Unusual phosphate concretions related to groundwater flow in a continental environment. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Sedimentary Research Année : 2006

Unusual phosphate concretions related to groundwater flow in a continental environment.

(1) , , (1)
1
Médard Thiry
Jean Galbois
  • Fonction : Auteur

Résumé

Occurrence of phosphate cemented-sandstone concretions in alluvial sand containing archaeological layers implies that they have formed during the last 2000 years. Morphology and petrography of the concretions indicates a relationship with groundwater cementation. The phosphate cement of the concretions consists of concentric isopachous aureoles, about 10 mm thick, that wrap the detrital grains. Aureoles are formed of collophane, the cryptocrystalline or amorphous variety of hydroxyapatite. Geochemical modeling indicates that the apatite cement likely results from the leaching of a preexisting phosphate deposit (bones?) in an acidic soil environment and the precipitation of dissolved phosphate under pH control at the mixing zone of down-moving soil-water with the calcite-saturated groundwater.
Fichier non déposé

Dates et versions

hal-00646828 , version 1 (30-11-2011)

Identifiants

Citer

Médard Thiry, Jean Galbois, Jean-Michel Schmitt. Unusual phosphate concretions related to groundwater flow in a continental environment.. Journal of Sedimentary Research, 2006, 76, pp.866-870. ⟨10.2110/jsr.2006.067⟩. ⟨hal-00646828⟩
42 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook Twitter LinkedIn More