Petrologic constraints for eoalpine eclogite facies metamorphism in the austroalpine Ötztal basement

Metabasites of the southern Otztal basement hitherto mapped as amphibolites, were identified as eclogites. Primary mineral parageneses are tschermakitic to pargasitic green amphiboles, omphacite (Jd40), garnet II (Gr20–30) Py10), phengite (Si3.5), zoisite, rutile and quartz. Al—pargasite (≈20 wt% Al2O3) rims between garnet and omphacite are interpreted as retrograde reaction products.