About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 53 (1969)

Issue: 9. (September)

First Page: 1880

Last Page: 1893

Title: Interdigitation Versus Arbitrary Cutoff: Resolution of an Upper Cretaceous Stratigraphic Problem, Western Saskatchewan

Author(s): R. A. H. Nichols (2), J. M. Wyman (2)

Abstract:

Previous workers have stated correctly that the Belly River and Lea Park Formations interdigitate in west-central Saskatchewan and east-central Alberta, but that relation is not shown in all published sections or logs. The usage of the terms "Belly River Formation" and "Lea Park Formation," which implies superposition and not interdigitation, is believed to obscure the relation of the units. Furthermore, the Ribstone Creek Member (Belly River Formation), for example, comprising sandstone and shale, has been traced by previous workers as a time-stratigraphic unit based on a lithologic datum or microfaunal zones. That practice also is believed to cause confusion, because sandstone bodies in any microfaunal zone are not necessarily continuous with those elsewhere in the zone Likewise, shale in any one zone may be indistinguishable from shale in another zone, and to separate the beds into different formations by various methods is misleading.

Because the members have been shown to extend beyond the formations, it is suggested that the members be called tongues. The upper and lower sandstone units of interbedded sequences of shale and sandstone were traced in western Saskatchewan to determine the extent of the tongues of the Belly River Formation as rock units, and their interdigitating relation with tongues of the Lea Park Formation. Tracing the tongues of the Belly River Formation as rock-stratigraphic units, with sea level as datum, yields a more accurate rock unit relation because the sandstone bodies are more persistent and conspicuous than the interbedded shale. The shale may be confused with that of the Lea Park Formation because of lithologic resemblance. Gas in the Whiteside gas pool is present in the Ribstone Cree tongue and not the Previous HitVictoriaTop Tongue of the Belly River Formation.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].