Breakup and early seafloor spreading between India and Antarctica

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doi: 10.1111/j.1365-246X.2007.03450.x
Author(s): Gaina, Carmen; Müller, R. Dietmar; Brown, Belinda; Ishihara, Takemi; Ivanov, Sergey
Author Affiliation(s): Primary:
Geological Survey of Norway, Center for Geodynamics, Trondheim, Norway
University of Sydney, Australia
National Institute of Advanced Industrial Science and Technology, Japan
Polar Marine Geophysical Research Expedition, Russian Federation
Volume Title: Geophysical Journal International
Source: Geophysical Journal International, 170(1), p.151-169. Publisher: Blackwell Science for the Royal Astronomical Society, the Deutsche Geophysikalische Gesellschaft and the European Geophysical Society, International. ISSN: 0956-540X
Note: In English. 108 refs.; illus., incl. geol. sketch map, sect.
Summary: We present a tectonic interpretation of the breakup and early seafloor spreading between India and Antarctica based on improved coverage of potential field and seismic data off the east Antarctic margin between the Gunnerus Ridge and the Bruce Rise. We have identified a series of ENE trending Mesozoic magnetic anomalies from chron M9o to M2o in the Enderby Basin, and M9o to M4o in the Princess Elizabeth Trough and Davis Sea Basin, indicating that India-Antarctica and India-Australia breakups were roughly contemporaneous. We present evidence for an abandoned spreading centre south of the Elan Bank microcontinent; the estimated timing of its extinction corresponds to the early surface expression of the Kerguelen Plume at the Southern Kerguelen Plateau around 120 Ma. We observe an increase in spreading rate from west to east, between chron M9 and M4, along the Antarctic margin and suggest the tectono-magmatic segmentation of oceanic crust has been influenced by inherited crustal structure, the kinematics of Gondwanaland breakup and the proximity to the Kerguelen hotspot. A high-amplitude, E-W oriented magnetic lineation named the Mac Robertson Coast Anomaly (MCA), coinciding with a landwards step-down in basement observed in seismic reflection data, is tentatively interpreted as the boundary between continental/transitional zone and oceanic crust. (mod. journ. abst.)
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; 20 Geophysics, Applied; Antarctica; Continental margin; Cretaceous; Crozet Basin; Davis Sea; Elastic waves; Enderby Basin; Geophysical methods; Geophysical profiles; Geophysical surveys; Gondwana; Gravity field; Hot spots; Indian Ocean; Indian Ocean Islands; Indian Plate; Kerguelen Islands; Leg 183; MacRobertson Coast; Magnetic anomalies; Mantle; Mantle plumes; Mesozoic; Mid-ocean ridges; ODP Site 1137; Ocean Drilling Program; Ocean floors; Plate tectonics; Potential field; Remote sensing; Satellite methods; Sea-floor spreading; Seismic methods; Seismic profiles; Seismic waves; Southern Ocean; Southwest Indian Ridge; Spreading centers; Surveys
Coordinates: S565000 S565000 E0680536 E0680536
Record ID: 2007111274
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