Abstract
A genetic model is proposed for pegmatitic Al2SiO5-bearing segregations in regionally metamorphosed rocks of the Lepontine Alps. Components that form the segregations were derived from the host rocks by dissolution of minerals in alkali-bearing aqueous fluids produced by metamorphic dehydration reactions. The segregations formed syntectonically within extensional (dilatant) fractures; infiltrations of fluids into the fractures was driven by fluid-pressure gradients (tectonic pumping). Precipitation of aluminum silicates from alkali aluminum complexes (rather than alkali silicates) was favored by reduced f H2O within the segregations. The transformation of kyanite to andalusite within the segregations resulted from localized pressure reduction (via dilatancy) during the later stages of decompression of the Pennine nappes subsequent to the main Alpine metamorphism.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
