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Ancient 'Snowball Earth' still had seasons

An artist's impression of 'snowball Earth'Getty Images

The snowball Earth theory suggests the planet was covered by ice during at least two extreme cooling events

A new study suggests Earth still had seasons and changes in its climate during its ancient Ice Ages.

Scientists at the University of Southampton been studying rocks that they say provide evidence of a period called 'Snowball Earth'.

The 'Snowball Earth' idea is that the planet's oceans and land were covered by ice during at least two extreme cooling events between 2.4 billion and 580-million-years-ago.

It was originally thought these conditions plunged Earth into a deep-freeze. But the new study suggests that seasons still happened every year, decade and century - just like today.

Professor Thomas Vernon, who took part in the study, said the discovery was "jaw-dropping".

Grassy, craggy Gravellach Islands in West Scotland are evidence of how old earth is. University of Southampton

The ancient rocks in Scotland show the climate did indeed fluctuate and have seasons, even during snowball Earth.

Scientists looked at layered rocks, known as varves, on the Garvellach Islands off the west coast of Scotland.

These rocks were deposited during a massive freeze, known as the Sturtian glaciation - which lasted a whopping 57 million years!

Scientists believe the rocks show the transition into 'Snowball Earth' from a previously warm and tropical environment.

Analysing the rocks showed that the layers likely formed through seasonal freeze-melt cycles. They found the cycles repeated every few years to decades.

Lead researcher Dr Chloe Griffin said: "These rocks are extraordinary. They act like a natural data logger, recording year-by-year changes in climate during one of the coldest periods in Earth's history."