Macquarie Island

Description

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Context

Macquarie Island is the only piece of land on the planet formed completely from the ocean floor.

Details

Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica.
Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 1978 and was inscribed as a UNESCO World Heritage Site in 1997.
The island is home to the entire royal penguin population during their annual nesting season. Ecologically, the island is part of the Antipodes Subantarctic Islands tundra ecoregion.
Macquarie Island is an exposed portion of the Macquarie Ridge and is located where the Australian Plate meets the Pacific Plate. The island lies close to the edge of the submerged continent of Zealandia but is not regarded as a part of it, because the Macquarie Ridge is oceanic crust rather than continental crust.
It is the only place on Earth where rocks from the Earth's mantle(6 km below the ocean floor) are being actively exposed above sea-level. These unique exposures include excellent examples of pillow basalts and other extrusive rocks. It also is the only oceanic environment with an exposed ophiolite Due to these unique geological exposures, it was made a UNESCO World Heritage Site.