Abstract

Correlation of an arenaceous microfauna of 41 species (44 subspecies) from the Hulcross Formation of the Monkman Pass area with that found in the Hulcross Shale on the Peace River has a further corroboration in matching spectra of volcanic ash beds at both localities. The Monkman Pass equivalents of both the basalmost portion and the upper part of the Hulcross beds on the Peace River are in sandy to continental facies. Diatoms are plentiful in the Monkman Pass section in the shaly facies.The foraminiferal genera include Bathysiphon, Thuramminoides, Psammosphaera, Hippocrepina, Saccammina, Reophax, Glomospira, Ammodiscus, Psamminopelta, Haplophragmoides, Ammobaculites, Trochammina, Textulariopsis, Pseudobolivina, Verneuilinoides, Uvigerinammina, Gaudryina, Eggerella, and Dorothia. Only Thuramminoides, Haplophragmoides, and Trochammina occur in abundance, indicating water of depth around 100 m at time of deposition and of salinity close to that of normal seawater. The low degree of bioturbation and the presence of Chondrites in the lower Hulcross suggest that poorly oxygenated bottom waters prevailed. Upwards, the diversity and abundance of bioturbation increase, indicating higher oxygenation contents caused by better circulation. As such, the Hulcross basin had a stratified water column.

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