Several well-preserved circa 2.6 Ga Archean granite-greenstone belts are exposed in the Slave Province of Northwest Territories, Canada. At Point Lake, a \"supracrustal sequence\" comprised mainly of mafic volcanic and metasedimentary rocks lies over and east of a granitoid gneissic terrane. Field and laboratory studies have helped to clarify the petrography and structural relationships of this fold-and-thrust belt. Traditional models have suggested that granite-greenstone belts in the Slave Province are relict continental rifts in which volcanic and sedimentary rocks filled troughs in older sialic crust. However, this study supports a collisional model for the Slave Province, in which oceanic crust and an accretionary wedge were scraped off an eastward subducting plate. The supracrustal sequence consists of a west-verging fold-and-thrust belt which contains metamorphosed graywacke turbidites, ultramafic and gabbroic rocks, pillow basalts, limestone, shale and tuff. A mylonite zone separates the gneissic terrane from the supracrustal sequence. The mylonite is interpreted to be a basal decollement along which the supracrustal sequence was emplaced over gneissic terrane. The sequence of lithologies and structures at Point Lake resembles Phanerozoic collision zones where rocks of oceanic affinity have been emplaced upon continental crust.
","abstract_html":"<p>Several well-preserved circa 2.6 Ga Archean granite-greenstone belts are exposed in the Slave Province of Northwest Territories, Canada. At Point Lake, a "supracrustal sequence" comprised mainly of mafic volcanic and metasedimentary rocks lies over and east of a granitoid gneissic terrane. Field and laboratory studies have helped to clarify the petrography and structural relationships of this fold-and-thrust belt. Traditional models have suggested that granite-greenstone belts in the Slave Province are relict continental rifts in which volcanic and sedimentary rocks filled troughs in older sialic crust. However, this study supports a collisional model for the Slave Province, in which oceanic crust and an accretionary wedge were scraped off an eastward subducting plate. The supracrustal sequence consists of a west-verging fold-and-thrust belt which contains metamorphosed graywacke turbidites, ultramafic and gabbroic rocks, pillow basalts, limestone, shale and tuff. A mylonite zone separates the gneissic terrane from the supracrustal sequence. The mylonite is interpreted to be a basal decollement along which the supracrustal sequence was emplaced over gneissic terrane. The sequence of lithologies and structures at Point Lake resembles Phanerozoic collision zones where rocks of oceanic affinity have been emplaced upon continental crust.</p>","abstract_has_math":false,"creators":["Considine, Patrick Rowan"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Ocean & Earth Sciences","degree_department":null,"school":null,"contributors":["Randall Spencer","Ramesh Venkatakrishnan","Frank O. Dudas"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1995,"date_issued":"1995-01-01T08:00:00Z","date_published":"1995-01-01T08:00:00Z","updated_at":"2026-07-24T03:34:39Z","subjects":["Archean greenstone belt","Point Lake (Canada)","Supracrustal sequence","Geology"],"languages":[],"rights":["In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.odu.edu/oeas_etds/22","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Randall Spencer","Ramesh Venkatakrishnan","Frank O. Dudas"]},{"key":"dc:creator","label":"Author","values":["Considine, Patrick Rowan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2019-04-10T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Ocean & Earth Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Archean greenstone belt","Point Lake (Canada)","Supracrustal sequence","Geology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.odu.edu/oeas_etds/22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Several well-preserved circa 2.6 Ga Archean granite-greenstone belts are exposed in the Slave Province of Northwest Territories, Canada. At Point Lake, a \"supracrustal sequence\" comprised mainly of mafic volcanic and metasedimentary rocks lies over and east of a granitoid gneissic terrane. Field and laboratory studies have helped to clarify the petrography and structural relationships of this fold-and-thrust belt. Traditional models have suggested that granite-greenstone belts in the Slave Province are relict continental rifts in which volcanic and sedimentary rocks filled troughs in older sialic crust. However, this study supports a collisional model for the Slave Province, in which oceanic crust and an accretionary wedge were scraped off an eastward subducting plate. The supracrustal sequence consists of a west-verging fold-and-thrust belt which contains metamorphosed graywacke turbidites, ultramafic and gabbroic rocks, pillow basalts, limestone, shale and tuff. A mylonite zone separates the gneissic terrane from the supracrustal sequence. The mylonite is interpreted to be a basal decollement along which the supracrustal sequence was emplaced over gneissic terrane. The sequence of lithologies and structures at Point Lake resembles Phanerozoic collision zones where rocks of oceanic affinity have been emplaced upon continental crust.
"]},{"key":"dc:title","label":"Title","values":["Geology of an Archean Greenstone Belt at Point Lake, Northwest Territories, Canada"]}]}],"canonical_facts":{"dc:contributor":["Randall Spencer","Ramesh Venkatakrishnan","Frank O. Dudas"],"dc:creator":["Considine, Patrick Rowan"],"dc:date.available":["2019-04-10T07:00:00Z"],"dc:description.abstract":["Several well-preserved circa 2.6 Ga Archean granite-greenstone belts are exposed in the Slave Province of Northwest Territories, Canada. At Point Lake, a \"supracrustal sequence\" comprised mainly of mafic volcanic and metasedimentary rocks lies over and east of a granitoid gneissic terrane. Field and laboratory studies have helped to clarify the petrography and structural relationships of this fold-and-thrust belt. Traditional models have suggested that granite-greenstone belts in the Slave Province are relict continental rifts in which volcanic and sedimentary rocks filled troughs in older sialic crust. However, this study supports a collisional model for the Slave Province, in which oceanic crust and an accretionary wedge were scraped off an eastward subducting plate. The supracrustal sequence consists of a west-verging fold-and-thrust belt which contains metamorphosed graywacke turbidites, ultramafic and gabbroic rocks, pillow basalts, limestone, shale and tuff. A mylonite zone separates the gneissic terrane from the supracrustal sequence. The mylonite is interpreted to be a basal decollement along which the supracrustal sequence was emplaced over gneissic terrane. The sequence of lithologies and structures at Point Lake resembles Phanerozoic collision zones where rocks of oceanic affinity have been emplaced upon continental crust.
"],"dc:identifier":["https://digitalcommons.odu.edu/oeas_etds/22"],"dc:rights":["In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
"],"dc:subject":["Archean greenstone belt","Point Lake (Canada)","Supracrustal sequence","Geology"],"dc:title":["Geology of an Archean Greenstone Belt at Point Lake, Northwest Territories, Canada"],"thesis:degree_discipline":["Ocean & Earth Sciences"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T03:34:39Z"}