{"id":{"repo_id":"laurentian","oai_identifier":"oai:laurentian.scholaris.ca:10219/3502"},"canonical_url":"https://search.dev.ndltd.org/etd/laurentian/oai:laurentian.scholaris.ca:10219/3502","repository":{"repo_id":"laurentian","name":"Laurentian University","base_url":"https://laurentian.scholaris.ca/server/oai/request"},"display":{"title":"Emplacement history of mafic-ultramafic volcanic rocks in the northern Pontiac subprovince, Quebec, Canada","abstract":"Detailed geological mapping of volcanic, sedimentary and intrusive rocks in the northern Pontiac subprovince of the Superior Province has identified multiple volcanic-sedimentary contacts at the margins of a 30 km long volcanic package of high-Fe tholeiites and Munro- to Barbertontype komatiitic flows and sills. Breccias displaying blocky, globular and tendril-like juvenile clasts in a massive sedimentary matrix were observed along the contacts of mafic-ultramafic intrusions with their host sedimentary rocks. These textures are consistent with peperite, a rock formed by the mixing and mingling of magma with wet, unconsolidated sediments. Geochemical data for one of the peperites indicates that the igneous component has a similar trace element composition to spinifex-bearing komatiite flows and the sedimentary component has a similar composition to the Pontiac Group wackes. Additionally, conformable unstrained contacts were observed between effusive volcanic rocks and turbiditic wackes. These relationships indicate a previously unrecognized ca. 2682 Ma mafic and ultramafic volcanic event synchronous with the deposition of the Pontiac subprovince sedimentary rocks. This suggests that the mafic-ultramafic volcanic package is synsedimentary and autochthonous, which is not consistent with previous interpretations of these rocks as structural thrust panels. We propose that the mafic-ultramafic volcanic package was emplaced during a previously unrecognized plume-related extensional event that facilitated the upward flow of mantle-derived magmas along major, mantle-penetrating structures during Pontiac sedimentation. Shortly after, tectonic compression folded and imbricated the Pontiac rocks and accreted them to the southern margin of the Abitibi subprovince.","abstract_html":"Detailed geological mapping of volcanic, sedimentary and intrusive rocks in the northern Pontiac subprovince of the Superior Province has identified multiple volcanic-sedimentary contacts at the margins of a 30 km long volcanic package of high-Fe tholeiites and Munro- to Barbertontype komatiitic flows and sills. Breccias displaying blocky, globular and tendril-like juvenile clasts in a massive sedimentary matrix were observed along the contacts of mafic-ultramafic intrusions with their host sedimentary rocks. These textures are consistent with peperite, a rock formed by the mixing and mingling of magma with wet, unconsolidated sediments. Geochemical data for one of the peperites indicates that the igneous component has a similar trace element composition to spinifex-bearing komatiite flows and the sedimentary component has a similar composition to the Pontiac Group wackes. Additionally, conformable unstrained contacts were observed between effusive volcanic rocks and turbiditic wackes. These relationships indicate a previously unrecognized ca. 2682 Ma mafic and ultramafic volcanic event synchronous with the deposition of the Pontiac subprovince sedimentary rocks. This suggests that the mafic-ultramafic volcanic package is synsedimentary and autochthonous, which is not consistent with previous interpretations of these rocks as structural thrust panels. We propose that the mafic-ultramafic volcanic package was emplaced during a previously unrecognized plume-related extensional event that facilitated the upward flow of mantle-derived magmas along major, mantle-penetrating structures during Pontiac sedimentation. Shortly after, tectonic compression folded and imbricated the Pontiac rocks and accreted them to the southern margin of the Abitibi subprovince.","abstract_has_math":false,"creators":["Rehm, Adrian Gerhard Nutting"],"institution":"Laurentian University of Sudbury","degree_name":"Master of Science (MSc) in Geology","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-05-15","date_published":"2020-05-15","updated_at":"2026-08-21T16:45:57Z","subjects":["Pontiac subprovince","peperites","synsedimentary volcanism","komatites","sedimentary basins,","Archean tectonics"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://laurentian.scholaris.ca/handle/10219/3502","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%2F3502","prefix":"dim"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Rehm, Adrian Gerhard Nutting"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2020-06-17T13:15:16Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2020-06-17T13:15:16Z"]},{"key":"dc:date.issued","label":"Date","values":["2020-05-15"]},{"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 