| 1.8 billion years ago, Baltica was part of the major supercontinent Columbia. Columbia began to break apart 1.5 billion years ago, the rifts from which have been found in the western United States and India. The rifted fragments formed the supercontinent Rodinia about 500 million years later, one of the oldest-known supercontinents, which contained most or all of Earth's current landmass. Rodinia both formed and rifted apart in the Neoproterozoic, existing as a single continent from 1 billion years ago until it began to break apart into eight smaller continents about 750 million years ago. It was surrounded by the superocean Mirovia. |  |
The Grenville orogeny occurred in the late Proterozoic eon, 1300-1000 million years ago (mya), as numerous continental plates collided around the edges of North America, forming folded mountains ranges formed in eastern North America, from Newfoundland to North Carolina, 1100-1000 mya. The East Coast of Laurentia lay adjacent to the West Coast of South America, while a conjoined Australia and Antarctica seem to have lain against the proto-North American West Coast. A third craton, what would become north-central Africa, was caught in between these two colliding masses. The absence of fossils of hard-shelled organisms make the movements of continents earlier in the Precambrian, prior to this event, uncertain and Rodinia's landmass was probably centered south of the equator. The eventual rifting of the continents created new oceans, and seafloor spreading. The result was a greater number of shallower oceans. All of this tectonic activity also introduced into the marine environment biologically important nutrients, which may have played an important role in the development of the earliest animals.
Extensive lava flows and volcanic eruptions around the Precambrian-Cambrian boundary, especially in North America, suggest that Rodinia began to rift apart no later than 750 million years ago. The eight continents that made up Rodinia later re-assembled into another global supercontinent called Pannotia and, after that, once more as Pangaea- supercontinent that existed during the Paleozoic and Mesozoic eras. 600 million years ago, Baltica was part of the major supercontinent Pannotia; Baltica collided against Laurentia, forming the minor supercontinent Euramerica during the Devonian. Baltica was part of the minor supercontinent Laurasia during the Jurasic when Pangaea rifted into two minor supercontinents: Laurasia and Gondwana.
At Present, Baltica is part of the forming minor supercontinent Eurafrasia.
During the Cretaceous, the late Paleozoic - early Mesozoic supercontinent of Pangea completed its breakup into present day continents, although their positions were substantially different at the time. As the Atlantic Ocean widened and South America drifted westwards, Gondwana itself broke up as Antarctica and Australia rifted away from Africa. Other important Cretaceous exposures occur in Europe and China. In the area that is now India, massive lava beds called the Deccan Traps were laid down in the very late Cretaceous and early Paleocene. Climates were warm, and even polar regions had no permanent. Marine reptiles included ichthyosaurs in the early and middle of the Cretaceous, plesiosaurs throughout the entire period, and mosasaurs in the Late Cretaceous. The Cretaceous also saw the first radiation of the diatoms in the oceans (freshwater diatoms did not appear until the Miocene).
The intensive mid-Cretaceous insect extinction began during the Albian (Aube in France) for that stage of the Cretaceous system which comes above the Aptian and below (before) the Cenomanian. Approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma (million years ago). The following representatives of the Albian stage are worthy of notice: the gaize and phosphatic beds of Argonne and Bray in France; the Flammenmergel of North Germany; the lignites of Iltrillas in Spain; the Upper Sandstones of Nubia, and the Fredericksburg beds of North America.