Open File Report 2011-03

Open File Report 2011-03

OFR 2011-03

Measured Outcrop Sections T2-R6W4-01 and T2-R6W4-02 of the Foremost and Oldman Formations (Belly River Group), Pinhorn Provincial Grazing Reserve, Milk River Valley, Southeastern Alberta (NTS 72E/02)

Author(s) Hathway, B. Banks, C.J. Hay, D.C. Prior, G.J. Date 2011-08-16

In this report, we present data on two measured outcrop sections (T2-R6W4-01 and T2-R6W4-02) of the Belly River Group measured on the Pinhorn Provincial Grazing Reserve on the northern side of the Milk River valley in southeastern Alberta. Both measured sections include the upper part of the Foremost Formation and a large part of the overlying Oldman Formation. The lowermost part of the exposed Foremost Formation interval consists mainly of dark grey-brown silty mudstone with thin sandstone and siltstone interbeds and isolated sand-filled gutter casts, both commonly showing HCS, overlain by a thick sandstone unit showing SCS. A coal seam at the top of the thick sandstone marks the base of the Taber coal zone, which forms the upper part of the exposed Foremost Formation interval. This consists mainly of mudstone and siltstone (commonly carbonaceous); a number of coal seams (up to 1.2 m thick); relatively thin (up to 1.5 m thick), commonly ripple crosslaminated sandstone units; and in the lower part, a thick sandstone unit showing SCS, horizontal planar stratification and cross-stratification.

The report includes graphic logs of the measured sections, with outcrop gamma-ray curves; detailed description of the sections (avoiding lithofacies interpretation but detailing stratigraphic context where appropriate) with selected photos; and the results of biostratigraphic work on a sample from the lower part of measured section T2-R6W4-02.