Replication Data for: Bivalve shell horizons in seafloor pockmarks of the last glacial-interglacial transition suggest a thousand years of methane emissions in the Arctic Ocean ...

• Main Authors: Ambrose, William G., Panieri, Giuliana, Schneider, Andrea, Plaza-Faverola, Andreia, Carroll, Michael. L., Åström, Emmelie K. L., Locke V, William L., Carroll, JoLynn
• Format: Dataset
• Language: unknown
• Published: DataverseNO 2016
• Subjects: Arctic; Arctic Ocean; Foraminifera*; Planktonic foraminifera; Svalbard
• Online Access: https://dx.doi.org/10.18710/fwukx0; https://dataverse.no/citation?persistentId=doi:10.18710/FWUKX0

The paper presents discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (ca. 1200 m water depth), western Svalbard (79° 00’ N, 06° 55’ W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20-30cm thick and centered at 250-400cm deep in the cores. The carbon isotope composition of inorganic (δ13C from -13.02‰ to +2.36‰) and organic (δ13C from -29.28‰ to -21.33‰) shell material and a two-end member mixing model indicate that these taxa derived between 8% and 43% of their nutrition from chemosynthetic bacteria. In addition, negative δ13C values for planktonic foraminifera (-6.7‰ to -3.1‰), micritic concretions identified as methane-derived authigenic carbonates, and pyrite encrusted fossil worm tubes at the shell horizons indicate a sustained paleo-methane seep environment. Combining sedimentation rates with 14C ages for ...