Panthalassa

The original, ancient ocean floor has now completely disappeared because of the continuous subduction along the continental margins on its circumference.

The North American Cordillera is an accretionary orogen, which grew by the progressive addition of allochthonous terranes along this margin from the Late Palaeozoic.

Most of the continental fragments, volcanic arcs, and ocean basins added to Laurentia this way contained faunas of Tethyan or Asian affinity.

[8] One such migrating atoll complex now form a two-kilometre-long (1.2 mi) and 100-to-150-metre-wide (330–490 ft) body of limestone in central Kyushu, south-west Japan.

Assuming a minimum accretion rate of 3 centimetres per year (1.2 in/year), the seamount chains on which those groups evolved would be separated by at least 3,000 km (1,900 mi).

The cause for the extinction is disputed, but a likely candidate is an episode of global cooling, which transformed a large amount of sea-water into continental ice.

[15] From the Late Devonian to the Carboniferous, Gondwana and Panthalassa converged along the eastern margin of Australia along a west-dipping subduction system, which produced (west to east) a magmatic arc, a forearc basin, and an accretionary wedge.

From the Late Carboniferous to the Early Permian the New England orogen was dominated by an extensional setting related to a subduction to strike-slip transition.

Subduction was re-initiated in the Permian and the granitic rocks of the New England Batholith were produced by a magmatic arc, indicating the presence of an active plate margin along most of the orogen.

Consequently, trade winds moved water away from Gondwana towards Laurasia in the northern Panthalassa Equatorial Current.

The accumulation of water along the western margin, coupled with the Coriolis effect, would have created a Panthalassa Equatorial Counter Current.