Geologic Modeling of Frasnian and Famennian Carbonate Platforms, Canning Basin, Western Australia

Frost, Ned¹ (1) The University of Texas at Austin, Austin, TX

The Late Devonian Frasnian and Famennian carbonate platforms of the Canning Basin represent two fundamentally different systems with markedly different facies patterns and stratal architecture. Geologic models of key Frasnian and Famennian outcrops have been constructed from a robust dataset of high-resolution ground-based LIDAR, measured sections, mapping data, core, and satellite imagery. These outcrop-calibrated 3-D geocellular models provide an important baseline for documenting the variability of Devonian reef complexes across the Frasnian-Famennian (F/F) boundary.

Platform-interior strata from Windjana Gorge (Frasnian) and Barnett Spring (Famennian) show dramatic changes in facies distribution and cyclicity across the F/F boundary. This transition is characterized in the backreef by a change from muddy stromatoporoid-biostromes to a complex mosaic of high-energy grainstone shoals, tepee-pisolite complexes, and fenestral laminites. A similar change from mud-dominated to grain-dominated facies is observed in the platform-margin/slope system in Windjana Gorge across the F/F boundary. Here, the shift from retrogradation to progradation in the latest Frasnian leads to dramatically different styles of slope architecture and facies heterogeneity.

The models generated from these world-class outcrops provide valuable information on stratal geometry and geobody dimensions, changes in facies patterns associated with the F/F boundary, and the effect that long-term changes in accommodation space and platform-margin trajectory have on shaping platform and slope architecture. Additionally, this information can be applied to further petroleum exploration in the Canning Basin, as well as to other age-equivalent reservoirs around the world.