Tracking compositional changes within the High Arctic Large Igneous Province using zircon Hf isotopes from altered volcanic ash layers of the Sverdrup Basin, Canada

2021 ◽  
Author(s):  
Michael Pointon ◽  
Michael Flowerdew ◽  
Peter Hülse ◽  
Simon Schneider ◽  
Ian Millar ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Volcanic Ash ◽  
Volcanic Belt ◽  
High Arctic ◽  
Ellesmere Island ◽  
Hf Isotope ◽  
Large Igneous Province ◽  
Volcanic Material ◽  
Igneous Province ◽  
Sverdrup Basin

<p>During Late Cretaceous times the Sverdrup Basin, Arctic Canada, received considerable air-fall volcanic material. This is manifested as numerous centimetre- to decimetre-thick diagenetically altered volcanic ash layers (bentonites) that occur interbedded with mudstones of the Kanguk Formation. Previous research on bentonite samples from an outcrop section in the east of the basin (Sawtooth Range, Ellesmere Island) revealed two distinct volcanic sources for the bentonites: most of the bentonites analysed (n=9) are relatively thick (0.1 to 5 m), were originally alkaline felsic ashes, and were likely sourced from local volcanic centres on northern Ellesmere Island or the Alpha Ridge that were associated with the High Arctic Large Igneous Province (HALIP). Two thinner (<5 cm) bentonites with contrasting subalkaline geochemistry were also identified. These were inferred to have been derived from further afield, from volcanic centres within the Okhotsk-Chukotka Volcanic Belt, Russia.</p><p>To better understand volcanism within the vicinity of the Sverdrup Basin during Late Cretaceous times, and further test the above interpretations, a larger suite of bentonite samples was investigated, drawing on samples from outcrop sections in the central and eastern Sverdrup Basin. Whole-rock geochemical analyses and combined zircon U-Pb age and Hf isotope analyses were undertaken. The vast majority of bentonites analysed to date have alkaline geochemistry and were likely sourced from proximal volcanic centres related to the HALIP. The combined U-Pb and Hf isotope data from these bentonites show a progression from evolved (-2 to 0) to moderately juvenile (+9 to +10) εHf<sub>(t)</sub> values between late Cenomanian and early Campanian times (<em>c</em>. 97–81 Ma). This is interpreted to record compositional change through time within the local HALIP magmatic system.</p>

scholarly journals New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
S.E. Grasby ◽  
J.P. Cuthbertson ◽  
N. Rayner ◽  
C. Tegner
Keyword(s):  
Volcanic Rocks ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
The Arctic ◽  
Trace Element Geochemistry ◽  
Volcanic Complex ◽  
Northern Coast ◽  
Element Geochemistry ◽  
Igneous Province

The High Arctic Large Igneous Province (HALIP) represents extensive Cretaceous magmatism throughout the circum-Arctic borderlands and within the Arctic Ocean (e.g., the Alpha-Mendeleev Ridge). Recent aeromagnetic data shows anomalies that extend from the Alpha Ridge onto the northern coast of Ellesmere Island, Nunavut, Canada. To test this linkage we present new bulk rock major and trace element geochemistry, and mineral compositions for clinopyroxene, plagioclase, and olivine of basaltic dykes and sheets and rhyolitic lavas for the stratotype section at Hansen Point, which coincides geographically with the magnetic anomaly at northern Ellesmere Island. New U-Pb chronology is also presented. The basaltic and basaltic-andesite dykes and sheets at Hansen Point are all evolved with 5.5−2.5 wt% MgO, 48.3−57.0 wt% SiO2, and have light rare-earth element enriched patterns. They classify as tholeiites and in Th/Yb vs. Nb/Yb space they define a trend extending from the mantle array toward upper continental crust. This trend, also including a rhyolite lava, can be modeled successfully by assimilation and fractional crystallization. The U-Pb data for a dacite sample, that is cut by basaltic dykes at Hansen Point, yields a crystallization age of 95.5 ± 1.0 Ma, and also shows crustal inheritance. The chronology and the geochemistry of the Hansen Point samples are correlative with the basaltic lavas, sills, and dykes of the Strand Fiord Formation on Axel Heiberg Island, Nunavut, Canada. In contrast, a new U-Pb age for an alkaline syenite at Audhild Bay is significantly younger at 79.5 ± 0.5 Ma, and correlative to alkaline basalts and rhyolites from other locations of northern Ellesmere Island (Audhild Bay, Philips Inlet, and Yelverton Bay West; 83−73 Ma). We propose these volcanic occurrences be referred to collectively as the Audhild Bay alkaline suite (ABAS). In this revised nomenclature, the rocks of Hansen Point stratotype and other tholeiitic rocks are ascribed to the Hansen Point tholeiitic suite (HPTS) that was emplaced at 97−93 Ma. We suggest this subdivision into suites replace the collective term Hansen Point volcanic complex. The few dredge samples of alkali basalt available from the top of the Alpha Ridge are akin to ABAS in terms of geochemistry. Our revised dates also suggest that the HPTS and Strand Fiord Formation volcanic rocks may be the hypothesized subaerial large igneous province eruption that drove the Cretaceous Ocean Anoxic Event 2.

