Origin and karst geomorphological significance of the enigmatic Australian Nullarbor Plain blowholes

Auteur(s) et Affiliation(s)



Description :
To elucidate blowhole distribution and mode of formation the AA. : (1) correlated existing location data with Shuttle Radar Topography Mission (SRTM) data, which distinguishes the subtle undulations (<10m per km) of the landscape, (2) surveyed blowhole morphology and (3) determined their rock surface hardness. The distribution of these enigmatic blowholes is not correlated with present topography. Blowholes are often connected to typically shallow cavities, which exhibit numerous ‘cupolas’ (dome-shaped pockets) in their ceilings. Hardness measurements indicate that salt weathering is not their main cause. The observations suggest that blowholes do not develop downwards, but occur where a cupola breaks through the surface. Lowering of the land surface is suggested to be the main cause for this breakthrough. Although cupolas may undergo some modification under the current climate, they, as well as the shallow caves they are formed in, are likely to be palaeokarst features formed under a shallower water table and wetter conditions in the past. The findings presented have implications for theories of dissolutional forms development in caves worldwide.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2012, vol. 37, n°. 3, p. 253-261, nombre de pages : 9, Références bibliographiques : 28 ref.

Date :
2012

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley