Composition and depositional environment of the siliceous Odanah Member (Campanian) of the Pierre Shale in Manitoba

Abstract

The Odanah Member of the Pierre Shale in southwestern Manitoba is a porcelanite of Late Cretaceous (Campanian) age that was deposited on the eastern platform area of the Western Interior Seaway.Odanah sediments were derived from erosion of preexisting sediments in the Cordilleran areas to the west, from contemporaneous volcanism, and from accumulation of siliceous biogenic material.The mineral assemblage of the Odanah is dominated by cristobalite (opal-CT) with lesser amounts of quartz, mixed layer clays, feldspar, and illite. Cristobalite, derived from the diagenesis of diatoms, radiolarians, and siliceous sponge spicules, occurs as cryptocrystalline cement, bladed crystals, and lepispheres. Diatoms are considered to be the major source of biogenic silica in the Odanah.Chemical analyses of the Odanah give Si0 2 values which range from 70 to 85% (mean, 81%). Apart from silica, major element concentrations are consistently lower than those of the average shale.Major factors restricting Odanah deposition to a geographically limited part of the Interior Seaway may include: (a) reduced supply of terrigenous material from the west due to the presence of a paleotectonic barrier near the Manitoba-Saskatchewan border, and (b) increased diatom productivity in a zone of upwelling related to the southward flow of Arctic water within the Interior Seaway.

New material of the mosasaur Plioplatecarpus nichollsae Cuthbertson et al., 2007, clarifies problematic features of the holotype specimen

“…80.5 Ma), lowermost middle Campanian (Nicholls, 1988;Ogg et al, 2004). Maps modified from Young and Moore (1994) and Nicholls (1988), stratigraphic column after Young and Moore (1994).…”

Upper Cretaceous - lower Tertiary lithostratigraphic relationships of three cores from Alberta, Saskatchewan, and Manitoba, Canada

“…Tyrrell (1890) discusses the Cretaceous stratigraphic section in Manitoba, including some brief remarks about the section in the Turtle Mountain area. Subsequent studies by Dowling (1903aDowling ( , 1903bDowling ( , 1921, Kirk (1930), Wickenden (1945), Bannatyne (1970Bannatyne ( , 1978, Bamburak (1978), McNeil and Caldwell (1981), Young and Moore (1994), Kurita and McIntyre (1995), and Catuneanu et al (1995) establish the stratigraphic sequence in and beneath Turtle Mountain (Fig. 6).…”

Progress in the taxonomy of Late Cretaceous high-latitude radiolarians: insights from the Horton River area, Northwest Territories, Canada

“…In the Arctic basins of North America, Upper Cretaceous radiolarians have only been reported from the Arctic Slope of northern Alaska (Tappan, 1960;Bergquist, 1966) and Ellef Ringnes Island in the Sverdrup Basin of Arctic Canada (Pugh et al, 2014). In the interior of North America, impoverished radiolarian assemblages have been recovered from the Pierre Shale Formation in the central United States (Schultz et al, 1980;Bergstresser, 1983) and Manitoba, Canada (Rust, 1892;Tyrrell, 1892;Young and Moore, 1994;Muehlbauer, 2014); the Lea Park and Bearpaw formations in Alberta, Canada (Wall, 1975); and the Niobrara Formation in southern Saskatchewan, Canada (Diaz and Velez, 2018). These studies provide information on the presence and vertical distribution of radiolarian species but do not address their taxonomy, which is crucial to constructing radiolarian biozones.…”