{"id":{"repo_id":"woods-hole","oai_identifier":"oai:darchive.mblwhoilibrary.org:1912/1723"},"canonical_url":"https://search.dev.ndltd.org/etd/woods-hole/oai:darchive.mblwhoilibrary.org:1912/1723","repository":{"repo_id":"woods-hole","name":"Woods Hole Oceanographic Institute","base_url":"https://darchive.mblwhoilibrary.org/server/oai/request"},"display":{"title":"The evolution of the Indian Ocean triple junction and the finite rotation problem","abstract":"A major goal in the study of plate tectonics is the acquisition of a knowledge of the history of relative motion among the rigid plates of the earth's lithosphere. The three papers of this thesis contribute to this effort and demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of the relative motions between two plates alone. Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8°N, 42°W since the Eocene. A detailed survey of the Indian Ocean triple junction reveals that the Indian Ocean plate motions have remained constant since 10 Ma. The stability conditions of the junction show that the general morphology of the Southwest Indian Ridge results from the evolution of the Indian Ocean triple junction. A method is presented for determining the finite rotations best reconstructing the past relative positions of three plates around a triple junction. The method is illustrated by reconstructions of the plates around the Labrador Sea triple junction at the times of anomalies 24 (56 Ma) and 21 (50 Ma). The region of uncertainty of the Greenland-North America finite pole is mapped for each reconstruction, and it demonstrates that consideration of the three plate system yields more well-constrained results than does a treatment of the two plates alone.","abstract_html":"A major goal in the study of plate tectonics is the acquisition of a knowledge of the history of relative motion among the rigid plates of the earth's lithosphere. The three papers of this thesis contribute to this effort and demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of the relative motions between two plates alone. Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8°N, 42°W since the Eocene. A detailed survey of the Indian Ocean triple junction reveals that the Indian Ocean plate motions have remained constant since 10 Ma. The stability conditions of the junction show that the general morphology of the Southwest Indian Ridge results from the evolution of the Indian Ocean triple junction. A method is presented for determining the finite rotations best reconstructing the past relative positions of three plates around a triple junction. The method is illustrated by reconstructions of the plates around the Labrador Sea triple junction at the times of anomalies 24 (56 Ma) and 21 (50 Ma). The region of uncertainty of the Greenland-North America finite pole is mapped for each reconstruction, and it demonstrates that consideration of the three plate system yields more well-constrained results than does a treatment of the two plates alone.","abstract_has_math":false,"creators":["Tapscott, Christopher Robert"],"institution":"Massachusetts Institute of Technology and Woods Hole Oceanographic Institution","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1979,"date_issued":"1979-06","date_published":"1979-06","updated_at":"2026-07-27T22:05:06Z","subjects":["Plate tectonics","Sea-floor spreading","Geology","Atlantis II (Ship : 1963-) Cruise AII93-5","Atlantis II (Ship : 1963-) Cruise AII93-6"],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.1575/1912/1723"],"render_values":[{"text":"10.1575/1912/1723","href":"https://doi.org/10.1575/1912/1723","code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/1912/1723","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Tapscott, Christopher Robert"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2007-06-25T18:57:42Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2007-06-25T18:57:42Z"]},{"key":"dc:date.issued","label":"Date","values":["1979-06"]},{"key":"dc:publisher","label":"Institution","values":["Massachusetts Institute of Technology and Woods Hole Oceanographic Institution"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Plate tectonics","Sea-floor spreading","Geology","Atlantis II (Ship : 1963-) Cruise AII93-5","Atlantis II (Ship : 1963-) Cruise AII93-6"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.1575/1912/1723"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1912/1723"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June, 1979"]},{"key":"dc:description.abstract","label":"Abstract","values":["A major goal in the study of plate tectonics is the acquisition of a knowledge of the history of relative motion among the rigid plates of the earth's lithosphere. The three papers of this thesis contribute to this effort and demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of the relative motions between two plates alone. Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8°N, 42°W since the Eocene. A detailed survey of the Indian Ocean triple junction reveals that the Indian Ocean plate motions have remained constant since 10 Ma. The stability conditions of the junction show that the general morphology of the Southwest Indian Ridge results from the evolution of the Indian Ocean triple junction. A method is presented for determining the finite rotations best reconstructing the past relative positions of three plates around a triple junction. The method is illustrated by reconstructions of the plates around the Labrador Sea triple junction at the times of anomalies 24 (56 Ma) and 21 (50 Ma). The region of uncertainty of the Greenland-North America finite pole is mapped for each reconstruction, and it demonstrates that consideration of the three plate system yields more well-constrained results than does a treatment of the two plates alone."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The evolution of the Indian Ocean triple junction and the finite rotation problem"]}]}],"canonical_facts":{"dc:creator":["Tapscott, Christopher Robert"],"dc:date.accessioned":["2007-06-25T18:57:42Z"],"dc:date.available":["2007-06-25T18:57:42Z"],"dc:date.issued":["1979-06"],"dc:description":["Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June, 1979"],"dc:description.abstract":["A major goal in the study of plate tectonics is the acquisition of a knowledge of the history of relative motion among the rigid plates of the earth's lithosphere. The three papers of this thesis contribute to this effort and demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of the relative motions between two plates alone. Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8°N, 42°W since the Eocene. A detailed survey of the Indian Ocean triple junction reveals that the Indian Ocean plate motions have remained constant since 10 Ma. The stability conditions of the junction show that the general morphology of the Southwest Indian Ridge results from the evolution of the Indian Ocean triple junction. A method is presented for determining the finite rotations best reconstructing the past relative positions of three plates around a triple junction. The method is illustrated by reconstructions of the plates around the Labrador Sea triple junction at the times of anomalies 24 (56 Ma) and 21 (50 Ma). The region of uncertainty of the Greenland-North America finite pole is mapped for each reconstruction, and it demonstrates that consideration of the three plate system yields more well-constrained results than does a treatment of the two plates alone."],"dc:format.mimetype":["application/pdf"],"dc:identifier.doi":["10.1575/1912/1723"],"dc:identifier.uri":["https://hdl.handle.net/1912/1723"],"dc:language.iso":["en_US"],"dc:publisher":["Massachusetts Institute of Technology and Woods Hole Oceanographic Institution"],"dc:subject":["Plate tectonics","Sea-floor spreading","Geology","Atlantis II (Ship : 1963-) Cruise AII93-5","Atlantis II (Ship : 1963-) Cruise AII93-6"],"dc:title":["The evolution of the Indian Ocean triple junction and the finite rotation problem"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T22:05:06Z"}