Ivrea zone

The Ivrea zone is a tectonic terrane in the Italian Alps, that consists of a steeply dipping piece of the Earth’s lower crust of the Apulian plate. The zone is named after the Italian city of Ivrea.

Dunite from the Ivrea zone at Finero

Geology of the Alps
The Alps
Tectonic subdivision
Helvetic Zone Penninic nappes Austroalpine nappes Southern Alps
Formation & rocks
Bündner schist flysch molasse
Geological structures
Aarmassif Dent Blanche klippe Engadine Line Engadine window Flysch zone Giudicárie line Greywacke zone Hohe Tauern window Molasse basin Penninic thrustfront Periadriatic Seam Ivrea zone Lepontin dome Rechnitz window Rhône-Simplon line Sesia unit
Paleogeographic terminology
Valais Ocean Briançonnais zone Piemont-Liguria Ocean Apulian or Adriatic plate

Geologically the Ivrea zone is considered a part of the Southern Alps. Most rocks in the zone are sedimentary, for example limestones that have been turned into marble by metamorphism. Most of the zone has been through granulite facies metamorphism and was intruded by mafic plutons. This is the type of rock common in the lower regions of the crust. When the terrane was uplifted during the formation of the Alps, the upper crust was eroded off so that these rocks are now at the surface.

Geophysical research shows the mantle is relatively close under the surface at the Ivrea zone. Some geologists think the boundary between pyroxenites and lherzolites, that is also found in outcrops in the Ivrea zone, represents the Mohorovičić discontinuity (the Moho). The Moho is seismologically defined as the boundary between the crust and mantle.