Multiple electron beam analyses applied to eclogite from the Western Alps

The occurrence of compositional and microtextural relies within metamorphic rocks can provide useful information on the pressure-temperature history o f the host rock. The grain-size of these microstructures, such as coronitic reaction microtextures, is mostly too fine to be detected by optical micro scopy, Therefore, a more detailed analytical approach is needed. In this pa per multiple electron beam techniques including the acquisition of X-ray mu lti-element maps, micro and nano-analysis performed by SEM/EDS and TEM/STEM -EDX systems were applied to a specific petrological problem related to met amorphism. Fine-grained decompressional reaction microtextures of an eclogi tic sample (Mt. Rosa Nappe, Western Alps) are described and discussed.