Cadotte and Paddy Members of Peace River Formation

Abstract

The Lower Cretaceous Peace River formation lies across the British Columbia and northwest Alberta boundaries. Its greatest extent lies in Alberta. The formation consists of three members: a basal marine shale (Harmon member), a middle, marine sand unit (Cadotte member), and an upper continental sand (Paddy member). The Cadotte member is a well-sorted, uniform, deltaic sandstone with a maximum thickness of over 200 feet. It has a lobate pattern typical of some deltas and it extends east to the middle of Lesser Slave Lake and north to Township 101. Its southern extensions are unknown. The overlying Paddy member is the continental phase of Peace River sedimentation and has a maximum thickness of over 120 feet. It too has the "bird's-f'oot" pattern of deltas built on a shallow shelf. This member extends to the western tip of Lesser Slave Lake, north to Township 91 and south to Township 66. Both members had a complex western source which probably consisted of igneous, metamorphic and clastic rocks lying, for the most part, west of the present day Rocky Mountain Trench.