Visualizing a process ichnology dataset, Lower Cretaceous McMurray Formation, NE Alberta, Canada

Abstract

Abstract Process ichnology emphasizes the use of trace fossils as proxies for sedimentary processes and conditions. The advantage of this method is that depositional stresses can be identified based on several process-ichnological parameters. The purpose of this paper is to demonstrate the use of process-ichnology data, with a focus of establishing how process ichnology metrics can be visualized with geomodeling to aid spatial interpretation. For this study, process ichnology metrics (including bioturbation index and size diversity index), which is the product of interval ichnogenera diversity and interval maximum burrow diameter, are presented from a core dataset of the Cretaceous McMurray Formation. These data are modeled using standard geostastistical techniques for effective visualization of spatial trends. The modeled ichnology data are compared to sedimentary facies in order to interpret the dominant stresses occurring at the time of infaunal colonization. Several interpretations are made from the process ichnology model. The size diversity index and bioturbation index values from inclined heterolithic stratification show strong spatial variability related to variable depositional conditions across and along inclined heterolithic stratification bar forms. Facies interpreted to represent tidal flat deposition are distinguishable on the basis of relatively high bioturbation index values coupled with intermediate to low size diversity index values. Overall, we interpret variability in salinity and sedimentation rates to be the dominant infaunal stresses in the studied stratigraphic interval.