The Evolution of the Carbonate Platforms of Northeast Australia
Published:January 01, 1989
Peter J. Davies, Philip A. Symonds, David A. Feary, Christopher J. Pigram, 1989. "The Evolution of the Carbonate Platforms of Northeast Australia", Controls on Carbonate Platforms and Basin Development, Paul D. Crevello, James L. Wilson, J. Frederick Sarg, J. Fred Read
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The carbonate platforms of northeast Australia, the Great Barrier Reef province and the Eastern, Queensland, and Marion Plateaus, contain a record of the complex interactions between the factors that controlled carbonate deposition over the past 60 m.y. Analysis of the extensive geological and geophysical data shows that both long-term (plate motion and subsidence) and short-term (rifting, eustasy, climate, oceanography, and collision) factors influenced platform evolution.
–The size, shape, and location of the high-standing structural features on which the carbonate platforms developed was determined by continental rifting.
–Northward plate movement controlled the distribution of climate-related facies within the Great Barrier Reef sequence, resulting in a tropical carbonate wedge that thins and becomes younger to the south and overlies temperate and subtropical facies.
–Large-scale facies distribution patterns reflect the complexities of the subsidence regimes that affected the northeast Australian platforms. The simple subsidence situation, where high-subsidence rates favoring backstepping are succeeded by lower subsidence rates favoring progradation, was complicated by episodes of accelerated subsidence.
–Sea-level variation directly controlled platform facies: rising and high sea-level periods favored increased carbonate deposition, whereas falling and low sea-levels restricted carbonate deposition, caused increased terrigenous input along the shelf, and in many cases resulted in exposure of the platforms and the formation of unconformities.
–In addition to the overall climatic consequence of northward plate motion, facies sequences show the effects of the development throughout the Cenozoic of more pronounced latitudinal climatic zonation and progressive high-latitude cooling.
–Chemical and physical oceanographic factors affected platform evolution in various ways, e.g., the inhibition of reef development by high oceanic-phosphate levels during the Early and Middle Miocene, and deposition of facies reflecting the progressive development of the east Australian current from the Miocene.
–The development of a foreland basin on the northern edge of the northeast Australian region initially caused a dramatic expansion of carbonate facies, but ultimately terminated carbonate deposition as a result of uplift and inundation by clastic detritus.
General conclusions applicable to other carbonate platforms may be deduced from analysis of the factors that controlled deposition on the northeast Australian platforms. The evolution of any particular carbonate platform will be fundamentally dependent on whether the subsidence history is simple or complex; whether plate motion is toward or away from the tropics; and whether movement from one climatic regime to another is slow or rapid. Short-term eustatic, climatic, and oceanographic factors are responsible for complexities in the facies sequences produced. The most complex and varied carbonate platform sequences will be those deposited under the influence of compound subsidence, together with plate motion through a range of climatic zones over a substantial time period. The northeast Australian carbonate platforms illustrate such a complex history and demonstrate that facies diachroneity is a fundamental characteristic of complex carbonate platform development.
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Controls on Carbonate Platforms and Basin Development
Controls on Carbonate Platform and Basin Development - This volume is derived from the SEPM Research Symposium of the same name that was formulated for the Los Angeles meetings of AAPG and SEPM in 1987. The volume covers many subjects relative to geology of carbonate platforms and adjoining slopes and basins. A preliminary section, based on principles of deposition and computer modeling studies, is followed by a group of papers devoted to examples of carbonate platforms on passive cratonal margins resulting from rifting. Some of the examples are from major platform systems around North America and the Mesozoic of Tethys. Other studies are of local and individual platform-basin systems. Examples of both ramps and rimmed platforms are included. The case histories presented span the whole of geologic time from early in the Proterozoic to the Holocene.