Rheic Ocean

A long time ago, there was a big ocean.

It sat between two large lands. Small pieces of land broke away. This made the ocean grow very wide.

Later, the lands began to move closer. They crashed into each other. This closed the big ocean.

The lands joined to make one giant land. This new land was called Pangaea.

Many plants grew on small islands in the water. The changing world helped many new sea animals live. The big ocean is gone now.

Long ago, there was a big ocean called the Rheic Ocean.

It sat between two huge lands. One land was Gondwana. The other was Laurussia.

At first, the land was mostly one big group near the south pole. This group was Gondwana. Small pieces of land broke away from it. These pieces drifted north. This created a gap. That gap became the Rheic Ocean.

As the pieces moved, the ocean grew very wide. It was widest during the Silurian period. Then, the lands began to move back together. The ocean started to close. Eventually, Gondwana and Laurussia crashed into each other. This made a giant land called Pangaea. This crash also made big mountain chains.

Life changed during this time too. Many plants grew on volcanic islands in the ocean. These islands were part of the Prague Basin. The changing world helped many sea animals grow. New kinds of life appeared in the water. This happened as the ocean closed and the world got colder.

An image showing how the ocean changed over time.

The Rheic Ocean was a huge body of water from a long time ago. It sat between two massive pieces of land called Gondwana and Laurussia. This ocean was one of the most important oceans during the Paleozoic Era. Today, we can still see where it once was. Its traces, called sutures, stretch from Mexico all the way to Turkey. The closing of this ocean helped create the supercontinent known as Pangaea.

This ocean formed through a slow way the Earth works. At first, most land was clustered near the south pole in Gondwana. A rift, or a long crack, began to form along the northern edge of Gondwana. This rift turned into a mid-oceanic ridge. This ridge pushed small pieces of land, like Avalonia and Carolina, away from Gondwana. As these pieces drifted north, the Rheic Ocean grew much wider. It reached its widest point during the Silurian period.

Scientists use special names to describe these ancient places. The ocean was named after Rhea, a figure from Greek mythology. Rhea was the sister of Iapetus. The Iapetus Ocean was a different ocean that came before the Atlantic. The Rheic Ocean existed from the Early Ordovician to the Early Carboniferous periods. It was a major part of the world's map for millions of years.

The ocean did not stay wide forever. The closing of the Rheic Ocean began in the Early Devonian. It was finished during the Mississippian period. This happened when Gondwana and Laurussia finally crashed into each other. This collision created the massive Pangaea landmass. It also built huge mountain chains. These are called the Variscan, Alleghanian, and Ouachita orogenies.

Changes in the ocean also changed life on Earth. The Prague Basin was a group of volcanic islands in the ocean. These islands were a hotspot for many different kinds of plants. As the ocean closed and the world got colder, life in the sea changed too. This may have caused a big burst of new marine life. Many new species of animals, like fusulinids and brachiopods, appeared. The moving lands helped drive these big changes in nature.

The Rheic Ocean was a major body of water during the Paleozoic Era. It separated two massive landmasses known as paleocontinents. One landmass was Gondwana, which sat near the south pole. The other was Laurussia, made of Laurentia, Baltica, and Avalonia. This ocean played a vital role in shaping the Earth's surface. Its eventual closure helped create the supercontinent Pangaea. Today, we can still see its history in the Earth's crust. Its sutures, or scars from land collisions, stretch from Mexico to Turkey.

The ocean formed through a specific geodynamic process. At the start of the Paleozoic, about 540 million years ago, Gondwana dominated the southern hemisphere. A volcanic arc called the Cadomian orogeny existed on Gondwana's northern edge. This occurred as oceanic crust subducted, or sank, below the continent. Eventually, a mid-oceanic ridge subducted at an oblique angle. This caused extensional basins to develop along the northern margin of Gondwana. These basins evolved into a rift, which is a long crack in the crust.

This rift eventually became a mid-oceanic ridge. This ridge acted as a divider between landmasses. It separated small fragments like Avalonia and Carolina from Gondwana. As these fragments drifted north, the Rheic Ocean began to form in the Early Ordovician. The ocean continued to grow as these pieces moved. It reached its maximum width during the Silurian period. During this same time, the older Iapetus Ocean was closing. The collision of Avalonia-Carolina with Laurentia created the Appalachian orogeny.

The name of the ocean comes from Greek mythology. It was named after Rhea, who was the sister of Iapetus. This naming follows the pattern of the Iapetus Ocean. The Iapetus Ocean was the predecessor to the modern Atlantic Ocean. The Rheic Ocean existed from the Early Ordovician until the Early Carboniferous. It was a defining feature of the ancient world's geography. The name connects the ancient oceans to the myths that inspired their naming.

The closure of the Rheic Ocean was a massive event. This process began in the Early Devonian period. It was completed during the Mississippian period. The closure happened because Gondwana and Laurussia collided. This collision resulted in the assembly of the supercontinent Pangaea. This event also triggered several large orogenies, which are mountain-building events. These include the Variscan and Alleghanian orogens. These formed between Gondwana's West African margin and southern Baltica. They also involved eastern Laurentia. Additionally, the Ouachita orogeny formed between the Amazonian margin of Gondwana and southern Laurentia.

Changes in the ocean also impacted the history of life. During the Silurian, the Prague Basin sat in the Rheic Ocean. This basin was an archipelago of humid volcanic islands. These islands were located on the outer edges of the Gondwanan shelf. The islands became a major hotspot for plant biodiversity. This happened during the early stages of the Silurian-Devonian Terrestrial Revolution. The rapid environmental changes from volcanic activity helped plants diversify. High rates of endemism, or species found nowhere else, likely drove this growth.

The closing of the ocean may have also changed marine life. This happened alongside the start of the Late Palaeozoic Ice Age. These combined factors may have sparked a major evolutionary event. This is known as the Carboniferous-Earliest Permian Biodiversification Event. This event saw a massive radiation of marine species. Specifically, there was an increase in the richness of fusulinids and brachiopods. The movement of the continents and the changing climate created new opportunities for life to flourish in the seas.