Late Cretaceous Sponge Borings - Indicators of Salinity and Sedimentation Drumheller, Alberta

Abstract

<p> A detailed study of sponge boring morphotypes within the molluscan fauna of Upper Cretaceous estuarine sediments near Drumheller, Alberta provides information relevant to the depositional environment. Problems with regard to utilizing Entobia as a paleoenvironmental indicator and as an indicator of salinity do not appear to be insurmountable.</p> <p> Distributions and characteristics of associated marine organisms (phoronid worms, gastropods and encrusting bryozoa) suggest that sponge colonies were affected by salinity and sedimentation. Boring networks in Ostrea glabra suggest that more than one species of sponge were present. Sponge distribution patterns, changes in papilla and chamber sizes and preferential occurrence of sponge borings on certain shell thicknesses provide good evidence for responses to salinity and sedimentation.</p>