Post-fossilization processes and their implications for understanding Ediacaran macrofossil assemblages

• Main Authors: Matthews, JJ, Liu, AG, McIlroy, D
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Geological Society of London 2017
• Subjects: 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 3705 Geology; Mistaken Point; Newfoundland
• Online Access: https://www.repository.cam.ac.uk/handle/1810/262112; https://doi.org/10.17863/CAM.7357

Fossil assemblages from Newfoundland’s Avalon Peninsula preserve diverse examples of the enigmatic Ediacaran macrobiota, offering some of the earliest evidence for large and complex multicellular life. These fossils are exposed on extensive coastal bedding planes in extraordinary abundances, permitting palaeoecological studies based on census data from spatially extensive palaeocommunities. Such studies have been used to constrain the reproductive strategy and phylogenetic placement of Ediacaran organisms. Geological mapping and stratigraphic correlation in the Mistaken Point Ecological Reserve reveal that some fossil-bearing surfaces can be tracked over distances of several kilometres. These laterally extensive surfaces reveal that the modern processes by which the sediment overlying a fossil surface is removed may impose important controls on the observed composition of fossil assemblages. Weathering and erosion – along with factors associated with tectonics, metamorphism and discovery – are here grouped as ‘post-fossilization processes’ and introduce biases that are often not explicitly accounted for in palaeoecological studies. Specifically, post-fossilization processes may differentially influence the preservational fidelity of individual specimens on a given surface and generate features that could be mistaken for original morphological characters. We therefore recommend that post-fossilization processes must be considered when undertaking palaeoecological studies in Ediacaran successions in Newfoundland and, potentially, elsewhere. This research was supported by the Natural Environment Research Council [grant numbers NE/J5000045/1 to JJM, and NE/L011409/1 to AGL]. Joe Stewart and Tom Hearing are thanked for assistance in gathering field data. Thanks are also extended to Martin Brasier, without whom this research would never have taken place. Reviews from Matthew Clapham and one anonymous reviewer greatly improved the manuscript. The Parks and Natural Areas Division, Department of Environment and ...