Short geology of the Monte Rosa Massif

Geology of a given region can be viewed by means of macro- and microstudy

The main snowy peaks of the Monte Rosa massif are composed of gneisses. This mass neighbours at the Stolemberg peak with Zermatt-Saas ophiolite geological unit. Going southward to Corno Rosso this ophiolitic geology meets the Combin meta-ophiolite near Lago Gabiet. Near Rifugio Citta di Mantova the migmatisation of rocks included pseudomorphosis after cordierite. In gneiss rocks there are seen leucocratic dykes. There were here two types of parageneses, an older one characterized by high temperature and low pressure as well as a younger metamorphism made by means of high pressure. This geological activity changes many minerals, e.g. biotite, plagioclase, ilmenite and cordierite into new ones like garnet, phengite, quartz, rutile and kyanite. Between Punta Indren and Stolemberg we can observe gneisses with garnet-micaschists and eclogite stones having some amphibole coloured in blue (crossite and glaucophane). At a contact between of Monte Rosa gneisses and a Zermatt-Saas ophiolite unit on slopes of Stolemberg one can also find some eclogite rocks consisting of omphacite, garnets and amphibole. On the Stolemberg peak the metabasalts are exposed. There is, on the southern slope of Stolemberg, a close contact between the Monte Rosa gneiss and serpentinite rocks of Corno del Camoscio. Here we can find amphibolite rocks with albite, talc and chlorites as well as some inclusions of metabasites in gneiss. Corno del Camoscio has also the mylonitic gabbro rocks and micaschists enriched by chloritite, epidote and tremolite. Main types of geological units and rocks in this area are marked on the attached diagram below.

The above data are also based on:
http://virtualexplorer.com.au/journal/2004/16/martin/field.html

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