Open AccessDonnées nouvelles sur la laumontite de la zone métamorphique de Libramont, Belgique [New mineralogical data on laumontite from the metamorphic zone of Libramont, Belgium]
Author(s) -
Frédéric Hatert
Publication year - 1998
Publication title -
geologica belgica (printed)/geologica belgica (online)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.227
H-Index - 21
eISSN - 2034-1954
pISSN - 1374-8505
DOI - 10.20341/gb.2014.001
Subject(s) - geology , albite , quartz , metamorphic rock , geochemistry , mineralogy , paleontology
New laumontite occurrences have been discovered at Bertrix, Ochamp and Luchy, in the metamorphic zone of Bastogne-Libramont. Wet chemical analyses lead to compositions close to Ca[Al2Si4O12].4H2O, with a slightly variable water content and a significant amount of potassium (up to 0.76% K2O). Infrared spectra show an ordered distribution of tetrahedral Si and Al, and relatively low hydrogen bonds between zeolitic water and crystal freamework. Laumontite crystallized in rocks fractures, under a presure lower than 3 kbar and a temperature between 170 and 280°C. The presence of albite in quartz veins and of laumontite in rocks fissures indicates a different geochemical behaviour for Na and Ca during this retrometamorphic phase.