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.

Pangaea was shaped like a C. About 200 million years ago, it began to split into pieces. This led to the continents we know today.

Origin of the concept

The name "Pangaea" means "all Earth." A man named Abraham Ortelius first thought that the continents were once connected and then moved apart. Later, a scientist named Alfred Wegener wrote about this idea in 1912. He called the old connected land a "supercontinent." Wegener had an idea about why Pangaea broke apart, but it was later shown to be wrong. Another scientist, Arthur Holmes, suggested that movements deep inside the Earth, called mantle convection, caused the continents to move. This helped people accept the theory of plate tectonics, which explains how Pangaea formed and broke apart.

Evidence of existence

The way the continents fit 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.

We also find clues in rocks and fossils. Mountains, rocks, and fossils found on continents now far apart look very similar. This suggests these lands were once connected. Scientists study tiny bits in rocks that act like a compass, showing 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. Supercontinents form and break apart in a cycle. There may have been several supercontinents before Pangaea.

Scientists study ancient rocks and fossils to learn where continents were long ago. These tools help them understand how landmasses moved. But maps of continents before Pangaea are not fully certain.

Previous supercontinents

Before Pangaea, there was a supercontinent called Columbia or Nuna. After that, another supercontinent named Rodinia formed. Rodinia existed for a very long time. Its shape and history are less clear than 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 near the equator. Later, a smaller landmass called Avalonia moved toward Laurentia. Eventually, Baltica, Laurentia, and Avalonia joined to form a new landmass called Euramerica or Laurussia. During this time, Gondwana moved toward the South Pole. This was the first step in forming Pangaea.

Collision of Gondwana with Euramerica

The next step was when Gondwana collided with Euramerica. By this time, Baltica had joined with Laurentia to form Euramerica. As Avalonia moved toward Laurentia, the ocean between them disappeared. Parts of southern Europe also moved toward Euramerica.

During the Carboniferous time period, northwest Africa reached the southeastern coast of Euramerica. South America moved northward toward Euramerica. 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, 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.

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 huge landmass that formed 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 big ocean named Panthalassa, and another ocean called the Paleo-Tethys.

By the Permian period, Pangaea stretched from the equator to both polar regions. Its size changed the oceans nearby. The Central Pangaean Mountains grew tall but then wore down. Later, in the Triassic period, Pangaea began to break apart. By the Jurassic period, it split into two smaller landmasses: Laurasia in the north and Gondwana in the south.

Paleoclimate

Pangaea existed for millions of years, from the late Carboniferous period to 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 drier and cooler than areas near the shores. They often had huge deserts. The climate was also affected by 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. Later, they became drier. By the Jurassic period, 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 huge supercontinent that existed for about 160 million years. During this time, many 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.

Rifting and break-up

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

The Atlantic Ocean formed slowly. 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 went 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.