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TitleTemporal and geochemical evolution of the Guichon Creek Batholith and Highland Valley porphyry copper district, British Columbia: implications for generation and tectonic setting of porphyry systems
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AuthorWhalen, J B; Davis, W J; Anderson, R A
SourceGeological Survey of Canada, Open File 8334, 2017, 46 pages, https://doi.org/10.4095/306147 (Open Access)
Year2017
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatreadme
File formatpdf (Adobe® Reader® v.6.0+); xls (Microsoft® Excel® 2003+); rtf
ProvinceBritish Columbia
NTS92I/02NE; 92I/02NW; 92I/03NE; 92I/03NW; 92I/05; 92I/07; 92I/10; 92I/11; 92I/14SE; 92I/14SW; 92I/15SE; 92I/15SW
AreaAshcroft; Guichon Creek; Highland Valley
Lat/Long WENS-121.4167 -120.6667 50.9167 50.0000
Subjectseconomic geology; tectonics; geochemistry; geochronology; igneous and metamorphic petrology; mineral exploration; exploration guidelines; mineral deposits; porphyry deposits; porphyry copper; bedrock geology; igneous rocks; intrusive rocks; mafic rocks; monzonites; granodiorites; diorites; volcanic rocks; sedimentary rocks; structural features; faults; mining activities; partial melting; intrusions; batholiths; dykes; magmatism; hydrothermal systems; mineralization; alteration; radiometric dating; uranium lead dating; argon argon dating; zircon dates; geochemical analyses; x-ray fluorescence; mass spectrometer analysis; isotopic studies; neodymium; strontium; yttrium; lanthanum; ytterbium; gadolinium; tectonic setting; tectonic evolution; magmatic arcs; downgoing slab; mantle; volcanism; emplacement; petrogenesis; modelling; host rocks; pressure-temperature conditions; Guichon Creek Batholith; Highland Valley Porphyry Copper District; Nicola Arc; Quesnel Terrane; Intermontane Belt; Bethlehem Copper Deposit; Bethsaida Pluton; Valley Deposit; Lornex Deposit; Highmount Deposit; Gnawed Mountain Porphyry; Nicola Group; geochemical signatures; cumulates; protoliths; Phanerozoic; Mesozoic; Triassic
Illustrationsgeoscientific sketch maps; plots; photomicrographs; tables; Concordia diagrams; photographs; variation diagrams
ProgramPorphyry systems, Targeted Geoscience Initiative (TGI-5)
Released2017 11 01
AbstractGuichon Creek Batholith, a Late Triassic, calc-alkaline composite batholith of the Nicola arc, British Columbia, hosts major porphyry copper deposits of the Highland Valley district. U-Pb zircon and Ar-Ar age dating of the main intrusive phases of this normally compositionally zoned batholith indicate that it evolved over a 7 M.y. period (215.6 ± 0.5 to 208.6 ± 0.6 Ma). The batholith consists of two distinct geochemical suites, the barren pre-211 Ma Highland Valley, and the mineralized post-211 Ma Bethlehem suite. Ages of host intrusion and a cross-cutting, post-mineralization dyke date the Bethlehem deposit to within a <1 M.y. period at ~210 Ma. This event predates the Bethsaida pluton, host to Valley, Lornex and Highmount deposits. These younger deposits formed after 209.1 ± 0.3 Ma, prior to or synchronously with the Gnawed Mountain porphyry at 208.6 ± 0.6 Ma. Ar-Ar and U-Pb ages are generally similar, indicating short-lived and rapidly cooled magmatic/hydrothermal systems. Published Re-Os molybdenite ages at Valley suggest a third mineralizing event at 206.5 Ma.
Mineralization is linked to the change in magma composition between the Highland Valley and Bethlehem suites, both of which have distinctive high Sr/Y, La/Yb and Gd/Yb signatures. The Bethlehem suite is more calcic, hydrous and oxidized than Highland Valley suite. Both suites were likely derived by melting hydrous, metal-enriched mafic lower crustal cumulates residual from earlier arc magmatism. Partial melting of such protoliths is thought to have been triggered by arc-arc collision, followed by slab detachment and upwelling of hot asthenospheric mantle-derived mafic magmas. Termination of Triassic arc calc-alkaline volcanism overlapped with the ca 216 Ma outer mafic Border phase. Emplacement (211-208 Ma) of batholith interior phases was accompanied by porphyry Cu formation at 210 and ~208 Ma. Based on this study, the fertile Guichon Creek Batholith represents a template for understanding porphyry deposit formation and distribution that can facilitate exploration targeting.
Summary(Plain Language Summary, not published)
Guichon Creek Batholith, a Late Triassic, calc-alkaline composite batholith of the Nicola arc, British Columbia, hosts major porphyry copper deposits of the Highland Valley district. U-Pb zircon and Ar-Ar age dating of the main intrusive phases of this normally compositionally zoned batholith indicate that it evolved over a 7 M.y. period (215.6 ± 0.5 to 208.6 ± 0.6 Ma). Emplacement (211-208 Ma) of batholith interior phases was accompanied by porphyry Cu formation at 210 and ~208 Ma. Based on this study, the fertile Guichon Creek Batholith represents a template for understanding porphyry deposit formation and distribution that can facilitate exploration targeting.
GEOSCAN ID306147