Delayed Subsidence After Rifting and a Record of Breakup for Northwestern Zealandia

Brian Boston, Yasuyuki Nakamura, Flora Gallais, Ron Hackney, Gou Fujie, Shuichi Kodaira, Seiichi Miura, Yuka Kaiho, Saneatsu Saito, Kazuya Shiraishi, Yasuhiro Yamada

Research output: Contribution to journalArticlepeer-review

Abstract

Continental rifting and breakup of eastern Gondwana during the Cretaceous separated northern Zealandia from eastern Australia, but the processes leading to this highly extended and largely submerged block of continental crust are unknown. We acquired and processed multichannel seismic reflection data across northern Zealandia and examine the stratigraphy of the Middleton Basin. We identified a two-phase formation process for the basin, as evidenced by an unconformity separating two postrift units. After initial basin formation and slow deposition of the lower postrift unit, deposition rates within the Middleton Basin rapidly increased in response to the latest stage of subsidence and to create the modern basin. We propose a tectonic model wherein the Middleton Basin initiated through oceanic spreading and the subsequent postrift subsidence of the newly created oceanic lithosphere was delayed due to thermal buoyancy associated with nearby oceanic spreading in the Tasman Basin. Our results provide new constraints on rifting and breakup processes of wide, magma-poor, and asymmetric margins and indicate that multiple regions of weak lithosphere may have influenced the breakup.

Original languageEnglish
Pages (from-to)3057-3072
Number of pages16
JournalJournal of Geophysical Research: Solid Earth
Volume124
Issue number3
DOIs
Publication statusPublished - Mar 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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