Bedrock Geology of the Foremost Area (NTS 72E)

This map shows the bedrock geology of the Foremost area (NTS 72E). Exposed bedrock in the area is composed dominantly of Upper Cretaceous to Paleogene clastic sedimentary rocks. The Eastend, Whitemud, Battle, Frenchman, and Ravenscrag, and Cypress Hills formations are restricted to the Cypress Hills, a topographically high region located along the eastern margin of the map sheet.

The Belly River Group is comprised of the Foremost, Oldman, and Dinosaur Park formations. South of Twp. 5, the Dinosaur Park and Oldman Formations cannot be differentiated based on well logs.

Selected bedrock units (Dinosaur Park,Oldman, Foremost, and Pakowki formations) were mapped in the subsurface using downhole geophysical well logs. Additional data points were obtained from measured outcrop sections, previously published maps, and air photo interpretation. Elevation data for outcrop locations were obtained using topographic contour data.

Subsurface data were modelled using ArcGIS Geostatistical Analyst to create structure surfaces for the top of each stratigraphic unit. The intersection of each surface with a model of bedrock topography provided the preliminary map trace for each unit. Structure surfaces were also intersected with a digital elevation model for comparison. Map traces were modified to honour the control data as best as possible. As the regional structure of the area is gentle, map patterns are controlled to a large degree by topography on the bedrock surface. Other contacts (Cypress Hills, Ravenscrag, Frenchman, Whitemud/Battle, Eastend, and Milk River formations) modified from maps by Prior et al. (2013) and Irish (1968).