The importance of lithologic and fossil zones in the Alberta shale, more commonly known as the “Benton” formation or group, in the foothills of the Rocky Mountains in southwestern Alberta, is indicated. The territory covered extends for 350 miles along the foothills belt. “Alberta shale” is a group term which includes three formations, in ascending order, the Blackstone, Cardium, and Wapiabi. There are many objections to the use of the terms “Benton” or “Colorado,” as either formation or group names in Alberta, and such usage should be discarded. Each of the three formations maintains a nearly uniform thickness northwest of Bow River, but toward the southeast the Blackstone and Cardium formations diminish in thickness, and the sandstone members of the Cardium become erratic in their distribution. liach formation is conveniently divided into zones or members, based on distinct lithologic differences, which were extremely useful in mapping and correlation on account of their persistence, for the most part, throughout the region. Fossil zones recognized are named, in ascending order, the Barren zone, the Inoceramus labiatus zone, the Scaphites ventricosus zone, and the Baculites ovatus zone. The Blackstone formation is of Lower Colorado (Turonian) age, the Cardium and the lower part of the Wapiabi are of Upper Colorado (Emscherian or Coniacian) age, and the uppermost part of the Wapiabi is of early Montana (Santonian) age.

First Page Preview

First page PDF preview
You do not currently have access to this article.