Macqarie Island
Macqarie Island in Australia and Gros Morne National Park in Canada have mantle-derived rocks that have risen to the surface.
Claims that there are only one or two places on Earth where people can “walk on the mantle” regularly circulate online, confusing scientific nuance with geological wonder.
Although the idea seems unlikely given that the mantle lies beneath the Earth’s crust and typically requires drilling kilometers deep to reach, geologists claim that there are, in fact, some rare places where the mantle rocks were brought to the surface.
Under normal conditions, Earth’s structure is stratified: crust on the surface, mantle underneath, followed by the outer and inner core. Volcanic eruptions bring material from the mantle to the surface in the form of lava, but once it cools, it becomes part of the crust. So simply standing on volcanic rocks is not equivalent to walking directly on the mantle.
The strongest case of actual mantle exposure is the Macquarie Islanda remote territory of Australia in the sub-Antarctic region. In 1997, UNESCO designated the island as a World Heritage Site, describing it as “the only place on Earth where tectonic forces have brought rocks derived from the oceanic mantle to the surface in the context of a currently active tectonic plate boundary.” Unlike volcanic landscapes, Macquarie Island largely consists of intact mantle material that has been thrust upward without melting.
The island sits on a 1,600-kilometer underwater mountain range formed where the Indo-Australian and Pacific plates meet. Although most of this mountain range remains submerged, mantle rocks have been forced to emerge above sea level at Macquarie Island and some nearby outcrops. The island itself is small and rigorously protectedwith the number of visitors limited to preserve its recovering wildlife, says .
A more accessible location is Gros Morne National Parkin Newfoundland, Canada, which also has the title of UNESCO World Heritage Site. The park’s plateaus expose ancient rocks from the oceanic mantle and crust that date back almost 500 million years. These iron-rich rocks, often red on the surface and green beneath, are inhospitable to vegetation and clearly visible, making Gros Morne one of the most studied mantle exposures on Earth.
However, the claim that only two places allow for cloak “walking” is debated. Similar geological formations exist elsewhere in Newfoundland, and Charles Darwin himself observed mantle-derived uplift in the St. Peter and St. Paul Archipelago in the South Atlantic. These small islands are rarely mentioned due to its size and vulnerability to rising sea levels.
Although it remains uncertain whether these are the only exposures of the Earth’s mantle, Macquarie Island and Gros Morne stand out as the sharpest and most impressive places where the planet’s deep interior can be explored on foot.
