This video summarises the scientific objectives of a field expedition conducted by Njord scientists in northern Patagonia in March 2026. The expedition focused on an extensive, eroded volcanic system to understand its evolution and the structure of its shallow plumbing system.
The goals of the expedition were two fold:
- Mapping the volcanic products of a Lower Miocene (23 to 16 Million years), large volcanic system: the Huantraico Volcano. This partly eroded volcano was huge, with an estimated diameter larger than 40 kilometers. The volcanic products have been eroded, such that the whole volcano stratigraphy is exposed. One goal was to constrain the volcanic evolution of the complex from its birth to its death through detailed characterisation of the volcanic products succession.
- Constrain the internal structure of a shallow, large and exhumed andesitic cryptodome: the Cerro Bayo de Huantraico intrusion. The second goal of the field work was to assess the potential geothermal reservoir properties of Cerro Bayon intrusion. We conducted detailed structural mapping of the interior of the intrusion from its contacts to its core. The study showed that numerous fractures and fracture types that formed successively affected the andesitic rock, and that these fractures formed during the emplacement and the cooling of the intrusion. Our observations suggest that such intrusions may be excellent fractured geothermal reservoirs, but with very heterogeneous properties that need further constraints.
The expedition was organised through the framework of the Masters project of Ole-Jacob Evensen (https://www.mn.uio.no/geo/om/aktuelt/aktuelle-saker/2026/feltarbeid-i-patagonia-masteroppgaven-i-geologi-.html). The field work was supported by a UNIFOR Orlaug L. Merkesdals legatgrant.
The expedition participants were Prof. Olivier Galland (Njord, UiO, expedition leader), Prof. Dougal Jerram (Njord, UiO/DougalEarth), Prof. Lars Eivind Augland (UiO) and MSc student Ole-Jacob Evensen.