The separation of Australia from other continents
Palaeomagnetism provides the chief constraints on models of the separation of Australia from other continents. Palaeomagnetic studies suggest that the various cratons that comprise the main Australian platform have maintained the same relative position from 1800 m.y. to 750 m.y. ago, and, in greater...
| Published in: | Earth-Science Reviews |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
1976
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| Subjects: | |
| Online Access: | https://researchers.mq.edu.au/en/publications/74b30e47-2140-4041-8e68-99889f7b3bd5 https://doi.org/10.1016/0012-8252(76)90003-9 http://www.scopus.com/inward/record.url?scp=0001305063&partnerID=8YFLogxK |
| Summary: | Palaeomagnetism provides the chief constraints on models of the separation of Australia from other continents. Palaeomagnetic studies suggest that the various cratons that comprise the main Australian platform have maintained the same relative position from 1800 m.y. to 750 m.y. ago, and, in greater detail, that the Australian platform, excluding the Tasman Fold Belt, has maintained its physical integrity from 750 m.y. to 450 m.y. ago. Furthermore, palaeomagnetic studies in Australia and the other Gondwanaland fragments indicate that Gondwanaland must have existed at least 750 m.y. ago until its disintegration about 150 m.y. ago. Geological studies suggest that the first clearly recorded separation of other continents from Australia occurred at the end of the Precambrian with the inception of the eastern (Pacific) and northwestern (Tethyan) margins by plate divergence between Australia and unknown continents. Thereafter, the active Pacific margin migrated eastward by the accretion of island-arc material, and the passive Tethyan margin, after its complete development in the Early Ordovician, was static until the Mesozoic. In contrast with this early phase of continental separation, the modern (Mesozoic-Palaeocene) separation of Australia from its Gondwanaland neighbours is traceable by information preserved on the existing ocean floor as well as on the formerly contiguous continents. In detail, the only obscurity remains on the Pacific margin due to a complex pattern of divergence. Greater India separated from Antarctica/Australia early in the Cretaceous (130 m.y. ago) and Antarctica separated from Australia at the end of the Palaeocene (53 m.y. ago). Each of these events was preceded by a period, 170 m.y. long between India and Australia and 110 m.y. long between Antarctica and Australia, of uplift, erosion, and thick terrigenous deposition in rift valleys. It is the subsequent deposition along the western and southern continental margins of fine marine sediments on porous coarse non-marine rift valley sediments ... |
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