he formation and eventual preservation of high-pressure mineral assemblages in subducted continental crust are a long-standing issue with kinetic aspects and important geophysical implications in terms of buoyancy. The issue is especially acute in the internal crystalline massifs of the Western Alps, in which the dominant rock-type, metagranite, hardly bears evidence for high-pressure transformation whereas subordinate rock types clearly point to high or very high pressure conditions. The discovery of well-preserved jadeite-bearing rocks in orthogneiss of the western Gran Paradiso massif, reported here, revives the questioning and is the opportunity to describe uncommon mineral assemblages involving nepheline, preiswerkite, as well as a new trioctahedral mica.
Jadeite in the Gran Paradiso massif: the high-pressure metamorphic evolution of upper continental crust
Maria Di RosaUltimo
2015-01-01
Abstract
he formation and eventual preservation of high-pressure mineral assemblages in subducted continental crust are a long-standing issue with kinetic aspects and important geophysical implications in terms of buoyancy. The issue is especially acute in the internal crystalline massifs of the Western Alps, in which the dominant rock-type, metagranite, hardly bears evidence for high-pressure transformation whereas subordinate rock types clearly point to high or very high pressure conditions. The discovery of well-preserved jadeite-bearing rocks in orthogneiss of the western Gran Paradiso massif, reported here, revives the questioning and is the opportunity to describe uncommon mineral assemblages involving nepheline, preiswerkite, as well as a new trioctahedral mica.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
