Pangaea

Pangaea or Pangea was a supercontinent that existed a very long time ago, during the late Paleozoic and early Mesozoic eras. It formed when earlier landmasses like Gondwana, Euramerica, and Siberia came together about 335 million years ago, during the Carboniferous period. This huge land stretched between Earth's northern and southern areas and was surrounded by a giant ocean called Panthalassa and other smaller seas.

Pangaea was shaped like a C, and it was the most recent supercontinent ever to exist. Scientists, called geologists, were the first to figure out how it looked and how it broke apart. About 200 million years ago, at the end of the Triassic and the start of the Jurassic period, Pangaea began to split into pieces. This breaking apart led to the continents we know today, changing the face of Earth forever.

Origin of the concept

The name "Pangaea" comes from ancient words meaning "all" and "Earth." A man named Abraham Ortelius was the first to suggest that the continents were once connected and later moved apart. Later, a scientist named Alfred Wegener wrote about this idea in 1912. He called the old connected land a "supercontinent." Wegener thought the Earth's spin caused Pangaea to break apart, but this idea was proven wrong. Another scientist, Arthur Holmes, suggested that movements deep inside the Earth, called mantle convection, caused the continents to move. This idea helped people accept the theory of plate tectonics, which explains how Pangaea formed and later broke apart.

Evidence of existence

The way the continents fit together around the Atlantic Ocean was the first clue that Pangaea might have existed. The coastlines of North America and South America look like they could match up with Europe and Africa very closely.

We also find clues in rocks and fossils. Mountains, rocks, and even ancient animal and plant fossils found on different continents now far apart look very similar. This suggests these lands were once connected. Scientists also study tiny bits in rocks that act like a compass, pointing to where Earth's magnetic poles were when the rock formed. This helps show how continents have moved over time.

Formation

Pangaea is the most recent supercontinent known from Earth's history, making it the best studied. The forming and breaking apart of supercontinents seems to happen in a cycle throughout Earth's past. There may have been several supercontinents before Pangaea.

Scientists use special tools to study ancient rocks and fossils to learn where continents were located long ago. These tools help them understand the positions and movements of landmasses. However, maps of continents before Pangaea are not fully certain and can look different depending on how scientists interpret the data.

Previous supercontinents

Before Pangaea, there was a supercontinent called Columbia or Nuna, which formed about 2 to 1.8 billion years ago. After Columbia/Nuna broke apart, another supercontinent named Rodinia formed. Rodinia existed from around 1.3 billion years ago until about 750 million years ago. Its shape and history are less clear than those of later supercontinents like Pannotia and Pangaea.

Formation of Euramerica (Laurussia)

In a time called the Cambrian, a landmass named Laurentia—which later became North America—was located near the equator. Around 480 million years ago, during a time called the Ordovician, a smaller landmass called Avalonia started moving toward Laurentia. Eventually, Baltica, Laurentia, and Avalonia joined together to form a new landmass called Euramerica or Laurussia. During this time, Gondwana, another large landmass, slowly moved toward the South Pole. This was the first step in forming Pangaea.

Collision of Gondwana with Euramerica

The next step in forming Pangaea was when Gondwana collided with Euramerica. By around 430 million years ago, Baltica had already joined with Laurentia to form Euramerica. As Avalonia continued moving toward Laurentia, the ocean between them slowly disappeared. Meanwhile, parts of southern Europe broke away from Gondwana and moved toward Euramerica.

By the time period called the Carboniferous, northwest Africa had reached the southeastern coast of Euramerica, creating mountain ranges. South America also moved northward toward Euramerica, while the eastern parts of Gondwana, including India, Antarctica, and Australia, moved toward the South Pole.

Formation of Laurasia

In the late Carboniferous period, a landmass called Kazakhstania collided with Baltica, closing an ocean and forming the Ural Mountains and a new landmass called Laurasia. This was the final step in forming Pangaea. By this time, South America had joined with southern Laurentia, and Gondwana was near the South Pole, where glaciers formed on several continents.

By the Early Permian period, a landmass called the Cimmerian plate broke away from Gondwana and moved toward Laurasia. Eventually, most landmasses were joined together. By the Late Triassic period, Pangaea began to break apart.

Paleogeography

Pangaea was a giant landmass that formed during the late Carboniferous period, about 335 million years ago. It had two big parts: Gondwana in the south and Laurussia in the northwest, with Siberia and Amuria nearby. Around it was a huge ocean called Panthalassa, and another ocean called the Paleo-Tethys.

By the time of the Permian period, Pangaea stretched from the equator to both polar regions. This huge size affected the oceans around it. The big Central Pangaean Mountains grew tall but then wore down over time. Later, during the Triassic period, Pangaea started to break apart, and by the Jurassic period, it split into two smaller landmasses: Laurasia in the north and Gondwana in the south.

Paleoclimate

Since Pangaea existed for millions of years, from the late Carboniferous period up until the early Jurassic period, its climate changed a lot. Because it was so big, different parts of Pangaea had very different weather.

The inner parts of Pangaea were much drier and cooler than the areas near the shores, often forming huge deserts. The climate was also affected by the oceans around Pangaea, like the superocean Panthalassa and the Paleo Tethys and Tethys seas. These warm waters brought moisture and rain to some areas.

During different times, some parts of Pangaea had lots of rain, while others were very dry. For example, in the late Carboniferous, parts of what is now Europe and eastern North America were very wet, but later became drier. By the Jurassic period, the big rains, called megamonsoons, stopped, and many areas became dry. When Pangaea finally broke apart, it changed the oceans and the climate even more.

Life

Pangaea was a giant supercontinent that existed for about 160 million years. During this time, many important changes happened in plants and animals. In the oceans, early seas had corals, brachiopods, bryozoans, sharks, and the first bony fish. On land, forests filled with lycopsids were home to insects, other arthropods, and the first tetrapods.

When Pangaea began to break apart, the oceans had molluscs, ammonites, ichthyosaurs, sharks, rays, and many bony fish. Land was covered with cycads, conifers, and many dinosaurs. The first true mammals also appeared. The formation of Pangaea changed Earth’s climate and landscapes, which helped shape the evolution of life. Some animals and plants spread widely, while others stayed in smaller areas due to climate differences. Mass extinctions during this time also affected which species survived and thrived.

Rifting and break-up

Pangaea, a giant supercontinent, broke apart in three major phases.

The Atlantic Ocean did not form all at once. It started with rifting in the north-central part. The first split happened around 230 million years ago in the central Atlantic. Rifting continued along the edges of North America and Africa. Later, around 175 million years ago, rifting extended from the Tethys Ocean in the east to the Pacific Ocean in the west, creating more splits between North America and Africa.

The second phase began around 150–140 million years ago when Gondwana split into Africa, South America, India, Antarctica, and Australia. This caused the opening of the South Indian Ocean. South America moved westward away from Africa, and Madagascar and India moved northward away from Antarctica.

The final phase happened in the early Cenozoic period. Laurasia split, opening the Norwegian Sea. Australia also split from Antarctica and moved northward. India collided with Asia, forming the Himalayas. Antarctica moved toward the South Pole, allowing glaciers to form. The break-up of Pangaea is still happening today in places like the Red Sea Rift and the East African Rift.