Seafloor Sediment Cores from Wilkes Land Offer Insight into Past and Future Climates
19.02.2010 - Atmosphere & Space, Water & Oceans, Land & Geology, Ice & Snow, Flora & Fauna, Antarctic
From onboard the JOIDES Resolution, a ship operated by the International Ocean Drilling Program (IODP), morethan 30 researchers from institutions including Stanford University have been drilling into the seafloor to collect sediments as old as 50 million years in an attempt to find clues about Earth's past climate.
The expedition to Wilkes Land in the deep sea off the East Antarctic Ice Sheet, has seen scientists extract sediment cores from strata laid down over the last 50 million years under the ocean, hauling up more than 2 km of sediment cores for analysis. Antarctica had a much milder climate and was covered with forests 50 million years ago, but the team is particularly interested in sediments from 34 million years ago, when a transition from a warm climate to a cooler one took place. Scientists believe this transition might have been triggered by changes in the levels of greenhouse gases in the atmosphere.
The main reason to drill in Wilkes Land is that it is covered by the East Antarctic Ice Sheet, the oldest and largest polar ice field on the planet. The team now seeks to determine whether this part of the Antarctic ice was unstable during past intervals of warming so they can hopefully learn more about future sea levels.
In addition to their climate work, the researchers are using the sediments to view Antarctica's tectonic history. Some of the sediments may have been eroded from Tasmania or other parts of Australia millions of years ago when the two continents were separated by only a few hundred kilometers. Fossil diatoms, common in seafloor sediments, will be used to determine the age of the sediment layers.
