Print this pageEffects of Paleogeography on Carbonate Slope Development, Upper Devonian, Canning Basin, Western Australia
Playton, Ted *1; Montgomery, 
Paul
2;
Tohver, Eric 3; Hillbun, Kelly N.4; Hansma, Jeroen 3;
Trinajstic, Kate 5; Pisarevsky, Sergei 3; Hocking, Roger 6;
Haines, Peter 6; Kirschvink, Joseph 7; Yan, Maodu 8;
Ratcliffe, Ken 9; Ducea, Mihai 10; Katz, David A.11;
Harris, Paul
(Mitch) 11
(1) Chevron ETC, Houston, TX.
(2) Chevron
Upstream Europe, Aberdeen, United Kingdom.
(3) University of Western Australia,
Perth, WA, Australia.
(4) University of Washington, Seattle, WA.
(5) Curtin
University of Technology, Perth, WA, Australia.
(6) Geological Survey of
Western Australia, Perth, WA, Australia.
(7) California Institute of
Technology, Pasadena, CA.
(8) Institute for Tibetan Plateau Research, Beijing,
China.
(9) Chemostrat Incorporated, London, United Kingdom.
(10) University of
Arizona, Tucson, AZ.
(11) Chevron ETC, San Ramon, CA.
High-resolution chronostratigraphic correlations are integral for the development of stratigraphic frameworks and understanding depositional variability, especially in highly heterogeneous, steep carbonate slope settings. Fine-scale correlation in the subsurface is challenging, thus the Canning Basin Chronostratigraphy Project (CBCP) was developed to demonstrate high-resolution correlation workflows on an ancient carbonate outcrop through the integration of multiple conventional and alternative approaches that can be tailored to the subsurface with available core and cuttings.
This subset of the CBCP dataset focuses on three stratigraphically-overlapping Frasnian-to-Famennian (Upper Devonian) carbonate slope outcrop exposures along the Lennard Shelf, Canning Basin, Western Australia. Each exposure represents a particular paleogeographic configuration along the Lennard Shelf related to underlying structure, consisting of 1) an isolated buildup detached from the main shelf, 2) an attached margin along a large-scale (~50km) embayment, and 3) an attached open ocean-facing margin with multiple smaller-scale (<2km) reentrants. Detailed measured sections were sampled for magnetostratigraphy (polarity and susceptibility), inorganic stable isotope geochemistry, inorganic whole rock geochemistry, and age constraints (conodont biostratigraphy and U-Pb absolute dating). These data were integrated using sequence stratigraphic guidelines to generate a high-resolution chronostratigraphy across the three transects.
The integrated correlation framework highlights the effects of different paleogeographic configurations on carbonate slope development, as well as unravels shelf-wide phenomena from local signals. The degree of stratigraphic and spatial heterogeneity in slope deposits, presence of siliciclastics, and thickness of age-equivalent intervals vary depending on an isolated versus attached shelf setting, platform interior width, and reentrant scale. Regionally recognizable features include extinction-related slope microbial encrustation and large-scale margin failure related to the onset of low-frequency progradation. These associations provide predictive linkages between carbonate slope heterogeneity, architecture, and structural antecedent topography that can be utilized in petroleum exploration and development scenarios.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California