Evidence for protracted High Arctic large igneous province magmatism in the central Sverdrup Basin from stratigraphy, geochronology, and paleodepths of saucer-shaped sills

2015 ◽  
Vol 127 (9-10) ◽  
pp. 1366-1390 ◽  
Author(s):  
Carol A. Evenchick ◽  
William J. Davis ◽  
Jean H. Bédard ◽  
Nathan Hayward ◽  
Richard M. Friedman
Keyword(s):  
High Arctic ◽  
Large Igneous Province ◽  
Igneous Province ◽  
Sverdrup Basin

scholarly journals Supplemental Material: New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
C. Tegner
Keyword(s):  
Environmental Impact ◽  
Trace Element ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
Supplementary Data ◽  
Bulk Rock ◽  
Igneous Province ◽  
Data Files ◽  
Discrimination Diagram

Supplementary Data Files: (1) Sample list and description; (2) GPS positions of samples; (3) Accuracy of major and trace element bulk rock compositions and precision of repeat analyses; (4) Photomicrographs; (5) Clinopyroxene, plagioclase and olivine compositions; (6) SHRIMP U-Pb methods and results; (7) 7. Nb-Zr-Y tectonic discrimination diagram; (8) Ti-Zr-Y tectonic discrimination diagram; (9) Ti-V tectonic discrimination diagram; (10) MgO-FeOtot_Al2O3 tectonic discrimination diagram; (11) AFM diagram; and (12) Th/Nb vs. SiO2 diagram.

scholarly journals Supplemental Material: New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
C. Tegner
Keyword(s):  
Environmental Impact ◽  
Trace Element ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
Supplementary Data ◽  
Bulk Rock ◽  
Igneous Province ◽  
Data Files ◽  
Discrimination Diagram

Supplementary Data Files: (1) Sample list and description; (2) GPS positions of samples; (3) Accuracy of major and trace element bulk rock compositions and precision of repeat analyses; (4) Photomicrographs; (5) Clinopyroxene, plagioclase and olivine compositions; (6) SHRIMP U-Pb methods and results; (7) 7. Nb-Zr-Y tectonic discrimination diagram; (8) Ti-Zr-Y tectonic discrimination diagram; (9) Ti-V tectonic discrimination diagram; (10) MgO-FeOtot_Al2O3 tectonic discrimination diagram; (11) AFM diagram; and (12) Th/Nb vs. SiO2 diagram.

Architecture of the Canadian portion of the High Arctic Large Igneous Province and implications for magmatic Ni–Cu potential

2016 ◽  
Vol 53 (5) ◽  
pp. 528-542 ◽  
Author(s):  
B.M. Saumur ◽  
K. Dewing ◽  
M.-C. Williamson
Keyword(s):  
Structural Characteristics ◽  
Critical Role ◽  
Regional Scale ◽  
High Arctic ◽  
Large Igneous Province ◽  
Intrusive Complex ◽  
Local Evidence ◽  
Igneous Province ◽  
Plumbing Systems ◽  
Sverdrup Basin

