Bulletin 002

Part I Lower Cenomanian Foraminifera from Peace River Area, Western Canada Part II Lower Cenomanian Ammonoidea and Pelecypoda from Peace River Area, Western Canada

Authors: Stelck, C.R.; Warren, P.S.; Wall, J.H.

Executive Summary

Sixteen species and subspecies of Foraminifera, one of which is named from the Lower Cenomanian portion of the St. John and Dunvegan formations of the Peace River area, Western Canada, are figured and described. Microfaunal assemblages are integrated with local megafaunal sequences of the Lower Cenomanian substage of the Upper Cretaceous. Lithologic sections are given for the Lower Cenomanian strata in the Fort St. John area. The Lower Cretaceous-Upper Cretaceous boundary occurs at a fish-scale sand marker-bed in the Shaftesbury formation in outcrop. Correlative fish-scale beds are found in the lower part of the Colorado shale of Alberta and Saskatchewan, and in the Mowry shale of the Black Hills area of the United States.

The foraminiferal assemblages are dominantly arenaceous. Micro and macrofauna indicate a progressive change from a relatively deep, cool, euxinic, normally saline environment to shallow, brackish and fresh, deltaic conditions.

Place Keywords: 83m; 83n; 83o; 84b; 84c; 84d; 84e; 84f; 84g; 84j; 84k; 84l; 84m; 84n; 84o; western canada

Theme Keywords: ammonoidea; dunvegan formation; fish-scale interval; foraminifera; fort st. john group; lower cenomanian; pelecypoda; shaftesbury formation; upper cretaceous-lower cretaceous boundary