Open File Report 1994-20

Open File Report 1994-20

OFR 1994-20

Quaternary Stratigraphy and Surficial Geology Peace River-Winagami Region Year One Report For The End Fiscal Year 1993-94

Author(s) Balzer, S.A. Leslie, L.E. Fenton, M.M. Date 1994-10-01

A reconnaissance survey of the southern half of the Peace River map area (84C/w 1/2) revealed the presence of predominantly two types of surficial glacial deposit they are: morainal and glaciolacustrine. Surficial moraine deposits that are thicker than 4 m are present in generally low lying areas and some are believed to overly deeply buried preglacial valleys. Indicator minerals were picked from thick (>10 m) till units intersected in two separate drill holes (BH-01 and -04). Surficial glaciolacustrine deposits, generally confined to the area south and east of the Peace River, range from 4 to 10 m thick and can be as much as 30 m thick locally. Synthesis of the Quaternary stratigraphy and glacial history is ongoing. Stratigraphic and geomorphic evidence collected to date, suggests that a single glacial advance has affected the area. A second field season in 1994 is planned.

The Quaternary geology and stratigraphy of the Winagami region (NTS 83N/w1/2) is consistent with at least one major ice advance. Distribution of the surface units and ice directional land forms indicate a strong southwest ice movement direction. Most of the surficial deposits are associated with ice stagnation and deglaciation. Ice-contact stagnation, glaciolacustrine and aeolian deposits are really extensive and can exceed 20 m in thickness. Stratigraphic correlation of the upper Quaternary units between boreholes and large sections increases in complexity towards the north of the map area. The lowermost glacial unit in all cores is a dark grey massive till. Preliminary lithologic identification of the clasts in the till indicate a Canadian Shield origin. The thickness of Quaternary deposits varies, ranging from a few metres near Reno to well over 30 m in the southeast of the map area. Bedrock topography is irregular due to the presence of several large paleochannels.