Facies heterogeneity, platform architecture and fracture patterns of the Devonian reef complexes, Canning Basin, Western Australia
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Carbonate facies patterns and stratal architecture are the product of the complex interaction of internal (e.g., reef-building biota, sediment production) and external drivers (e.g., tectonics, climate, and relative sea level). In the Canning Basin of Western Australia, many of these drivers are in flux across the Late Devonian Frasnian--Famennian (F--F) boundary and significant variations in reefbuilding biota and long-term accommodation are observed. This study documents the evolution of the Canning Basin's Devonian reef complexes across the F--F boundary and proposes a new interpretation of the stratal architecture and paleobathymetric profile of the Famennian. Data presented here demonstrate the evolutionof a shelf-crest system in the Famennian, with beds expanding basinward and the reef growing in water depths of approximately 5-15 m. The paleobathymetric profile of the Famennian described by this study represents a departure from the well-documented barrier-reef system of the Frasnian. Digital outcrop models help capture the heterogeneity of the Famennian system and allow for characterization of the Devonian reef complexes across the F--F boundary. Syndepositional fractures are a ubiquitous feature of high-relief, reefrimmed carbonate systems and these features exert a profound influence on many facets of platform evolution. This study documents strong variability in syndepositional fracture patterns as a function of lithofacies and depositional setting and evidence for the temporal evolution of the mechanical properties of the Devonian reef complexes is presented. A statistically significant relationship is documented between syndepositional fracture development and variations in stratigraphic architecture, approximated here by platform-margin trajectory. This relationship implies a significant stratigraphic control on syndepositional deformation in carbonate platforms and suggests that external drivers are not required to generate early fractures in high-relief carbonate platforms.