Structure-Forming Peculiarities at the Early Stage of Antarctic–Australia Separation Based on Physical Modeling

The peculiarities of the formation of the structure of the Earth’s crust in the Australian–Antarctic basin during the early break-up between Australia and Antarctica are considered. The study period encompasses long-lasting rifting (~160–80 Ma), ultraslow spreading (~80–45 Ma) with the formation of...

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Bibliographic Details
Published inIzvestiya. Physics of the solid earth Vol. 55; no. 2; pp. 256 - 269
Main Authors Dubinin, E. P., Leitchenkov, G. L., Grokholsky, A. L., Sergeeva, V. M., Agranov, G. D.
Format Journal Article
LanguageEnglish
Published Moscow Pleiades Publishing 01.03.2019
Springer Nature B.V
Subjects
Earth
Earth and Environmental Science
Earth crust
Earth Sciences
Geophysics/Geodesy
Lithosphere
Modelling
Morphology
Ocean floor
Ocean models
Oceanic crust
Profiles
Ridges
Rifting
Seismic analysis
Seismic profiles
Spreading
Spreading centres
Australia
crustal structure
ocean
physical modeling
ultraslow sea-floor spreading
Mawson Sea
passive margin
Antarctic
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Summary:The peculiarities of the formation of the structure of the Earth’s crust in the Australian–Antarctic basin during the early break-up between Australia and Antarctica are considered. The study period encompasses long-lasting rifting (~160–80 Ma), ultraslow spreading (~80–45 Ma) with the formation of the proto-oceanic mainly ultrabasic crust, spreading (~45–40 Ma), and stationary sea-floor spreading with intermediate velocities (after 40 Ma). The various stages of the oceanic opening clearly manifest themselves by the change in the basement morphology (the top of the second oceanic layer) on the seismic profiles. Physical modeling has made it possible to reveal the peculiarities of the surface morphology of the oceanic (magmatic) crust which developed in the conditions of the transition from ultraslow to slow and intermediate spreading. Our experiments established that (1) the presence of a stronger block in the pre-breakup model lithosphere in the pathway of the propagating rift faults can significantly affect the geometry of the spreading axis in its vicinity and lead to the development of transverse structures and a highly rugged relief; (2) under the conditions of ultraslow spreading, numerous ridge jumps occur; (3) the temporary cessation of the sea-floor spreading leads to the development of linear high-amplitude rises which in the natural conditions correspond to amagmatic ridges.
ISSN:1069-3513
1555-6506
DOI:10.1134/S1069351319020022