Reaction-Weakening in Phyllonites Formed in Granite
Document Type
Contribution to Book
Journal/Book Title/Conference
Atlas of Mylonitic and Fault-Related Rocks
Publisher
Princeton University Press
Publication Date
1998
Abstract
These examples of microstructures and textures associated with reaction weakening come from the Gessaman fault in southern Arizona, U.S.A., and were first described in Janecke and Evans (1988). Phyllonitic textures are concentrated in a 2-3 m wide zone formed in Proterozoic Oracle Granite. The protolith granite consists of 10-25 mm diameter quartz grains, 5-12 mm diameter orthoclase grains, 5-10 mm plagioclase grains, and minor amounts of biotite and accessory minerals. Deformation occurred during the early Tertiary, probably at temperatures of 250-400°C.
Recommended Citation
Evans, J. P., 1998, Reaction-weakening in phyllonites formed in granite, in: Atlas of mylonitic and fault-related rocks, A. W. Snoke, J. A. Tullis, and V. R. Todd, eds., Princeton University Press.
