Laterite Karst - large scale features

Large scale Laterite Karst features include the broad but shallow pans which are a distinctive features of many flat tropical plains which overlie a lateritic deep weathering profile (DWP). These are sometimes associated with shallow flat-bottomed and unchanneled valleys that are called "Dambos" in Africa. McFarlane & others (1995) describe examples from near Darwin, NT.

The hollows are assumed to be mainly a result of the removal of material in solution, i.e. silicate karst; but once they have formed, deflation of seasonally dry pan surfaces may help to deepen and extend them.

Large collapse dolines have been reported from the lateritic Stuart Plain of central Northern Territory (McFarlane & Twidale, 1987), but as the laterite is underlain at a depth of 50-100m by a limestone formation it may be that these are subjacent karst features rather than due to silicate solution.

Some duricrusts have strong jointing which forms fissures or cutters, and these can break up into "stone cities" analogous to those found in sandstone "silicate parakarst".

Further readings

  • Extracts from Grimes 1974. of sections discussing deep weathering profiles (laterites) and laterite karst features from a geological report on part of NW Queensland.
    Grimes, KG., 1974: Mesozoic and Cainozoic geology of the Lawn Hill, Westmoreland, Mornington and Cape Van Diemen 1:250 000 sheet areas, Queensland. Bureau of Mineral Resources, Geology & Geophysics, Australia, Record 1974/106 (unpublished).
    McFarlane, M.J., Ringrose, S., Giusti, L. & Shaw, P.A.,1995: The origin and age of karstic depressions in the Darwin - Koolpinyah area of the Northern Territory of Australia. in Brown, A.G. (editor) Geomorphology and Groundwater, Wiley, pp.93-120.
    McFarlane, M.J. & Twidale, C.R., 1987: Karstic features associated with tropical weathering profiles. Zeitschrift fur Geomorphology(NF), Suppl-Bd. 64: 73-95.

    Selected photographs and diagrams

    To view full size images, click on the displayed image.

    Solution Dolines, or "Pans"

    Aerial oblique view of a shallow pan on a lateritic plain in the Gulf of Carpentaria, Queensland.
    S690731.jpg
    Landsat image of unusually angular pans on the lateritic Doomadgee Plain, Gulf of Carpentaria, Queensland. See Extract from Grimes (1974).
    Click the image to see a detailed view
    There is now high-resolution Ikonos imagery of part of this area available via Google Earth (Lat 17°32'S, Long 139°05'E)
    Doomadgee-123.jpg
    Grey swampy soil on the floor of a laterite pan. Weipa, N. Qld.
    S900219.jpg
    Landsat image of the west coast of Cape York Peninsula, Queensland. On the eastern side, dambos and pans occur on a low-lying lateritic surface. Along the coast are Quaternary beachridges (Qp & Qh). The inner, last interglacial (Qp), ridges also have pans, but in that case the formation is probably solution of shelly material in the beach sands, rather than silicate karst.
    Click the image to see a detailed view
    There is now high-resolution Ikonos imagery of part of this area available via Google Earth (Lat 14°36'S, Long 141°40'E)
    Holroyd2-123.jpg
    Landsat image of pans on the undissected parts of a low-lying laterite plateau overlying Cretaceous sandstone. Arnhem Bay region, Northern Territory.
    Click the image to see a detailed view
    There is now high-resolution Ikonos imagery of part of this area available via Google Earth (Lat 12°34'S, Long 135°20'E)
    ArnhemBay-123.jpg

    Collapse Dolines

    Inside a large collapse doline in lateritised Cretaceous mudstone, Sturt Plateau, near the Buchanan Highway, NT.
    See McFarlane & Twidale (1987)
    KG083069s.JPG

    Giant grikes and Stone Cities

    Joint blocks in duricrust on the edge of a plateau form a small "stone city"
    Donors Plateau, NW Qld.
    S69-H08.jpg
    Ground view of the duricrust joint blocks.
    Donors Plateau, NW Qld.
    S690501.jpg
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