A micromorphological view through a Namaqualand termitaria (Heuweltjie, a Mima-like mound)

Auteur(s) et Affiliation(s)



Description :
The AA. investigated the genesis of the Hardpans associated with the heuweltjie mound, with a particular focus on the build-up of calcite and sepiolite. The micromorphological study examined a transect through a representative sepiolite-bearing heuweltjie on the coast near the Olifants River mouth, and revealed evidence of termite activity in the central (petro)calcic part of the mound. It is showed that mounds contain calcite, sepiolite, silica not found in surrounding landscape and that centre of mounds enriched in basic cations due to vegetation foraging by termites. The presence of the sepiolite, with its Mg-rich composition and hydrophilic character, together with organic acids generated from the vegetation collected by the termites, is considered to be an explanation for the formation of ooids, radial calcite crystals associated with a core of sepiolite. The presence of faecal spherulites in termite excrement is significant since it shows that faecal spherulites can be distributed over a wider area than that directly associated with mammalian herbivores.


Type de document :
Article de périodique

Source :
Catena (Giessen), issn : 0341-8162, 2013, vol. 100, p. 57-73, nombre de pages : 17, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Allemagne, Cremlingen-Destedt, Catena