Study Reconciles Long-Standing Contradiction of Deep-Earth Dynamics

Aug 25, 2005
Study Reconciles Long-Standing Contradiction of Deep-Earth Dynamics

Scientists at Columbia University's Lamont-Doherty Earth Observatory (LDEO) have solved a long-standing contradiction about the workings of the deep Earth.

Image: The chemical composition of ocean-island lavas support the idea that the Earth's deep mantle has been continually moving and mixing. Credit: LDEO

While some geochemists have argued that parts of the deep mantle have remained unchanged since the formation of the Earth, some geophysicists and others have believed that the entire mantle has been moving throughout geologic time. The question of whether the deep-Earth changes is central to scientists' understanding of the process of heat loss from deep beneath the surface.

LDEO earth scientists Cornelia Class and Steven Goldstein now show that the evidence favors a moving mantle, with the deepest parts of the Earth affected by the same tectonic processes that occur at the surface. The study appears in the Aug. 25 issue of the journal Nature.

"For 30 years scientists have debated whether there is a layer of the mantle that has remained unchanged since the formation of the Earth," said Class. "We found the strongest evidence yet that indicates the opposite is true."

Class and Goldstein's re-evaluation of this concept of the inner Earth is based on their work with two new databases: the Petrological Database of Ocean Floor Basalts (PetDB) and Geochemistry of Rocks from the Oceans and Continents (GEOROC).

Scientists have known that upper mantle basalt found at mid-ocean ridges, formed by sea-floor spreading, comes from previously formed oceanic and continental crust. The new global data synthesis demonstrates that ocean island lavas, chemically most like mid-ocean ridge basalt, were previously processed by plate tectonics, say Class and Goldstein, indicating that the deep mantle has been continually moving and mixing.

This result adds to growing evidence "that most of Earth's mantle has been subject to the same forces that drive the movements of Earth's crust," said Sonia Esperanca, a program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

Source: NSF

Explore further: Researchers discover low-grade nonwoven cotton picks up 50 times own weight of oil

add to favorites email to friend print save as pdf

Related Stories

Molecular gate that could keep cancer cells locked up

2 hours ago

In a study published today in Genes & Development, Dr Christian Speck from the MRC Clinical Sciences Centre's DNA Replication group, in collaboration with Brookhaven National Laboratory (BNL), New York, ...

Taking great ideas from the lab to the fab

3 hours ago

A "valley of death" is well-known to entrepreneurs—the lull between government funding for research and industry support for prototypes and products. To confront this problem, in 2013 the National Science ...

SR Labs research to expose BadUSB next week in Vegas

4 hours ago

A Berlin-based security research and consulting company will reveal how USB devices can do damage that can conduct two-way malice, from computer to USB or from USB to computer, and can survive traditional ...

Recommended for you

Rosetta measures comet's temperature

7 hours ago

(Phys.org) —ESA's Rosetta spacecraft has made its first temperature measurements of its target comet, finding that it is too hot to be covered in ice and must instead have a dark, dusty crust.

How Rosetta arrives at a comet

10 hours ago

After travelling nearly 6.4 billion kilometres through the Solar System, ESA's Rosetta is closing in on its target. But how does a spacecraft actually arrive at a comet?

Lunar occultation of Saturn

10 hours ago

On the night of Monday August 4, mainland Australia will see Saturn disappear behind the moon. It's the third time this year that the moon and Saturn will perfectly line up, as viewed from our part of the ...

User comments : 0