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dc.contributor.author
Hofbauer, Barbara
dc.contributor.author
Viehmann, Sebastian
dc.contributor.author
Gier, Susanne
dc.contributor.author
Bernasconi, Stefano M.
dc.contributor.author
Meister, Patrick
dc.date.accessioned
2022-06-03T07:58:07Z
dc.date.available
2021-12-28T03:58:38Z
dc.date.available
2022-06-03T07:58:07Z
dc.date.issued
2021-01
dc.identifier.other
10.17738/ajes.2021.0004
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/522377
dc.identifier.doi
10.3929/ethz-b-000522377
dc.description.abstract
The conditions in ancient evaporative environments conducive to authigenic carbonate (especially dolomite [CaMg(CO3)(2)]) formation are still insufficiently understood. Insights from microfacies analysis can help to constrain the conditions in these environments. We provide a brief overview of the microfacies association and carbon and oxygen isotope compositions of dolomite beds intercalated in a claystone-rich succession from the Norian Arnstadt Formation in Thuringia and Lower Saxony (Germany) in order to gain further insight into the depositional conditions and processes leading to the formation of authigenic Mg/Ca-carbonates in the Germanic Basin. The studied intervals are ascribed to lacustrine, partially evaporitic conditions, while the sedimentary structures were not obliterated by recrystallization. The microfacies of the dolomites is diverse, showing homogeneous micrite, mudclasts, lamination, and peloidal structures, and reflects a shallow to deeper water (below wave base) and episodically evaporative environment. The dolomites exhibit oxygen isotope values (delta O-18) in the range from -5.21 to -0.36 parts per thousand VPDB and, hence, only represent a weak meteoric influence, suggesting that the authigenic carbonate generally formed under evaporative conditions. Carbon isotope values (delta C-13) in the range of -4.28 to 1.39 parts per thousand VPDB indicate a small contribution of remineralized organic carbon, mainly in sediments that were presumably deposited in deeper water or under brackish conditions. Sedimentary structures, such as lamination with graded silt layers, reworked mudclasts embedded in a fine dolomicrite matrix, and peloids showing plastic deformation, indicate that the sediment was still unlithified. These observations would be consistent with an authigenic formation of Mg/Ca-carbonates directly from the lake water, and their deposition under variable conditions in a large playa-lake/perennial lake system.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Sciendo
en_US
dc.rights.uri
http://creativecommons.org/licenses/by-nc-nd/3.0/
dc.subject
Primary dolomite
en_US
dc.subject
Germanic Basin
en_US
dc.subject
playa lake
en_US
dc.subject
Arnstadt Formation
en_US
dc.subject
authigenic carbonates
en_US
dc.subject
microfacies
en_US
dc.title
Microfacies and C/O-isotopes in lacustrine dolomites reflect variable environmental conditions in the Germanic Basin (Arnstadt Formation, Upper Triassic)
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
dc.date.published
2021-12-17
ethz.journal.title
Austrian Journal of Earth Sciences
ethz.journal.volume
114
en_US
ethz.journal.issue
1
en_US
ethz.pages.start
66
en_US
ethz.pages.end
86
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Warsaw
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09601 - Stoll, Heather / Stoll, Heather
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09601 - Stoll, Heather / Stoll, Heather::08806 - Bernasconi, Stefano (Tit.-Prof.)
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09601 - Stoll, Heather / Stoll, Heather
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02704 - Geologisches Institut / Geological Institute::09601 - Stoll, Heather / Stoll, Heather::08806 - Bernasconi, Stefano (Tit.-Prof.)
ethz.date.deposited
2021-12-28T03:59:22Z
ethz.source
WOS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2022-06-03T07:58:16Z
ethz.rosetta.lastUpdated
2022-06-03T07:58:16Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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