| Autor: |
Jacques Fabriès, Louis Latouche, Michel Guiraud |
| Rok vydání: |
1992 |
| Předmět: |
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| Zdroj: |
Tectonophysics. 205:387-407 |
| ISSN: |
0040-1951 |
| DOI: |
10.1016/0040-1951(92)90444-b |
| Popis: |
Metamorphism in the Vosges massif is characterized by rocks formed under a wide range of pressures and temperatures: high-pressure rocks (garnet peridotites and eclogites facies rocks) are found together with low-pressure rocks (garnetcordierite stability field). Hitherto, metamorphism has been interpreted within the framework of an identical P-T evolution for all rock types corresponding to either two separate geotectonic events or a unique P-T evolution from high-pressure to low-pressure conditions. We studied gneisses from the Vosges massif in order to constrain the P-T-t path they followed. P-T estimation indicates that gneisses equilibrated between 5 and 7 kbar during peak metamorphism time. Rocks later experienced cooling from temperatures above 650°C down to 550°C. It is possible that the entire P-T evolution of the gneisses took place within the lower part of the amphibolite facies; which is inconsistent with the P-T evolution of the high-pressure rocks. The noteworthy absence of muscovite + staurolite assemblages is attributed to conditions of low H2O and low O2 activity. The consequences for the geodynamics in the Vosges massif are that at least two separate geotectonic events are required in order to explain the juxtaposition of high-pressure rocks with low-pressure amphibolite facies rocks. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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