Making Northern Zealandia: The Breakup of Eastern Gondwana
Abstract
The Late Cretaceous continental rifting and breakup of eastern Gondwana isolated northern Zealandia, a 94% submerged ribbon of continental crust, from eastern Australia. Because the processes that led to this asymmetric breakup are poorly constrained, we used multi-channel seismic reflection data and wide-angle seismic velocity constraints to determine how the continental rifting and breakup occurred in northern Zealandia. These results show a sliver of oceanic crust in the Middleton Basin is surrounded by the continental blocks of the Dampier Ridge and Lord Howe Rise. The sediment depositional pattern between these continental blocks indicates that the breakup of eastern Gondwana first started at the Middleton Basin and later jumped to the west to open the Tasman Basin. Multibeam bathymetry and seismic data show that the Dampier Ridge expresses a range of seafloor features that contrast the largely featureless seafloor of the Lord Howe Rise. The pattern of syn-rift fault strikes on the Dampier Ridge is similar to what has been inferred from previous work on the Lord Howe Rise and suggests a regional stress change linked to the two-stage breakup of eastern Gondwana. The breakup first involved E-W extension in the Middleton Basin and on the Lord Howe Rise, followed by NE-SW extension during formation of the Tasman Basin.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.T11B..06B
- Keywords:
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- 8105 Continental margins: divergent;
- TECTONOPHYSICSDE: 8109 Continental tectonics: extensional;
- TECTONOPHYSICSDE: 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICSDE: 8159 Rheology: crust and lithosphere;
- TECTONOPHYSICS