Artigo De: scopus, cienciavitae, orcid

Linking serpentinization, hyperalkaline mineral waters and abiotic methane production in continental peridotites: an integrated hydrogeological-bio-geochemical model from the Cabeço de Vide CH4-rich aquifer (Portugal)

Applied Geochemistry

Marques, J.M.; Etiope, G.; Suzuki, S.2018Elsevier

Informações chave

Autores:

Marques, J.M. (José Manuel Vaz Velho Barbosa Marques); Etiope, G.; Neves, M.O. (Maria Orquídia Teixeira Neves); Carreira, P.M. (Paula Maria Mimo Carreira Paquete); Rocha, C. (Carla Sofia Almeida da Rocha); Vance, S.D.; Christensen, L.; Miller, A.Z.; Suzuki, S.

Publicado em

01/09/2018

Resumo

Continental active serpentinization of ultramafic rocks is today recognized as a key process triggering a sequence of phenomena involving the passage from inorganic, to organic and metabolic reactions. These may have a role in the origin of life, and may explain the occurrence of abiotic hydrocarbons on Earth and other planets. Production of hyperalkaline waters and abiotic methane (CH4) are two critical steps in this sequence. They were described independently by specific hydrogeological and geochemical models. Here, we update and combine these models into a unified scheme using and integrating geological, hydrogeological, hydrogeochemical, gas-geochemical and microbial analyses acquired from 2002 to 2014 in the Cabeço de Vide (CdV) study site, Portugal. The hyperalkaline (pH > 10.5), Na-Cl/Ca-OH mineral water of CdV evolve from groundwater-peridotite interaction (serpentinization) generating hydrogen (H2), which, according to multiple theoretical, laboratory and field evidence, likely reacted with CO2 within metal- (catalyst) rich rocks, abiotically producing CH4 (up to 1.2 mg/L; -24.4°/oo < δ13C-CH4 < -14.0°/oo and -285°/oo < δ2H-CH4 < -218°/oo). The hyperalkaline water hosts hydrogen oxidizing bacteria “Serpentinomonas”, which may explain the paucity of H2 observed in the dissolved gas. The CdV gas-rich mineral waters ascend along a fault at the boundary of the peridotite intrusion. Temporal changes of pH and CH4 concentration result from episodic mixing with shallower Mg-HCO3-type waters. Soil-gas analyses show that methane migrates to the surface along the fault, also independently from the water emergences, consistently with non-aqueous abiotic CH4 production. Our integrated model is generally compatible with observations from other gas-bearing continental serpentinization sites.

Detalhes da publicação

Autores da comunidade :

Versão da publicação

VoR - Versão publicada

Editora

Elsevier

Ligação para a versão da editora

https://www.sciencedirect.com/journal/applied-geochemistry

Título do contentor da publicação

Applied Geochemistry

Primeira página ou número de artigo

287

Última página

301

Volume

96

ISSN

0883-2927

WoS (Web of Science)

442098100026

Domínio Científico (FOS)

earth-and-related-environmental-sciences - Ciências da Terra e Ciências do Ambiente

Palavras-chave

  • Hyperalkaline mineral waters
  • Ultramafic rocks
  • Serpentinization
  • Abiotic methane
  • Portugal

Idioma da publicação (código ISO)

eng - Inglês

Identificador alternativo (URI)

http://dx.doi.org/10.1016/j.apgeochem.2018.07.011

Acesso à publicação:

Acesso apenas a metadados