{"id":{"repo_id":"laurentian","oai_identifier":"oai:laurentian.scholaris.ca:10219/2229"},"canonical_url":"https://search.dev.ndltd.org/etd/laurentian/oai:laurentian.scholaris.ca:10219/2229","repository":{"repo_id":"laurentian","name":"Laurentian University","base_url":"https://laurentian.scholaris.ca/server/oai/request"},"display":{"title":"Early neoproterozoic marine redox conditions recorded in black shale from the little Dal Group, Northwest Territories, Canada","abstract":"Black 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.","abstract_html":"Black shale in the Little Dal Group (ca. &lt;817 Ma), Mackenzie Mountains Supergroup (&lt;1005 Ma; &gt;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 &gt;0.5 and DOP &lt;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 (&lt;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 &gt;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.","abstract_has_math":false,"creators":["O’Hare, Sean Patrick"],"institution":"Laurentian University of Sudbury","degree_name":"Master's","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-08-11","date_published":"2014-08-11","updated_at":"2026-08-21T16:45:57Z","subjects":["black shale deposits","Little Dal Group","Mackenzie Mountains Supergroup","Neoproterozoic"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://laurentian.scholaris.ca/handle/10219/2229","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"source_record":{"url":"https://laurentian.scholaris.ca/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Alaurentian.scholaris.ca%3A10219%2F2229","prefix":"dim"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["O’Hare, Sean Patrick"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-08-11T18:01:29Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-08-11T18:01:29Z"]},{"key":"dc:date.issued","label":"Date","values":["2014-08-11"]},{"key":"dc:publisher","label":"Institution","values":["Laurentian University of Sudbury"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master's"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Laurentian University of Sudbury"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["black shale deposits","Little Dal Group","Mackenzie Mountains Supergroup","Neoproterozoic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://laurentian.scholaris.ca/handle/10219/2229"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Black 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."]},{"key":"dc:title","label":"Title","values":["Early neoproterozoic marine redox conditions recorded in black shale from the little Dal Group, Northwest Territories, Canada"]}]}],"canonical_facts":{"dc:creator":["O’Hare, Sean Patrick"],"dc:date.accessioned":["2014-08-11T18:01:29Z"],"dc:date.available":["2014-08-11T18:01:29Z"],"dc:date.issued":["2014-08-11"],"dc:description.abstract":["Black 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."],"dc:identifier.uri":["https://laurentian.scholaris.ca/handle/10219/2229"],"dc:language.iso":["en"],"dc:publisher":["Laurentian University of Sudbury"],"dc:subject":["black shale deposits","Little Dal Group","Mackenzie Mountains Supergroup","Neoproterozoic"],"dc:title":["Early neoproterozoic marine redox conditions recorded in black shale from the little Dal Group, Northwest Territories, Canada"],"dc:type":["Thesis"],"thesis:degree_name":["Master's"],"thesis:institution_name":["Laurentian University of Sudbury"]},"updated_at":"2026-08-21T16:45:57Z"}