Agulhas Plateau facts for kids
Quick facts for kids Agulhas Plateau |
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The Agulhas Plateau is limited by the Agulhas Passage to the north; by the Agulhas Basin to the west; and by the Transkei Basin to the north-east.
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| Summit depth | 2,500 m (8,200 ft) |
| Height | 2,500 m (8,200 ft) |
| Summit area | 300,000 km2 (120,000 sq mi) |
| Location | |
| Location | 500 km (310 mi) south of Africa |
| Coordinates | 39°S 26°E / 39°S 26°E |
| Country | South Africa/International |
| Geology | |
| Type | LIP, hotspot volcano |
| Age of rock | 100 to 94 Ma |
The Agulhas Plateau is a huge, flat-topped underwater mountain, also known as an oceanic plateau. It lies about 500 kilometers (310 miles) south of South Africa in the southwestern Indian Ocean. This amazing underwater landform is a remnant of a "large igneous province" (LIP), which means it was created by massive volcanic eruptions long ago.
The plateau formed between 100 and 94 million years ago. This happened when the Earth's crust in that area moved over a "hotspot" – a place deep inside the Earth where super-hot molten rock (magma) rises to the surface. This same volcanic activity also created other underwater features like the Northeast Georgia Rise and Maud Rise, which are now located far away near the Falkland Islands and Antarctica. The Agulhas Plateau is a key piece in understanding how the ancient supercontinent Gondwana broke apart.
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Exploring the Agulhas Plateau's Secrets
The Agulhas Plateau is a very important place for scientists studying how the Earth's continents and oceans have changed over millions of years. It helps us understand the "breakup" of an ancient supercontinent called Gondwana.
A Giant Underwater Mountain Range
Imagine a huge, flat-topped mountain hidden deep under the ocean. That's what an oceanic plateau is! The Agulhas Plateau rises about 2.5 kilometers (1.5 miles) above the surrounding ocean floor. It's a massive structure, covering an area of about 300,000 square kilometers (115,800 square miles).
How Scientists Uncovered Its Past
Scientists first started mapping this area in 1964. For many years, they weren't sure if the Agulhas Plateau was made of continental rock (like the land we walk on) or oceanic rock (like the seafloor). It was a big mystery!
They used many tools to study it, including special maps of the ocean floor and measurements of gravity and magnetism. Some clues suggested it might be continental, while others pointed to an oceanic origin.
Finally, using advanced seismic technology (which uses sound waves to "see" under the Earth's surface), scientists confirmed the truth. They found that the Agulhas Plateau is a "large igneous province" (LIP) made entirely of oceanic crust. This means it was formed by huge amounts of volcanic rock erupting from the ocean floor.
The Story of Its Volcanic Birth
The Agulhas Plateau is a key part of a much larger story about Earth's ancient past and how continents moved.
When Supercontinents Broke Apart
Millions of years ago, all the continents we know today were joined together in giant landmasses. One of these was Gondwana, a supercontinent that included what is now Antarctica, South America, and Africa. Around 140 to 95 million years ago, Gondwana began to break apart. This was a huge event that reshaped our planet!
The Agulhas Plateau formed during this time of great change. It's part of what scientists call the "Southeast African LIP," a massive area of volcanic activity.
Massive Eruptions and Moving Plates
The formation of the Agulhas Plateau was linked to a "hotspot." Imagine a giant, fixed "blowtorch" deep inside the Earth. As the Earth's tectonic plates slowly moved over this hotspot, it caused huge amounts of molten rock to erupt. This created vast areas of volcanic rock on the ocean floor.
Around 100 million years ago, the main eruptions that formed the Agulhas Plateau began. This volcanic activity was so powerful that it created a huge underwater landmass. Later, around 94 million years ago, as the seafloor continued to spread, parts of this volcanic landmass, like the Northeast Georgia Rise and Maud Rise, separated from the Agulhas Plateau and drifted away.
Today, the Agulhas Plateau and another volcanic feature called the Mozambique Ridge are connected by a raised area called the Transkei Rise. This rise shows that there was continuous, though smaller, volcanic activity between the formation of these two huge features.
Ocean Currents: Water Highways Around the Plateau
The Agulhas Plateau isn't just a static underwater mountain; it plays an important role in how ocean currents flow around Africa. Think of these currents as giant rivers of water moving through the ocean.
Deep Ocean Waters
One important current is the Antarctic Bottom Water (AABW). This super cold and dense water forms near Antarctica and flows deep beneath the ocean surface. It travels northeastward, passing through the Agulhas Passage and around the southern edge of the Agulhas Plateau, eventually reaching the Mozambique Basin.
Another deep current is the North Atlantic Deep Water (NADW). This water flows from the North Atlantic Ocean. It travels north of the Agulhas Plateau, also through the Agulhas Passage, and then splits to flow into other parts of the Indian Ocean.
Surface and Mid-Depth Currents
Closer to the surface, we find the Antarctic Intermediate Water (AAIW). This water starts near Antarctica and flows northward into the Indian Ocean. At about 1,500 meters (4,900 feet) deep, it then turns westward along the African coast before looping back eastward across the Agulhas Plateau.
The famous Agulhas Current is a powerful, warm current that flows southward along the east coast of Africa. When it reaches the area southwest of South Africa, it makes a sharp turn back into the Indian Ocean, becoming the Agulhas Return Current. As this return current encounters the Agulhas Plateau, it forms a large loop to go around it, showing just how big and influential this underwater plateau is!
See also
- African superswell
