Title | The stratigraphic succession and paleoenvironmental interpretation of the McMurray Formation, O.S.L.O. northeastern Alberta |
Publication Type | Thesis |
Year of Publication | 1996 |
Authors | Bechtel, D. J. |
Volume | Geology |
Issue | M. Sc. |
Pagination | 168 |
Place Published | University of Alberta |
Publication Language | en |
Abstract | The McMurray Formation/Wabiskaw Member succession in the Other Six Leases Operation (O.S.L.O.) area of northern Alberta records a Lower Cretaceous transgression of paleovalleys incised on the pre-Cretaceous unconformity. A study of 25 cores incorporating sedimentological, ichnological, and stratigraphic analysis indicates that the succession records a well preserved and pervasively drilled incised valley fill. Lowstand fluvial channel and flood basin deposits of the lower member of the McMurray were deposited unconformably on Devonian carbonates. Rising sea levels resulted in the conversion of the paleovalley into an estuary. The middle member of the McMurray Formation is separated from the lower member by a transgressive surface of erosion associated with transgression of the valley. Ichnological and sedimentological evidence suggest the McMurray estuary within the study area was deposited under a mixed wave- and tide-dominated energy regime. The trace fossil assemblage reflects brackish water conditions. Continued transgression resulted in a landward migration of the outer estuary mouth complex and incision of a high-relief tidal ravinement surface. Reflecting the proximity to the marine environment these upper McMurray deposits have abundant burrowing, an increased diversity of forms, rhythmically interlaminated sand and mud/carbnaceous debris, and evidence of storm deposition. The uppermost McMurray Formation and the overlying Wabiskaw Member of the Clearwater Formation reflect progradation of shoreface successions and their distal equivalents during stillstands within the overall transgression. The trace fossil assemblage records a more diverse assemblage and more robust counterparts to those found within the underlying estuarine deposits. |
URL | http://search.proquest.com/docview/89282720 |
Topics | Oil & Other Non-renewable Fuels |
Locational Keywords | Fort McMurray |
Active Link | |
Group | Science |
Citation Key | 40723 |