COLLABORATIVE RESEARCH: A Sequence-, Chemo-, and Biostratigraphic Study of Late Early Cambrian Rocks, Southern Selwyn Basin, Mackenzie Mountains, Canada

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ABSTRACT Collaborative Research: A Sequence-, Chemo-, Biostratigraphic Study of Late Early Cambrian Rocks, Southern Selwyn Basin, Mackenzie Mountains, Canada This project investigates how early episodes of animal evolution, which occurred roughly 520 million years ago during the so-called Cambrian radiation, were influenced by environmental changes. To investigate these issues we will study the sedimentology, paleontology, and geochemistry of the Early Cambrian rocks of the Mackenzie Mountains, Northwest Territories, Canada. This is a remote location, but it has a remarkably complete geological record for the Early Cambrian interval. This gives us a window into the life forms and environments of both shallow and deep water settings, a situation found nowhere else for this time period. The types of environmental changes we will study include both changes in the relative level of the seas as well as temperature changes: the two are partly linked. During the Cambrian radiation there may have been rapid oscillations between relatively warm and cold climates. To determine the nature of these environmental changes, it is necessary to understand the variations in the rock types, which we will study in detail. It is also necessary to study when these variations occurred; this we will accomplish by documenting the sequence of fossil species and through use of chemical isotopes. Evolutionary changes and extinction events in this region, and elsewhere, and their relationship to the environmental changes, will also be documented. In this manner, we will not only come to better understand the nature of the environmental changes that occurred during this critical interval in earth history, but we will also determine how one of the key episodes in the history of life may have been fundamentally driven by climatic changes.