Forum for Science, Industry and Business
Sponsored by:     Siemens  n-tv 
Search our Site:

Topic (optional):

 

Home Reports Earth Sciences Content

Crystallographers explain seismic anisotropy of Earth’s D’’layer

next article
12.05.2006

 


ETH researchers discovered a very unusual mechanism of plastic deformation in the Earth’s mantle. Furthermore, they have predicted a new family of mantle minerals. These discoveries shed new light on the plastic flow of mantle rocks inside our planet - the process that controls plate tectonics and the associated earthquakes, volcanism, and continental drift.


Plastic flow in the Earth’s mantle is the microscopic process behind plate tectonics and the associated continental drift, volcanism and earthquakes. Seismic anisotropy is the main signature of plastic flow inside the Earth. Its character depends on the properties of Earth-forming minerals. Simulations have provided a new insight that leads to a more consistent picture of the dynamics of our planet. According to seismic observations, the lowermost 150 km of the Earth’s mantle, known as the D"layer, possess many unusual properties. Many of these anomalies were explained by the properties of post-perovskite (Mg,Fe)SiO3, the dominant mineral of the D"layer. Still, it remained difficult to explain the observed strong seismic anisotropy of the D"layer. Now, thanks to metadynamics, a novel simulation methodology, ETH researcher Artem R. Oganov and colleagues have explained these seismic observations. They came up with an unexpected mechanism of plastic deformation of post-perovskite involving the formation of nanoscale slices of the lower-pressure perovskite structure along the (110) planes of post-perovskite. The ETH researchers could show that this mechanism fully explains the observed seismic anisotropy and some geophysical observations are consistent only with this mechanism.

New minerals in the Earth’s mantle

Structures containing slices of the perovskite and post-perovskite structures are not only a result of plastic deformation. Researchers have predicted a whole infinite family of minerals of the same composition, (Mg,Fe)SiO3, built of alternating nanoscale slices of the perovskite and post-perovskite structures. According to quantummechanical calculations of ETH researcher Artem R. Oganov and colleagues, such unusual minerals could become important stable minerals in the Earth’s mantle. Several research groups are now trying to synthesize these predicted minerals. If successful, these attempts will lead to a new mineralogical model of the Earth’s interior. The research results have been published in the end of 2005 in "Nature".

For more information and pictures:
Prof. Artem R. Oganov
ETH Zurich, Laboratory of Crystallography
Phone +4 +41(0)44 632 37 52 or +41(0)43 300 18 73
E-Mail a.oganov@mat.ethz.ch

Anke Poiger | Source: Informationsdienst Wissenschaft
Further information: www.crystal.mat.ethz.ch/research/theory_proj
www.nature.com/nature/journal/v438/n7071/full/nature04439.html

next article

More articles from Earth Sciences:

nachricht NASA's QuikScat and Aqua providing important data on Tropical Storm Anja
20.11.2009 | NASA/Goddard Space Flight Center

nachricht Oceans' uptake of manmade carbon may be slowing
19.11.2009 | The Earth Institute at Columbia University

All articles from Earth Sciences >>>

B2B Search

Product / Service
Company / Organisation

Latest News

Scientists Unravel Evolution of Highly Toxic Box Jellyfish

20.11.2009 | Life Sciences

When good companies do bad things: Examining illegal corporate behavior

20.11.2009 | Business and Finance

UCR plant scientist's research spawns new discoveries showing how crops survive drought

20.11.2009 | Agricultural and Forestry Science

VideoLinks

Event News

Multidisciplinary meeting on Urological Cancers aims to benefit cancer patients

20.11.2009 | Event News

'Golden Age' for clinical psychology in Northern Ireland

20.11.2009 | Event News

New Perspectives in Marine Anti-Fouling Research

11.11.2009 | Event News