Protolithic shields once close together
Near each other until the Mesozoic break-up
Younger continental assemblage
Three of a kind now far apart
Up to the Siderian era range
When Ur joins Nena and Atlantica
On early Earth's archaic tectonics
Three worlds collide
The Zimgarn hypothesis surfaces
Extensive carbonate platforms develop
Differing magmatic signatures
Primordial magnetism affected
Expanding continuing stabilisation
Intracontinental within the southern margin
Ur, the longest lived landmass
Yet it remains hopelessly obscure