GEOSCAN Search Results: Fastlink


TitleLac des Bois, a locality in the northern Western Interior Seaway (Canada) with Tethyan faunal connections during the Cenomanian/Turonian Thermal Maximum
AuthorCumbaa, S L; Day, R; Gingras, M; Haggart, J W; Holmes, R B; Murray, A M; Schröder-Adams, C
SourceCretaceous Research vol. 91, 2018 p. 412-428,
Alt SeriesNatural Resources Canada, Contribution Series 20180161
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNorthwest Territories
AreaLac des Bois
Lat/Long WENS-125.5000 -125.2500 66.9167 66.8333
Subjectspaleontology; stratigraphy; geochronology; Upper Cretaceous; Turonian; Cenomanian; paleoenvironment; paleogeography; paleoclimatology; fossil assemblages; faunal assemblages; macrofossils; invertebrates; vertebrates; fossil fish; trace fossils; microfossils; micropaleontology; correlations; radiometric dating; bentonite; concretions; bedrock geology; lithology; sedimentary rocks; shales; sandstones; Western Interior Seaway; Tethys Sea; Cenomanian-Turonian Thermal Maximum; Oceanic Anoxic Event 2; Actinopterygii; Acanthomorpha; Foraminifera; Mollusks; Skolithos; Planolites; Taenidium; Alcyonidopsis; fugichnia; Bohemian Cretaceous Basin; Slater River Formation; Little Bear Formation; Trevor Formation; Phanerozoic; Mesozoic; Cretaceous
Illustrationslocation maps; aerial photographs; photographs; stratigraphic columns; stratigraphic charts; photomicrographs; tables
ProgramGSC Pacific Division
Released2018 07 24
AbstractEarly Turonian fishes are known from only a few localities in the Northern Hemisphere, including three in the present-day European/Mediterranean region and three in northern Canada. One of the latter localities, Lac des Bois (66º 52.087? N), preserves a diverse marine fauna composed of trace fossils, foraminifera, molluscs and actinopterygian fishes including early acanthomorphs. The molluscan fauna, as well as a radiometric date from bentonites recovered from the site, support an age of latest Cenomanian/early Turonian for the locality. This interval spans the global Oceanic Anoxic Event 2, a time characterized globally by high temperatures and high carbon burial. Although the Cenomanian/Turonian boundary interval has been documented in North America in the Arctic Sverdrup Basin and the southern Interior Seaway, the present study provides the first account of a faunal assemblage that inhabited the northern Western Interior Seaway during this interval. Organic-rich shales and sandstones indicate limited organic decomposition and low oxygen conditions, although the presence of trace fossils (Skolithos, Planolites, Taenidium and Alcyonidopsis, as well as fugichnia) indicates that the sea floor was not completely anoxic. The presence of coiled planktic foraminifera indicates warmer water and extends the known migration limit of these Tethyan-derived forms some 6º further north. Surprisingly, the fish fauna of localities in the Bohemian Cretaceous Basin (Czech Republic) bears a close resemblance to that of Lac des Bois, although acanthomorph fish have not been recorded from the former. This suggests faunal connections between the two regions, either through the northern Polar Sea, or through the postulated Hudson Strait.
Summary(Plain Language Summary, not published)
The authors have described the life forms present in sedimentary rock deposits that accumulated in an ocean formerly located at present-day Lac des Bois in Northwest Territories, Canada. This ocean was present during the Late Cretaceous period of geologic time, approximately 93 million years ago. The authors describe fish and ammonite mollusks that lived in the marine water column of the ocean, as well as bivalve clams and other forms that lived on the ocean bottom. The ocean bottom at this time experienced a distinct lack of oxygen, relative to that seen in today's oceans.

Date modified: