Please use this identifier to cite or link to this item: https://zone.biblio.laurentian.ca/handle/10219/2229
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dc.contributor.authorO’Hare, Sean Patrick-
dc.date.accessioned2014-08-11T18:01:29Z-
dc.date.available2014-08-11T18:01:29Z-
dc.date.issued2014-08-11-
dc.identifier.urihttps://zone.biblio.laurentian.ca/dspace/handle/10219/2229-
dc.description.abstractBlack shale in the Little Dal Group (ca. <817 Ma), Mackenzie Mountains Supergroup (<1005 Ma; >779 Ma), was deposited during the early Neoproterozoic, and is one of the few known black shale deposits from this crucial time in Earth’s evolutionary history. Relative iron enrichment (FeT/Al) and conventional iron speciation (DOP), along with enrichment in molybdenum, total sulphur, and total organic carbon, were studied. Iron systematics (FeT/Al >0.5 and DOP <0.80) indicate ferruginous, anoxic, and possibly oxic bottom-water conditions over the time of deposition of the entire black shale unit. The enrichment factors of several of the authigenic redox-sensitive trace elements (U, Mo, V) are strongly correlated, and appear to be related to both the FeT and the organic carbon content of the black shale. Molybdenum enrichment (<10 ppm) is limited, which is in very good agreement with data from Mesoproterozoic black shales, but is much lower than Mo enrichments in Paleozoic black shales (typically >100 ppm). Several black muddy siltstones yielded similar results, but authigenic iron was greatly overwhelmed by siliciclastic sedimentation. These new data support the theory that ocean bottom-waters returned from sulphidic to ferruginous prior to development of oxygenated conditions in the Ediacaran open ocean. This study documents a predominantly open-marine basin that was characterised by ferruginous conditions, similar to Archean and early Paleoproterozoic conditions, with brief intervals when oxic conditions developed.en_CA
dc.language.isoenen_CA
dc.publisherLaurentian University of Sudburyen_CA
dc.subjectblack shale depositsen_CA
dc.subjectLittle Dal Groupen_CA
dc.subjectMackenzie Mountains Supergroupen_CA
dc.subjectNeoproterozoicen_CA
dc.titleEarly neoproterozoic marine redox conditions recorded in black shale from the little Dal Group, Northwest Territories, Canadaen_CA
dc.typeThesisen_CA
dc.description.degreeMaster'sen_CA
dc.publisher.grantorLaurentian University of Sudburyen_CA
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Master's Theses

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