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dc.contributor.authorHong, W.-L.
dc.contributor.authorPape, T.
dc.contributor.authorSchmidt, C.
dc.contributor.authorYao, H.
dc.contributor.authorWallmann, K.
dc.contributor.authorPlaza-Faverola, A.
dc.contributor.authorRae, J.W.B.
dc.contributor.authorLepland, A.
dc.contributor.authorBünz, S.
dc.contributor.authorBohrmann, G.
dc.date.accessioned2021-04-12T13:30:03Z
dc.date.available2021-04-12T13:30:03Z
dc.date.issued2021-05
dc.identifier.citationHong , W-L , Pape , T , Schmidt , C , Yao , H , Wallmann , K , Plaza-Faverola , A , Rae , J W B , Lepland , A , Bünz , S & Bohrmann , G 2021 , ' Interactions between deep formation fluid and gas hydrate dynamics inferred from pore fluid geochemistry at active pockmarks of the Vestnesa Ridge, west Svalbard margin ' , Marine and Petroleum Geology , vol. 127 , 104957 . https://doi.org/10.1016/j.marpetgeo.2021.104957en
dc.identifier.issn0264-8172
dc.identifier.otherPURE: 273735382
dc.identifier.otherPURE UUID: f65194be-523b-4923-a129-99ba56aa5648
dc.identifier.otherRIS: urn:572DADF3D4C13CC8CD1D4E5380D3E908
dc.identifier.otherScopus: 85101084263
dc.identifier.otherORCID: /0000-0003-3904-2526/work/92020063
dc.identifier.otherWOS: 000630924600002
dc.identifier.urihttps://hdl.handle.net/10023/23013
dc.descriptionCruise MSM57-1/-2 was funded by the German Research Foundation ( DFG ), the Research Center/Excellence Cluster “The Ocean in the Earth System” at MARUM–Center for Marine and Environmental Sciences, University of Bremen and funds from CAGE. This work is partly supported by the Research Council of Norway (RCN) through Petromaks2-NORCRUST (project number 255150 ) and the Centre of Excellence funding scheme for CAGE (project number 223259 ). APF’s contribution was part of the SEAMSTRESS project supported by starting grants from the Tromsø Research Foundation and the Research Council of Norway (grant nr. 2878659 ).en
dc.description.abstractSeafloor seepage sites along the Vestnesa Ridge off west-Svalbard have been, for decades, a natural laboratory for the studies of fluid flow and gas hydrate dynamics along passive continental margins. The lack of ground truth evidence for fluid composition and gas hydrate abundance deep in the sediment sequence however prohibits us from further assessing the current model of pockmark evolution from the region. A MARUM-MeBo 70 drilling cruise in 2016 aims to advance our understanding of the system by recovering sediments tens of meters below seafloor from two active pockmarks along Vestnesa Ridge. We report pore fluid composition data focusing on dissolved chloride, stable isotopes of water (δ18O and δD), and the isotopic composition of dissolved boron (δ11B). From one of the seepage sites, we detect a saline formation water with two layers where gas hydrates were recovered. This saline formation pore fluid is characterized by elevated chloride concentrations (up to 616 mM), high B/Cl ratios (9 × 10−4 mol/mol), high δ18O and δD isotopic signatures (+0.6‰ and +3.8‰, respectively) and low δ11B signatures (+35.0‰), which collectively hint to a high temperature modification at great depths. Based on the dissolved chloride concentration profiles, we estimated up to 47% of pore space occupied by gas hydrate in the sediments shallower than 11.5 mbsf. The observation of bubble fabric in the recovered gas hydrates suggests formation during past periods of intensive gaseous methane seepage. The presence of these gas hydrates without associated positive anomalies in dissolved chloride concentrations however suggests that the decomposition of gas hydrate is as fast as its formation. Such a state of gas hydrates can be attributed to a relatively low methane supply transported by the saline formation water at present. Our findings based on pore fluid composition corroborate previous inferences along Vestnesa Ridge that fluids sustaining seepage have migrated from great depths and that the variable gaseous and aqueous phases through the gas hydrate stability zone control the distributions of authigenic carbonates and gas hydrates. 
dc.format.extent13
dc.language.isoeng
dc.relation.ispartofMarine and Petroleum Geologyen
dc.rightsCopyright © 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).en
dc.subjectPockmarken
dc.subjectGas hydrateen
dc.subjectMeBo drillingen
dc.subjectIsotope geochemistryen
dc.subjectQE Geologyen
dc.subjectDASen
dc.subject.lccQEen
dc.titleInteractions between deep formation fluid and gas hydrate dynamics inferred from pore fluid geochemistry at active pockmarks of the Vestnesa Ridge, west Svalbard marginen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Earth & Environmental Sciencesen
dc.contributor.institutionUniversity of St Andrews. St Andrews Isotope Geochemistryen
dc.identifier.doihttps://doi.org/10.1016/j.marpetgeo.2021.104957
dc.description.statusPeer revieweden
dc.identifier.urlhttps://www.sciencedirect.com/science/article/pii/S0264817221000611?via%3Dihub#appsec1en


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