A new angle on glaciations perhaps, but HeritageDaily quotes one of the researchers: ‘The mechanism driving these expansions of southern sourced water into the deep Atlantic still needs working on.’
The North Atlantic Ocean played a key role in the last great tipping point in Earth’s climate system, pioneering new research has shown. An international research team has discovered ground-breaking new reasons why large continental ice-sheets first grew in North America and Scandinavia during the late Pliocene Epoch era, 2.7 millions of years ago.
The collaborative team was led by Dr Ian Bailey from the University of Exeter and Prof Paul Wilson from the University of Southampton, and also involved scientists from Woods Hole Oceanographic Institute in the USA and GEOMAR in Germany. The researchers measured the composition of isotopes of the chemical element neodymium that can be found in fish teeth preserved in a North Atlantic marine core to track the origin of deep waters bathing the bottom of the Atlantic Ocean during this climate transition.
For the past 2.7 million years Earth’s climate has switched more than 50 times between a cold glacial state and warm interglacial state much like today. Contrary to previous assertions, they found that the first of these glacial events in the northern hemisphere were associated with major expansions of carbon-rich southern-sourced deep waters into the northwestern Atlantic abyss, over one million years earlier than previously thought.
The team also found that three of the largest glacial cycles between 2.5 and 2.7 million years ago appear to be associated with southern-sourced water incursions into the deep Atlantic that were as significant as those documented for the last glacial maximum.
The research is published in leading scientific journal, Nature Geoscience, on Monday, 4 April 2016. Dr Bailey, a Geology Lecturer from the Camborne School of Mines, based at the University of Exeter’s Penryn Campus in Cornwall said: “We could not have made these new findings with confidence using only a classic method for tracing watermass origin such as carbon isotopes.
“But when we combined such data with an alternative novel proxy such as neodymium isotopes, we were able to reveal a dramatically new picture of water mass mixing in the deep North Atlantic during late Pliocene glacial intensification.”