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.
|Number of pages||4|
|Publication status||Published - 2000|
- Hotspots bends