Kaskapau Formation

Kaskapau Formation
Name	Kaskapau Formation
Type	Geological formation
Period	Late Cretaceous (Turonian–Coniacian)
Primary lithology	Shale, siltstone
Other lithology	Sandstone, bentonite
Region	Western Canada Sedimentary Basin
Country	Canada

Kaskapau Formation The Kaskapau Formation is a Late Cretaceous shale-dominated succession exposed in the Western Canada Sedimentary Basin and recognized in Alberta, British Columbia, and the Northwest Territories; it was first described in the context of bentonite studies, measured sections, and petroleum exploration by provincial surveys and academic teams from the Geological Survey of Canada, the Alberta Geological Survey, and university geology departments. The unit is correlated with coeval strata in the Western Interior Basin and has been the subject of studies in sequence stratigraphy, biostratigraphy, and paleoecology by researchers associated with the Canadian Society of Petroleum Geologists, the American Association of Petroleum Geologists, and museum paleontology programs.

Description and lithology

The formation consists predominantly of fissile dark grey to black marine shale interbedded with argillaceous siltstone, fine-grained sandstone, and discrete bentonite beds, described in core logs, outcrop studies, and subsurface mapping by industry geoscientists working for Imperial Oil, Petro-Canada, and Shell Canada. Sedimentological descriptions reference lamination, pyrite nodules, and calcitized concretions documented by field teams from the University of Alberta, the University of British Columbia, and McGill University alongside analytical work at the Canadian Light Source and provincial laboratories. Petrographic and geochemical analyses by researchers affiliated with the Society of Economic Geologists, the Geological Association of Canada, and the Royal Society of Canada emphasize clay mineralogy, total organic carbon, and trace-element signatures in correlation with bentonite chronostratigraphy used by chronostratigraphers and paleontologists.

Stratigraphy and age

The Kaskapau Formation is placed within the Upper Cretaceous, principally Turonian to Coniacian stages, based on ammonite biostratigraphy, inoceramid zonation, and palynological assemblages compiled by teams at the Natural History Museum, the Smithsonian Institution, and the Canadian Museum of Nature. It conformably overlies the Dunvegan and Buckinghorse units in some localities and is overlain by the Smoky Group, the Bad Heart Formation, or the Dunvegan Sandstone equivalent in others, with stratigraphic frameworks refined through correlation efforts by the International Commission on Stratigraphy, the North American Commission on Stratigraphic Nomenclature, and regional geological surveys. Radiometric ages from bentonite layers and integrated magnetostratigraphy studies published by researchers at Stanford University, the University of Toronto, and the University of Calgary provide absolute age control supporting Turonian–Coniacian correlations with Western Interior Seaway sequences studied in Nebraska, Kansas, and Texas.

Distribution and thickness

The formation extends from northeastern British Columbia through northwestern Alberta into the southern Northwest Territories across the Western Canada Sedimentary Basin, documented on provincial geological maps produced by the Alberta Energy Regulator, the British Columbia Ministry of Energy and Mines, and the Northwest Territories Geological Survey. Thickness varies widely, reaching several hundred metres in depocentres identified by basin analysis groups at the Canadian Society of Petroleum Geologists, regional seismic interpretation by Schlumberger and Halliburton, and subsurface well log correlations maintained by provincial regulators and oil companies such as Husky Energy. Lateral facies changes and pinch-outs mapped by academic groups at the University of Saskatchewan, the University of Manitoba, and Dalhousie University reflect the influence of the Western Interior Seaway, tectonic loading from the Cordilleran orogeny, and sediment supply from the Canadian Shield.

Paleontology and fossil content

Fossil assemblages include ammonites, inoceramid bivalves, benthic and planktonic foraminifera, and marine vertebrate remains such as ichthyosaurs and mosasaurs recorded by museum paleontologists at the Royal Tyrrell Museum, the Canadian Museum of Nature, and the Royal Ontario Museum. Microfossils and palynomorphs used for biostratigraphy have been documented by palynologists affiliated with the American Association of Stratigraphic Palynologists, the International Paleontological Association, and university labs at McMaster University and Queen’s University, enabling correlations with faunal provinces described in the Western Interior Basin and Arctic Canada. Trace fossils, molluscan assemblages, and occasional plant debris recorded in core and outcrop studies by field teams from Parks Canada, the Canadian Fossil Discovery Centre, and provincial parks contribute to regional paleoecological reconstructions.

Depositional environment and paleoecology

Sedimentological, ichnological, and geochemical evidence indicates deposition in an outer shelf to slope marine environment influenced by the Western Interior Seaway, with dysoxic to anoxic bottom waters inferred from black shale, pyrite, and high organic-carbon values documented by geochemists at the Geological Survey of Canada, the University of British Columbia, and the University of Alberta. Sea-level fluctuations linked to global Turonian–Coniacian events recognized by the International Geoscience Programme and sequence stratigraphers produced transgressive and highstand systems tracts recorded in facies patterns described by researchers at the American Geophysical Union, the Society for Sedimentary Geology, and the Canadian Society of Petroleum Geologists. Paleoecological interpretations drawing on comparisons with contemporaneous faunas from Montana, North Dakota, and the Arctic cite nutrient upwelling, basin restriction, and climatic influences documented in oxygen-isotope studies by laboratories at McGill University, the University of California, Berkeley, and the Woods Hole Oceanographic Institution.

Economic significance and resource potential

The Kaskapau Formation is of interest for hydrocarbon exploration because of organic-rich shales, potential source-rock maturity assessed by vitrinite reflectance studies from labs at the Alberta Geological Survey, gas shows in exploration wells drilled by Encana and ConocoPhillips, and basin modeling conducted by petroleum systems analysts at the Canadian Energy Research Institute. Bentonite layers have been evaluated for industrial uses by mining studies associated with the Canada Minerals and Metals Plan, provincial mineral inventories, and private companies involved in clay and rare-metal exploration. Additionally, the formation’s stratigraphic relationships and reservoir potential have been integrated into unconventional resource assessments by industry consortia, academic petroleum research centers, and the National Energy Board in regional energy assessments.

Category:Geologic formations of Canada