ores
Minerals
Data structures

Cite this

Walker, A. T. ; Evans, K. A. ; Kirkland, C. L. ; Martin, L. ; Kiddie, O. C. ; Spaggiari, C. V. / Tracking mineralisation with in situ multiple sulphur isotopes : a case study from the Fraser Zone, Western Australia. In: Precambrian Research. 2019 ; Vol. 332.
@article{5da281b950814d36bda0d5a46671d9ca,
title = "Tracking mineralisation with in situ multiple sulphur isotopes: a case study from the Fraser Zone, Western Australia",
abstract = "Sulphur isotopes have become a widely deployed tool to address the sources of fluids in ore systems, given the widespread interaction of H2S, HS− and S2 - with metals. However, the sensitivity of sulphur isotopes to magma source composition relative to other radiogenic isotopes and the nature of processes differentially affecting isotopic systems have not been extensively explored in magmatic mineral systems. In this work we present a case study of sulphide bearing magmas within the Fraser Zone of the Albany-Fraser Orogen in Western Australia that seeks to evaluate the sensitivity of sulphur isotopes to track magma source composition in space and time. New δ34S data from mineralised NRM, Plato and Octagonal localities of the Fraser Zone indicate variable degrees of assimilation of local sediments of the Snowys Dam Formation. Despite an Archean heritage in the Fraser Zone magmas being indicated by radiogenic isotopes, sparse xenocrystic zircon, and whole rock geochemical modelling, Δ33S data from these localities reveal Archean sulphur is absent; implying decoupling of the sulphur component from other geochemical and isotopic systems. This is consistent with a mechanism by which Archean sulphur was removed from detrital material incorporated in the Fraser Zone. We conclude that sulphides were stripped from sediments during uplift, erosion and transport to the Fraser Zone, with these Archean-sulphur depleted sediments then assimilated by the Fraser Zone parental magmas. Our results indicate a coupling between variable assimilation of external sulphur by Fraser Zone magmas and the mineralisation present at the prospects studied. However assimilated sulphur cannot account for all of the sulphur within mineralised samples, indicating the involvement of additional processes such as tenor upgrading.",
keywords = "Fraser Zone, Magmatic sulphides, Multiple sulphur isotopes, Sulphide minerals, Western Australia",
author = "Walker, {A. T.} and Evans, {K. A.} and Kirkland, {C. L.} and L. Martin and Kiddie, {O. C.} and Spaggiari, {C. V.}",
year = "2019",
month = "9",
day = "15",
doi = "10.1016/j.precamres.2019.105379",
language = "English",
volume = "332",
journal = "Precambrian Research",
issn = "0301-9268",
publisher = "Pergamon",

}

Tracking mineralisation with in situ multiple sulphur isotopes : a case study from the Fraser Zone, Western Australia. / Walker, A. T.; Evans, K. A.; Kirkland, C. L.; Martin, L.; Kiddie, O. C.; Spaggiari, C. V.

In: Precambrian Research, Vol. 332, 105379, 15.09.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tracking mineralisation with in situ multiple sulphur isotopes

T2 - a case study from the Fraser Zone, Western Australia

AU - Walker, A. T.

AU - Evans, K. A.

AU - Kirkland, C. L.

AU - Martin, L.

AU - Kiddie, O. C.

AU - Spaggiari, C. V.

PY - 2019/9/15

Y1 - 2019/9/15

N2 - Sulphur isotopes have become a widely deployed tool to address the sources of fluids in ore systems, given the widespread interaction of H2S, HS− and S2 - with metals. However, the sensitivity of sulphur isotopes to magma source composition relative to other radiogenic isotopes and the nature of processes differentially affecting isotopic systems have not been extensively explored in magmatic mineral systems. In this work we present a case study of sulphide bearing magmas within the Fraser Zone of the Albany-Fraser Orogen in Western Australia that seeks to evaluate the sensitivity of sulphur isotopes to track magma source composition in space and time. New δ34S data from mineralised NRM, Plato and Octagonal localities of the Fraser Zone indicate variable degrees of assimilation of local sediments of the Snowys Dam Formation. Despite an Archean heritage in the Fraser Zone magmas being indicated by radiogenic isotopes, sparse xenocrystic zircon, and whole rock geochemical modelling, Δ33S data from these localities reveal Archean sulphur is absent; implying decoupling of the sulphur component from other geochemical and isotopic systems. This is consistent with a mechanism by which Archean sulphur was removed from detrital material incorporated in the Fraser Zone. We conclude that sulphides were stripped from sediments during uplift, erosion and transport to the Fraser Zone, with these Archean-sulphur depleted sediments then assimilated by the Fraser Zone parental magmas. Our results indicate a coupling between variable assimilation of external sulphur by Fraser Zone magmas and the mineralisation present at the prospects studied. However assimilated sulphur cannot account for all of the sulphur within mineralised samples, indicating the involvement of additional processes such as tenor upgrading.

AB - Sulphur isotopes have become a widely deployed tool to address the sources of fluids in ore systems, given the widespread interaction of H2S, HS− and S2 - with metals. However, the sensitivity of sulphur isotopes to magma source composition relative to other radiogenic isotopes and the nature of processes differentially affecting isotopic systems have not been extensively explored in magmatic mineral systems. In this work we present a case study of sulphide bearing magmas within the Fraser Zone of the Albany-Fraser Orogen in Western Australia that seeks to evaluate the sensitivity of sulphur isotopes to track magma source composition in space and time. New δ34S data from mineralised NRM, Plato and Octagonal localities of the Fraser Zone indicate variable degrees of assimilation of local sediments of the Snowys Dam Formation. Despite an Archean heritage in the Fraser Zone magmas being indicated by radiogenic isotopes, sparse xenocrystic zircon, and whole rock geochemical modelling, Δ33S data from these localities reveal Archean sulphur is absent; implying decoupling of the sulphur component from other geochemical and isotopic systems. This is consistent with a mechanism by which Archean sulphur was removed from detrital material incorporated in the Fraser Zone. We conclude that sulphides were stripped from sediments during uplift, erosion and transport to the Fraser Zone, with these Archean-sulphur depleted sediments then assimilated by the Fraser Zone parental magmas. Our results indicate a coupling between variable assimilation of external sulphur by Fraser Zone magmas and the mineralisation present at the prospects studied. However assimilated sulphur cannot account for all of the sulphur within mineralised samples, indicating the involvement of additional processes such as tenor upgrading.

KW - Fraser Zone

KW - Magmatic sulphides

KW - Multiple sulphur isotopes

KW - Sulphide minerals

KW - Western Australia

UR - http://www.scopus.com/inward/record.url?scp=85068527608&partnerID=8YFLogxK

U2 - 10.1016/j.precamres.2019.105379

DO - 10.1016/j.precamres.2019.105379

M3 - Article

VL - 332

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

M1 - 105379

ER -