The Supermountains That Dwarfed The Himalayas

Summary

Earth’s surface is continually reshaped by plate tectonics: plates collide, separate, sink, and melt, while mountain ranges are gradually worn down by erosion. The Himalayas formed when the Indian Plate collided with the Eurasian Plate roughly 40–50 million years ago. The collision continues today: India is moving north, and Everest is still rising slowly. Some geologists think part of the Indian Plate may be sliding beneath Eurasia, adding extra crust beneath the range.

What counts as the “highest mountain” depends on how height is measured. Everest is highest above sea level, but other contenders lead by different measures: Chimborazo is farther from Earth’s center because Earth bulges at the equator; Denali has a greater rise from its base above sea level; and Mauna Kea rises farther from its seafloor base to its summit.

Ancient supermountain ranges

The video describes three ancient supermountain ranges—ranges notable for their enormous length and area, not necessarily for being taller than the Himalayas:

• Central Pangaean supermountains: Formed when Gondwana and Laurentia collided as Pangaea came together. Their remnants include parts of the Appalachians, Scottish Highlands, Scandinavian Mountains, and Atlas ranges. The Atlantic Ocean later opened through the former mountain belt.
• Transgondwanan supermountains: Formed as eastern and western parts of Gondwana collided. The range may have stretched more than 8,000 km and is described as possibly the largest mountain range in Earth’s history.
• Nuna (or Columbia) supermountains: Formed during collisions between ancient continental cores, or cratons, around 2.1–1.8 billion years ago. Their original dimensions are highly uncertain.

Because erosion has largely erased these ranges, scientists infer their former size from geological clues. The video outlines one approach:

1. Find ancient zircons with unusually low lutetium content.
2. Heavy mountain belts create intense pressure beneath them, encouraging garnet formation.
3. Garnets absorb lutetium, leaving nearby zircons depleted in the element.
4. This pattern can indicate that a large mountain range once existed above the rocks.

The evidence can suggest the scale of the former mountains, but it cannot establish their exact height.

Mountains, erosion, and life

The video presents a proposed connection between mountain building and the evolution of life. As mountains eroded, they delivered minerals and nutrients—including calcium, iron, and phosphorus—to the oceans. This may have affected biological change around the emergence of early eukaryotic life and, later, the Cambrian explosion. The enormous sediment deposits associated with Gondwana’s erosion illustrate the scale of this process. The connection is presented as a possible influence, not a settled explanation.

Limits on mountain height

Whether Earth’s ancient supermountains exceeded Everest remains uncertain. The video notes two limits on mountain growth: glaciers can erode peaks above the snow line, and the weight of very large mountains can push the crust downward. These factors support a debated theoretical upper limit of about 10,000 metres, putting Everest relatively close to it.

Mountains beyond Earth

For comparison, Olympus Mons on Mars reaches about 21,287 metres above the Martian surface. Mars’s weaker gravity, thinner atmosphere, and lack of moving plates allow a volcano to grow for a long time over one hotspot.

The video also discusses Rheasilvia’s central peak on asteroid Vesta. It is about 23 km above the crater floor, though much lower when measured from Vesta’s average surface. These examples highlight how definitions and measurement methods affect claims about the “tallest” mountain.

Researchers and sources featured

• Shanan Peters — Geoscientist at the University of Wisconsin; discussed the effects of continental weathering on seawater and life.
• Mike Akerson — Geologist at the Smithsonian Institution; interviewed for the documentary The Oldest and Newest Places on Earth.
• Jesse Remnick — Planet Geo podcast; joined the documentary filming with Mike Akerson.
• USGS volcanologists — Consulted about Hawaiian volcanism and the formation of the Hawaiian Islands.