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dc.contributor.authorFrisk, Å. M.
dc.contributor.authorOrmö, J.
dc.date.accessioned2021-02-12T22:30:27Z
dc.date.available2021-02-12T22:30:27Z
dc.date.issued2007-01-01
dc.identifier.citationFrisk, Å. M., & Ormö, J. (2007). Facies distribution of post‐impact sediments in the Ordovician Lockne and Tvären impact craters: Indications for unique impact‐generated environments. Meteoritics & Planetary Science, 42(11), 1971-1984.
dc.identifier.issn1945-5100
dc.identifier.doi10.1111/j.1945-5100.2007.tb00554.x
dc.identifier.urihttp://hdl.handle.net/10150/656360
dc.descriptionFrom the proceedings of the Workshop on Impact Craters as Indicators for Planetary Environmental Evolution and Astrobiology held in June 2006 in Östersund, Sweden.
dc.description.abstractThe Lockne and Tvären craters formed in the Late Ordovician Baltoscandian epicontinental sea. Both craters demonstrate similarities concerning near-synchronous age, target seabed, and succeeding resurge deposits; however, the water depths at the impact sites and the sizes of the craters were not alike. The post-impact sedimentary succession of carbonates, i.e., the Dalby Limestone, deposited on top of the resurge sediments in the two craters, is nevertheless similar. At least three main facies of the Dalby Limestone were established in the Lockne crater, depending on sea-floor topography, location with respect to the crater, and local water currents. The dominating nodular argillaceous facies, showing low values of inorganic carbon (IC), was distributed foremost in the deeper and quiet areas of the crater floor and depressions. At the crater rim, consisting of crushed crystalline basement ejecta, a rim facies with a reef-like fauna was established, most certainly due to topographical highs and substrate-derived nutrients. Between these facies are occurrences of a relatively thick-bedded calcilutite rich in cephalopods (cephalopod facies). In Tvären, the lower part of the succession consists of an analogous argillaceous facies, also showing similar low IC values as in Lockne, followed by calcareous mudstones with an increase of IC. Occasionally biocalcarenites with a distinctive fauna occur in the Tvären succession, probably originating as detritus from a facies developed on the rim. They are evident as peaks in IC and lows in organic carbon (Corg). The fauna in these biocalcarenites corresponds very well with those of erratic boulders derived from Tvären; moreover, they correspond to the rim facies of Lockne except for the inclusion of photosynthesizing algae, indicating shallower water at Tvären than Lockne. Consequently, we suggest equivalent distribution patterns for the carbonates of the Dalby Limestone in Lockne and Tvären.
dc.language.isoen
dc.publisherThe Meteoritical Society
dc.relation.urlhttps://meteoritical.org/
dc.rightsCopyright © The Meteoritical Society
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectfacies
dc.subjectpost impact sediments
dc.subjectDalby Limestone
dc.subjectLockne
dc.titleFacies distribution of post-impact sediments in the Ordovician Lockne and Tvaren impact craters: Indications for unique impact-generated environments
dc.typeProceedings
dc.typetext
dc.identifier.journalMeteoritics & Planetary Science
dc.description.collectioninformationThe Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume42
dc.source.issue11
dc.source.beginpage1971
dc.source.endpage1984
refterms.dateFOA2021-02-12T22:30:27Z


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