Seafloor magnetic anomalies and ages observed from shipboard and airborne measurements from New Zealand to the Amundsen Sea (south of 64°S)

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Auteurs principaux: Wobbe, Florian, Gohl, Karsten, Chambord, A, Sutherland, R
Format: Dataset Open Access
Langue:en
Publié: PANGAEA 2012
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author Wobbe, Florian
Gohl, Karsten
Chambord, A
Sutherland, R
author_facet Wobbe, Florian
Gohl, Karsten
Chambord, A
Sutherland, R
collection Datos científicos de ciencias marinas y ambientales
contents Geophysical data acquired using R/V Polarstern constrain the structure and age of the rifted oceanic margin of West Antarctica. West of the Antipodes Fracture Zone, the 145 km wide continent-ocean transition zone (COTZ) of the Marie Byrd Land sector resembles a typical magma-poor margin. New gravity and seismic reflection data indicates initial continental crust of thickness 24 km, that was stretched 90 km. Farther east, the Bellingshausen sector is broad and complex with abundant evidence for volcanism, the COTZ is ~670 km wide, and the nature of crust within the COTZ is uncertain. Margin extension is estimated to be 106-304 km in this sector. Seafloor magnetic anomalies adjacent to Marie Byrd Land near the Pahemo Fracture Zone indicate full-spreading rate during c33-c31 (80-68 Myr) of 60 mm/yr, increasing to 74 mm/yr at c27 (62 Myr), and then dropping to 22 mm/yr by c22 (50 Myr). Spreading rates were lower to the west. Extrapolation towards the continental margin indicates initial oceanic crust formation at around c34y (84 Myr). Subsequent motion of the Bellingshausen plate relative to Antarctica (84-62 Myr) took place east of the Antipodes Fracture Zone at rates <40 mm/yr, typically 5-20 mm/yr. The high extension rate of 30-60 mm/yr during initial margin formation is consistent with steep and symmetrical margin morphology, but subsequent motion of the Bellingshausen plate was slow and complex, and modified rift morphology through migrating deformation and volcanic centers to create a broad and complex COTZ.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_858217
institution PANGAEA
language en
publishDate 2012
publisher PANGAEA
record_format pangaea
spellingShingle Seafloor magnetic anomalies and ages observed from shipboard and airborne measurements from New Zealand to the Amundsen Sea (south of 64°S)
Wobbe, Florian
Gohl, Karsten
Chambord, A
Sutherland, R
Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; SPP1158
Geophysical data acquired using R/V Polarstern constrain the structure and age of the rifted oceanic margin of West Antarctica. West of the Antipodes Fracture Zone, the 145 km wide continent-ocean transition zone (COTZ) of the Marie Byrd Land sector resembles a typical magma-poor margin. New gravity and seismic reflection data indicates initial continental crust of thickness 24 km, that was stretched 90 km. Farther east, the Bellingshausen sector is broad and complex with abundant evidence for volcanism, the COTZ is ~670 km wide, and the nature of crust within the COTZ is uncertain. Margin extension is estimated to be 106-304 km in this sector. Seafloor magnetic anomalies adjacent to Marie Byrd Land near the Pahemo Fracture Zone indicate full-spreading rate during c33-c31 (80-68 Myr) of 60 mm/yr, increasing to 74 mm/yr at c27 (62 Myr), and then dropping to 22 mm/yr by c22 (50 Myr). Spreading rates were lower to the west. Extrapolation towards the continental margin indicates initial oceanic crust formation at around c34y (84 Myr). Subsequent motion of the Bellingshausen plate relative to Antarctica (84-62 Myr) took place east of the Antipodes Fracture Zone at rates <40 mm/yr, typically 5-20 mm/yr. The high extension rate of 30-60 mm/yr during initial margin formation is consistent with steep and symmetrical margin morphology, but subsequent motion of the Bellingshausen plate was slow and complex, and modified rift morphology through migrating deformation and volcanic centers to create a broad and complex COTZ.
title Seafloor magnetic anomalies and ages observed from shipboard and airborne measurements from New Zealand to the Amundsen Sea (south of 64°S)
topic Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; SPP1158
url https://doi.org/10.1594/PANGAEA.858217