About This Item
- Full TextFull Text(subscription required)
- Pay-Per-View PurchasePay-Per-View
Purchase Options Explain
Share This Item
The AAPG/Datapages Combined Publications Database
AAPG Bulletin
Abstract
AAPG Bulletin, V.
David
A. Feary2 and Noël P.
James
1Manuscript received August 2, 1996; revised manuscript received
April 14, 1997; final acceptance January 15, 1998.
2Australian Geological Survey Organization, G.P.O. Box 378,
Canberra 2601, Australia.
3Department of Geological Sciences, Queens University,
Kingston, Ontario K7L 3N6, Canada.
This research was largely carried out while Feary was a Canadian Commonwealth
Research Fellow at Queens University. James is supported by the Natural
Sciences and Engineering Research Council of Canada. We gratefully acknowledge
reviews by A. R. Isern, D. F. McNeill, R. Sarg, and P. Crevello. The Geological
Society of America granted permission to reprint Figures 1, 5, 9, 11, and
18. Feary publishes with permission of the Executive Director, Australian
Geological Survey Organization.
ABSTRACT
This platform, the first large cool-water carbonate shelf imaged by
high-quality seismic reflection data, demonstrates the interaction between
regional tectonic and local and global paleo-oceanographic processes. As
Australia drifted northward during the Cenozoic, the Great Australian Bight
moved from high to middle latitudes, and the regional oceanographic regime
remained cool water largely because of coeval development of the Antarctic
Circumpolar Current in the evolving Southern Ocean. Short episodes of warm-water
deposition probably reflect incursions of a proto-Leeuwin current from
the Indian Ocean, whereas growth of the Miocene coral-algal "Little Barrier
Reef" resulted from a short-term global increase in sea-surface temperatures.
This platform, dominated by stacked carbonate ramps, is most similar to
the West Florida Shelf, but contains many more biogenic mounds. The western
Great Australian Bight carbonate platform is an excellent modern analog
for the mesoscale structure of cool-water platforms in the older geologic
record.
Seismic images of the continental margin in the western Great Australian
Bight reveal the internal anatomy of a long-lived Cenozoic cool-water carbonate
shelf. The Cenozoic succession is divisible into seven seismic sequences
that reflect four depositional phases. Phase A (Paleocene-middle Eocene)
is a progradational siliciclastic wedge deposited in a depositional sag,
and represents lowstand and transgressive sedimentation. Phase B (middle
Eocene- earliest middle Miocene) contains cool-water ramp carbonates with
biogenic mounds (Eocene- Oligocene), overlain by a warm-water, flat-topped
platform rimmed by the early middle Miocene(?) Little Barrier Reef. Coeval
deep-water carbonate deposition formed a multi-lobed sediment apron. This
phase was terminated by gentle uplift and tilting throughout southern Australia
in the late middle Miocene. Phase C (late Miocene-early Pliocene) represents
cool-water lowstand wedge and ramp deposition, and contains numerous biogenic
mounds in the youngest sequence. This phase is terminated by an unconformity
attributed to marine erosion. Phase D (Pliocene-Quaternary) is a thick
succession of cool-water carbonates with spectacular clinoform ramp geometry
that forms most of the modern outer shelf, and contains large deep-water
biogenic mounds.
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
Watermarked PDF Document: $14 | |
Open PDF Document: $24 |
AAPG Member?
Please login with your Member username and password.
Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].