Plankton Creates Mountains

A world without the great mountain ranges – the Himalayas, the Alps, the Rockies, the Andes – is unimaginable, but they were not always a part of the Earth’s geography. Mountains didn’t start forming widely until 2 billion years ago, half way through the planet’s history. Now our research has revealed how primitive life played a key role in their introduction to the planet.

While the formation of mountains is usually associated with the collision of tectonic plates causing huge slabs of rock to be thrust skywards, our study has shown that this was triggered by an abundance of nutrients in the oceans 2 billion years ago which caused an explosion of planktonic life.

Timeline for the formation of mountains on Earth. J Johnston/University of Aberdeen, Author provided

Making mountains
Mountains are not just a beautiful backdrop for recreation, they are essential to the way the world works, through their influence on weather, climate, the distribution of fresh water and the erosion of rock to make cultivable soil.

Before there were mountains, the plate movements that reshape the distribution of oceans and continents only occurred on a limited scale. But the movement of these plates are essential to making mountains. The pressure of one plate pushing against another – typically an ocean plate hitting a continental plate – causes slabs of ocean rock to break off and stack up on top of each other as they are pushed from behind.  READ MORE...

Ocean's Tiniest Orgasms Helped

Without an explosion in ocean life more than 2 billion years ago, many of Earth's mountains might never have formed, according to new research.

When tiny organisms in the shallows of the sea, like plankton, die and sink to the bottom, they can add organic carbon to Earth's crust, making it weaker and more pliable.

A case study of 20 mountain ranges around the world, including those in the Rockies, the Andes, Svalbard, central Europe, Indonesia, and Japan, has now linked the timing of high carbon burial in the ocean with the very generation of our planet's peaks.

"The additional carbon allowed easier deformation of the crust, in a manner that built mountain belts, and thereby plate margins characteristic of modern plate tectonics," the researchers write.

The changes seem to have begun roughly 2 billion years ago, in the middle of the Paleoproterozoic Era, when biological carbon from plankton and bacteria began to add exceptionally high concentrations of graphite to the ocean floor's shale. This made the rock brittle and more likely to stack.

Within 100 million years, most mountain ranges began to form in these weakened slices of crust. Mountain ranges that emerged more recently follow the same pattern.

In the Himalayas, for instance, tectonic thrusting around 50 million years ago was focused on Paleoproterozoic sediments with the most organic-rich beds.

The timing and location implies that biological carbon in graphite continues to shape the geology of our planet.  READ MORE...