The Cretaceous to Paleogene High Arctic Large Igneous Province (HALIP) occurs in circum-Arctic regions, and the largest portion of the province occurs in Canada’s Arctic Archipelago. This paper reviews and documents the geometry and distribution of the Canadian portion of the HALIP, focussing most notably on the architecture of its intrusive component. The extent of dyke swarms and sills of the Canadian HALIP is updated and is shown to be greater than previously acknowledged. Sills, in particular, occur throughout the Sverdrup Basin and crop out extensively on Axel Heiberg Island within Triassic to Cretaceous strata. The HALIP event is dominantly intrusive, with 3–5 times more intrusive rocks than extrusive rocks, by volume. There is local evidence of syn-emplacement fault activity, possibly involving the reactivation of older faults, controlling the emplacement of dykes. In the eastern Sverdrup Basin, exposures of components of the HALIP are controlled by tectonic elements of the Eocene Eurekan Orogeny, with plumbing systems (dykes, sills) exposed along regional-scale anticlines or the hanging walls of thrusts. Portions of the HALIP have been shown to be prospective for magmatic Ni – Cu – platinum group elements (PGEs) based on geochemistry, and although geochemical controls play a critical role in the genesis of such deposits, structural and magma dynamic controls are also important to consider at the scale of 1–10 km magmatic complexes. Underpinned by the architecture of the Canadian HALIP, we document the structural characteristics of three 1–10 km-scale volcanic–intrusive complexes of the province that show Ni–Cu–PGE prospectivity: the volcanic–intrusive complex of the Strand Fiord – Expedition Fiord area, the Surprise Fiord dykes, and the Wootton Intrusive Complex. All three represent physico-structural environments that would likely promote high magma flowthrough and sulphide transport, and could be targeted for Ni–Cu–PGE magmatic sulphide mineralization.

scholarly journals Supplemental Material: New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
C. Tegner
Keyword(s):  
Environmental Impact ◽  
Trace Element ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
Supplementary Data ◽  
Bulk Rock ◽  
Igneous Province ◽  
Data Files ◽  
Discrimination Diagram

Supplementary Data Files: (1) Sample list and description; (2) GPS positions of samples; (3) Accuracy of major and trace element bulk rock compositions and precision of repeat analyses; (4) Photomicrographs; (5) Clinopyroxene, plagioclase and olivine compositions; (6) SHRIMP U-Pb methods and results; (7) 7. Nb-Zr-Y tectonic discrimination diagram; (8) Ti-Zr-Y tectonic discrimination diagram; (9) Ti-V tectonic discrimination diagram; (10) MgO-FeOtot_Al2O3 tectonic discrimination diagram; (11) AFM diagram; and (12) Th/Nb vs. SiO2 diagram.

U–Pb geochronology of bentonites from the Upper Cretaceous Kanguk Formation, Sverdrup Basin, Arctic Canada: constraints on sedimentation rates, biostratigraphic correlations and the late magmatic history of the High Arctic Large Igneous Province

2016 ◽  
Vol 154 (4) ◽  
pp. 757-776 ◽  
Author(s):  
WILLIAM J. DAVIS ◽  
CLAUDIA J. SCHRÖDER-ADAMS ◽  
JENNIFER M. GALLOWAY ◽  
JENS O. HERRLE ◽  
ADAM T. PUGH
Keyword(s):  
Upper Cretaceous ◽  
High Arctic ◽  
Large Igneous Province ◽  
Lower Latitude ◽  
Sedimentation Rates ◽  
Oceanic Anoxic Event ◽  
Igneous Province ◽  
Sverdrup Basin ◽  
History Of ◽  
Magmatic History

AbstractU–Pb ages of zircon from bentonites within the upper Cretaceous Bastion Ridge and Kanguk formations, Sverdrup Basin, provide constraints on sedimentation rates, biostratigraphic correlations, timing of Oceanic Anoxic Event 2 (OAE2) in the High Arctic, and the late magmatic history of the High Arctic Large Igneous Province (HALIP). A late Cenomanian to early Turonian age for the base of the Kanguk Formation is confirmed that supports correlations of the global OAE2 in the High Arctic. Sedimentation rates varied from 19 m Ma−1between 93 and 91 Ma to 26 m Ma−1between 91 and 83 Ma at Axel Heiberg Island. At Ellef Ringnes Island, the lower Kanguk Formation records high rates of ~70 m Ma−1between 94 and 93 Ma, which decrease to rates comparable to those of the upper Axel Heiberg section. Differences in sedimentation rates may reflect differences in setting prior to the major transgression in the latest Cenomanian to early Turonian. The timing of Arctic occurrences of theScaphites nigricollensisandScaphites depressusammonite zones is shown to be broadly comparable to that of lower-latitude occurrences within the Western Interior Seaway. An eruption frequency of 0.5–2.5 Ma characterizes the late alkaline phase of HALIP magmatism. Volcanic bed thicknesses of 10–50 cm suggest ash transport distances of less than 1000 km. Long-lived volcanic centres, in the area of the Alpha Ridge, northern Ellesmere Island or northern Greenland, were the likely source of volcanic ash over a period of 10–15 Ma.

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