It feels noteworthy to bring this up in reference to Michelangelo Frammartino’s “Il Buco” because such are the thoughts you might find yourself dwelling upon throughout this alternately challenging and absorbing sit. Of course, the fact that the film both welcomes and nourishes such mental digressions is neither a feature nor a bug (or, depending on how you look at it, maybe both) but a direct and inevitable outcome of an uncompromised and uncompromising deep dive into the nature of screen representation that is — very much by design — painstakingly dry.

If “Il Buco” constructs a fiction using the tools of documentary, it’s a far cry from the land of Christopher Guest. Showcasing crystalline HD footage of the Calabrian wilderness, and offering no spoken dialogue or musical cues, “Il Buco” wants to be mistaken for a hands-off, ethnographic nature doc about a group of young spelunkers in the southern Italian mountains. And it is very much that, though this 1960s-set excavation has been entirely mounted and period-staged for the purposes of a conceptually rigorous film. Rigorous is the operative word here in a project that employs a substantial cast of actors without ever showing anyone’s face in full (save for one). The film is scored by nothing but the distant jangle of livestock (for all its sparsity, “Il Buco” needs no more cowbell) and allows whatever occasional snippets of overhead talk to go by muddled and without subtitles. The effect is one of immediate distancing, as if Frammartino is simply relaying what his camera caught on the fly and not what he and his team worked to organize, choreograph, and meticulously design. In its digital photography and evocation of tradition, of an unchanged and unchanging pastoral unaffected by the passage of time, the film makes us question such arbitrary distinctions when classifying film styles. With so many long stretches simply capturing the natural world and presenting it as is, you wonder, “Who’s to say this isn’t nonfiction?” Then the spelunkers pull out a period-appropriate magazine covering the Nixon/Kennedy election, and the answer arrives. As the film dispassionately follows those members of (a true-to-life, if fictionalized) expedition into the darkest depths of the Bifurto Abyss, the only real figure to come into the fore (read: to be seen in anything other than a long shot) is an aged mountain shepherd. He’s reminiscent of the main figure from Frammartino’s previous film, “Le Quattro Volte,” and observes the goings-on from a bemused distance. (The film doesn’t do much by way of inner-life illumination.) We first come to know this figure as the only one offered a close-up — intense ones, cutting from the rugged mountain landscape to the craggy lines on his weathered face — though as the film goes on, a slight B-plot emerges as the figure (to say character would be a step too far) falls ill, confounding the local healers in his liminal state between life and the grave.

As the shepherd makes his way toward one kind of underworld, so too do the spelunkers, exploring the sprawling subterranean landscape in a series of golden-hued chiaroscuro compositions. To engage with this film on its own terms is to welcome this kind of exploration of the natural sublime. When Frammartino tries his hand at narrative, he does so on his own oblique terms, tracking a soccer ball kicked about by a pair of distant explorers that, like the promise of Chekhov’s gun, is destined to go off into the abyss below. Like that abyss, the film offers a substantial degree of exploration for those willing to do the work and take the dive. A prologue featuring a black-and-white TV report about the building of (Northern) Italy’s first skyscraper, followed by an immediate cut to this southern cavern that plunges downward, seems a clear comment on the country’s geographic division of wealth and opportunity. And linking these earnest explorers so keen to chart the unknown with that Kennedy magazine cover, which is later seen burning into ash, might be a way for Frammartino to evoke that era’s optimism for new frontiers now wholly lost to us. But for the most part, “Il Buco” simply allows us to share in the experience of discovery with a group of explorers who, if given the chance to explain their motives, might answer with the same line George Mallory said about Everest. “Because it’s there.”

Grade: B-

“Il Buco” premiered in the official competition at the Venice Film Festival. It is currently seeking U.S. distribution. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.