Everything about Laurasia totally explained
Laurasia was a
supercontinent that most recently existed as a part of the split of the
Pangaean supercontinent in the late
Mesozoic era. It included most of the landmasses which make up today's continents of the
northern hemisphere, chiefly
Laurentia (the name given to the North American craton),
Baltica,
Siberia,
Kazakhstania, and the
North China and
East China cratons.
The name combines the names of Laurentia and Eurasia.
Origin
Although Laurasia is known as a Mesozoic phenomenon, today it's believed that the
same continents that formed the later Laurasia also existed as a coherent supercontinent after the breakup of
Rodinia around 1 billion years ago. To avoid confusion with the Mesozoic continent, this is referred to as
Proto-Laurasia. It is believed that Laurasia didn't break up again before it recombined with the southern continents to form the late Precambrian supercontinent of
Pannotia, which remained until the early
Cambrian. Laurasia was assembled, then broken up, due to the actions of
plate tectonics,
continental drift and
seafloor spreading.
Break up and reformation
During the Cambrian, Laurasia was largely located in equatorial latitudes and began to break up, with
North China and
Siberia drifting into latitudes further north than those occupied by continents during the previous 500 million years. By the
Devonian, North China was located near the
Arctic Circle and it remained the northernmost land in the world during the
Carboniferous Ice Age between 300 and 280 million years ago. There is no evidence, though, for any large scale Carbonifeous
glaciation of the northern continents. This cold period saw the re-joining of Laurentia and Baltica with the formation of the
Appalachian Mountains and the vast
coal deposits which are today a mainstay of the economy of such regions as
West Virginia and parts of the
British Isles and
Germany.
Siberia moved southwards and joined with
Kazakhstania, a small continental region believed today to have been created during the Silurian by extensive volcanism. When these two continents joined together, Laurasia was nearly reformed, and by the beginning of the
Triassic, the East China craton had rejoined the redeveloping Laurasia as it collided with
Gondwana to form
Pangaea. North China became, as it drifted southwards from near-Arctic latitudes, the last continent to join with Pangaea.
Final split
Around 200 million years ago, Pangaea started to break-up. Between eastern
North America and northwest
Africa, a new ocean formed - the
Atlantic Ocean, even though
Greenland (attached to North America) and
Europe were still joined together. The separation of Europe and Greenland occurred around 60 million years ago (in the
Paleocene). Laurasia finally divided into the continents after which it's named:
Laurentia (now North America) and
Eurasia (excluding
India and
Arabia).
Further Information
Get more info on 'Laurasia'.
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