March 18, 2013
Inner Earth Could Have Caused Ancient Climate Change
Lee Rannals for redOrbit.com — Your Universe OnlineNew York University and Ottawa's Carleton University scientists say activity below the earth's surface has played a role before in ancient rises in sea levels and global warming. Although it may seem like welcoming news for climate change skeptics, the authors point out these changes took place in periods ranging from 60 million to 140 million years.
The team's analysis considers long-term fluctuations in global climate, diversity of marine organisms, and sea level changes, hoping to identify a unified cause for all of these changes. Little scientific attention has focused on the changes that have taken place deep within our planet, while most of the focus has been on what has happened above the earth's crust.
In past studies, researchers have examined the upwelling of mantle plumes, which is the rising of heated rocks from the Earth's mantle. These plumes have an impact on the eruption of large igneous provinces (LIPs), which are large accumulation of rocks formed from congealed lava.
For the latest study, the team observed mantle plumes coincide with cyclical surface changes, which suggests the plumes may be cyclical in nature. They found many geological changes had cycles of 60 and 140 million years, suggesting the cyclical uprising of these plumes help form hotspots.
They also write that mantle plumes push up against the earth's crust, shifting water to continents, producing sea-level rise. This also creates volcanic activity, which produces additional CO2 and leads to a warmer climate.
"Mantle plumes appear to show regular cycles," said Michael Rampino, of New York University. "So what's remarkable is there is a strong indication of a connection between changes on the earth's surface–such as volcanic activity and rising sea levels–and what's occurring deep inside the earth. This suggests a fascinating and powerful union between below-surface geological events and changes in our climate."
Scientists described a new technique in Science in February that could help reveal the composition of the interior of Earth. Researchers from Amherst College and the University of Texas at Austin developed a technique that relies on a fifth force of nature that has not been detected yet, known as “long-range spin-spin interaction.” This new force would connect matter at Earth's surface with matter deep in the mantle, hundreds to thousands of miles below.
“If the long-range spin-spin interactions are discovered in future experiments, geoscientists can eventually use such information to reliably understand the geochemistry and geophysics of the planet´s interior,” Jung-Fu “Afu” Lin, associate professor at The University of Texas at Austin´s Jackson School of Geosciences, said in a statement.