Carboniferous of Western Canada, Extent and Salient Problems: ABSTRACT

Abstract

The outcrop of Carboniferous rocks in western Canada forms an almost continuous belt extending from the International Boundary to the Peace River and beyond. In the Rocky Mountains of Alberta, Carboniferous strata form the highest points of many of the mountains lying within the tectonic province of the eastern ranges. To the west they are overridden by Cambrian and other sediments; eastward, they disappear beneath the Mesozoic deposits in the complex structures of the Foothills; and are present in the subsurface of much of Southern Alberta. Two of the major valleys which cut across the strike of the eastern ranges, the Bow and the Athabasca, gave early access to the pioneer geologists. G. M. Dawson first recognized the existence of Carboniferous strata in 1886 and a year later, McConnell published a stratigraphic subdivision of the great succession of Devonian and Carboniferous rocks in the Bow Valley. In later years McConnell's Lower Banff shales became the Banff formation and his Upper Banff limestone was renamed the Rundle formation by Kindle. From these early beginnings the Carboniferous succession in Alberta came to be subdivided into three somewhat loosely defined units, the Banff, Rundle, and Rocky Mountain formations. Paleontological studies have shown that strata representing the whole span of Mississippian time are present but there may be some gaps. Whether or not the Pennsylvanian is present is still an open question. Although the succession is not abundantly fossiliferous, the faunas offer some means of broad regional control. The Carboniferous seas were relatively shallow and of considerable extent, and correlation of lithological units deposited under these conditions could be expected to present many problems. End_of_Article - Last_Page 417------------