Variations in Gas and Water Pulses at an Arctic Seep: Fluid Sources and Methane Transport

Citeable URL: https://ir.library.oregonstate.edu/concern/articles/js956n34j

Descriptions

Attribute Name	Values
Creator	Hong, Wei-Li Torres, Marta E. Portnov, A. Waage, M. Haley, B. Lepland, A.
Abstract	Methane fluxes into the oceans are largely dependent on the methane phase as it migrates upward through the sediments. Here we document decoupled methane transport by gaseous and aqueous phases in Storfjordrenna (offshore Svalbard) and propose a three-stage evolution model for active seepage in the region where gas hydrates are present in the shallow subsurface. In a preactive seepage stage, solute diffusion is the primary transport mechanism for methane in the dissolved phase. Fluids containing dissolved methane have high Sr-87/Sr-86 ratios due to silicate weathering in the microbial methanogenesis zone. During the active seepage stage, migration of gaseous methane results in near-seafloor gas hydrate formation and vigorous seafloor gas discharge with a thermogenic fingerprint. In the postactive seepage stage, the high concentration of dissolved lithium points to the contribution of a deeper-sourced aqueous fluid, which we postulate advects upward following cessation of gas discharge.
License	Attribution 4.0 (CC BY 4.0)
Resource Type	Article
DOI	https://doi.org/10.1029/2018gl077309
Date Issued	2018-05-16
Journal Title	Geophysical Research Letters
Journal Volume	45
Rights Statement	In Copyright
Language	English [eng]
ISSN	0094-8276

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