Dempster, T. J. and Martin, J.C. and Shipton, Zoe (2008) Zircon dissolution in a ductile shear zone, Monte Rosa granite gneiss, northern Italy. Mineralogical Magazine, 72 (4). pp. 971-986. ISSN 0026-461XFull text not available in this repository. (Request a copy from the Strathclyde author)
The sizes, distributions and shapes of zircon grains within variably deformed granite gneiss from the western Alps have been studied. Zircon shows numerous indicators of a metamorphic response in both the host gneiss and a 5 cm wide continuous ductile shear zone, within which the zircon grain sizes range from <1 μm to >50 μm. However, the very fine grain sizes are virtually absent from grain boundaries. Within this zone, zircons consistently have more rounded and embayed margins, which are interpreted as evidence of dissolution in response to fluid influx during shearing. Zircons are preferentially located near metamorphic muscovite in both the host gneiss and the shear zone and tend to show the poorest crystal shape, indicating that fluids linked to the formation and presence of muscovite may enhance both the crystallization of zircon and its subsequent dissolution. Larger zircon crystals typically show a brittle response to deformation when adjacent to phyllosilicates, with fractures consistently perpendicular to the (001) mica cleavage. The variety of metamorphic behaviour observed for zircon indicates that it may be highly reactive in sub-solidus mid-crustal metamorphic environments.
|Keywords:||deformation, zircon, shear zone, metamorphism, dissolution, Engineering (General). Civil engineering (General), Geochemistry and Petrology|
|Subjects:||Technology > Engineering (General). Civil engineering (General)|
|Department:||Faculty of Engineering > Civil and Environmental Engineering|
|Depositing user:||Pure Administrator|
|Date Deposited:||28 Mar 2011 11:12|
|Last modified:||27 Jan 2017 03:41|