Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous
Quantifying past motions of tectonic plates in the southwest Pacific is important because the Pacific-Antarctic ridge is the only non-destructive boundary between the Pacific plate and other major plates. However, formation of sea-ice near Antarctica impairs the collection of magnetic anomaly data t...
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ftsmithonian:oai:figshare.com:article/17060495 2023-05-15T14:03:39+02:00 Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous Chambord, Amandine (11738216) 2017-01-01T00:00:00Z https://doi.org/10.26686/wgtn.17060495.v1 unknown https://figshare.com/articles/thesis/Quantitative_analysis_of_New_Zealand-Antarctica_plate_motions_during_the_Paleogene_and_Late_Cretaceous/17060495 doi:10.26686/wgtn.17060495.v1 Author Retains Copyright Magnetism and Palaeomagnetism Tectonics Magnetic anomaly Fracture zone Southwest Pacific Magnetic anomalies Plate reconstructions School: School of Geography Environment and Earth Sciences 040406 Magnetism and Palaeomagnetism 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geophysics Degree Level: Doctoral Degree Name: Doctor of Philosophy Text Thesis 2017 ftsmithonian https://doi.org/10.26686/wgtn.17060495.v1 2021-12-19T21:04:06Z Quantifying past motions of tectonic plates in the southwest Pacific is important because the Pacific-Antarctic ridge is the only non-destructive boundary between the Pacific plate and other major plates. However, formation of sea-ice near Antarctica impairs the collection of magnetic anomaly data that are necessary to calculate plate rotations. A detailed analysis of all ship-track magnetic data available in the southwest Pacific (61 cruises, 153 profiles, including several cruises collected after 1995) is presented here. Four different sources of uncertainty are quantified: (1) confidence of magnetic anomaly identification, (2) magnetic reversal location picking precision, (3) ship navigation precision, and (4) magnetic data quality. Finite plate rotations are calculated for the southwest Pacific (42.5 to 79 Ma) using the resulting magnetic anomaly database (1528 magnetic reversal data). Finite rotations were calculated using the Hellinger criterion, or by a new method presented here that assumes orthogonality between fracture zones and ridge segments. The new method requires less parameters and is hence able better estimate rotations in cases with an uneven distribution of sparse magnetic data. Rotations and formal uncertainties are calculated for thirty-one chrons (c20y to c33o). They confirm the existence of a three plate system (Pacific, Marie Byrd Land, Bellingshausen) in the southwest Pacific from before c31o (68.7 Ma) until c28y (62.5 Ma). After c28y, the Bellingshausen and Marie Byrd Land plates moved as a single plate. Thesis Antarc* Antarctic Antarctica Marie Byrd Land Sea ice Unknown Antarctic Byrd Marie Byrd Land ENVELOPE(-130.000,-130.000,-78.000,-78.000) New Zealand Pacific |
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ftsmithonian |
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topic |
Magnetism and Palaeomagnetism Tectonics Magnetic anomaly Fracture zone Southwest Pacific Magnetic anomalies Plate reconstructions School: School of Geography Environment and Earth Sciences 040406 Magnetism and Palaeomagnetism 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geophysics Degree Level: Doctoral Degree Name: Doctor of Philosophy |
spellingShingle |
Magnetism and Palaeomagnetism Tectonics Magnetic anomaly Fracture zone Southwest Pacific Magnetic anomalies Plate reconstructions School: School of Geography Environment and Earth Sciences 040406 Magnetism and Palaeomagnetism 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geophysics Degree Level: Doctoral Degree Name: Doctor of Philosophy Chambord, Amandine (11738216) Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
topic_facet |
Magnetism and Palaeomagnetism Tectonics Magnetic anomaly Fracture zone Southwest Pacific Magnetic anomalies Plate reconstructions School: School of Geography Environment and Earth Sciences 040406 Magnetism and Palaeomagnetism 970104 Expanding Knowledge in the Earth Sciences Degree Discipline: Geophysics Degree Level: Doctoral Degree Name: Doctor of Philosophy |
description |
Quantifying past motions of tectonic plates in the southwest Pacific is important because the Pacific-Antarctic ridge is the only non-destructive boundary between the Pacific plate and other major plates. However, formation of sea-ice near Antarctica impairs the collection of magnetic anomaly data that are necessary to calculate plate rotations. A detailed analysis of all ship-track magnetic data available in the southwest Pacific (61 cruises, 153 profiles, including several cruises collected after 1995) is presented here. Four different sources of uncertainty are quantified: (1) confidence of magnetic anomaly identification, (2) magnetic reversal location picking precision, (3) ship navigation precision, and (4) magnetic data quality. Finite plate rotations are calculated for the southwest Pacific (42.5 to 79 Ma) using the resulting magnetic anomaly database (1528 magnetic reversal data). Finite rotations were calculated using the Hellinger criterion, or by a new method presented here that assumes orthogonality between fracture zones and ridge segments. The new method requires less parameters and is hence able better estimate rotations in cases with an uneven distribution of sparse magnetic data. Rotations and formal uncertainties are calculated for thirty-one chrons (c20y to c33o). They confirm the existence of a three plate system (Pacific, Marie Byrd Land, Bellingshausen) in the southwest Pacific from before c31o (68.7 Ma) until c28y (62.5 Ma). After c28y, the Bellingshausen and Marie Byrd Land plates moved as a single plate. |
format |
Thesis |
author |
Chambord, Amandine (11738216) |
author_facet |
Chambord, Amandine (11738216) |
author_sort |
Chambord, Amandine (11738216) |
title |
Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
title_short |
Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
title_full |
Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
title_fullStr |
Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
title_full_unstemmed |
Quantitative analysis of New Zealand-Antarctica plate motions during the Paleogene and Late Cretaceous |
title_sort |
quantitative analysis of new zealand-antarctica plate motions during the paleogene and late cretaceous |
publishDate |
2017 |
url |
https://doi.org/10.26686/wgtn.17060495.v1 |
long_lat |
ENVELOPE(-130.000,-130.000,-78.000,-78.000) |
geographic |
Antarctic Byrd Marie Byrd Land New Zealand Pacific |
geographic_facet |
Antarctic Byrd Marie Byrd Land New Zealand Pacific |
genre |
Antarc* Antarctic Antarctica Marie Byrd Land Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Marie Byrd Land Sea ice |
op_relation |
https://figshare.com/articles/thesis/Quantitative_analysis_of_New_Zealand-Antarctica_plate_motions_during_the_Paleogene_and_Late_Cretaceous/17060495 doi:10.26686/wgtn.17060495.v1 |
op_rights |
Author Retains Copyright |
op_doi |
https://doi.org/10.26686/wgtn.17060495.v1 |
_version_ |
1766274437882052608 |