Open Access. Powered by Scholars. Published by Universities.®

Geology Commons

Open Access. Powered by Scholars. Published by Universities.®

Western University

Eustasy

Articles 1 - 4 of 4

Full-Text Articles in Geology

Allostratigraphy Of The Lower Colorado Group (Cretaceous) In South-West Alberta, Slavena Galic Oct 2021

Allostratigraphy Of The Lower Colorado Group (Cretaceous) In South-West Alberta, Slavena Galic

Electronic Thesis and Dissertation Repository

Clastic, upper Albian-lower Cenomanian strata were deposited in a low-accommodation backbulge depozone of the Western Canada Foreland Basin in SW Alberta. These strata are lithologically very heterogeneous and encompass a spectrum of depositional environments along an alluvial to offshore transect. These rocks are assigned, in subsurface, to the Lower Colorado Group, and in outcrop to the upper Blairmore Group. Lithological heterogeneity, as a result of rapid lateral facies changes, resulted in diverse nomenclature that obscured genetic relationships between time-equivalent strata. The present study integrates wireline log, core, and outcrop data to establish a high-resolution allostratigraphic framework which allowed recognition of …


Stratigraphic Studies Of Late Albian Strata, North-Eastern Alberta., Arwa Zourob Jan 2020

Stratigraphic Studies Of Late Albian Strata, North-Eastern Alberta., Arwa Zourob

Electronic Thesis and Dissertation Repository

Late Albian rocks of the Upper Viking, Westgate and lower Fish Scales alloformations were deposited about 101-100 Ma in the Western Canada Foreland Basin. Sediments in the study area span the forebulge, and are dominated by mudstone which forms 5-15 m thick, siltier-or sandier-upward sucessions bounded by marine flooding surfaces. Stratification is on a mm scale and represents storm deposits and fluid muds. Viking allomember VD and Westgate allomembers WA, WB and WC all thin towards the E and S and progressively onlap the forebulge. They record relative sea-level rise and gradual drowning and subsidence of the forebulge. In contrast, …


Allostratigraphy, Sedimentology And Paleogeography Of The Cretaceous Upper Fort St. John Group (Upper Albian-Lower Cenomanian) In Northeastern British Columbia, Piotr Jan Angiel Aug 2013

Allostratigraphy, Sedimentology And Paleogeography Of The Cretaceous Upper Fort St. John Group (Upper Albian-Lower Cenomanian) In Northeastern British Columbia, Piotr Jan Angiel

Electronic Thesis and Dissertation Repository

The upper Albian to lower Cenomanian succession in northeastern British Columbia was deposited in the proximal foredeep and is greatly vertically expanded relative to the more eastern part of the basin. The study interval has a wedge-shaped geometry, and is ~780 m thick in the west and thins dramatically to ~280 metres over a distance of ~170 km. Rapid facies changes result in lithostratigraphic units being strongly diachronous. In order to determine depositional history, the present study subdivided the Upper Fort St. John Group into 16 genetically-related allomembers. The new allostratigraphic correlations established in this thesis combined with previous studies, …


Sedimentology And Allostratigraphy Of The Cardium Formation (Turonian-Coniacian) In Southern Alberta, And Equivalent Strata In Northern Montana, Joel Shank May 2012

Sedimentology And Allostratigraphy Of The Cardium Formation (Turonian-Coniacian) In Southern Alberta, And Equivalent Strata In Northern Montana, Joel Shank

Electronic Thesis and Dissertation Repository

The Turonian-Coniacian Cardium Formation of southern Alberta consists of marine sandstone and mudstone, deposited in a foreland basin over ~2.3 m.y. The formation thins from 150 m in the western foredeep to 50 m 350 km to the east. Correlation of 10 regional flooding surfaces in >1200 well logs and 25 outcrops provides an allostratigraphic framework. Mapping of two previously-unrecognized erosion surfaces (E5.2 and E5.5) reveals additional complexity within sandstone of the Raven River Member.

Facies successions coarsen upwards from thinly-bedded and bioturbated mudstone, to heterolithic facies (either bioturbated or bedded), to clean sandstone. Where conglomerate unconformably overlies this succession, …