Spatial and Temporal Significance of Process Ichnology Data From Silty-Mudstone Beds of Inclined Heterolithic Stratification, Lower Cretaceous McMurray Formation, Ne Alberta, Canada

Using ichnological relationships to interpret heterolithic fabrics in fluvio‐tidal settings

“…As such, the deposition of bioturbated IHS packages is more likely linked to seasonal or annual variations in river discharge. In addition, it has been quantitatively demonstrated that the cyclicity of physical and chemical palaeoecological stresses at the estuary scale is linked to climatic variation periods (possibly El Niño–Southern Oscillation cycles) (Timmer et al ., 2016b). Nevertheless, examples from the McMurray Formation (Timmer et al ., 2016a) and Amazon Basin (Hovikoski et al ., ) have shown that the interlaminated portions of IHS can be consistent with tidal periodicities.…”

“…Since IHS was defined more than three decades ago, it has been recognized as a volumetrically‐important constituent of tidally influenced sedimentary systems (Dalrymple & Choi, ). Apart from identifying the temporal nature of regularly bedded IHS as semi‐diurnal or annual using ancillary features such as bioturbation (Gingras et al ., , ; Sisulak & Dashtgard, ) and frequency analyses (Hovikoski et al ., ; Labrecque et al ., ; Timmer et al ., 2016b), the concept of IHS has evolved little since its introduction. Using examples from fluvio‐tidal parts of the McMurray Formation in Alberta, Canada, this paper presents a framework – using detailed ichnological analysis – to determine the relative depositional position that IHS accumulated within the fluvio‐tidal system.…”