Cardium sandstone bodies, Crossfield-Garrington area, Alberta

The oil-producing Cardium Formation of the Crossfield-Garrington area, south-central Alberta, consists of two and locally three marine sandstone members separated by marine shale. The lower member consists of two lenticular sandstone masses called the Crossfield and the Garrington sandstone bodies. The Crossfield trends northwest-southeast, is 60 miles long, 1 to 2 1/2 miles wide, and attains a thickness of 20 feet. It has a gradational lower and a sharp upper contact, is lenticular in cross section having a flat bottom and a concave upper surface. It was deposited parallel to the western shore of the Turonian (early Late Cretaceous) seaway and it is interpreted to be an offshore bar. The Garrington sandstone body appears to be a stratigraphic equivalent to the Crossfield but deposited several miles seaward from it. Oil is produced from both sandstone bodies.