Open File Report 2015-02

Open File Report 2015-02

OFR 2015-02

Outcrops of the Upper Devonian Moberly Member (Waterways Formation) on the Athabasca River North of Fort McMurray, Alberta (NTS 74D/14, 74E/3, and 74E/4)

Joint fieldwork completed by Alberta Geological Survey geologists and University of Alberta paleontologists over the summers of 2010-2012 resulted in the description and correlation of Moberly Member (Waterways Formation, Devonian) outcrops along the Athabasca River. The outcrops visited fall within townships 91-93 along the north-flowing Athabasca River, north of Fort McMurray. The Moberly Member along this stretch of the river consists of mainly nodular to bedded, argillaceous limestone interrupted by thinner resistant limestone beds. Most of the units described in this report are fossiliferous.

A biostromal unit is the most correlatable unit observed, as it is easily recognized for its abundant stromatoporoids and is the thickest resistant limestone unit along this stretch of the river. To the south, this biostromal unit changes from a rudstone (through a bindstone of diverse stromatoporoids and other fossils) into a framework of massive stromatoporoids surrounded by a Radiatrypa-brachiopod rudstone.

Of all of the Athabasca River outcrops visited, this section of the river contains the youngest beds of the Moberly Member.