Drilling the Ivrea-Verbano zonE (DIVE)

The lower continental crust is typically the bottom third or half of the continental crust, and is composed of silica-poor mafic rocks, like gabbro. In a very few places on the planet this part of the crust is brought to the surface due to tectonic forces and mountain building. The Ivrea-Verbano Zone in the Southern Alps in Italy is such a place and was the site of an ambitious drilling project to recover about 1.5 km of cores from the continental lower crust. The successful campaign collected a unique and continuous set of geophysical, geochemical and structural data on the nature of the continental lower crust, which help to better understand deep crustal processes (such as metamorphism, magma fluxes, deformation) and related physical and chemical conditions. Among other topics, the project investigates the thermal structure and distribution of heat producing elements across a continuous, finely banded sequence of lower crustal rocks, major pre-Alpine and Alpine crustal shear zones, alteration processes, fluid and gas compositions, as well as microbiological questions. At large scale, it studies the Ivrea-Verbano Zone's formation and its relationships to the major orogenic fault structure of the Alps, the Insubric Line.

The project's next phase is aiming to drill deeper, both structurally to cross the crust-mantle transition and better understand what the Moho is, and also to connect further disciplines through fluid-rock interaction studies.