Australia: The Land Where Time Began

A biography of the Australian continent 

Regimes in Australia

During the Phanerozoic Australia had 3 regimes, the Uluru, 570-320 Ma, the Innamincka, 320-90 Ma, and the Potoroo, 97-0 Ma, each being a complex of uniform plate tectonic and palaeoclimatic events at a similar or slowly changing latitude that produced deposits with a sequence of distinct facies bounded by disconformities at the margins and stratigraphic gaps in the interior. The Uluru of the continental interior is predominately low-latitude, shallow-water deposits, that include marine carbonates. The Innamincka regime is composed of high-latitude, non-marine, including glacial, deposits. The Potoroo sequence is increasingly lower latitude deposits, almost all of which are confined to the margins. A change from a Chilean- to Mariana-type subduction is marked by the boundary between the Innamincka and the Potoroo regimes. The Innamincka regime resembles the Gondwana sequence of peninsula India. In general, the Australian regimes resemble those of other component landmasses of Gondwana. The Gondwanan regimes reflect those from the rest of the world, being part of 2 Phanerozoic super-cycles, each about 400 million years long. The first covered the period from the Palaeozoic to the Early Mesozoic and the 2nd from the Late Mesozoic to the Cainozoic, each of  which reflected a cycle of mantle convection, expressed in variation over time of plutonism, and so the CO2 concentration of the atmosphere, and the swings from greenhouse to icehouse conditions, as well as continental congregation and dispersion, Pangaea, and eustatic sea level, and from marine platform sediment at times of high sea level  to non-marine during periods of low sea level.

Regimes were a concept originally devised for dealing with the historical evolution of North America (Sloss, 1963), and employed by Haq et al.(1987). Veevers introduced the concept of regimes to discuss the geological history of Australia. Two of Veevers' regimes, the Innamincka, that ended in the Cenomanian, and the Potoroo, up to the Recent. There are 2 features that identify the boundary between the regimes, during the Cenomanian there was a major retreat of the sea from central Australia, and a widespread depositional change from sediments of terrestrial origin to biogenic carbonate sediment.

Australian Palaeogeography

Sources & Further reading

  1. Veevers, J. J  (ed.), 2000, Billion-year earth history of Australia and neighbours in Gondwanaland, GEMOC Press Sydney.
Journey Back Through Time
Experience Australia
Aboriginal Australia
National Parks
Photo Galleries
Site Map
                                                                                           Author: M.H.Monroe  Email:     Sources & Further reading