Project DIVE (Drilling the Ivrea-Verbano zonE): A joint petrological, geochemical, and geophysical exploration of the lower continental crust

Despite the structural complexity of the Alps at numerous scales, geological and geophysical investigations have respectively mapped and imaged tremendous amounts of information near the surface and at depth. However, there is an inherent gap between the two sets of approaches, leaving the middle and lower crust poorly constrained. This has been one of the main motivations to initiate the ICDP project DIVE (Drilling the Ivrea-Verbano zonE), in which three geological sites of the Ivrea-Verbano Zone will be explored through scientific drilling. In this zone, near-complete sections of the continental crust are exposed at the surface, and with careful geological preparation and geophysical site surveys we have targeted three areas with a great potential of further discoveries during DIVE. Almost all physical and chemical properties will be characterized on the recovered rock core samples, in borehole logging investigations, and additional surveys around each site. Taken together, these should cover a large range of spatial scales covering at least 6 orders of magnitude (mm to km), investigate structures and their variations in bulk properties within the lower crust, and the transition to mantle rocks in an unprecedented way. The interdisciplinary approach not only allows to correlate numerous geophysical and petrological properties, but with modelling it will also allow to investigate the causative relationships.

The detailed aims, preparatory steps, as well as the current status of project DIVE, will be presented at the conference. By that time, drilling of the first hole is expected to start near Ornavasso, followed by a second hole in Megolo (both in Val d’Ossola). For the third site near Balmuccia, which is planned for later, site survey results will be presented.