Arctica no relation supercontinent
Ur is a hypothetical supercontinent that formed in the Archean  3,100 million years ago (3.1 billion).
In a reconstruction by Rodgers, Ur is half a billion years older than Arctica and, in the early period of its existence, it was probably the only continent on Earth, and as such can be considered a supercontinent, though it was probably smaller than present-day Australia.  In more recent works geologists often refer to both Ur and other proposed Archaean continental assemblages as supercratons.  Ur can, nevertheless, be half a billion years younger than Vaalbara, but the concepts of these two early cratonic assemblages are incompatible.
no relation