Document Type
Article
Publication Date
1-2004
Publication Title
Journal of Structural Geology
Abstract
Numerous rod-shaped calcite crystals occur in the blueschist to eclogite facies marbles of Syros, Greece. The rods show a shape-preferred orientation, and the long axes of the rods are oriented at a large angle to foliation. The crystals also have a crystallographic-preferred orientation: calcite c-axes are oriented parallel to the long axes of the rods. Based on their chemical composition, shape, and occurrence in high-pressure marbles, these calcite crystals are interpreted as topotactic pseudomorphs after aragonite that developed a crystallographic-preferred orientation during peak metamorphism. This interpretation is consistent with deformation of aragonite by dislocation creep, which has been observed in laboratory experiments but has not been previously reported on the basis of field evidence. Subsequent to the high-pressure deformation of the aragonite marbles, the aragonite recrystallized statically into coarse rod-shaped crystals, maintaining the crystallographic orientation developed during deformation. During later exhumation, aragonite reverted to calcite, and the marbles experienced little further deformation, at least in the pseudomorph-rich layers. Some shearing of pseudomorph-bearing marble layers did occur and is indicated by twinning of calcite and by a variable inclination of the pseudomorphs relative to foliation.
Keywords
Aragonite, Pseudomorph, Greek Aegean Island, High-pressure metamorphism, Marble, Deformation
Volume
261
First Page
3
Last Page
9
DOI
10.1016/S0191-8141(03)00099-3
Recommended Citation
Brady, John B.; Markley, Michelle J.; Schumacher, John C.; Cheney, John T.; and Bianciardi, Grace A., "Aragonite Pseudomorphs in High Pressure Marbles of Syros, Greece" (2004). Geosciences: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/geo_facpubs/202
Comments
Peer reviewed accepted manuscript.