Lac Pavin or Lake Pavin is a

meromictic A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters. The term ''meromictic'' was coined by the Austria ...

crater lake, located in the Dore mountains, in Auvergne ( Massif central), in the territory of the commune of Besse-et-Saint-Anastaise,

Puy-de-Dôme Puy-de-Dôme (; or ''lo Puèi Domat'') is a department in the Auvergne-Rhône-Alpes region in the centre of France. In 2021, it had a population of 662,285.France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, between Besse-en-Chandesse and Super-Besse. Formed by phreatomagmatism 6,900 years ago, this crater lake is the youngest

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

in mainland

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

It gives its name to a cheese:

Pavin cheese Pavin is a List of French cheeses, French cheese made in the Auvergne (region), Auvergne region of central France. The cheese got its name because of a nearby meromictic Volcanic crater lake, crater lake called Lac Pavin. It is in the same cheese ...

Description

Located at an altitude of 1,197 m a the lake was formed by phreatomagmatism, in other words it is a

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

. Generally circular in shape with a diameter of 700 to 800 m and an area of 44 ha, it has an average depth of 29.5m and a maximum depth of 92m , making it the deepest in Auvergne ( i.e. a volume of approximately 13 million m 3 of water). It is visited by approximately 200,000 people per year. The Couze Pavin river which passes 300m from the lake is only partially fed by the latter. It is of very recent origin unlike the Dore Mountains massif. It was formed after the period of volcanic activity which created the Puys chain, around 6,900 years ago, making it one of the youngest volcanic structures in mainland France.« Le lac Pavin : un lac méromictique »
(invité Michel Meybeck) dans l'émission ''Planète terre'' de

France Culture France Culture () is a French public radio channel and part of Radio France Radio France () is the French national public radio broadcaster. Stations Radio France offers seven national networks: *France Inter — Radio France's "generalist ...

du 22 septembre 2010. It is not linked to the Puys chain. The explosion which formed it was very violent: traces of this event were found as far away as the sediments of Lake Geneva and other Swiss lakes. The volume of the eruption is estimated at 75 million m³. On a clear day, with the blue sky reflecting in the water, it appears very colourful, almost midnight blue. On the other hand, in stormy weather, its deep waters appear very dark, which undoubtedly earned it its name Pavin (from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

pavens, terrible). The oxygenated waters of Lake Pavin are home to zooplankton and fish, notably Arctic char, which live in deep water (30 to 70m). Deep waters have a density of more than 10 million bacteria per millilitre of water (density ten times that of standard lakes), including methanogenic (i.e. methane -producing ),

archaea Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even thou ...

, as well as other methane consuming species. Certain archaea oxidize some of the methane they produce in order to consume it.

Toponymy

"Pavin" is a

Francization Francization (in American English, Canadian English, and Oxford English) or Francisation (in other British English), also known as Frenchification, is the expansion of French language use—either through willful adoption or coercion—by more an ...

of its local Occitan name: Lac Pavent which means "terrible lake". This same word comes from the Latin pavens (adjective participle of pavere which means "to be struck with terror"). The name of "Lake Pavin" would therefore mean, word for word both in Occitan and in its ancestor Latin, "terrible lake".

Meromictic lake

Lake Pavin is unique in France:The only other was Lac de la Girotte, a natural lake (dissolution in gypsum) 99 meters deep over 57 hectares in

Haute-Savoie Haute-Savoie () is a Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region of Southeastern France, bordering both Switzerland and Italy. Its Prefectures in France, prefecture is Annecy. To the north is Lake Gene ...

. Having been converted to a reservoir, it has lost this characteristic. Lake Bourget and

Lake Geneva Lake Geneva is a deep lake on the north side of the Alps, shared between Switzerland and France. It is one of the List of largest lakes of Europe, largest lakes in Western Europe and the largest on the course of the Rhône. Sixty percent () ...

come close to this category but their monimolimnion is not totally anoxic. it is a meromictic lake, officially classified as such in 1951. The mixing of water, annual or biennial, only takes place over the first 60 meters: this property is explained by the almost conical shape of the volume of water, its enclosed and protected location from wind and the existence of underground sources, which mineralize deep waters and make them denser. The anoxic waters of the lake bottom, between 60 and 92 meters, are confined and loaded with gases such as carbon dioxide, nitrogen, methane and hydrogen sulphide, linked to the decomposition of organic matter, which gives them a bad odour. The gas and its composition is monitored because an increase could lead to risks of catastrophic degassing, a phenomenon called " limnic eruption" by some researchers, but according to the work of Haroun Tazieff, a phreato-gaseous eruption could occur. However, ground movements (significant rock falls) or seismic events could disrupt this balance and lead to sudden degassing.

New hypotheses concerning the activity of Lake Pavin

The lake has been studied by scientists since the 18th century: the Count of Montlosier in his Study on the Volcanoes of Auvergne of 1789 proposed that the lake came from a "powdery explosion". Its unaltered characteristics (meromictic lake and pristinePrimitive lake little anthropised.) has meant that it has been widely studied, particularly with regard to hydrobiology. Scientific teams attached to the CNRS from

Lyon Lyon (Franco-Provençal: ''Liyon'') is a city in France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, Switzerland, north ...

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

Clermont-Ferrand Clermont-Ferrand (, , ; or simply ; ) is a city and Communes of France, commune of France, in the Auvergne-Rhône-Alpes regions of France, region, with a population of 147,284 (2020). Its metropolitan area () had 504,157 inhabitants at the 2018 ...

and

Orléans Orléans (,"Orleans"
(US) and Other legends say that if you throw a stone in the middle of the lake, he wakes up and a throw of stones hits him. December 31 at midnight you can hear the bells of the old church of Besse ringing.

Representation in culture

Television

The site is the main location of the TV film ''Meurtres en Auvergne'' (2016) from the collection of Franco-Belgian police TV films called ''Meurtres à...''.

Climbing

The climbing site, located on the western edge of Lake Pavin, is a cliff resulting from a basalt flow escaped from the Puy de Montchal, just over 1 km away. Although located at an altitude of 1,200 meters, this cliff faces southwest and climbing can therefore be practiced from April to December. The paths run through basalt organs where dihedrons (with large cracks at the bottom) and rectilinear pillars alternate . Initially equipped by the Super-Besse mountain gendarmerie platoon, the site offers 24 routes20 to 25 m high, rated 4 to 6c, with predominance of levels 6a and 6b.

Old postcards of the Lake

Lac Pavin-FR-63-carte postale-vers 1929-a01.jpg Lac Pavin-FR-63-carte postale-vers 1929-a03.jpg Lac Pavin-FR-63-carte postale-vers 1929-a04.jpg Lac Pavin-FR-63-carte postale-vers 1929-a09.jpg

References

External links

*
Accumulation of mantle gases in a permanently stratified volcanic lake(Lac Pavin, France)
1999 paper concluding CO2 levels in Lac Pavin were not at the time in danger of a limnic eruption
The Mysterious Lake Pavin
article by Visit Auvergne, 2023 {{DEFAULTSORT:Pavin, Lac Lakes of Puy-de-Dôme Volcanic crater lakes Meromictic lakes Maars of France