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The Kenn Plateau Off Northeast Australia: an Important Continental Fragment in the Southwest Pacific Jigsaw

Created 17/10/2025

Updated 17/10/2025

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The submarine Kenn Plateau has an area of about 140,000 km² and lies 500 km east of central Queensland beyond the Marion Plateau. It is one of several thinned continental fragments lying east of Australia that were once part of Australia, and it originally fitted south of the Marion Plateau as far south as Brisbane. It is cut into smaller blocks by east and northeast trending faults, with thinly sedimented basement highs separated by basins containing several kilometres of sediment. In the Cretaceous, it was probably underlain by rocks of the New England Fold Belt on which were stacked Late Triassic to Late Cretaceous basins. Late Cretaceous stretching and breakup was followed by Paleocene drifting, and the Kenn Plateau moved away to the northeast, rotating 45 degrees clockwise and leaving the Tasman Basin oceanic basalts behind. During these processes, siliciclastic sediments poured into the basins from the mainland and from locally eroding highs, but this sequence was terminated by a regional Late Paleocene to Early Eocene unconformity. Rift volcanics are common on the northern plateau. Radiolarian chalks were widely deposited until biosiliceous sedimentation ended with the regional Late Eocene to Early Oligocene unconformity, and warming surface waters led to younger chalk deposition. Some seismic profiles show the Middle to Late Eocene compression so well exemplified in the New Caledonian obduction to the east. Hotspots formed two volcanic chains as the plateau moved northward: the Oligocene Tasmantid chain in the west, and the Neogene Lord Howe chain in the east. As the volcanoes subsided they were fringed by reefs, some of which have persisted until the present day, whereas other reefs have not kept up with subsidence so guyots formed. The plateau has subsided 2000 m or more since breakup and is now subject solely to pelagic carbonate sedimentation.

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Additional Info

Field Value
Title The Kenn Plateau Off Northeast Australia: an Important Continental Fragment in the Southwest Pacific Jigsaw
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/4d1d1471-0106-4c32-ba62-6d82955d6c8a
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 22/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        154.0,
        -26.0
      ],
      [
        160.0,
        -26.0
      ],
      [
        160.0,
        -19.0
      ],
      [
        154.0,
        -19.0
      ],
      [
        154.0,
        -26.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The Kenn Plateau Off Northeast Australia: an Important Continental Fragment in the Southwest Pacific Jigsaw". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-kenn-plateau-off-northeast-australia-an-important-continental-fragment-in-the-southwest-pac