The Kanguk Formation: A Late Cretaceous Source Rock in the Sverdrup Basin, Canadian Arctic Islands

Abstract

The Kanguk Formation is a Cenomanian-Maastrichtian source rock in the Sverdrup Basin. Source rocks of similar age are also present to the west of the basin and may be present in Baffin Bay. In 2013 and 2014 three sections were logged through the Kanguk Formation on Ellesmere and Axel Heiberg islands. The basal contact of the Kanguk Formation is sharp. On Ellesmere Island Kanguk Formation shales overlie deltaic sandstones of the Albian-Cenomanian Hassel Formation; on Axel Heiberg Island they overlie the Strand Fiord Formation volcanic rocks of the High Arctic Large Igneous Province. Dark shales, showing traces of bioturbation near the base of the formation indicate an offshore environment below storm wave base. These are overlain by black, papery, bituminous shales, which potentially indicate anoxic bottom water conditions during the OAE 2. Bentonites are abundant in this part of the succession but occur throughout. Upwards, thin, silty layers exhibiting faint cross lamination become more common. Higher up in the section, on Axel Heiberg Island, these beds are arranged in several coarsening-upward cycles that contain hummocky cross stratification indicating deposition in a lower shoreface setting. These sediments are overlain by a more homogeneous, silty interval containing several distinct, red weathering horizons with abundant Late Santonian to Early Campanian Inoceramid shells. This interval is present in the upper part of all three sections and appears to be a marker horizon. Near the top of the formation grain size increases rapidly. Herringbone cross stratification and mud drapes indicate a tidal environment. These beds grade into very low angle cross bedded beach sandstones. Overlying trough cross bedded sandstones with basal conglomerates and reworked red mudclasts indicate a rapid facies change from shoreface to fluvial deposition at the base of the Paleogene Eureka Sound Group. The thickness of the Kanguk Formation decreases from +500 m in the basinal setting on Axel Heiberg Island to approximately 130 m in the most marginal section on Ellesmere Island. Shale samples were collected at meter intervals from the formation for ongoing TOC, biomarker and palynological analyses, Rock Eval Pyrolysis, kerogen typing, vitrinite reflectance, mudstone petrography, XRD, and microfossils studies. Zircons were separated from bentonites for ongoing U-Pb age dating using ion-microprobes and chemical abrasion isotope dilution thermal ionization mass spectrometry.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015