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dc.contributor.authorCourtney-Davies, Liam
dc.contributor.authorCiobanu, Cristiana
dc.contributor.authorTapster, Simon
dc.contributor.authorCook, Nigel
dc.contributor.authorEhrig, Kathy
dc.contributor.authorCrowley, James
dc.contributor.authorVerdugo-Ihl, Max
dc.contributor.authorWade, Benjamin
dc.contributor.authorCondon, Daniel
dc.date.accessioned2020-12-07T05:04:24Z
dc.date.available2020-12-07T05:04:24Z
dc.date.issued2020
dc.identifier.citationCourtney-Davies, L. and Ciobanu, C. and Tapster, S. and Cook, N. and Ehrig, K. and Crowley, J. and Verdugo-Ihl, M. et al. 2020. Opening the magmatic-hydrothermal window: high-precision U-Pb geochronology of the mesoproterozoic Olympic Dam Cu-U-Au-Ag deposit, South Australia. Economic Geology. 115 (8): pp. 1855-1870.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/81955
dc.identifier.doi10.5382/econgeo.4772
dc.description.abstract

Establishing timescales for iron oxide copper-gold (IOCG) deposit formation and the temporal relationships between ores and the magmatic rocks from which hydrothermal, metal-rich fluids are sourced is often dependent on low-precision data, particularly for deposits that formed during the Proterozoic. Unlike accessory minerals routinely used to track hydrothermal mineralization, iron oxides are dominant components of IOCG systems and are therefore pivotal to understanding deposit evolution. The presence of ubiquitous, magmatic-hydrothermal U-(Pb)-W-Sn-Mo–bearing zoned hematite resolves a range of geochronological issues concerning formation of the ~1.6 Ga Olympic Dam IOCG deposit, South Australia, at up to ~0.05% precision (207Pb/206Pb weighted mean; 2σ) using isotope dilution-thermal ionization mass spectrometry (ID-TIMS). Coupled with chemical abrasion-ID-TIMS zircon dates from host granite and volcanic rocks within and enclosing the ore-body, a confident magmatic-hydrothermal chronology is defined. The youngest zircon date from the granite intrusion hosting Olympic Dam indicates magmatism was occurring up until 1593.28 ± 0.26 Ma. The orebody was principally formed during a major mineralizing event following granite uplift and during cupola collapse, whereby the hematite with the oldest age is recorded in the outer shell of the deposit at 1591.27 ± 0.89 Ma, ~2 m.y. later than the youngest documented magmatic zircon. Hematite dates captured throughout major lithologies, different ore zones, and the ~2-km vertical extent of the deposit support ~2 m.y. of hydrothermal activity. New age constraints on the spatial-temporal evolution of the formation of Olympic Dam are considered with respect to a mantle to crustal continuum model. Cyclical tapping of magma reservoirs to maintain crystal mushes for extended time periods and incremental building of batholiths on the million-year scale prior to main mineralization pulses can explain the ~2-m.y. temporal window temporal window inferred from the data. Despite the challenge of reconciling such an extended window with contemporary models for porphyry deposits (≤1 m.y.), formation of Proterozoic ore deposits has been addressed at high-precision and supports the case that giant IOCG deposits may form over millions of years.

dc.publisherSociety of Economic Geologists
dc.relation.sponsoredbyhttp://purl.org/au-research/grants/arc/IH130200033
dc.titleOpening the magmatic-hydrothermal window: high-precision U-Pb geochronology of the mesoproterozoic Olympic Dam Cu-U-Au-Ag deposit, South Australia
dc.typeJournal Article
dcterms.source.volume115
dcterms.source.number8
dcterms.source.startPage1855
dcterms.source.endPage1870
dcterms.source.issn0361-0128
dcterms.source.titleEconomic Geology
dc.date.updated2020-12-07T05:04:18Z
curtin.departmentJohn de Laeter Centre (JdLC)
curtin.accessStatusFulltext not available
curtin.facultyFaculty of Science and Engineering
curtin.contributor.orcidCourtney-Davies, Liam [0000-0002-7362-1786]
curtin.contributor.scopusauthoridCourtney-Davies, Liam [57191572926]


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