The province of Neuquén, in southwestern Argentina, is a true natural laboratory for geology and volcanology enthusiasts, thanks to its privileged location atop the imposing Andes mountain range. Marked by tectonic and volcanic activity, this region presents a contrasting landscape where the aridity of the north and west intersperses with the lush forests and glacial lakes of the south, all sculpted, in part, by the influence of its numerous volcanoes.
If you've ever wondered how and why there are so many volcanoes in Neuquén or what role they play in shaping its landscape, you've come to the right place. This guide offers an in-depth look at the volcanic geology of southern Argentina, detailing the province's main volcanic complexes, describing their eruptive history, and their impact on daily life and tourism. You'll not only discover iconic volcanoes such as Lanín, Copahue, and Tromen, but you'll also understand how volcanic activity has shaped the terrain and continues to influence the area's natural hazards and attractions.
Geological context and formation of the Neuquén relief
El Neuquén's landscape is defined by the interaction between tectonic and volcanic processes over millions of years.The Andes Mountains, the result of the collision of the South American and Nazca plates, act as the region's backbone and are home to a wide variety of volcanoes, both active and dormant. This mountainous environment has fostered the development of glacial lakes and deep valleys, marking a sharp contrast between the arid north and west and the vegetated south. In the north and west, the aridity is due to the rain shadow caused by the Andes, while in the south, glacial lakes and forests dominate the landscape.
Volcanoes have not only shaped the terrain, but have also been key to the formation of fertile soils, geothermal resources, and hot springs. To understand the province's genesis and current morphology, it is vital to analyze the volcanic and orogenic evolution over successive geological eras, as well as the relationship between lake formation, eruptions, and glaciers.
Main volcanoes in Neuquén and their geological importance
Neuquén has at least six emblematic volcanoes, each with unique geological characteristics and contexts. The most notable are described below:
Copahue Volcano
- State: Active
- Level: 2.997 m
- Location: Border with Chile, within the Copahue-Caviahue complex
Copahue is one of the most closely monitored Argentine volcanoes due to its persistent activity and potential risk to nearby populations. Located on the border with Chile, it is known for its frequent eruptive activity, fumaroles, and the emission of magmatic and hydrothermal gases. Scientific research (Agusto et al. 2013, Caselli et al. 2016, among others) has documented the chemistry of the gases emitted and the associated hazards, including explosive eruptions and the emission of pyroclastic sulfur.
The Copahue Volcano is also the epicenter of an active thermal system, with world-renowned sulfurous waters. Furthermore, the thermal village of Copahue, located at its foot, is a popular destination for both its medicinal properties and stories of miraculous cures, such as the famous anecdote of the girl cured of tuberculosis in the 19th century thanks to the hot springs.
From a geological point of view, Copahue is related to the active tectonics of the Andes and its activity is controlled by deep structures. Research has identified recent eruptive cycles, such as the one in December 2012, and has underscored the importance of ongoing monitoring due to the proximity of towns and constant tourist traffic.
Lanin Volcano
- State: Active
- Level: 3.776 m
- Location: Lanín National Park, border with Chile
Lanín is undoubtedly Neuquén's most emblematic volcano, not only for its majesty but also for its symbolic and sacred value to Mapuche culture. Its last significant eruption dates back approximately 1.600 years, although smaller episodes have been recorded, such as the one in February 2017. Lanín dominates the surrounding area, being visible from several points in the province and featuring on the provincial coat of arms and anthem.
From a scientific perspective, post-glacial pyroclastic deposits and a morpho-structural evolution related to the retreat of Quaternary-era glaciers have been documented. Recent research has delved into the hazards (rapid flows, tephrostratigraphic deposits) and the presence of lava tubes, which attest to the region's volcanic and geological richness.
Domuyo Volcano
- Level: 4.707 m
- Location: Northern Neuquén
Although traditionally classified as a volcano, Domuyo is actually a tectonic structure with volcanic and geothermal manifestations at its base. The geysers that erupt in the area are evidence of a deep magma chamber, hence its nickname "Roof of Patagonia." The hot springs and geothermal field at the foot of Domuyo provide an added attraction for both science and adventure tourism.
