About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

Journal of Sedimentary Research (SEPM)

Abstract


Journal of Sedimentary Petrology
Vol. 49 (1979)No. 3. (September), Pages 995-1004

The Pliocene Glenns Ferry Oolite: Lake-margin Carbonate Deposition in the Southwestern Snake River Plain

Krystyna Swirydczuk, Bruce H. Wilkinson, Gerald R. Smith

ABSTRACT

An extensive fresh-water oolitic carbonate representing the remnant deposits of a Pliocene low-salinity lake occurs at the base of the Glenns Ferry Formation along the western margin of the Snake River Plain. This oolite crops out in a 45 kilometer-long belt that treads northwest-southeast and parallels the southwestern shoreline of fossil Lake Idaho. It consists almost entirely of ooids ranging in size from 0.5 mm to 6.0 mm in diameter. Optical and scanning electron microscopy reveal a random mixture of radial laths and equant blocky grains of low-magnesian calcite in the ooid cortices. The primary mineralogy of the lath-shaped crystals is interpreted as having been aragonite and the radial orientation of these crystals as having been synsedimentary based upon comparison with crystal in the cortex of Great Salt Lake ooids. Crenulation of concentric laminae is indicative of significant algal influence during ooid formation, suggesting accretionary processes more typical of algal oncoids. Cortex deposition took place in a shallow agitated environment on a nearshore lacustrine bench, while ooid deposition took place lakeward on the deeper water bench slope.


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