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PORTAIL D'INFORMATION GÉOGRAPHIQUE

Weathering of basalt and sandstone by wetting and drying : a process isolation study

Southern African geomorphology : looking back, moving forward

Auteur(s) et Affiliation(s)

LOUBSER, M.J.
Dept. of Geography, Geoinformatics and Meteorology, Univ., Pretoria, Afrique du Sud
SUMNER, P.D.
Dept. of Geography, Geoinformatics and Meteorology, Univ., Pretoria, Afrique du Sud
NEL, W.
Dept. of Geography and Environmental Science, Univ. of Fort Hare, Alice, Afrique du Sud
HOLMES, P.J.
Dept. of Geography, Univ. of the Free State, Bloemfontein, Afrique du Sud


Description :
Rock samples from Marion Island in the Sub-Antarctic and from the Drakensberg, South Africa were divided into sets and subjected to wetting and drying at 2 different moisture amplitudes to determine changes in physical rock properties. Rock porosity and water absorption capacity was determined both at the beginning and at the end of the experiment and compared. Results varied from set to set, but not as a result of variations in moisture amplitude. Three key findings are presented : 1) the number of wetting and drying cycles is a more important factor than the degree to which the samples have been saturated; 2) changes in rock properties were detected for the control samples as well as the field samples, suggesting that the experimental techniques used for determining the rock properties have themselves affected the samples; 3) samples that outwardly appeared very similar have responded differently to wetting and drying. This implies that even small changes in internal rock structure can have a profound effect on the ultimate nature of the weathering taking place.


Type de document :
Article de monographie

Source :
Geografiska annaler. Series A. Physical geography, issn : 0435-3676, 2013, vol. 95, n°. 4, p. 295-304, nombre de pages : 10, Références bibliographiques : 25 ref.

Date :
2013

Editeur :
Pays édition : Suede, Stockholm, Svenska sällskapet för antropologi och geografi

Langue :
Anglais
Droits :
Tous droits réservés © Prodig - Bibliographie Géographique Internationale (BGI)