One might reasonably ponder The Searchers when sitting through the latest contemplative oddity from Argentinian master Lisandro Alonso. The film does, after all, concern an enigmatic wanderer looking for a young woman across swathes of unwelcoming wilderness. But the film is even weirder than John Ford's durable masterpiece. For most of its duration Jauja – named for a mythical paradise – suggests one of Michelangelo Antonioni's frustrating trips. In its later stages we swing into something weirder still. Journeys are dangerous things in arthouse faux-westerns. Ask Alejandro Jodorowsky.

Viggo Mortensen plays Gunnar Dinesen, a Danish engineer working with Argentinian forces in a hostile part of Patagonia. The film’s action (such as it is) kicks off when his 15-year-old daughter, after enduring one soldier’s advances, runs dangerously away with another. Dinesen seems, at first, like a civilised man among invading brutes. There is talk of extermination and occupation. As the protagonist advances into the inner nowhere, however, we begin to wonder – hello, Joseph Conrad – if any man can remain untainted when engaged in colonial enterprises.

Mind you, we probably stop wondering that after a while. The longer the film goes on the more it gives into vivid expressionist nightmare. There is talk of a soldier named Zuluaga (a pseudo-Kurtz?) who may have been turned by the hostile surroundings. We hear awful screams. We see bodies. Could the film be the autopsy of a deranged brain?

At times Jauja is too oblique for its own good. For all its proud oddness, the picture too often brandishes familiar tropes of post-colonial magic realism. But it is beautifully carried off. Mortensen has just the right class of vacant charisma for such a gouged-out protagonist and Timo Salminen's photography bathes every image in surprising lights. Mention should also be made of the fine score co-written by the star. Sadly, his collaborator, Buckethead, strips the project of some solemnity by being called Buckethead.