Lake Pavin History, geology, biogeochemistry, and sedimentology of a deep meromictic maar lake

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neighborhood of these mountains are fi lled with mineral oil,
coal and asphalt ” (Guettard 1752b , p.8). Instead, other
authors, such as the chemist Montet, proposed, after Lemery
in the preceding century, the reaction of iron with sulphur
and water. Dolomieu , after a visit in Auvergne, noted that the
volcanic edifi ces were aligned side by side but not piled up
as at Etna or Vesuvius, and that they all laid on the granite
bedrock. He therefore wrote: “ je pense que partout, c’est à
de grandes profondeurs dedans ou au-dessous de l’écorce
solide du globe que résident les agens volcaniques, ainsi que
les bases de toutes les déjections; que là restent cachées les
causes qui contribuent à l’infl ammation dont sont accompa-
gnées les irruptions, et celles qui produisent la fl uidité des
laves/I think that everywhere, it is at great depth inside or
below the solid earth’s crust that the volcanic agents lie as
well as the bases of all the excretions; there the causes
remain hidden to what contributes to the ignition by which
the irruptions are accompanied, and also to what produces
the fl uidity of lava ” (Dolomieu 1797 , p. 398).
At that time the prevailing paradigm of a volcano is that
of a conical landform having been built and composed by
red, black scoriae or pumice, adorned with a crater, and hav-
ing emitted ‘fl oods of molten lava’ from the depth of the
Earth. Hence, it is obvious that this concept could not apply
to the Lake Pavin.

5.2 First Research Reports on Lake Pavin

at the End of the Eighteenth Century

However, at the same time, the Earl of Montlosier , a

famous naturalist from Auvergne (Larouzière 2003 ), who

was facing a number of similar lakes in Auvergne: Pavin,

Tazenat et Servière, stressed that their common characters

did not fi t the model of volcano that was otherwise shared:

“ On les a jugés tout de suite, assez vaguement, des cratères

: Des cratères, à la bonne heure; mais encore tous nos

cratères en général sont à sec, et ceux-ci sont plein d’eau,

et cette eau est d’une profondeur immense. Voilà, ce me

semble, un caractère bien tranchant, et dont il eût été assez

intéressant de chercher à assigner la cause. / They were

considered immediately, rather vaguely, as being craters:

well, craters, this would be fi ne, but in contrast with all our

craters which are usually dry, those are full of water, and

this water shows an immense depth. That, I think, is a

sharp character, and he would have been quite interesting

to try to assign the cause. [...]

Ils ont tous les trois des traits de ressemblance bien frap-

pans; mais d’abord il faut y distinguer deux parties impor-

tantes. L’abîme qui les constitue lacs, et qui est d’une

profondeur qu’on a crue pendant longtemps incommensu-

rable, et la partie évasée au-dessus du niveau de leurs eaux,

Fig. 5.2 Detail of the
posthumous map after
Desmarest ( 1823 ), showing
the lake Paven [Pavin] not
associated to any given
“ courant de lave / current of
lava ”. This map was
published in 6 sheets. The
document presented here is
the juxtaposition of sheets IV
and V, with different drawn
symbols

5 The Origin of Lake Pavin: Two Centuries of Controversy