Volcanoes sparked `Jurassic ice age`

Washington D.C.: Around 170 million years ago, our world faced an ice-age and now, the scientists are trying to explore the causes behind it.

The international team of experts, including researchers from the Camborne School of Mines, has found evidence of a large and abrupt cooling of the Earth's temperature during the Jurassic Period, which lasted millions of years.

The scientists found that the cooling coincided with a large-scale volcanic event, called the North Sea Dome, which restricted the flow of ocean water and the associated heat that it carried from the equator towards the North Pole region.

The team suggest that it is this volcanic event, preventing the ocean flow, rather than a change in CO2 in the atmosphere (which causes today's climate change), that led to an extended Ice age in a period more synonymous with very warm conditions.

Geology expert Stephen Hesselbo said that they tend to think of the Jurassic as a warm 'greenhouse' world where high temperatures were governed by high atmospheric carbon dioxide contents, adding that this study suggests that re-organization of oceanic current patterns may also have triggered large scale climate changes.

Hesselbo further noted that though the occurrence of cold periods during greenhouse times have been known for a while, their origins have remained mysterious. This work suggests a mechanism at play that may also have been important for driving other climate change events in the Jurassic and at other times in Earth history.

The research appears in Nature Communications.