Nothing enhances lightweight summer fun like 3-D, and director Eric Brevig makes great use of that technique’s most profound artistic effects by chucking things in your face and floating objects in space. Some would call this gimmicky and excessive; they are deluded. Such effects are the very soul of 3-D. I ducked twice.

The story gives Brevig ample opportunity for chuckage. A geologist (Brendan Fraser), his nephew (Josh Hutcherson) and their guide (Anita Briem) fall through a hole in Iceland into a prehistoric world of dinosaurs, luminous birds and carnivorous plants. Adventures ensue, and Brevig proves a deft hand at creating suspense while keeping things light with casual humour.

Fraser is pleasing, as always. After three outings in The Mummy franchise, he’s no stranger to this sort of role. But here he gets to balance heroism with braininess, spouting geologi­cal facts about schist and muscovite that, surprisingly, turn out to be plot points. The smart script is very pro-science and, in its open admiration for Jules Verne’s source novel, pro-literature.

The actors interact well and bring a cheery zest to their chores that probably comes across in 2-D. But go for that extra dimension. That’s where the fun is.