Tamarugite, NaAl(SO4)2·6H2O, as a valuable indicator of soil degradation in a Spanish coastal wetland receiving acidic leachates from spilled mine waste

This paper documents the first occurrence of tamarugite in a Spanish coastal wetland registered as a UNESCO Biosphere Reserve, and discusses its origin and environmental significance. Tamarugite occurs as bladed crystals in efflorescent coatings on the topsoil of marshy areas, alongside an abandoned...

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Detalles Bibliográficos
Autor: Fernández Caliani, Juan Carlos
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universidad de Huelva (UHU)
Repositorio:Arias Montano. Repositorio Institucional de la Universidad de Huelva
Idioma:inglés
OAI Identifier:oai:ariasmontano.uhu.es:10272/22539
Acceso en línea:https://hdl.handle.net/10272/22539
Access Level:acceso abierto
Palabra clave:Tamarugite
Pyrite
Acid sulfate soil
Salt efflorescence
Tidal wetland
Huelva estuary
2506 Geología
Descripción
Sumario:This paper documents the first occurrence of tamarugite in a Spanish coastal wetland registered as a UNESCO Biosphere Reserve, and discusses its origin and environmental significance. Tamarugite occurs as bladed crystals in efflorescent coatings on the topsoil of marshy areas, alongside an abandoned mining railroad. Tamarugite formation is described as a sequential process involving: (1) Oxidative dissolution of pyrite ore spilled on the former railway tracks and generation of acidic sulfate-rich waters; (2) decomposition of layer minerals under acidic conditions and release of Al3+ ions into solution; (3) interaction between acid discharges and estuarine water during flood tidal periods; and (4) precipitation of tamarugite and associated sulfate salts (sideronatrite, epsomite, pickeringite) under strongly evaporative conditions. These transient minerals have potential to release acid and associated major elements (Al, Fe, Mg, Na, S) and trace metals (e.g. Zn) into the solution causing detrimental effects. The occurrence of tamarugite is, therefore, a valuable indicator of environmental degradation in wetland ecosystems.