Kerguelen Plateau
A sunken microcontinent in the southern Indian Ocean, built by the Kerguelen hotspot.
Last updated
via Wikipedia: Kerguelen Plateau · see source
The Kerguelen Plateau, also called the Kerguelen–Heard Plateau, is an oceanic plateau and large igneous province on the Antarctic Plate in the southern Indian Ocean. Lying about 3000 km southwest of Australia and roughly as large as South Africa, it stretches more than 2200 km from northwest to southeast. Only small pieces rise above the waves: the French Kerguelen Islands and the Australian Heard and McDonald Islands, where volcanic activity still occurs. Its intrigue lies in its past, since much of it once stood above sea level as a forested microcontinent before sinking.
Quick Facts
- Area
- 1226230 km2
- Length
- More than 2,200 km / 1,367 mi
- Origin
- Kerguelen hotspot
- Submerged
- 20 million years ago
- Current depth
- 1000 - 2000 m below sea level
Facts from the source article.
Lore & Background
The plateau was built by the Kerguelen hotspot, which became active with or after the breakup of Gondwana about 130 million years ago. Over time the hotspot produced widely scattered structures: the Southern Kerguelen Plateau formed 120–110 million years ago, the Central Kerguelen Plateau 101–100, and the Northern Kerguelen Plateau much later.
Broken Ridge, now west of Australia, was once joined to the plateau before a mid-ocean ridge split them. The hotspot also built the 5000 km Ninety East Ridge between 82 and 38 million years ago. Parts such as the Elan Bank started as Indian continental crust and were stranded as India drifted north.
Reader's Guide
Covering 1226230 km2 and standing 2000 m above surrounding basins, it ranks among the largest igneous provinces anywhere. Charcoal and soil layers in its basalt show the land was exposed for three spells between 100 million and 20 million years ago; the southern section may have been an island of 500,000 km2.
Fossil wood suggests conifer forests of araucarians and cypresses. It sank 20 million years ago and now lies 1000 - 2000 m down. Sperm, minke and humpback whales feed along its southern end in summer.
Did You Know?
- A once-proposed land bridge between India and Antarctica across the plateau is now considered unsupported.
- The Southeast Indian Ridge and Southwest Indian Ridge meet near it at the Rodriguez Triple Junction.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Kerguelen Plateau (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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