of Science (MSc) in Geology"]},{"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":["Pontiac subprovince","peperites","synsedimentary volcanism","komatites","sedimentary basins,","Archean tectonics"]}]},{"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/10219/3502"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Detailed geological mapping of volcanic, sedimentary and intrusive rocks in the northern Pontiac subprovince of the Superior Province has identified multiple volcanic-sedimentary contacts at the margins of a 30 km long volcanic package of high-Fe tholeiites and Munro- to Barbertontype komatiitic flows and sills. Breccias displaying blocky, globular and tendril-like juvenile clasts in a massive sedimentary matrix were observed along the contacts of mafic-ultramafic intrusions with their host sedimentary rocks. These textures are consistent with peperite, a rock formed by the mixing and mingling of magma with wet, unconsolidated sediments. Geochemical data for one of the peperites indicates that the igneous component has a similar trace element composition to spinifex-bearing komatiite flows and the sedimentary component has a similar composition to the Pontiac Group wackes. Additionally, conformable unstrained contacts were observed between effusive volcanic rocks and turbiditic wackes. These relationships indicate a previously unrecognized ca. 2682 Ma mafic and ultramafic volcanic event synchronous with the deposition of the Pontiac subprovince sedimentary rocks. This suggests that the mafic-ultramafic volcanic package is synsedimentary and autochthonous, which is not consistent with previous interpretations of these rocks as structural thrust panels. We propose that the mafic-ultramafic volcanic package was emplaced during a previously unrecognized plume-related extensional event that facilitated the upward flow of mantle-derived magmas along major, mantle-penetrating structures during Pontiac sedimentation. Shortly after, tectonic compression folded and imbricated the Pontiac rocks and accreted them to the southern margin of the Abitibi subprovince."]},{"key":"dc:title","label":"Title","values":["Emplacement history of mafic-ultramafic volcanic rocks in the northern Pontiac subprovince, Quebec, Canada"]}]}],"canonical_facts":{"dc:creator":["Rehm, Adrian Gerhard Nutting"],"dc:date.accessioned":["2020-06-17T13:15:16Z"],"dc:date.available":["2020-06-17T13:15:16Z"],"dc:date.issued":["2020-05-15"],"dc:description.abstract":["Detailed geological mapping of volcanic, sedimentary and intrusive rocks in the northern Pontiac subprovince of the Superior Province has identified multiple volcanic-sedimentary contacts at the margins of a 30 km long volcanic package of high-Fe tholeiites and Munro- to Barbertontype komatiitic flows and sills. Breccias displaying blocky, globular and tendril-like juvenile clasts in a massive sedimentary matrix were observed along the contacts of mafic-ultramafic intrusions with their host sedimentary rocks. These textures are consistent with peperite, a rock formed by the mixing and mingling of magma with wet, unconsolidated sediments. Geochemical data for one of the peperites indicates that the igneous component has a similar trace element composition to spinifex-bearing komatiite flows and the sedimentary component has a similar composition to the Pontiac Group wackes. Additionally, conformable unstrained contacts were observed between effusive volcanic rocks and turbiditic wackes. These relationships indicate a previously unrecognized ca. 2682 Ma mafic and ultramafic volcanic event synchronous with the deposition of the Pontiac subprovince sedimentary rocks. This suggests that the mafic-ultramafic volcanic package is synsedimentary and autochthonous, which is not consistent with previous interpretations of these rocks as structural thrust panels. We propose that the mafic-ultramafic volcanic package was emplaced during a previously unrecognized plume-related extensional event that facilitated the upward flow of mantle-derived magmas along major, mantle-penetrating structures during Pontiac sedimentation. Shortly after, tectonic compression folded and imbricated the Pontiac rocks and accreted them to the southern margin of the Abitibi subprovince."],"dc:identifier.uri":["https://laurentian.scholaris.ca/handle/10219/3502"],"dc:language.iso":["en"],"dc:publisher":["Laurentian University of Sudbury"],"dc:subject":["Pontiac subprovince","peperites","synsedimentary volcanism","komatites","sedimentary basins,","Archean tectonics"],"dc:title":["Emplacement history of mafic-ultramafic volcanic rocks in the northern Pontiac subprovince, Quebec, Canada"],"dc:type":["Thesis"],"thesis:degree_name":["Master of Science (MSc) in Geology"],"thesis:institution_name":["Laurentian University of Sudbury"]},"updated_at":"2026-08-21T16:45:57Z"}