Diving into the roots of continents: Completion of the Phase 1 of scientific drilling of the ICDP-sponsored DIVE project

Diving into the roots of continents: Completion of the Phase 1 of scientific drilling of the ICDP-sponsored DIVE project

The project DIVE (Drilling the Ivrea-Verbano zonE), sponsored by the International Continental Scientific Drilling Program (ICDP), completed the Phase 1 of scientific drilling activities in the second borehole in Megolo in Val d’Ossola in the core of the Ivrea-Verbano Zone (Western Alps, Italy). This geological body is worldwide known as an almost complete section of the continental crust exposed on the Earth’s surface.

The scientific exploration of Phase 1 consisted of full recovery of pristine rock cores from the deepest portions of the Earth’s lower crust and transition towards the upper mantle (supposedly equivalent to the Moho transition zone from a geophysical standpoint), which are located at much shallower depth thanks to the Alpine orogenesis. The first borehole (DT-1B) in Ornavasso was completed in December 2022. At this drill site, the DIVE scientific team reached the depth of 578.5 meters and retrieved mainly felsic and metamafic metasedimentary rocks composing the middle to lower crustal domain. The borehole (DT-1A) in Megolo was completed in April 2024 by reaching a depth of 909.5 m. At this drill site, the full recovery of rock cores captured different magmatic lithologies including dominant gabbros, gabbronorites, and pyroxenitic bodies along with lenses of metapelitic horizons. This succession of lithologies is characterized by an increase of rock density ranging from 2600 to 3200 kg/m³, suggestive of the potential transitional domain from the lower crust to the upper mantle. At each site, cohorts of early career scientists (postdocs, students) and senior scientists and PIs of the DIVE project worked for months through weekly shifts dedicated to classifying the pristine rocks from a petrological, geophysical, and microbiological standpoint.

Currently, the rock cores retrieved from both drill sites (a total of > 1,500 m rock coring) are located in the ICDP National Archive in Spandau-Berlin (Germany) where the DIVE sampling party will conduct detailed analyses including X-ray fluorescence and multi-sensor core logger, and rock sampling for both non-destructive and destructive analyses at the home institutions. The University of Georgia is one of the leading institutions within the DIVE project. For additional information and news, refer to these links: http://www.dive2ivrea.org and https://www.icdp-online.org. Go DIVE!