--> Abstract: The Cretaceous Colorado Group in the Cold Lake Heavy Oil Area, East-Central Alberta: The Role of Microfossil Analysis in Sea-Level Reconstruction, by Qiang Tu, Claudia Schröder-Adams, and Jim Craig; #90039 (2005)
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The Cretaceous Colorado Group in the Cold Lake Heavy Oil Area, East-Central Alberta: The Role of Microfossil Previous HitAnalysisNext Hit in Sea-Level Reconstruction

Qiang Tu1, Claudia Schröder-Adams2, and Jim Craig3
1 N/A, Edmonton, AB
2 Carleton University, Ottawa, ON
3 N/A, Bragg Creek, AB

The Colorado Group in the Cold Lake area, east-central Alberta represents a relatively condensed section of Albian to Santonian mudstone-dominated sedimentation within the Western Interior Sea. Two cores covering the entire Colorado Group provide a unique opportunity for a detailed multidisciplinary study in order to establish a biostratigraphic framework and to interpret Previous HitpaleoenvironmentalTop changes in an area that has received attention only for its heavy-oil bearing Mannville Group.

The Cold Lake cores represent sedimentation in an area of low accommodation space distant to sediment sources. Sequence boundaries are indicated by subtle biological changes without pebble beds. Transgressive lag deposits are of bioclastic nature. These are followed by highstand phases that allowed Tethyan-derived planktic foraminifera and nannofossils to enter the basin during Turonian and Santonian time.

Strata include the Joli Fou, Viking, Westgate, Belle Fourche, Second White Specks and Niobrara formations. Foraminiferal assemblages are subdivided into five zones and nine subzones. Several intervals are barren of foraminifera or contain minute taxa indicating phases of bottom water anoxia/dysoxia. During the Late Albian, changes of wall textures and sizes of agglutinated foraminiferal tests reflect fluctuation of water depth and energy. While lithological variations associated with lowstand deposition of the Viking Formation are subtle, occurrence of two foraminiferal subzones implies a sea-level fall within Viking strata. Faunal and floral evidence coupled with wireline log correlations have indicated that the Middle to Late Turonian Carlile Formation is missing partly extending the Middle Turonian to Coniacian unconformity, as recognized in central Saskatchewan, westwards into Alberta.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005