Abstract
Metamorphic rocks of the Osor complex (NE Iberian peninsula) show quartz-rich gneissic semi-pelitic, and quartz-absent, mica-rich, schistose domains that have been related to the effects of infiltration of a magmatic fluid evolved during cooling of syntectonic peraluminous leucogranites and pegmatites. The infiltrating fluid became progressively alkali-rich through leaching of these elements from the enclosing metamorphic rocks as it became progressively focused in developing micaceous, high-strain domains subparallel to the main crenulation cleavage. The flux took place around the peak of the HT-LP metamorphism during nearly isobaric heating followed by initially nearly isobaric cooling evolving towards decompressional cooling. Channels of focused flow became the loci of late- to post-tectonic Na-rich plagioclase, muscovite and biotite growth. The growth of the alkali-rich phases promoted further weakening of the domains that continued to be zones of high-strain during a late extension coeval with cooling and decompression.
Original language | English |
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Pages (from-to) | 589-593 |
Journal | Journal of Geochemical Exploration |
Volume | 69 |
Issue number | 70 |
DOIs | |
Publication status | Published - 1 Jan 2000 |
Keywords
- Fluid channeling
- HT-LP metamorphism
- Magmatic fluids
- Metasomatism