See more from this Division: Topical Sessions
See more from this Session: Discovering Petrologic Truth in Minerals II: In Honor of Bernard W. Evans
Abstract:
The Sivrihisar Massif is one of the few lawsonite eclogite localities in the world and is dominated by HP rocks, but in the southern part of the massif, HP/LT rocks grade into higher-T rocks. The transition zone is characterized by progressive recrystallization of HP phases, the presence of pseudomorph textures, and complex Ar spectra for white mica. The Sivrihisar rocks record a difference in metamorphic P-T conditions of 20 kbar (25-5 kbar) and 300 C (400-700 C) from the eclogite facies rocks to the highest-grade Barrovian domain. Barrovian zones include chloritoid, garnet, staurolite, kyanite, and sillimanite. Mica-rich quartzite in the Sil zone contains andalusite + kyanite + prismatic sillimanite, in which Sil is the texturally latest polymorph. Intrusion of a granitic pluton at the late stages of Barrovian metamorphism resulted in an overprinting zone of contact metamorphism. The metamorphic history of the entire sequence, from subduction to Barrovian metamorphism to late orogenic magmatism and cooling, occurred within 30 million years.
See more from this Division: Topical Sessions
See more from this Session: Discovering Petrologic Truth in Minerals II: In Honor of Bernard W. Evans