Targeting Ni-Cu mineralization in the Canadian High Arctic large igneous province: integrating geochemistry, magmatic architecture and structure

Saumur, B M; Williamson, M C; Bédard, Jean H.

doi:10.1007/s00126-021-01054-3

Cited by 5 publications

(19 citation statements)

References 111 publications

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“…S1), but Type x rocks only occur along the northern coast of Ellesmere Island (Fig. S1d) and are spatially associated with HALIP alkaline rocks (Estrada et al, 2016Naber et al, 2021;Bédard et al, 2021), to which they show many resemblances (Figs S8, S9).…”

Section: ' Seriesmentioning

confidence: 99%

“…Age data on dykes and sills and stratigraphic constraints show that intermittent basaltic magmatism spanned the apparent gap in volcanism, however, implying the area was continuously magmatically active for about 50 myr (Estrada & Henjes-Kunst, 2013;Evenchick et al, 2015;Dockman et al, 2018;Naber et al, 2021). Small volumes of transitionalalkaline to alkaline HALIP lavas and intrusions of the Hassel Formation and Fulmar Suite are coeval with the Strand Fiord Formation (Osadetz & Moore, 1988;Estrada, 2015;Bédard et al, 2021). Younger, more strongly alkaline lavas and associated intrusions of the Audhild Bay Suite (ABS, previously referred to as the Hansen Point Volcanics: Naber et al, 2021), were emplaced along the northern coast of Ellesmere Island, and alkaline magmatism continued until ~80 Ma (Trettin & Parrish, 1987;Dewing & Embry, 2007;Tegner et al, 2011;Estrada & Henjes-Kunst, 2013;Dockman et al, 2018).…”

Section: Geological Setting Stratigraphic and Age Constraintsmentioning

confidence: 99%

“…Younger, more strongly alkaline lavas and associated intrusions of the Audhild Bay Suite (ABS, previously referred to as the Hansen Point Volcanics: Naber et al, 2021), were emplaced along the northern coast of Ellesmere Island, and alkaline magmatism continued until ~80 Ma (Trettin & Parrish, 1987;Dewing & Embry, 2007;Tegner et al, 2011;Estrada & Henjes-Kunst, 2013;Dockman et al, 2018). Alkaline HALIP magmatism is dicussed more extensively in the companion paper (Bédard et al, 2021). Post-HALIP horizontal shortening of Paleozoic and Mesozoic strata related to the Eurekan Orogeny began in earliest Paleocene (Thorsteinsson & Tozer 1970;Piepjohn et al, 2007Piepjohn et al, , 2016Piepjohn & von Gose, 2018;Ruppel et al, 2018).…”

Section: Geological Setting Stratigraphic and Age Constraintsmentioning

confidence: 99%

“…Of the new data, 93 analyses are provided as a spreadsheet in the supplementary content, together with details about analytical procedures (E-Appendices 1 and 2). Additional new data (235 analyses) considered here are in Saumur et al (2021). Representative analyses are in Table 1.…”

Section: Geochemistry Samples Classification Petrologymentioning

confidence: 99%

“…Older and younger pulses of HALIP mafic tholeiitic lavas are both dominated by low-MgO (<7 wt%) basalt with sparse plagioclase + clinopyroxene ± olivine phenocrysts (Dostal & MacRae, 2018;Dockman et al, 2018;Naber et al, 2021). Swarms of compositionally similar basaltic sills and dykes are associated with the Strand Fiord and Isachsen Formation volcanism (Saumur et al, , 2021, and some are interpreted as sub-volcanic feeders. These intrusions are typically fine to medium-grained, sparsely plagioclase + clinopyroxene ± olivine-phyric dolerite.…”

Section: Geochemistry Samples Classification Petrologymentioning

confidence: 99%

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Geochemical Systematics of High Arctic Large Igneous Province Continental Tholeiites from Canada—Evidence for Progressive Crustal Contamination in the Plumbing System

Bédard

Saumur

Tegner

et al. 2021

Journal of Petrology

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Cretaceous High Arctic Large Igneous Province (HALIP) sub-alkaline magmatic rocks in Canada are mostly evolved (MgO 2-7 wt%), sparsely plagioclase + clinopyroxene ± olivine-phyric tholeiitic basalts. There were two main HALIP Continental Flood Basalt (CFB) eruption episodes: 135-120 Ma (Isachsen Fm.) and 105-90 Ma (Strand Fiord Fm.); both associated with cogenetic doleritic sills and dykes. Building on a large modern database, 16 HALIP tholeiite Types are defined and grouped into genetic Series using Ce <vsi> Sm/YbNMORB distributions. Comparison with model melting curves imply higher-Sm/Yb HALIP basalt Types record low degree melting of garnet-bearing mantle sources. More voluminous intermediate- and low-Sm/Yb HALIP basalt Types separated from the mantle at shallower levels after further extensive melting in the spinel-peridotite field. Within a given Sm/Yb range, increases in incompatible elements like Ce are coupled with progressive clockwise rotation of normalized incompatible trace element profiles. Trace element modeling implies this cannot be due to closed system fractional crystallization but requires progressive and ubiquitous incorporation of a component resembling continental crust. The fractionation models imply low-Sm/Yb HALIP basalts (∼7 wt% MgO) initially crystallized olivine gabbro assemblages, with lower-MgO basalts successively crystallizing gabbro and ilmenite-gabbro assemblages. In contrast, higher-Sm/Yb basalts fractionated more clinopyroxene and ilmenite, but extensive plagioclase fractionation is still required to explain developing negative Sr-Eu anomalies. Backfractionation models require about 40% addition of olivine to bring the most primitive HALIP basalts (∼7% MgO) into equilibrium with Fo<su89b> mantle. Inverse fractionation-assimilation modeling shrinks the CFB signature, making decontaminated model parental melts more similar to E-MORB. The progressive increase of the contamination signature within each HALIP tholeiitic differentiation series is not consistent with models involving derivation of HALIP basalts from a mantle source previously enriched by subduction. Strong interaction of basalt with Sverdrup Basin sedimentary rocks may cause localized over-enrichment in K-Rb-Th-U, but cannot explain strong Ba-enrichment in the absence of concomitant K-Rb-Th-U-enrichment. The localized Ba enrichment could reflect either a Ba-rich lithospheric mantle component that is strongly manifested in the coeval HALIP alkaline suites, or syn- to post-emplacement fluid-mediated transfer from Ba-rich host rocks.

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Section: ' Seriesmentioning

confidence: 99%