Stratigraphy and Sedimentology of the Bowser Lake Group, Muskaboo Creek Assemblage, in Southern Bowser Basin

Gareth T. Smith¹, Peter S. Mustard¹, and Filippo Ferri^2
1 Simon Fraser University, Burnaby, BC
² B.C. Ministry of Energy and Mines, Victoria, BC

The Muskaboo Creek assemblage is an Upper Jurassic to Lower Cretaceous succession of shallow marine siliciclastics within the Bowser Lake Group. At its southern most extent in the Hazleton, Nass and Smithers map areas, it has previously been mapped as undivided Bowser Lake Group or as part of the overlying Lower Cretaceous Skeena Group. In this area the Muskaboo Creek Assemblage is greater than 250 metres thick and dominated by medium to fine grained lithic arenite with lesser siltstone and mudstone. Most of the sandstones are clean and well sorted with abundant sedimentary structures indicative of tidal and shoreface marine environments, including extensive hummocky, swaley and trough cross stratification and flaser/lenticular bedding features. In several places this unit grades upward into non-marine fluvial and minor deltaic strata which have been previously considered to be part of the lower Skeena Group. This suggests that at its southern extent the Skeena Group is gradational laterally and vertically from the underlying Bowser Lake Group and as such was part of a single continuous sedimentary basin during latest Jurassic and Early Cretaceous time.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005