Time travel?

Spare me please if this was already talked about here but... I found an interesting post about the works of "Prometheus" filming crew in Iceland. There is even a picture of the "barracks" on location. The link is: http://www.scriptflags.com/2011/07/ridley-scott-talks-prometheus-hr-giger.html It seems there were two main shoots in two locations: one at the base of the volcano Hekla, the other at the Dettifoss waterfall. The Dettifoss is unanbigously the shoot where we can see the great disk hovering above a waterfall in the trailler. The Hekla shoot must be that one of the vehicles running to the ship _ but maybe also the final one where we can see the derelict falling. What I found interesting is this: "The shoot, which is scheduled to last roughly 2 weeks includes actors Charlize Theron, Michael Fessbender, Guy Pearce & Noomi Rapace. A second location for the production is the Dettifoss waterfall [Europe’s most powerful.]" The problem is, the post also talks about a primeval Earth. If the main actors were forced to travel there to be filmed, can we imply a time-travel plot? The alternative is, for economic reasons, Scott filmed two shots in Iceland: one, of the primeval Earth, and another, of the alien planet. Nothing really obliges Scott to keep a "coherence" or "sense of unity" between locations and the movie plot, but I keep thinking that Icelandic locations have some kind of relatedness that would make difficult to separate them...maybe I´m seeing too much here...