Report 72

Report 72

REP 72

Geology of the McMurray Formation; Part I: Foraminifera of the Upper McMurray and Basal Clearwater Formations; and Part II: Heavy Minerals of the McMurray Formation

Author(s) Mellon, G.B. Wall, J.H. Date 1956-01-01

Part I of this report describes fifteen species and subspecies of Foraminifera--of which twelve are new--from the upper part of the McMurray formation and the basal part of the Clearwater formation in the lower Athabasca River area of northeastern Alberta are figured and described. These faunas are correlated with foraminiferal assemblages from the Cummings member of the Mannville formation of east-central Alberta and from the upper part of the Loon River formation of the Peace River area of northwestern Alberta. The suites are dated Middle Albian in age (late Lower Cretaceous). Environment of deposition appears to have been brackish lagoonal and shallow marine.

Part II of this report describes how heavy mineral residues from sands of the McMurray formation show two distinct suites: (1) first-cycle minerals derived from an igneous-metamorphic terrane, and (2) second-cycle tourmaline and zircon derived from pre-existing sediments. "Unstable" minerals, such as amphiboles and pyroxenes, are absent or very rare. It follows that the source area of the McMurray sediments was a low-lying land to the east, made up in part of the igneous-metamorphic rocks of the Canadian Shield, and in part of a thin veneer of late Precambrian-early Paleozoic sediments.

Mellon, G.B. and Wall, J.H. (1956): Geology of the McMurray Formation; part I: Foraminifera of the upper McMurray and basal Clearwater formations; and part II: Heavy minerals of the McMurray Formation; Research Council of Alberta, RCA/AGS Report 72, 50 p.