About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Special Volumes

Abstract

G. P. Eberli, J. L. Masaferro, and J. F. ldquoRickrdquo Sarg, 2004, Seismic imaging of carbonate reservoirs and systems: AAPG Memoir 81, p. 291-307.

Copyright copy2004. The American Association of Petroleum Geologists. All rights reserved.

A Neogene Carbonate Platform, Slope, and Shelf Edifice Shaped by Sea Level and Ocean Currents, Marion Plateau (Northeast Australia)

Alexandra R. Isern,1 Flavio S. Anselmetti,2 Peter Blum3

1National Science Foundation, Arlington, Virginia, U.S.A.
2Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
3Ocean Drilling Program, College Station, Texas, U.S.A.

ACKNOWLEDGMENTS

We acknowledge the excellent support provided by the Australian Geological Survey Organisation (AGSO) seismic technicians who faced many challenges resulting from the use of a new system on a vessel that had not previously performed such a survey as on FR 03/99. Mike Sexton, shore-based at AGSO, was essential for solving processing bugs and faxing software updates to the ship. We also greatly appreciate the hard work of the R/V Franklin crew. Their efforts helped make the cruise a great success. Above all, we acknowledge the funding for this cruise provided by AGSO and the Australian Research Council. We also thank the scientists, technical staff, and the crew of the JOIDES Resolution for their hard work during ODP Leg 194. This manuscript was greatly improved by reviews from Christian Betzler, Craig Fulthorpe, and Gregor Eberli.

ABSTRACT

More than 1700 km of high-resolution seismic data were collected over the Marion Plateau, northeast Australia, to investigate the influence of sea level and oceanography on subtropical carbonate platforms growing on the plateau surface. Seismic data, interpreted in combination with sediments recovered during Ocean Drilling Program Leg 194 and modern oceanographic data, have enabled characterization of the parameters controlling platform growth and development in this region.

Most modern carbonate platforms, such as the Bahamas Platform, have sedimentation patterns that reflect the prevailing wind direction where sediments are forced off the platform on the leeward side, leaving the windward side relatively sediment-starved. This results in platform asymmetry with steep windward and gentler leeward slopes. The seismic data presented here indicate that the carbonate platforms off northeast Australia, although similar in morphology to the Bahamas Platform in many respects, are dominated by oceanographic currents as the primary energy source creating a similar asymmetrical platform geometry where the upcurrent side of the platform is relatively sediment starved and most sediment is deposited on the downcurrent slope. Currents in the study area are dominated by the southward-flowing East Australian Current that generally flows opposite to the prevailing Southeast Trade Winds. This current likely determines not only the morphology, but also the growth potential of the platforms, as well as the volume and final location of sediment transported from the platform top.

Despite the massive, tablelike structures exhibited in the seismic data, Leg 194 drilling demonstrated that the platforms are almost entirely composed of the remains of cool, subtropical organisms, such as red algae, bryozoans, and larger benthic foraminifera. Coralline algae were notably absent from most sequences. These calcite-dominated organic remains have a low diagenetic potential, resulting in uncemented and friable slope successions. Nevertheless, the platform tops are well cemented. The fact that the cool subtropical faunal assemblages produce platform geometries that are similar to tropical carbonates suggests that physical parameters, such as current flow and sea level change, may be more important than biofacies in establishing platform architectures.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24