About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

Utah Geological Association

Abstract


Central Utah: Diverse Geology of a Dynamic Landscape, 2007
Pages 75-80

New U-Pb Zircon Ages from an Ash Bed in the Brushy Basin Member of the Morrison Formation Near Hanksville, Utah

Bart J. Kowallis, Brooks B. Britt, Brent W. Greenhalgh, Douglas A. Sprinkel

Abstract

A bentonitic ash bed 8.7 m below the top of the Upper Jurassic Morrison Formation near Hanksville, Utah, has been dated by laser ablation multi-collector inductively coupled plasma mass spectrometry and gives a single-crystal U-Pb zircon age of 149.0 +2.5/−2.2 Ma. This age is statistically the same as the 149.3 ± 0.5 Ma age of an ash bed located 0.5 m below the top of the Brushy Basin Member of the Morrison Formation near Notom, Utah, about 25 km to the west. The Hanksville section has a short section of possible Cedar Mountain Formation (between 0.4 and 7.3 m thick) on top of the Morrison section. Two young contaminant zircons with a peak age of 122.5 Ma in the Brushy Basin ash sample indicate that the Cedar Mountain sediments present here are from the lowermost part of the Cedar Mountain 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