Methane flux and authigenic carbonate in shallow sediments overlying methane hydrate bearing strata in Alaminos Canyon, Gulf of Mexico

Date

2014-09-23

Authors

Coffin, Richard B.
Smith, Joseph P.

ORCID

Journal Title

Journal ISSN

Volume Title

Publisher

MDPI

Abstract

In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and dissolved inorganic carbon (DIC) concentrations in porewaters, headspace methane, and solid phase carbonate concentrations were measured at each core location to investigate the cycling of methane-derived carbon in shallow sediments overlying the hydrate bearing strata. When integrated with stable carbon isotope ratios of DIC, geochemical results suggest a significant fraction of the methane flux at this site is cycled into the inorganic carbon pool. The incorporation of methane-derived carbon into dissolved and solid inorganic carbon phases represents a significant sink in local carbon cycling and plays a role in regulating the flux of methane to the overlying water column at Alaminos Canyon. Targeted, high-resolution geochemical characterization of the biogeochemical cycling of methane-derived carbon in shallow sediments overlying hydrate bearing strata like those in Alaminos Canyon is critical to quantifying methane flux and estimating methane hydrate distributions in gas hydrate bearing marine sediments.

Description

Keywords

methane, hydrate, gulf of mexico, alaminos, alaminos canyon, sediments, pore water, carbon cycling

Sponsorship

Rights:

Attribution 4.0 International

Citation

Smith, J.P. and Coffin, R.B., 2014. Methane flux and authigenic carbonate in shallow sediments overlying methane hydrate bearing strata in Alaminos Canyon, Gulf of Mexico. Energies, 7(9), pp.6118-6141.