Tracing the high pressure stage in the polymetamorphic Texel Complex (Austroalpine basement unit, Eastern Alps): P–T–t–d constraints |
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Authors: | G Habler M Thöni H Sölva |
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Institution: | (1) Department of Geological Sciences, University of Vienna, Vienna, Austria |
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Abstract: | Summary Integration of new mineral chemical, geochronological and structural data from the Texel Complex yielded information on (re)crystallization
and deformation processes in metapelites, eclogites and tonalitic orthogneisses during eclogite facies metamorphism. Maximum
P–T conditions reached 1.2 to 1.4 GPa and 540–620 °C in the Upper Cretaceous. In tonalitic orthogneisses and metapelites, substantial
garnet growth took place prior to eclogite facies metamorphism and Sm–Nd data indicate the presence of pre-Cretaceous mineral
relics. In contrast, complex garnet-growth and -resorption processes are inferred for eclogites, which produced characteristic
atoll microstructures and occurred close to the pressure peak of a single, coherent high pressure event. Garnet Sm–Nd data
indicate eclogite facies crystallization at 85 ± 5 Ma. While eclogites retained information on the maximum burial stage, matrix
phases in metapelites and orthogneisses were intensely recrystallized during the amphibolite facies metamorphic decompression.
All the meso- and macro-scale deformation structures formed during the high pressure event and subsequent exhumation. The
major mylonitic foliation is represented by the high pressure phases but was refolded during amphibolite facies exhumation.
A biotite-whole-rock Rb–Sr age of 70–80 Ma indicates that cooling below about 300 °C occurred in the Upper Cretaceous.
Supplementary material to this paper is available in electronic form at
Appendix available as electronic supplementary material |
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