Paleogeography of the Bluesky Formation, Greater Boyer Area, NW Alberta

Robinson, Kimberly D.¹, S. George Pemberton¹, Murray Gingras¹ (1) University of Alberta, Edmonton, AB

The Lower Cretaceous (Early Albian) Bluesky Formation was deposited in a variety of environments throughout northeastern BC and northern Alberta during the overall transgression of the boreal Moosebar-Clearwater Sea. Within the Greater Boyer area (T 102-113, R 20W5-4W6) of northwestern Alberta, the Bluesky is found at depths of 200-400 meters and is a shallow gas reservoir, but has never before been studied in detail and therefore little is understood about the paleogeography of the area.

The examination of drill core from the study area revealed the presence of several regular, regionally correlatable siditerized intervals that are continuous throughout Greater Boyer, and a proliferation of glaucony occurring as a film on and between organic pellets. Preservation is entirely limited to the lower part of the section (offshore to middle shoreface), and the sideritized surfaces indicate the occurrence of numerous cyclic periods of non-deposition and erosion. The lithological and ichnological data gained from core logging was integrated with well logs in order to create an accurate paleogeographical picture of the Bluesky Formation within the study area, resulting in the depiction of a prograding shoreline with evidence of localized deltaic influence.