Soffioni (sometimes spelt ''suffioni''), a name applied in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

to certain

volcanic A volcano is a rupture 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 often found where tectonic plates a ...

vents which emit jets of steam, generally associated with hydrogen sulfide and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

, sometimes also with a little

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

and

marsh gas Marsh gas, also known as swamp gas or bog gas, is a mixture primarily of methane and smaller amounts of hydrogen sulfide, carbon dioxide, and trace phosphine that is produced naturally within some geographical marshes, swamps, and bogs. The surfac ...

. The soffioni are usually arranged in groups, and are best represented in the

Maremma The Maremma (, ; from Latin , "maritime and) is a coastal area of western central Italy, bordering the Tyrrhenian Sea. It includes much of south-western Tuscany and part of northern Lazio. It was formerly mostly marshland, often malarial, bu ...

Tuscany it, Toscano (man) it, Toscana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Citizenship , demographics1_footnotes = , demographics1_title1 = Italian , demogra ...

, where they contain a small proportion of

boric acid Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula . It may also be called hydrogen borate or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolve ...

, for which they are utilized industrially. For such natural steam-holes, the French geologists often use the term ''soufflards'' in place of the Italian ''soffioni''.

References

Volcanology {{volcanology-stub