Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists aboard drilling vessel recover rocks from Earth’s crust far below seafloor

07.04.2005


But Earth’s elusive mantle is a near miss



Scientists affiliated with the Integrated Ocean Drilling Program (IODP) and seeking the elusive "Moho"--the boundary, which geologists refer to as the Mohorovicic discontinuity, between Earth’s brittle outer crust and its hotter, softer mantle--have created the third deepest hole ever drilled into the ocean bottom’s crust.

Scientists had hoped to drill into Earth’s mantle, but found instead that their efforts had missed the mark, they now believe by less than 1,000 feet. The X that marks the spot, they now think, is located a short distance to the side of the drill hole.


From the ocean drilling vessel, JOIDES Resolution, the researchers recovered rocks from more than 4,644 feet (1416 meters) below the sea floor that will provide valuable information about the composition of the Earth. And despite coming up short, "This is one of the best efforts to date," said Rodey Batiza, NSF program director for ocean drilling, "to drill into ocean crust and find mantle. It will provide important clues on how ocean crust forms."

IODP’s initial 10-year, $1.5 billion program is supported by two lead agencies, the U.S. National Science Foundation and Japan’s Ministry of Education, Culture, Sports, Science, and Technology.

Scientists aboard two consecutive oceanographic cruises, known as Legs 304 and 305, drilled into the Atlantis Massif, located at the intersection between the Mid-Atlantic Ridge and the Atlantis fracture zone. The central portion of this region is made up of a shallower sea floor feature than the area around it. That "core," scientists believed, would turn out to be composed of rocks that make up Earth’s lower crust and upper mantle, providing a first-ever opportunity to sample the mantle.

The cored rocks, however, are clearly part of Earth’s crust.

Benoit Ildefonse of the Université Montpellier, a co-chief scientist on the expeditions, said, "Deep coring in the ocean crust is a challenging endeavor, and has been a long-term goal for geoscientists since the late 1950s. Post-cruise research [on samples recovered by the drilling] will expand our knowledge of processes at slow spreading mid-ocean ridges, a key component of the Earth’s dynamics."

Co-chief scientists Ildefonse, Donna Blackman of the Scripps Institution of Oceanography, Barbara John of the University of Wyoming and Yasuhiko Ohara of the Hydrographic and Oceanographic Department of Japan, and IODP scientist Jay Miller of Texas A&M University led the expeditions, which drew scientists from IODP’s 18 member countries.

"The rocks cored," said John, "have compositions that represent some of the deepest crust ever sampled. They’re unique in ocean drilling records, and provide an unprecedented opportunity to learn about formation of Earth’s crust."

More drilling to locate the mantle may take place in the same location; at the end of the expedition, the drill hole was open and in good condition, IODP scientists said, and ready to be drilled deeper.

Miller said scientists have a largely preconceived idea of how the Earth evolved, based on previously acquired geophysical data. "The types of rocks we recovered show that this interpretation is oversimplifying many of the features of the ocean’s crust. Each time we drill a hole, we learn that Earth’s structure is more complex. Our understanding of how the Earth evolved is changing accordingly."

The Integrated Ocean Drilling Program (IODP) is an international marine research drilling program dedicated to advancing scientific understanding of the Earth by monitoring and sampling sub-seafloor environments. Scientists affiliated with IODP are conducting research on its principal themes: the deep biosphere, environmental change, and solid earth cycles.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>