Interrogating the Rock Record for Low- and High-Latitude Trace-Fossil Signatures to Better Know the Ichnological Response to Depositional Temperature

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Ichnology is the study of trace fossils, which are the preserved tracks, trails and burrows of animals in the rock record. This field has very broad application. Burrows represent survival strategies of sediment-dwelling animals and they show a surprising range in their shape, size and occurrence. Many trace-fossil types occur through space and time and their paleontological significance is well understood. Trace-fossil models provide interpretations of paleoenvironmental conditions such as dissolved O2 concentration in the water, salinity and sedimentation rates. This proposal is to develop a a model that associates trace fossils to depositional temperature for climate studies, using the burrows of invertebrates (e.g. worms, shrimp, starfish, anenomes) in marine environments. An understanding of trace-fossil occurrence as a function of depositional temperature is crucial. Canada continually looks northwards for new oil and gas discoveries, and an ichnological model that reveals past climate would be highly relevant to oil and gas exploration and development. This is because understanding changing climatic conditions helps predict what geological levels have the best resource potential and what their regional distributions might be. This is owing to the role that climate plays in dictating source-rock quality and reservoir composition. Notably, industry considers ichnological analyses to be an important part of sedimentary rock interpretation, and this would be a welcome addition to their ichnological tool belt.Canadian geoscientists have been heavily engaged, and are leaders in climate-change research. Data used for climate change analyses include geochemical and body-fossil datasets, but ichnological datasets are largely ignored. Yet, trace-fossil assemblages contain inportant paleoecological information. Moreover, most marine deposits contain abundant ichnological data that stand to contribute to a deeper understanding of climate change, but with respect to climate we presently do not know exactly how to interpret the ichnofossil distributions that we can observe in the sedimentary record.This proposal outlines an approach to investigate the differences between low- and high-latitude trace-fossil successions to address the ichnological recognition of depositional temperature. The proposed studies will focus on marine environments. The rationale behind this investigation is that physical and chemical parameters in tropical (warm) versus arctic (cold) latitudes, including food resources, hydraulic energy, dissolved oxygen content, and oxygen- and salinity-distributions are very different at different latitudes and will thus lead to different ichnological assemblages in each of those settings. The research plan considers Permian, Cretaceous, Eocene and modern datasets that will build on modest earlier efforts. Importantly, the strategy proposed is not simply to identify recurring ichnological assemblages that relate to latitude, but to establish a shelf to shoreline trace-fossil characterization that can be reliably associated with the temperature of the depositional marine waters.