TY  - JOUR
A1  - Rötzler, Jochen
A1  - Romer, Rolf L.
T1  - P-T-t evolution of ultrahigh-temperature granulites from the Saxon Granulite Massif, Germany : Part I: Petrology.
N2  - The granulites of the Saxon Granulite Massif equilibrated at high pressure and ultrahigh temperature and were exhumed in large part under near-isothermal decompression. This raises the question of whether P-T-t data on the peak metamorphism may still be retrieved with confidence. Felsic and mafic granulites with geochronologically useful major and accessory phases have provided a basis to relate P-T estimates with isotopic ages presented in a companion paper. The assemblage garnet + clinopyroxene in mafic granulite records peak temperatures of 1010-1060 ° C, consistent with minimum estimates of around 967 ° C and 22.3 kbar obtained from the assemblage garnet + kyanite + ternary feldspar + quartz in felsic granulite. Multiple partial overprint of these assemblages reflects a clockwise P-T evolution. Garnet and kyanite in the felsic granulite were successively overgrown by plagioclase, spinel + plagioclase, sapphirine + plagioclase, and biotite + plagioclase. Most of this overprinting occurred within the stability field of sillimanite. Garnet + clinopyroxene in the mafic granulite were replaced by clinopyroxene + amphibole + plagioclase + magnetite. The high P-T conditions and the absence of thermal relaxation features in these granulites require a short-lived metamorphism with rapid exhumation. The ages of peak metamorphism (342 Ma) and shallow-level granitoid intrusions (333 Ma) constrain the time span for the exhumation of the Saxon granulites to about 9 Ma.
Y1  - 2001
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/18538
ER  -