Late Devonian stratigraphy, stable isotopic analyses, and paleoecology in the Napier, Oscar, and Emanuel Ranges, Canning Basin, Western Australia

The Canning Basin contains excellent exposures of Frasnian and Famennian reefs, from which models of Upper Devonian reef development can be developed. Facies distribution and composition of these reefs record interactions among sea level changes, sediment supply, ocean chemistry, and paleoecology. Biostratigraphy, sequence stratigraphy and, carbon isotope stratigraphy allow the regional correlation of strata across facies boundaries. Results demonstrate that sea level-driven, carbonate-siliciclastic reciprocal sedimentation at Windjana Gorge correlates to spatial shifts in reef facies in the Oscar Range and Dingo Gap. Transgressive intervals correspond to positive carbon-isotopic excursions within the Canning Basin and can be correlated to time-equivalent carbon isotopic curves from Europe and Canada.; Following the Frasnian-Famennian mass extinction, Famennian reefs were constructed primarily by microbial framestones and bindstones. The morphology and distribution of the microbial communities were controlled by their physical environment. Fenestral stromatolites and porous thrombolites formed in high energy, reef-flat environments. These microbial textures are associated with very coarse grainstone and truncation surfaces, suggesting proximity to sea level. The reef-margin subfacies contains mounds of porous thrombolites, which are more delicate than reef-flat thrombolites, suggesting lower wave energy. Deep-water reefal-slope environments had delicate microbialites composed mostly of Rothpletzella with abundant stromatactis pores.; Renalcids, an enigmatic group of encrusting fossils, are reinterpreted as calcifying biofilms. In the Canning Basin, renalcids grew downwards in cryptic reef environments, such as the undersides of laminar stromatoporoid and within the pores of microdigitate thrombolites. The micritic chambers of the renalcids, Shuguria and Izhella, have carbon isotope values 0.3–1.8‰ lower than contemporaneous early marine cements, suggesting incorporation of respired CO₂ into the micrite. Based on growth environment and carbon-isotope geochemistry, renalcids are neither fossilized cyanobacteria nor marine algae. Renalcids may be fossilized biofilm clusters, which calcified due to heterotrophic bacterial activity following pulses of rapid biofilm growth.