Laurasia

Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago (Mya). The other landmass was called Gondwana. Laurasia separated from Gondwana 215 to 175 Mya, beginning in the late Triassic period, as the supercontinent began to break apart. After this split, Laurasia drifted further north and eventually broke apart with the opening of the North Atlantic Ocean around 56 million years ago.

The name Laurasia comes from a combination of two parts: Laurentia and Eurasia, which are two of the ancient lands that made it up. Over time, many smaller land pieces, called terranes, came together to form Laurasia. These included places like Avalonia, Baltica, and others that collided in a major event known as the Caledonian orogeny. Later, Kazakhstania and Siberia also joined, helping create the big landmass we call Laurasia. This landmass played an important role in the history of Earth's continents and the animals and plants that lived on them.

Terminology and origin of the concept

Laurentia, the core of North America and parts of Europe, joined with Baltica and Avalonia to form Laurussia. Later, Laurussia joined with Gondwana to create the supercontinent Pangaea. Siberia and Kazakhstania also joined, forming Laurasia.

The idea of Laurasia was proposed by several scientists over time. In 1904–1909, Eduard Suess talked about Gondwana. In 1915, Alfred Wegener suggested Pangaea. In 1937, Alexander du Toit split Pangaea into Laurasia and Gondwana. The term "Laurussia" was defined in 1988 by Peter Ziegler.

Proto-Laurasia

Main article: Rodinia

Main article: Pannotia

Laurentia and Baltica first came together to form a landmass called Proto-Laurasia as part of an even larger supercontinent called Columbia, which existed about 2,100 to 1,800 million years ago. This early landmass included many of today's continents, with traces of its formation still visible in modern geology.

Later, these lands became part of another supercontinent called Rodinia, which formed around 1,260 to 900 million years ago. Rodinia eventually broke apart, leading to the formation of new oceans and the movement of continents to their current positions. During these changes,Laurentia moved northward toward the Equator, while Baltica stayed closer to the southern latitudes.

Euramerica/Laurussia

Main article: Pangaea

Laurentia stayed near the Equator during the early Palaeozoic era, far from Baltica because of the wide Iapetus Ocean. Over time, changes in ocean movements created a new ocean called the Rheic Ocean. During this period, land pieces called Avalonia, Carolinia, and Armorica moved away from Gondwana.

Eventually, Avalonia moved toward Baltica and they joined together near Laurentia, forming a new landmass called Laurussia, also known as Euramerica. This continent covered a huge area and had many different landscapes. During the Devonian period, many sea creatures lived in the shallow waters around Laurussia, and the first tetrapods, or four-legged animals, evolved from fish.

Later, Laurussia joined with Gondwana to form the supercontinent Pangaea. This huge landmass had many changes in climate and plant life over millions of years, from tropical rainforests to drier areas.

Laurasia

During the Carboniferous to Permian periods, Siberia, Kazakhstania, and Baltica collided to form Laurasia. This landmass was part of the larger supercontinent Pangaea, which began to break apart around 215 to 175 million years ago. Laurasia was the northern part of Pangaea, while Gondwana was the southern part.

As Pangaea split, Laurasia drifted further north. Eventually, the opening of the North Atlantic Ocean around 56 million years ago caused Laurasia to break apart into the continents we know today. During its time, Laurasia was home to many different plants and animals, including early pine trees and various dinosaurs. The movement of Earth's plates reshaped the landmasses and influenced the climate and life that developed on them.