Schäfer, Nadine

[["dc.bibliographiccitation.firstpage","94"],["dc.bibliographiccitation.journal","Palaeogeography Palaeoclimatology Palaeoecology"],["dc.bibliographiccitation.lastpage","115"],["dc.bibliographiccitation.volume","390"],["dc.contributor.author","Agirrezabala, Luis M."],["dc.contributor.author","Kiel, Steffen"],["dc.contributor.author","Blumenberg, Martin"],["dc.contributor.author","Schaefer, Nadine"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T09:17:31Z"],["dc.date.available","2018-11-07T09:17:31Z"],["dc.date.issued","2013"],["dc.description.abstract","Late Albian deep-water sediments of the Black Flysch Group in the Basque-Cantabrian Basin (western Pyrenees) preserve a fossil pockmark field including methane seep carbonates and associated macrofauna. The geometry of the pockmarks is reconstructed from repeated lens-shaped turbidite deposits with centrally located carbonate bodies. Early diagenetic carbonate phases such as clotted micrite and yellow calcite with delta C-13 values as low as -41.6%, and hydrocarbon biomarkers (e.g. 2,6,10,15,19-pentamethylicosane) with strong depletions in C-13 indicate that the carbonates precipitated due to anaerobic oxidation of methane. The pockmarks probably formed due to subsidence induced by dewatering and degassing of the gas-charged seabed perhaps enhanced by the weight of the carbonate bodies. The macrofauna resembles that of other late Mesozoic deep-water methane-seeps world-wide, and is dominated by large lucinid and Caspiconcha bivalves, and hokkaidoconchid gastropods. During late diagenesis the carbonate delta O-18 values were reset to a narrow range of -12 to -10%., the remaining pore spaces and fissures were filled with pyrobitumen, and additional carbonate phases precipitated, potentially due to thermochemical sulfate reduction processes. (C) 2012 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.palaeo.2012.11.020"],["dc.identifier.isi","000328438600009"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28188"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1872-616X"],["dc.relation.issn","0031-0182"],["dc.title","Outcrop analogues of pockmarks and associated methane-seep carbonates: A case study from the Lower Cretaceous (Albian) of the Basque-Cantabrian Basin, western Pyrenees"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","641"],["dc.bibliographiccitation.journal","Marine and Petroleum Geology"],["dc.bibliographiccitation.lastpage","652"],["dc.bibliographiccitation.volume","66"],["dc.contributor.author","Reitner, Joachim"],["dc.contributor.author","Blumenberg, Martin"],["dc.contributor.author","Walliser, Eric-Otto"],["dc.contributor.author","Schaefer, Nadine"],["dc.contributor.author","Duda, Jan-Peter"],["dc.date.accessioned","2018-11-07T09:52:08Z"],["dc.date.available","2018-11-07T09:52:08Z"],["dc.date.issued","2015"],["dc.description.abstract","Peculiar carbonate bodies occur in distinct marl layers of the Marnes Bleues Formation (Aptian-Albian, Vocontian Basin, Southern France). The carbonate conduits exhibit pipe- or sausage-like forms and a central channel. Their sizes range between 30 and 60 cm in length and 5-10 cm in diameter. The conduit carbonates consist of automicrite authigenically formed within the sediment. Millimeter-sized aggregates of framboidal pyrite are abundant within the conduit automicrites, probably representing former colonies of sulfate reducing bacteria. The central channel reflects former pathways of reduced fluids in the carbonate conduit. Ni-enrichments at the margins of the central cavity are may be due to the activity of methane-related metabolism as Ni is an important bio-element for respective microbes. Light stable carbon isotope ratios of the conduit automicrites (-25.86 parts per thousand, to -23.10 parts per thousand, VPDB) point to carbonate precipitation linked to anaerobic oxidation of methane (AOM), while less depleted stable carbon isotope ratios of microspar in marginal zones of the central opening (-8.96 parts per thousand VPDB) are in line with microbial sulfate reduction. A methane-related origin of the conduit carbonates is confirmed by the presence of authigenic lipid biomarkers tentatively sourced by archaea most of which are characterized by strong C-13 depletions (delta C-13 values down to -104 parts per thousand). The presence of organically bound sulfur is well in line with microbial sulfate reduction. Isorenieratane potentially point to the presence of brown pigmented green sulfur bacteria. The methane was probably sourced by older OAE black shales which are known to contain isotopically (delta C-13) heavy biomarkers of archaea as reported elsewhere. (C) 2015 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.marpetgeo.2015.05.029"],["dc.identifier.isi","000365056000013"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36052"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1873-4073"],["dc.relation.issn","0264-8172"],["dc.title","Methane-derived carbonate conduits from the late Aptian of Salinac (Marne Bleues, Vocontian Basin, France): Petrology and biosignatures"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]