DEVELOPMENT OF REGIONAL STRATIGRAPHIC FRAMEWORKS AND GEOLOGICAL IMPLICATIONS IN UPPER DEVONIAN CARBONATES USING INTEGRATED CHRONOSTRATIGRAPHY, CANNING BASIN, WESTERN AUSTRALIA

The development of meaningful stratigraphic frameworks requires high-resolution chronostratigraphic correlations. Such frameworks are integral for shelf-to-slope correlation, characterization of strike variability, and sequence stratigraphic interpretation, especially in heterogeneous, steep-sided carbonate platform systems. The primary goal of the Canning Basin Chronostratigraphy Project (CBCP) is to develop a correlation approach using an ancient carbonate outcrop dataset that integrates multiple independent signals in the rock record to arrive at a well-constrained chronostratigraphic framework. The approach can be tailored to subsurface characterization using core and cuttings.

The CBCP dataset encompasses >4 km of measured stratigraphy and >7000 samples of Upper Devonian (Frasnian and Famennian) carbonate platform-top, reef, foreslope, and basinal deposits from outcrop exposures and shallow cores along the Lennard Shelf, Canning Basin, Western Australia. Detailed measured sections and cores were sampled for magnetostratigraphy, stable isotope chemostratigraphy, conodont biostratigraphy, and elemental chemostratigraphy. These independent data signals were integrated in conjunction with sequence stratigraphic concepts to generate a high-resolution, regional chronostratigraphy across 250 km of the Lennard Shelf.

The resultant integrated framework allows for unprecedented examination of Lennard Shelf carbonate transitions, spatial heterogeneity, paleogeographic variability, and stratigraphic evolution. Important highlights include: 1) a better-constrained composite regional stratigraphic shelf-to-basin reconstruction of the Lennard Shelf system; 2) models and stacking pattern rules for slope sequence stratigraphy; 3) non-layer-cake inner-to-outer platform transition architecture; 4) shelf-to-slope correlation across a 2^nd-order maximum flooding surface; and 5) development of a Famennian regional sequence stratigraphic framework. This study successfully documents an integrated chronostratigraphic approach that generated a high-resolution, well-constrained correlation framework from shallow platform-top to deep-water carbonate settings, and across multiple positions along strike; correlations that were not formerly possible.