Scientists have found new evidence showing the scale of the Late Antique Little Ice Age.

The University of Southampton team, working with Queen's University Canada and the Chinese Academy of Sciences, studied unusual rocks on Iceland's west coast.

They discovered that these rocks were carried by icebergs during a brief ice age that began around 540 AD and lasted 200 to 300 years.

This period of climatic cooling is believed to have played a significant role in the collapse of the Roman Empire.

Tom Gernon, professor of earth science at the University of Southampton, said: "When it comes to the fall of the Roman Empire, this climate shift may have been the straw that broke the camel's back."

The ice age is thought to have been triggered by volcanic ash from three massive eruptions, which blocked out sunlight and lowered global temperatures.

The scientists' findings, published in the journal Geology, provide new insights into a climate disruption that affected the wider North Atlantic region.

Dr Christopher Spencer, associate professor at Queen's University in Kingston, Ontario, and lead author of the research, said: "We knew these rocks seemed somewhat out of place because the rock types are unlike anything found in Iceland today, but we didn't know where they came from."

The team were able to pinpoint the source of the rocks by analysing the age and composition of tiny mineral crystals called zircon locked inside them.

Dr Spencer said: "Zircons are essentially time capsules that preserve vital information including when they crystallised as well as their compositional characteristics.

"The combination of age and chemical composition allows us to fingerprint currently exposed regions of the Earth’s surface, much like is done in forensics."

The team determined that these ice-rafted rocks were likely deposited during the 7th century, coinciding with a major climate shift known as the Bond 1 event.

Professor Gernon said: "This timing coincides with a known major episode of ice-rafting, where vast chunks of ice break away from glaciers, drift across the ocean, and eventually melt, scattering debris along distant shores."

Dr Spencer added: "What we’re seeing is a powerful example of how interconnected the climate system is."