rubanement colloforme

OBS: Voir «rubanement» et «colloforme».

CONT: ... colloform banding ... is a very fine scale banding involving one or more sulphides very like the banding in agate. Some workers believe that it results from colloidal deposition and that the banding is analogous to the Liesegang rings formed in some gels. This banding is very susceptible to destruction by recrystallization and may be partially or wholly destroyed by diagenesis or low grade metamorphism, producing a granular ore.
CONT: Textures vary with the degree of recrystallization. The dominant original textures appear to be colloform banding of the sulphides with much development of framboidal pyrite, perhaps reflecting colloidal deposition. Commonly however, recrystallization, often due to some degree of metamorphism, has destroyed the colloform banding and produced a granular ore.