--> Abstract: Shale Diapirism in the Canadian Beaufort Mackenzie Basin, by Peter P. Graham and Christopher L. Bergquist; #90039 (2005)

Datapages, Inc.Print this page

Shale Diapirism in the Canadian Beaufort Mackenzie Basin

Peter P. Graham and Christopher L. Bergquist
Devon Canada, Calgary, AB

Seismic data indicates that the west central region of the Beaufort Mackenzie Basin is an area of significant shale diapirism. These diapirs appear to be forming from the deep (7000m+) underlying upper Cretaceous Boundary Creek / Smoking Hills shale belt. The Boundary Creek / Smoking Hills shales are organic- rich shelf to basinal deposits varying in thickness, by 10's of metres to 500m+, primarily by northern depositional thinning and erosion. In outcrop these shales are thinly bedded, soft and fissile and are prone to deformation. This shale belt has been overlain by a series of northerly prograding deltaic sequences (10km+) throughout the Tertiary and continues today from the discharge of the Mackenzie River. In association, this thick stratigraphic package has undergone deformation in response to a late Laramide NE-SW compression that formed the extensive western Beaufort fold belt and likely initiated shale diapirism. Beaufort Mackenzie Basin shale diapirs were first recognized by industry from early 2-D seismic acquired during the 1960's and 70's. Many of the compressional ridges in the western Beaufort fold belt may in fact be cored by ‘shale flowage'. Some of these ridges have been locally ‘pierced' by shale diapirs, which often occur along pre-existing and reactivated fault trends. Much of this diapirism seems to have been active from Late Eocene to Mid Miocene. Devon Canada's Beaufort 3-D marine seismic program, shot during the summer of 2001 and 2002, imaged a complete shale diapir complex. The 3-D has allowed for a complete dimensional image that has an afforded a comprehensive understanding of the evolution and possible hydrocarbon trapping capacity of shale diapirs in the Beaufort Mackenzie Basin.

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