Seismic Characterization of Large-Scale Platform-Margin Collapse Along the Zhujiang Carbonate Platform (Miocene) of the South China Sea, Based on Miocene Outcrop Analogs from Mut Basin, Turkey
Xavier Janson, Gregor P. Eberli, Anthony J. Lomando, Florence Bonnaffé, 2010. "Seismic Characterization of Large-Scale Platform-Margin Collapse Along the Zhujiang Carbonate Platform (Miocene) of the South China Sea, Based on Miocene Outcrop Analogs from Mut Basin, Turkey", Cenozoic Carbonate Systems of Australasia, William A. Morgan, Annette D. George, Paul M. (Mitch) Harris, Julie A. Kupecz, J. F. (Rick) Sarg
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Redeposition of carbonate sediment on all scales produces heterogeneous stratigraphic architecture along platform margin, slopes, toe of slope, and basin. Larger features, such as margin collapse or slumps, are visible on seismic sections, but their internal architecture is commonly beyond seismic resolution. Seismic data across the lower Miocene Zhujiang Platform margin in the subsurface of Pearl River Mouth Basin in the South China Sea show truncation of the margin associated with contorted and rotated reflections at the toe of slope and in the basin. This seismic facies occurs discontinuously along the margin in an area approximately 6 to 8 km wide paralleling the margin and 2 to 3 km wide in the dip direction. These seismic features are compared with similar geometries and bedding patterns observed in an analog Miocene platform margin that crops out in south-central Turkey. There several slump scars truncate barrier-margin deposits and are associated downslope with rotated and folded strata that are still connected to these detachment surfaces. The margin-collapse observed in the outcrop allows interpretation of margin truncation and the contorted reflection package observed in the seismic as a large-scale redeposited feature. The margin of the lower Miocene Zhujiang Platform displays multiple large-scale slumping events distributed along strike. In the outcrop, large-scale margin collapse internal architecture is made up of blocks of cemented margin material several tens of meters to a few of hundred meters wide. Using half-time energy instantaneous seismic attributes reveals that large cemented blocks imaged as small energy anomalies on 2D seismic data might also exist within the margin collapse observed in Zhujiang Platform.
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The Cenozoic carbonate systems of Australasia are the product of a diverse assortment of depositional and post-depositional processes, reflecting the interplay of eustasy, tectonics (both plate and local scale), climate, and evolutionary trends that influenced their initiation and development. These systems, which comprise both land-attached and isolated platforms, were initiated in a wide variety of tectonic settings (including rift, pas-sive margin, and arc-related) and under warm and cool-water conditions where, locally, siliciclastic input af-fected their development. The lithofacies, biofacies, growth morphology, diagenesis, and hydrocarbon reser-voir potential of these systems are products of these varying influences. The studies reported in this volume range from syntheses of tectonic and depositional factors influencing carbonate deposition and controls on reservoir formation and petroleum system development, to local studies from the South China Sea, Indonesia, Kalimantan, Malaysia, the Marion Plateau, the Philippines, Western Australia, and New Caledonia that incor-porate outcrop and subsurface data, including 3-D seismic imaging of carbonate platforms and facies, to un-derstand the interplay of factors affecting the development of these systems under widely differing circum-stances. This volume will be of importance to geoscientists interested in the variability of Cenozoic carbonate systems and the factors that controlled their formation, and to those wanting to understand the range of po-tential hydrocarbon reservoirs discovered in these carbonates and the events that led to favorable reservoir and trap development.