About This Item
- Full TextFull Text(subscription required)
- Pay-Per-View PurchasePay-Per-View
Purchase Options Explain
Share This Item
The AAPG/Datapages Combined Publications Database
AAPG Special Volumes
Abstract
Pub. Id:
First Page:
Last Page:
Book Title:
Article/Chapter:
Subject Group:
Spec. Pub. Type:
Pub. Year:
Author(s):
Abstract:
The Upper Cretaceous strata of the Western Interior of North America contain a rich molluscan fauna and abundant intercalated bentonites. This combination has permitted the development of a detailed time scale for the Late Cretaceous. Volcanic rocks are rare in the Lower Cretaceous of North America. Several isolated time-scale points have been reported for Lower Cretaceous rocks, but the Early Cretaceous time scale is not well defined.
Nearly all of the available isotopic ages are K-Ar mineral ages. Data have been recalculated using decay constants for K40 based on the refined activity data for K40 and the isotopic abundance of K40. The best current estimates for system and series boundaries are: Cretaceous-Tertiary boundary-65 to 66 m.y.; Lower Cretaceous-Upper Cretaceous boundary--96 m.y.; Jurassic-Cretaceous boundary--138 ± 3 m.y.
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 |