Skip to main content

Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments

Author(s): Thiagarajan, Nivedita; Crémière, Antoine; Blättler, Clara; Lepland, Aivo; Kirsimäe, Kalle; et al

To refer to this page use:
Full metadata record
DC FieldValueLanguage
dc.contributor.authorThiagarajan, Nivedita-
dc.contributor.authorCrémière, Antoine-
dc.contributor.authorBlättler, Clara-
dc.contributor.authorLepland, Aivo-
dc.contributor.authorKirsimäe, Kalle-
dc.contributor.authorHiggins, John A-
dc.contributor.authorBrunstad, Harald-
dc.contributor.authorEiler, John-
dc.identifier.citationThiagarajan, Nivedita, Antoine Crémière, Clara Blättler, Aivo Lepland, Kalle Kirsimäe, John Higgins, Harald Brunstad, and John Eiler. "Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments." Geochimica et Cosmochimica Acta 279 (2020): 204-219. doi:10.1016/j.gca.2020.03.015.en_US
dc.description.abstractCold seep environments are characterized by methane-rich fluid migration and discharge at the seafloor. These environments are also intimately linked to microbial communities, which oxidize methane anaerobically, increase alkalinity and promote authigenic carbonate precipitation. We have analyzed a suite of methane-derived authigenic carbonate (MDAC) crusts from the North and Barents Sea using stable and clumped isotopes (δ13C, δ18O, δ44Ca, and Δ47) to characterize the sources of fluids as well as the environment of carbonate authigenesis. We additionally assess the potential of MDACs as a Δ47-based paleotemperature archive. The MDACs occur as three main textural-mineralogic types: micritic Mg-calcite cements, micritic aragonite cements and cavity filling aragonite cements. We find that micritic Mg-calcite cements have low δ13CVPDB values (−30 to −47‰), high δ44CaSW values (−0.4 to −0.8‰), and Δ47-temperatures (0–6 °C) consistent with shallow sub-seafloor precipitation in isotopic equilibrium. Micritic aragonite cements and cavity filling aragonite cements both have a wider range in δ13CVPDB values (−18 to −58‰), lower δ44CaSW values (−0.8 to −1.6‰) and a larger range in Δ47-based apparent temperatures (–2 – 25 °C) with samples displaying equilibrium and disequilibrium clumped isotope values. The range in apparent temperatures as well as δ44CaSW values seen in the aragonite MDACs suggest two kinetic processes: a kinetic isotope effect (KIE) due to the incomplete equilibration of carbon and oxygen isotopes among DIC species from the different sources of DIC (i.e., seawater, methane-sourced DIC and DIC residual to CO2 degassing or diffusion) and a KIE due to a fast, irreversible precipitation affecting the cations, particularly Ca, bound to carbonate mineral. Our results improve the understanding of kinetic effects on clumped isotope temperatures in MDACs and demonstrate how the multi-isotopic approach combined with textural-mineralogic criteria can be used to identify MDACs for accurate paleotemperature reconstructions.en_US
dc.format.extent204 - 219en_US
dc.relation.ispartofGeochimica et Cosmochimica Actaen_US
dc.rightsAuthor's manuscripten_US
dc.titleStable and clumped isotope characterization of authigenic carbonates in methane cold seep environmentsen_US
dc.typeJournal Articleen_US

Files in This Item:
File Description SizeFormat 
Stable_clumped_isotope_characterization_authigenic_carbonates_methane_cold_seep.pdf2.15 MBAdobe PDFView/Download

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.