Rodinia was a supercontinent formed about 1.1 billion years ago (that's 1,100,000,000 years). 750 million years ago, Rodinia broke into three pieces that drifted apart as a new ocean formed between the pieces. Then, about 600 million years ago, those pieces came back together with a big crunch known as the Pan-African orogeny (mountain building event). This formed a new supercontinent, with the name of Pannotia. By about 550 million years ago, Pannotia was breaking up into several small fragments, Laurentia (the core of what is now North America), Baltica (northern Europe), and Siberia, among others, and one very large piece. This large piece, containing what would become China, India, Africa, South America, and Antarctica, was called Gondwana. It is considered a supercontinent in its own right because it is so big, but it is only part of the earlier supercontinents.

Over the next 200 million years many of the small pieces came together to form another large continent called Laurasia. Laurasia and Gondwana joined approximately 275 million years ago to form the supercontinent of Pangea. The breakup of Pangea is still going on today and contributes in the formation of the Atlantic Ocean. Eventually a new supercontinent will form and then it will break apart and so on.

As you can see, the earth's continents have seen a lot of action over time. There were probably some supercontinents formed in the 4300 million years of earth's history that came before Rodinia was formed, however, we have a much harder time understanding the history of rocks that old because there were not very many life forms to help determine the age of the rocks and because so much has happened to the rocks since they formed that the record of the original events is not very clear any more (imagine that five different people each taped over different parts of your favorite video and then from the little pieces that were left of the original, you had to go back and try to put the whole story together) - geologists who do this work are a lot like detectives.

Rodinia (from the Russian word Rodina, for 'homeland') was an early supercontinent thought to exist from 1.1 billion to 700 million years ago,in the Proterozoic period. It contained many of the older parts of the continents, termed cratons, that we we know today (parts of North America, Russia, Africa, Australia).

Between 750-650 million years ago it progressively fragmented into the supercontinents Gondwana (Africa, South America, India, Antarctica, Australia) and Laurasia ( North America, Europe and Asia), along with a few other continental chunks such as Baltica currently Scandinavia) and Siberia (Russia).

The existence of Rodinia has been difficult to prove with certainty, as fossil evidence is lacking for periods that long ago (continents that were formerly joined, now separated, often have similar fossils). One line of evidence that supports Rodinia formation is palaeomagnetism: when magnetic minerals grow in rocks they preserve the orientation of the Earth's magnetic field at the time of growth, thus telling you where North was at the time, and allowing you to reconstruct the positions of all the plates if you look at rocks from a particular time period.

Although data from the Proterozoic period are limited, they suggest that many of the planets older land masses were in a similar latitude that long ago. Also, there are some rocks dating from that time, particularly along the east coast of the US & Canada, and also in Australia, that record the collision of land masses during the assembly of Rodinia (the US/Canada one is called the Grenville orogenic belt). Other lines of evidence use the similarity or contrast between different chemical isotopes in rocks from the Proterozoic period to link various older parts of the continents together.

Try this website for some cool plate tectonic reconstructions throughout geological time - here

I'm glad to see you're studying plate tectonics, and particularly in such detail to be interested about the existence of Rodinia. You're right, there isn't much about Rodinia that's easily accessible (or understandable!), but I hope this answers your question.