3 ms·
The paper disagrees. Quote: The edges of Australia and Zealandia continental crust approach to within 25 km across the Cato Trough (Fig. 2). The Cato Trough is
by niftich 10y ago
The paper disagrees. Quote:
The edges of Australia and Zealandia continental crust approach to within 25 km across the Cato Trough (Fig. 2). The Cato Trough is 3600 m deep and floored by oceanic crust (Gaina et al., 1998; Exon et al., 2006). The Australian and Zealandian COBs [continent-ocean boundaries] here coincide with, and have been created by, the Cato Fracture Zone along which there has been ~150 km of dextral strike slip movement, linking Paleogene spreading centers in the Tasman and Coral seas (Fig. 2; Gaina et al., 1998). This spatial and tectonic separation, along with intervening oceanic crust, means that the Zealandia continental crust is physically separate from that of Australia. If the Cato Trough did not exist, then the content of this paper would be describing the scientific advance that the Australian continent was 4.9 Mkm2 larger than previously thought.
- mc32 10y agoI wonder whether geologically they are separate or was that trough created after the plate formed --that is is it a contiguous mass with an eroded trough or were these separate masses mashed together via tectonics?
- niftich 10y agoSee their Figure 5 [1] where they hypothesize how Zealandia was formed from the breakup of Gondwana, before which it did in fact lie adjacent to what later became a separate 'Australia' continent. Some of the definitions are complicated by the fact that continents join and break up, and their continuity across multiple continental cycles is not a given -- but that of cratons is, which are sort of an inner core of really old rocks that managed to survive all sorts of tectonic abuse. Zealandia has yet to be shown to contain a craton, presence of which would probably result in its undisputed acceptance as a continent. All of today's "classical" continents are amalgamations of contiguous continental crust around one or more neighboring cratons. See the 'Geology' section for discussion. [1] https://www.geosociety.org/gsatoday/archive/27/3/figure/GSATG321A.1-f05.htm https://www.geosociety.org/gsatoday/archive/27/3/figure/GSAT...