Tromen Volcano
- State: Active
- Level: 4.114 m
The Tromen volcano stands out for its dark lava flows that cover the north and northeast of the mountain, visible even from the town of Buta Ranquil. Although its geological development parallels that of the volcanoes of the main Andean chain, it responds to different origins. Its last significant eruptions are estimated to have occurred between 1820 and 1828, placing it among the most recently active volcanoes outside the main chain.
Batea Mahuida Volcano
- State: Inactive
- Level: 1.948 m
Batea Mahuida, known for its crater-turned-lake, has gained notoriety in recent decades thanks to the development of tourism and the ski resort managed by the Puel Mapuche community. From its summit, you can enjoy panoramic views of other volcanoes in Neuquén and Chile, as well as lakes of volcanic and glacial origin.
Auca Mahuida Volcano
- State: Inactive
- Level: 2.253 m
Located alone in northern Neuquén, Auca Mahuida is special because it is isolated from the main mountain ranges. At its base are exceptional paleontological sites, such as the world's largest deposit of dinosaur eggs, as well as abandoned mines and a wide variety of native flora and fauna. Its still-unexplored caves and Mapuche legends add an aura of mystery and allure to this place.
Geological processes and formation of glacial lakes
La The geology of Neuquén is marked by the succession of volcanic eruptive cycles, orogenic periods and the action of glaciersThe lakes in the south of the province are of glacial origin, the result of the advance and retreat of glaciers that carved out depressions later filled with water. Volcanoes, at the same time, have shaped the terrain, accumulating lava flows, pyroclasts, and ash that form volcanic plateaus and alter river courses.
During the last Ice Age and the Holocene, volcanoes such as Lanín and Copahue experienced significant eruptive events, the ash of which can still be identified in lake sediments and peat bogs. These strata are valuable for reconstructing their eruptive history and potential hazards.
Volcanic risks and monitoring
La The presence of active volcanoes implies the constant assessment of risks to the population and infrastructureCopahue, Lanín, and Tromen, among others, are regularly monitored by organizations such as the Argentine Volcano Surveillance Observatory. The main threats include explosive eruptions, ash and gas emissions, mudflows, and lahars that can affect roads, cities, and economic activities.
A concrete example was the eruption of the Puyehue complex (Chile) in 2011, whose ash affected vast areas of Neuquén. Localities near the Copahue volcano, such as Caviahue, and areas under the influence of Lanín, must have emergency plans and be familiar with volcanic risk maps, which are developed based on the location and activity of each volcano.
Tourist and cultural impact of Neuquén's volcanoes
Tourism in Neuquén is closely linked to its volcanoes, lakes, and hot springs. Trekking, mountain climbing, ski resorts, and visits to geothermal hot springs are centered around these natural monuments. The connection with the Mapuche culture, which considers several of these volcanoes sacred, enriches the visitor experience.
The development of virtual tourist guides and educational materials fosters appreciation for geological and natural heritage, while promoting responsible practices in at-risk areas. Volcanoes have also inspired legends, songs, and countless artistic and folkloric expressions.
Recommendations for the study and dissemination of volcanic geology in Neuquén
- Use physical and conceptual maps to deepen understanding of the relief and location of volcanoes, identifying risk areas and potential sites of interest for scientific tourism.
- Compare historical events with recent eruptions and analyze the impacts on the population, the environment, and the local economy through reports and multimedia resources.
- Promote collaboration between institutions, researchers, and communities to generate accessible, up-to-date, and multidisciplinary materials that integrate scientific, educational, and cultural perspectives.
Neuquén is arguably a showcase of the volcanic geology of southern Argentina, combining a natural, scientific, and cultural wealth worthy of appreciation. From the sacred mountains of Lanín to the geysers of Domuyo and the hot springs of Copahue, each volcano tells a part of our planet's history, inviting adventure and reminding us of the importance of coexisting with a constantly changing environment.