Our new Evolution Timeline rocks

Rocks have become life. As rocks erode and flow into the oceans and weather into soil, their minerals provide vital nutrients that underpin both the abundance and evolution of life.

In turn, life has become rocks. Coal was once prehistoric forests of seed ferns and other plants. Millions of years ago tiny marine creatures sunk to the bottom of the ocean and became limestones such as chalk.

You can experience the interconnectedness of rocks and life in our new Evolution Garden, where rocks, fossils, plants and sculpture tell the story of evolution and geological change.

Begin your journey with the UK’s oldest rocks

When you arrive at the Natural History Museum by Tube and walk from the underground station through the South Kensington subway, you’ll emerge into our new Evolution Garden. Your journey will begin in an immersive timeline canyon of ancient rocks that leads you through geological time, from the oldest rocks in the UK to the present day.

“When you come out of the TFL tunnel, you walk into a canyon where you’re able to literally touch the oldest rocks in the UK. These are more than 2.7 billion years old,” says our Principal Researcher Dr Paul Kenrick, who’s been advising on the garden’s design.

“The whole garden then opens up in front of you,” he adds.

The canyon’s walls are made of ancient rocks from Scotland, and further along there’s also rocks from England, Wales and Northern Ireland. In total there’s more than 26 different types of rock, spanning Earth’s geological time periods.

“Each of the rocks is associated with a time period,” explains Paul.

To give you a sense of the length of geological time as you journey through, we’ve created our Evolution Timeline so that the length of each time period in millions of years is scaled to the distance along the path. One metre marks five million years.

Starting at the beginning of the Cambrian Period around 540 million years ago, it then moves through the Ordovician, Silurian, Devonian and Carboniferous periods, all the way to the present.

Each of these geological periods is represented by one or more rocks from the UK either in the timeline wall or the landscaping.

The oldest rock in our garden comes from the Western Isles and the west coast of Scotland, where a rock formation called the Lewisian Gneiss Complex contains the oldest rocks in the UK. Gneiss has a very distinctive banding where the minerals crystallise out and form distinctive darker and paler bands.

“We also have rocks that formed in the Cambrian Period. There’s a dark, purply grey slate from North Wales and a white quartzite from Scotland. This quartzite is a familiar feature of the landscape of the Northwest Highlands. These two rocks were formed in the same period, but in very different ways,” explains Paul.

As you move through the garden, you can touch many more rocks, including a red sandstone from Scotland that formed in the Permian Period. This sandstone was laid down in a desert dune system. “It’s kind of striking and really amazing to think that back in the Permian Period there were deserts in Scotland,” remarks Paul.

The importance of granite

Some of the granite in our Evolution Garden is part of a large formation found deep underneath Cornwall and Devon. Called the Cornubian batholith, it dates back to 295 to 275 million years ago when all the world’s land masses came together to form the supercontinent Pangea. This granite was in fact formed when the huge landmass Gondwana collided with continents in the northern hemisphere.

Today, you can see this type of granite exposed on the surface in places such as Dartmoor, Bodmin Moor, St Austell, Land’s End and the Isles of Scilly. Ours comes from Carnmenellis near Redruth in Cornwall. Historically it’s been mined for the tin, copper, tungsten and lead it contains.

Chalk is living creatures turned to rock

Chalk is formed out of the calcite shells and scales of plankton – marine microorganisms that are far too small to see by eye. It commonly contains bands of very hard flint nodules, which are formed from a type of quartz. Marine organisms are also the source of the silica in these nodules. We’re using chalk from Northern Ireland in the garden rather than chalk from southern England because it’s much harder and less easily weathered.

Much of southern England is sitting on a bedrock of chalk and this has resulted in a very distinct landscape, including the iconic White Cliffs of Dover. These chalk habitats are home to a unique range of plants and animals. If you head over to the other side of our gardens, you’ll find a small chalk meadow where you can see these animals and plants for yourself.

The largest mass extinction event is marked with volcanic rock

As you walk through time in our gardens, you’ll pass through the biggest extinction event in Earth’s history – the Permian-Triassic extinction, marked with a band of red rock called scoria.

This scoria is the youngest rock in the garden, and it was formed in a volcanic eruption in Iceland. “This is a volcanic rock, as we think that this extinction was driven by processes within Earth itself as a massive outpouring of volcanic gases,” explains Paul.

More than 90% of life on Earth disappeared in this extinction event. Luckily, some life survived, leading to the age of dinosaurs.

Spot these rock-stars

A London icon: Portland stone

In the Jurassic part of the garden – one of the three periods when dinosaurs thrived – we’re using a pale limestone called Portland stone. This rock comes from southern England and is well known in London because it’s widely used in buildings.

You can see this stone in the V&A’s building across the road from us in South Kensington. A number of other buildings in London are made from this stone, including St Paul’s Cathedral, the Cenotaph and the Monument to the Great Fire of London.

Unlike the perfect stone used for those buildings, the Portland stone we’re using around our bronze Diplodocus has fossils of marine molluscs in it.

Where giants walk: Columnar basalt

In our Evolution Garden you’ll see columnar basalt. It’s the rock the famous Giant’s Causeway formation in Northern Ireland is made from, though we got ours from Iceland.

Columnar basalts are formed when a large lake of lava cools slowly and evenly, shrinking to create hexagonal-shaped columns. The lavas of the Giant’s Causeway formed when the ancient continent of Laurasia began to fragment, causing the opening of the northern part of the Atlantic Ocean.

A slice of Stonehenge: Sarsen stones

At the end of our timeline wall we’ve included amazing sarsen stones – big blocks of quartz-cemented sandstone that sit in the chalk landscape of the UK.

“Famously they were used by Neolithic people to build things and they’re still quite widely used to build walls and buildings today,” says Paul.

The rocks in our garden came from near to where the sarsen megaliths of Stonehenge are originally from in West Woods, Wiltshire, in southwest England. These stones formed in river systems where water flowed through sands, and those sands became cemented by silica in the water.

Over time, the landscape erodes away and leaves these stones just sitting on the surface of the chalk, where they’re thought to indicate the position of river channels some 20–30 million years ago

Come and see these rocks and the new gardens for yourself.