Abstract
The clockwise bend at 99 Ma (mid-Cretaceous) in linear volcanic chains in the tropical Pacific coincides with a change from pre-99 Ma head-on Chilean-type subduction of the Pacific plate beneath eastern Gondwana to 99-43 Ma sinistral oblique Mariana-type subduction and strike-slip breakup by simple sea-floor spreading between Australia and Antarctica and by backarc spreading in the southwest Pacific. The 99 Ma breakup of Australia from Antarctica is documented by a mid-Cretaceous unconformity. This tectono-stratigraphic change founded modern Australia, with a mountain chain along an upper plate margin in the east and lowlands on the lower plate margin in the south. The counterclockwise bend at 43 Ma (mid-Eocene)-the Emperor-Hawaiian bend-coincides with the onset of structure in the Challenger Rift of New Zealand, the Eromanga-Cooper basin of central Australia, and the oil-shale grabens of coastal Queensland.
Original language | English |
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Pages (from-to) | 47-50 |
Number of pages | 4 |
Journal | Geology |
Volume | 28 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2000 |
Keywords
- Australia
- Hotspots bends
- Mid-Cretaceous
- Mid-Eocene
- Pacific