Pangaea

Pangaea (from the Greek pan, meaning “all,” and Gaia, meaning “Earth”) refers to the supercontinent that existed during the late Palaeozoic and early Mesozoic eras, approximately 335 to 175 million years ago. It was a vast landmass comprising almost all of the Earth’s continental crust, unified into a single gigantic continent surrounded by a global ocean called Panthalassa. The concept of Pangaea is central to the theory of continental drift, which later evolved into the modern understanding of plate tectonics.

Formation and Geological Background

The formation of Pangaea was the result of the gradual convergence and collision of earlier continental masses. Throughout Earth’s geological history, continents have repeatedly assembled and dispersed in a cycle known as the supercontinent cycle. Before Pangaea, earlier supercontinents such as Rodinia (about 1.1 billion years ago) and Pannotia (around 600 million years ago) had existed.
Pangaea began forming approximately 335 million years ago, during the Carboniferous Period, when the smaller continents and landmasses—Laurasia (comprising North America, Europe, and parts of Asia) and Gondwana (including South America, Africa, Antarctica, Australia, and the Indian subcontinent)—moved together due to tectonic activity.
This convergence was driven by plate movements and subduction zones, where oceanic crust was forced beneath continental plates. The eventual collision of Laurasia and Gondwana closed the Rheic Ocean, giving rise to the unified landmass of Pangaea by the early Permian Period (around 299 million years ago).

Structure and Geography of Pangaea

Pangaea was roughly C-shaped, stretching from the northern polar regions to the southern polar regions, covering about one-third of the Earth’s surface. The interior of the supercontinent was vast, arid, and subject to extreme temperature fluctuations due to its distance from the ocean. Surrounding Pangaea was the immense ocean Panthalassa, while smaller marginal seas such as the Tethys Sea lay between the eastern parts of Gondwana and Laurasia.
The geography of Pangaea can be broadly divided into two main regions:

• Laurasia in the north, which included present-day North America, Europe, and northern Asia.
• Gondwana in the south, comprising South America, Africa, Antarctica, Australia, and the Indian subcontinent.

Between them lay the Tethys Ocean, a shallow tropical sea that later became the site of significant geological transformations during the breakup of Pangaea.

Climate and Environment

The climate of Pangaea varied greatly across its vast expanse. The coastal regions were more humid and supported lush vegetation, while the interior regions experienced arid and semi-arid conditions due to the absence of moisture-bearing winds from the sea. This created large desert zones, as evidenced by extensive red sandstones and evaporite deposits found in fossil records.
During the Permian Period, much of Pangaea lay near the equator, but its southern regions extended toward the South Pole, where glaciation occurred. The equatorial areas hosted extensive coal-forming tropical forests, which later contributed to the vast coal deposits of present-day Europe, North America, and Asia.
Fluctuations in sea levels and climate changes, coupled with volcanic activity, also influenced biological evolution and extinction patterns. The Permian–Triassic extinction event (around 252 million years ago), the most severe extinction in Earth’s history, is believed to have been influenced in part by environmental changes occurring on Pangaea.

Biodiversity and Evolutionary Implications

Pangaea’s formation had profound effects on global biodiversity and the distribution of life. The unification of continents allowed species to migrate freely across vast distances, reducing regional diversity but facilitating the spread of certain terrestrial animals and plants. Fossil evidence supports these connections—for instance, the presence of the reptile Lystrosaurus in Africa, India, and Antarctica, and the plant Glossopteris across Gondwanan continents.
However, the large landmass also created environmental extremes that led to mass extinctions and evolutionary pressures. Arid interiors and climatic fluctuations favoured the evolution of species adapted to dry conditions, such as early reptiles and gymnosperms. Marine ecosystems also changed drastically due to the reduced continental shelf area and altered ocean circulation patterns caused by the supercontinent’s configuration.

Breakup of Pangaea

Pangaea began to fragment around 175 million years ago, during the Jurassic Period, due to the movement of tectonic plates driven by mantle convection. The breakup occurred in multiple stages:

1. Initial Rifting (Late Triassic–Early Jurassic): The supercontinent began to split along a rift zone that would later form the Central Atlantic Ocean, separating North America from Africa.
2. Formation of Laurasia and Gondwana: The division resulted in two major landmasses—Laurasia in the north and Gondwana in the south—by the early Jurassic period.
3. Further Fragmentation (Cretaceous Period): Gondwana itself began breaking apart into present-day South America, Africa, Antarctica, Australia, and India. The Indian subcontinent started drifting northwards, eventually colliding with Asia to form the Himalayas.

This gradual disintegration reshaped the global geography and ocean circulation systems, setting the stage for the distribution of continents as we recognise them today.

Evidence Supporting Pangaea

The concept of Pangaea was first proposed by the German meteorologist and geophysicist Alfred Wegener in 1912 as part of his Continental Drift Theory. Wegener argued that continents had once been joined together in a single landmass and had since drifted apart. Although initially controversial, his ideas were later supported by multiple lines of evidence:

• Fossil Correlation: Identical fossil species (e.g., Mesosaurus, Glossopteris) found on continents now separated by oceans.
• Geological Continuity: Similar rock formations, mountain ranges, and mineral deposits across different continents, such as the Appalachian Mountains (North America) and the Caledonian Mountains (Europe).
• Palaeoclimatic Evidence: Traces of glaciation in tropical regions and coal deposits in polar areas indicating continental movement.
• Palaeomagnetism: Studies of magnetic minerals in rocks showing patterns consistent with continental drift.

With the development of plate tectonic theory in the 1960s, Wegener’s hypothesis gained robust scientific acceptance. Seafloor spreading, subduction zones, and the movement of lithospheric plates provided a mechanistic explanation for the formation and breakup of Pangaea.

Geological and Modern Significance

Pangaea’s history is crucial for understanding the dynamic nature of Earth’s lithosphere and the processes that drive continental drift and plate tectonics. Its assembly and breakup influenced oceanic circulation, atmospheric composition, and biological evolution over millions of years.
The formation of Pangaea also contributed to the creation of major orogenic belts (mountain ranges) such as the Appalachians, Ural Mountains, and Hercynian ranges, which remain prominent features today. The fragmentation of the supercontinent gave rise to new oceans—most notably the Atlantic Ocean—and determined the configuration of modern continents.