Meanwhile they may be being menaced by the ghosts of dead vikings, or they may be going a bit bonkers from stress.
The story is told through a series of 'last letters home' written by each of the team. For a story featuring the possible extinction of the human race it is subdued and introverted, more of a chamber piece. I thought it was an easy fast read, enjoyable, probably got enough substance to make a decent low-budget film.
BTW there is a long standing sub-genre - which I don't think has a name (?) - in which a modern person uncovers some old text or diary, and then her life parallels the historic person, probably in alternating chapters. This seems to be a new variant - shenanigans on an archaeological expedition, with something being uncovered. This is the second such novel I have read in a month (the other was The Hidden).