Sierra de las Quijadas

Red-rock amphitheatres carved by ancient rivers, where pterosaur fossils surface from Cretaceous sandstone.

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The red sandstone amphitheatre of Sierra de las Quijadas in San Luis Province was the bed of a Cretaceous lake 100 million years ago, and the tracks of the pterosaurs and dinosaurs that walked its shores are preserved in the same formations now exposed by erosion into a canyon landscape of arches, badlands, and viewpoints over a plain of cardon and quebracho. The Hoyada de las Quijadas — the central depression — is 15 kilometres across and accessible only by 4WD track from the park administration, but the canyon rim above it is reachable on foot from the main road.

Parque Nacional Sierra de las Quijadas covers 150,000 hectares in northwestern San Luis Province, protecting a Cretaceous geological sequence of the Lagarcito Formation that has yielded over 1,500 documented pterosaur footprints — the most significant pterosaur trackway site in South America. The fossil-bearing strata, deposited approximately 100 million years ago during the Cretaceous period, also contain the remains of Pterodaustro guinazui — a filter-feeding pterosaur unique to this formation whose diet and lifestyle have been compared to flamingos. The canyon landscape is composed of red sandstone eroded into a series of badland formations, arches, and mesas that concentrate a diverse fauna of Chacoan armadillos, pumas, guanacos, and birds in the dry monte vegetation. The park receives fewer than 15,000 visitors annually, giving the 150,000-hectare area a visitor density that makes genuine wildlife encounters statistically probable.

32.492° S · 67.021° W

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Best For

Solo

Sierra de las Quijadas is the Argentine canyon park that has not been discovered by the tourist circuit that knows Talampaya and Ischigualasto — the red sandstone amphitheatre, the pterosaur trackways, and the dry monte wildlife are equivalent in geological interest and completely without the queues. A self-guided rim walk in the afternoon light produces exactly the right ratio of effort to reward.

Couple

The drive from San Luis city through the western plains to the park, arriving at the canyon rim in the late afternoon when the red sandstone turns deep crimson, is the kind of road trip payoff that justifies a detour from the standard Argentine highlight route. The pterosaur trackway requires a guided tour; the canyon rim walk does not.

Why This Place

Pterosaur bones found here in 1993 yielded a new species to science — the fossils remain embedded in the sandstone.
The main amphitheatre at Potrero de la Aguada is a 4km-wide bowl of red rock that turns purple by 4pm.
Rangers lead guided walks to fossil sites not on the public map — book at the entrance station.
Flash floods carved the canyon system — the dry riverbeds are passable in summer but sealed off in the rainy season.