Icy Ebb And Flow Influenced by Hydrothermal Activity
The last million years of Earth's history was dominated by the cyclic advance and retreat of ice sheets over large swaths of North America. During cold glacial intervals, ice sheets reached as far south as Long Island and Indiana, while during warm interglacial periods the ice rapidly retreated to Greenland. It has long been known that ice ages occur every 40,000 years or so, but the cause of rapid transition between glacial and interglacial periods has remained a mystery.
While conventional wisdom says that this icy ebb and flow is an interaction between the world's oceans, the ice itself, and the earth's atmosphere, an article appearing in the Jan. 28, 2016 issue of the journal Science sheds new light on the role that the earth itself may play in this climatological ballet.
David Lund of the Department of Marine Sciences at the University of Connecticut and his colleagues have studied hydrothermal activity along the mid-ocean ridge system -- the longest mountain range in the world which extends some 37,000 miles along the ocean floor. Their research suggests that the release of hot molten rock, or magma, from beneath the earth's crust in response to changes in sea level plays a significant role in the earth's climate. This change is attributed to the release of heat and carbon dioxide (CO2) into the deep ocean.
Lund says, "Mid-ocean range magmatism -- the release of molten rock through volcanic vents or fissures -- is driven by seafloor spreading and decompression melting of the upper mantle" -- the partially molten layer just beneath the earth's crust.
http://www.sciencenewsline.com/news/2016013010500040.html