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TitleU-Pb geochronology of bentonites from the Late 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
AuthorDavis, W J; Schröder-Adams, C; Galloway, J; Herrle, J; Pugh, A
SourceGeological Magazine vol. 154, issue 4, 2017 p. 757-776, https://doi.org/10.1017/S0016756816000376
Year2017
Alt SeriesEarth Sciences Sector, Contribution Series 20150287
PublisherCambridge
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut
AreaSverdrup Basin
Subjectsgeochronology; uranium lead dates; zircon dates; bentonite; Turonian; Cenomanian; geochronometry; Bastion Ridge formation; Kanguk formation; Oceanic Anoxic Event 2 (OAE2); Cretaceous
ProgramWestern Arctic Sverdrup Basin, GEM2: Geo-mapping for Energy and Minerals
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-1 between 93 and 91 Ma to 26 m Ma-1 between 91 and 83 Ma at Axel Heiberg Island. At Ellef Ringnes Island, the lower Kanguk Formation records high rates of ~70 m Ma-1 between 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 the Scaphites nigricollensis and Scaphites depressus ammonite 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.
Summary(Plain Language Summary, not published)
The Sverdrup sedimentary basin in the Canadian high Arctic is an important area for potential hydrocarbon and mineral resources. The Cretaceous Kanguk Formation is an important basin-wide shale unit that is a key hydrocarbon source rock. It also preserves information on the global Cretacous climate record and volcanic activity within the High Arctic Large Igneous Province. This paper presents high-precision age data that calibrates the depositional history of the Kanguk Formation, improving regional geological correlations, and providing a better understanding of the tectonic evolution of the basin.
GEOSCAN ID297286