Sea level data spanning 35 million years pulled from 6,000-foot hole

Last Updated: Wed, Jan 27, 2010 10:20 hrs

A team of scientists has drilled more than 6,000 feet into the Earth's crust, making it the deepest hole in scientific ocean drilling history, which has retrieved a 35-million-year record of sea level fluctuations.

For eight weeks beginning in November 2009, off the coast of New Zealand, an international team of 34 scientists and 92 support staff and crew on board the scientific drilling vessel JOIDES Resolution (JR) were at work investigating sea level change in a region called the Canterbury Basin, according to the US National Science Foundation (NSF).

The JR is one of the primary research vessels of an international research program called the Integrated Ocean Drilling Program (IODP).

"At present, 10 percent of the world's population lives within 10 meters (33 feet) of sea level. Current climate models predict a 50-centimeter (20-inch) to more than one-meter (39 inches) rise in sea level over the next 100 years, posing a threat to inhabitants of low-lying coastal communities around the world," NSF said.

To better understand what drives changes in sea level and how humans are affecting this change, scientists are "looking to our past for answers and digging back as far as 35 million years into the Earth's history to understand these dynamic processes," said Rodey Batiza of the NSF's division of ocean sciences.

From November 4, 2009 to January 4, 2010, the IODP research team drilled four sites in the seafloor.

Canterbury Basin was selected as a premier site for further sea level history investigations because it expanded the geographic coverage needed to study a global process.

Data from both the Canterbury Basin and the New Jersey shelf IODP expeditions will be integrated to provide a better understanding of global trends in sea level over time.

The Canterbury Basin expedition set out to recover seafloor sediments that would capture a detailed record of changes in sea level that occurred during the last 10 to 12 million years, a time when global sea level change was largely controlled by glacial/interglacial ice volume changes.

The research team also recovered samples documenting changes in ocean circulation that began when movements in Earth's tectonic plates separated Antarctica from Australia, creating a new seaway between the two continents about 34 million years ago.

"Canterbury Basin is one of the best sites in the world for this type of survey because it is located in a tectonically-active region and therefore has a relatively high rate of sedimentary deposition, which, like the pages of a book, record detailed events in Earth's climate history," the researchers said. (ANI)