Two notable wetlands are located within the diapir: the Salt Valley of Añana and Lake Arreo.

[2] The Añana Diapir was formed by evaporites from the Keuper which ascended through Jurassic, Cretaceous and Tertiary layers.

[4] In the hypersaline waters of the Salt Valley, the only animals present are Artemia parthenogenetica and Ochthebius notabilis, with more species in areas of lower salinity.

[5][6] About half of the diapir is covered by forests, consisting mostly of Pinus sylvestris and Quercus faginea.

[3] Several hydrophytes are found in Lake Arreo, while its shores are covered by common reed and other plants.