Open File Report 2013-02

Open File Report 2013-02

OFR 2013-02

Notes to Accompany Map 600: Bedrock Geology of Alberta

Author(s) Prior, G.J. Date 2013-10-01

Map 600 shows the bedrock geology of Alberta at a scale of 1:1 000 000. Alberta Geological Survey (AGS) staff prepared this map based upon a combination of new mapping and compilation. The representation of the Canadian Shield and Athabasca Basin is based on compilation. The geology of the Rocky Mountains and the Rocky Mountain Foothills is also the product of compilation with rare instances of new geological interpretation (e.g., the interpretation of bedrock geology beneath drift-filled valleys). The Devonian geology of northeastern Alberta is also largely a product of compilation with some reinterpretation based partly on field observations. The Cretaceous geology of the Plains throughout most of northern and east-central Alberta is based on new geological mapping of the Fort St. John Group, the Dunvegan Formation, the Smoky Group, the Mannville Group, the Colorado Group, and the Belly River Group. In addition, the Battle Formation (Cretaceous) and the Scollard Formation (Cretaceous-Paleogene) are based on new mapping north of Township 17 and east of Range 4, West of the 6th Meridian.

Mapping in support of Map 600 included field observations and creating three-dimensional models of subsurface stratigraphy based on the interpretation of geophysical logs from oil and gas wells. Each three-dimensional formation surface was projected to a model of the bedrock surface and the intersection formed the first approximation of the position of the geological contact at the base of the surficial deposits. These preliminary contacts were then adjusted to honour outcrop data and the interpretation of the bedrock unit immediately below surficial deposits in individual wells.