Panthalassa

Long ago, there was a huge ocean.

This ocean was called Panthalassa. It was much bigger than our ocean today. It went all around the world.

One big piece of land sat in the water. This land was called Pangaea.

The ocean covered most of the Earth. The land only took up a small part.

Today, the old ocean floor is gone. It was pulled down into the Earth. Our Pacific Ocean is a part of it now.

A long time ago, Earth had a massive ocean. It was called Panthalassa. The name comes from Greek words meaning "all sea."

Panthalassa was much bigger than the Pacific Ocean. It covered almost 70% of the Earth. A giant landmass called Pangaea sat in the middle. Pangaea took up the rest of the world.

Most of the old ocean floor is gone now. This happened because of subduction. Subduction is when parts of the ocean floor sink into the Earth. This process destroyed the ancient floor.

The Pacific Ocean is a direct continuation of Panthalassa. Some scientists call it the "old Pacific."

Many small life forms lived in these waters. One group was called fusuline foraminifera. These were tiny, single-celled organisms. Some grew very large. They lived on underwater mountains called seamounts. These mountains were often covered in coral reefs. A big change in the world caused many of these creatures to die out. This happened about 252 million years ago.

{ "text": "Long ago, Earth looked very different than it does today. A massive superocean called Panthalassa covered most of our

Panthalassa was a massive superocean that once covered most of the Earth. Its name comes from the Greek words for "all" and "sea." During the transition between the Paleozoic and Mesozoic eras, about 250 million years ago, this ocean was enormous. It occupied nearly 70% of the entire planet's surface. The remaining one-third of the Earth was taken up by the supercontinent Pangaea.

Because it was so large, Panthalassa is sometimes called the "Proto-Pacific." This is because the modern Pacific Ocean is a direct continuation of this ancient body of water.

Scientists study Panthalassa through a process called reconstruction. They cannot look at the original ocean floor because it has disappeared. This happened because of continuous subduction. Subduction occurs when one tectonic plate slides beneath another and sinks into the Earth's mantle. Most of the original Panthalassic plates have been swallowed this way. Instead, researchers use magnetic lineations and fracture zones in the western Pacific to map it. They also use seismic tomography. This technique uses seismic waves to identify subducted slabs hidden deep within the Earth's mantle.

Panthalassa had very complex margins and many different types of volcanic structures. Along its edges, there were volcanic arcs, which are chains of volcanoes formed by subduction. Some of these are known today as allochthonous terranes. These are pieces of crust that have moved far from their original location. Examples include the Kolyma–Omolon and Anadyr–Koryak arcs in Asia. In western North America, terranes like Wrangellia and Stikinia were added to the continent. These pieces brought different types of life and rocks to the growing landmass.

The history of these landmasses is tied to the breakup of even older supercontinents. The supercontinent Rodinia began to break apart about 870 to 845 million years ago. This was likely caused by a superplume, which is a massive upwelling of heat from the mantle. Later, around 750 million years ago, the western half of Rodinia began to rift apart. This separation moved pieces like Australia and East Antarctica away from other landmasses. By the Early Jurassic, the Pacific Plate began to open. This happened at a triple junction where the Farallon, Phoenix, and Izanagi plates met.

Life in Panthalassa was shaped by its vast size. During the Permian period, tiny single-celled organisms called fusuline foraminifera flourished. These organisms showed incredible diversity and even reached large sizes. One genus, Eopolydiexodina, grew up to 10 centimeters long. These creatures lived in complex relationships with photosynthesizing algae. However, the Capitanian mass extinction event 260 million years ago changed everything. This was followed by the "Great Dying" 252 million years ago, which wiped out most of these large forms.

Only much smaller, dwarf versions of these organisms survived through the Permian.

The ocean's massive scale also created unique weather and water patterns. Because it was so large, scientists expected very simple water circulation. They thought there might only be one large circular current, called a gyre, in each hemisphere. However, models suggest the ocean was more complex. There was a temperature gradient, meaning water temperatures changed from east to west. Cold water rose to the surface in the east through a process called upwelling. In the north, trade winds moved water away from the land toward Laurasia. This created the North Panthalassa Equatorial Current.

These currents worked together to move heat and nutrients around the planet. In the northern hemisphere, a large subtropical gyre rotated in an anti-cyclonic direction. This means the water moved in a clockwise circle. In the southern hemisphere, the currents rotated counterclockwise. The South Equatorial Panthalassa Current flowed westward near the Equator. This eventually fed into the intense South Panthalassa Current. These massive systems of moving water helped define the ancient climate of the Earth. Panthalassa shows us how a single, giant ocean can influence the entire world's systems.