| Antarctic plate | |
|---|---|
 | |
| Type | Major |
| Approximate area | 60,900,000 km2 (23,500,000 sq mi)[1] |
| Movement1 | South-west |
| Speed1 | 12–14 mm (0.47–0.55 in)/year |
| Features | Antarctica,Kerguelen Plateau,Southern Ocean |
| 1Relative to theAfrican plate | |
TheAntarctic plate is atectonic plate containing thecontinent ofAntarctica, theKerguelen Plateau, andsome remote islands in theSouthern Ocean and other surroundingoceans. After breakup fromGondwana (the southern part of thesupercontinentPangea), the Antarctic plate began moving the continent of Antarctica south to its present isolated location, causing the continent to develop a much colder climate.[2] The Antarctic plate is bounded almost entirely by extensionalmid-ocean ridge systems. The adjoining plates are theNazca plate, theSouth American plate, theAfrican plate, theSomali plate, theIndo-Australian plate, thePacific plate, and, across atransform boundary, theScotia andSouth Sandwich plates.
The Antarctic plate has an area of about 60,900,000 km2 (23,500,000 sq mi).[3] It is Earth's fifth-largest tectonic plate.
The Antarctic plate's movement is estimated to be at least 1 cm (0.4 in) per year towards theAtlantic Ocean.[4]
The Antarctic plate started tosubduct beneath South America 14 million years ago in theMiocene epoch. At first it subducted only in the southernmost tip ofPatagonia, meaning that theChile triple junction lay near theStrait of Magellan. As the southern part of theNazca plate and theChile Rise became consumed by subduction the more northerly regions of the Antarctic plate began to subduct beneath Patagonia so that the Chile triple junction lies at present in front ofTaitao Peninsula at 46°15' S.[5][6] The subduction of the Antarctic plate beneath South America is held to have upliftedPatagonia as it reduced the previously vigorous down-dragging flow in theEarth's mantle caused by the subduction of theNazca plate beneath Patagonia. Thedynamic topography caused by this uplift raisedQuaternary-agedmarine terraces and beaches across the Atlantic coast of Patagonia.[6]
