just adding to the above...
According to visir.is, shooting will take place in Dómadalur valley by geothermal area Landmannalaugar in the south-central highlands.
Ruv.is adds that Skógafoss waterfall, Fjađrárgljúfur canyon and Skeiđarársandur plains will also serve as locations for the movie.
Up to 300 people will come from the U.S. to work on the shooting in addition to the almost 200 Icelanders who will also be involved in the project. The film crew is serviced by Icelandic film production company True North.
One of the actors at the Stonehenge shoot is playing a tv reporter