CHRONO-, CHEMO-, LITHO-, CYCLO- AND BIOSTRATIGRAPHY OF THE LATE CRETACEOUS MANITOBA ESCARPMENT IN SASKATCHEWAN AND MANITOBA, CANADA

Stratigraphic correlations of Late Cretaceous Western Interior Seaway (WIS) deposits of the Manitoba Escarpment with coeval deposits across North America have proven historically challenging due to poor surface exposures and the repeating nature of calcareous and non-calcareous, massive mudstone units bound by unconformable contacts. Stratigraphic work over the last two decades, including an improved lithostratigraphic framework, radiometric ages of several horizons, well-defined foraminiferal zones, and chemostratigraphic profiles of drillcore, have significantly improved regional correlations, although until recently, little information has been available concerning the Escarpments’ vertebrate biostratigraphy.

Vertebrate faunal occurrences were analyzed by construction of a biostratigraphic chart using genera as x values and lithostratigraphic members and regional stratigraphic marker beds as y values. Reported chronostratigraphic data and field observations of lithology were integrated into the biostratigraphic chart in order to align faunal occurrences with the timing and duration of WIS transgressive and regressive marine cycles. Integration of multiple stratigraphic constraints with the addition of vertebrate biostratigraphic data from the Manitoba Escarpment allow for valuable insights into the relationship between relative changes in sea level and vertebrate diversity of the WIS over a broad temporal range (Cenomanian-Maastrichtian) from a biogeographically important, north-central locality.