Grant: Discovery Grants Program - Individual

Largely due to their lack of obvious heterogeneities in sedimentary texture, structure and mineralogy that normally form the basis of conventional sedimentological studies, mudrocks are notoriously difficult to interpret with respect to their depositional origins. However, it is becoming increasingly apparent that their contained fossils can serve as alternative sources of such information. The proposed research aims to explore potential use of such remains as indicators of the sedimentary dynamics in mud-dominated marine environments, based largely on the paleoecologic and taphonomic (post-mortem) attributes of the fossil remains. Much of the applicant's previous research has focused on the use of shell-rich deposits to bridge the stratigraphies of the Middle Devonian Hamilton Group in the Appalachian and Michigan sedimentary basins via the Chatham Sag of southwestern Ontario. The proposed research will focus more on their use as paleoenvironmental indicators, and more specifically, as tools for interpreting the depositional dynamics recorded in ancient, mudrock-dominated marine successions that are otherwise lacking in sedimentary structures. ) The other major component of the proposed research will address the nature of the common association of carbonate concretions with mudrock-hosted fossils. It is generally agreed that concretion genesis is related to the generation of alkalinity by microbial decay processes, but the reasons why some macrofaunal remains influence concretion growth and not others remains unclear. To address this issue, the fossil content, physical structure, mineralogy, elemental geochemistry, and stratigraphic context of fossiliferous concretions from a variety of ancient mud-dominated successions will be compared. Previous studies have suggested that concretion growth can accompany either rapid sedimentation or sediment starvation. Accordingly, a better understanding of concretion formation may provide an additional tool that can be used in conjunction with shell beds to interpret the nature of sedimentation in ancient mud-dominated marine environments.