Mr Panetta took the opportunity to announce a delayed timeframe for planned cuts to the Lajes Air Base in Portugal's Azores, a group of nine volcanic islands located almost 1, 000 miles (1, 600km) west of the Iberian peninsula.

BBC: Leon Panetta makes final international trip to Europe

The science team likened its chemistry to some relatively rare but well-studied alkaline rocks on Earth found on oceanic islands such as Hawaii and the Azores, and also in rift zones like the Rio Grande.

BBC: Cosmic coincidence on the road to Glenelg