Evolution of the Southwest Australian Rifted Continental Margin During Breakup of East Gondwana: Results From International Ocean Discovery Program Expedition 369
- Author(s)
- Dennis L. Harry, Maria Luisa Garcia Tejada, Eun Young Lee, Erik Wolfgring, Carmine C. Wainman, Hans Brumsack, Bernhard Schnetger, J.-I. Kimura, Laurent Riquier, Irina Borissova, Richard W. Hobbs, Tao Jiang, Y.-X. Li, Alessandro Maritati, Mathieu Martinez, Carl Richter, Gabriel T. Tagliaro, Lloyd T. White
- Abstract
International Ocean Discovery Program Expedition 369 drilled four sites on the southwestern Australian continental margin, in the deep water Mentelle Basin (MB) and on the neighboring Naturaliste Plateau (NP). The drillsites are located on continental crust that continued rifting after seafloor spreading began further north on the Perth Abyssal Plain (PAP) between magnetochrons M11r and M11n (133–132 Ma), ending when spreading began west of the NP between chrons M5n and M3n (126–124 Ma). Drilling recovered the first in situ samples of basalt flows overlying the breakup unconformity on the NP, establishing a magnetostratigraphically constrained eruption age of >131–133 Ma, and confirming a minimal late Valanginian age for the breakup unconformity (coeval with the onset of PAP seafloor spreading). Petrogenetic modeling indicates the basalts were generated by 25% melting at 1.5 GPa and a potential temperature of 1380°C–1410°C, consistent with proximity of the Kerguelen plume during breakup. Benthic foraminiferal fossils indicate that the NP remained at upper bathyal or shallower depths during the last 6 Myr of rifting and for 3–5 Myr after breakup between India and Australia. The limited subsidence is attributed to heat from the nearby Kerguelen plume and PAP spreading ridge. The margin subsided to middle bathyal depths by Albian time and to lower bathyal (NP) or greater (MB) depths by late Paleogene time. Periods of rapid sedimentation accompanied a westward jump of the PAP spreading ridge (108 Ma), rifting on the southern margin (100–84 Ma), and opening of the southern seaway between Australia and Antarctica (60–47 Ma).
- Organisation(s)
- Department of Palaeontology, Department of Geology
- External organisation(s)
- Chonnam National University, Japan Agency for Marine-Earth Science and Technology, China University of Geosciences, Nanjing University, Colorado State University, University of Adelaide, Carl von Ossietzky Universität Oldenburg, Université Paris IV - Paris-Sorbonne, Geoscience Australia, Durham University, University of Tasmania, Université Rennes-I, University of Louisiana at Lafayette, University of Texas, Austin, University of Wollongong
- Journal
- Geochemistry, Geophysics, Geosystems
- Volume
- 21
- Pages
- 1-26
- No. of pages
- 26
- ISSN
- 1525-2027
- DOI
- https://doi.org/10.1029/2020GC009144
- Publication date
- 11-2020
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105121 Sedimentology, 105124 Tectonics, 105120 Petrology
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/a12030bb-c1f8-40bc-b625-ecf81643aeaf