Journal article
Crystal size distribution of periclase in contact metamorphic dolomite marbles from the southern Adamello Massif, Italy
Journal of petrology, Vol.50(3), pp.451-465
03/2009
DOI: 10.1093/petrology/egp007
Abstract
Crystal size distributions (CSD) of periclase in contact metamorphic dolomite marbles are presented for two profiles near the Cima Uzza summit in the southern Adamello Massif (Italy). The database was combined with geochemical and petrological information to deduce the controls on the periclase-forming reaction. The contact metamorphic dolomite marbles are exposed at the contact of mafic intrusive rocks and are partially surrounded by them. Brucite is retrograde and pseudomorphs spherical periclase crystals. Prograde periclase growth is the consequence of limited infiltration of water-rich fluid at T near 605 degrees C. Stable isotope data show depletion in (super 13) C and (super 18) O over a narrow region ( approximately 40 cm) near the magmatic contact, whereas the periclase-forming reaction front extends up to 4 m from the contact. CSD analyses along the two profiles show that the median grain size of the periclase crystals does not change, but that there is a progressively greater distribution of grain sizes, including a greater proportion of larger grains, with increasing distance from the contact. A qualitative model, based on the textural and geochemical data, attributes these variations in grain size to changing reaction affinities along a kinetically dispersed infiltration front. This study highlights the need to invoke disequilibrium processes for metamorphic mineral growth and expands the use of CSDs to systems of mineral formation driven by fluid infiltration.
Details
- Title: Subtitle
- Crystal size distribution of periclase in contact metamorphic dolomite marbles from the southern Adamello Massif, Italy
- Creators
- Thomas Mueller - Universite de Lausanne, Institut de Mineralogie et Geochimie Lausanne CHE SwitzerlandL. P Baumgartner - University of LausanneC. T Foster - University of IowaJ. R Bowman - University of Utah
- Resource Type
- Journal article
- Publication Details
- Journal of petrology, Vol.50(3), pp.451-465
- Publisher
- Oxford University Press
- DOI
- 10.1093/petrology/egp007
- ISSN
- 0022-3530
- eISSN
- 1460-2415
- Language
- English
- Date published
- 03/2009
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229298302771
Metrics
3 Record Views