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<div>We'd like to call your attention to the following session at the
International Geological Congress, August 6-14, 2008, Oslo,
Norway.</div>
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<div><font face="Times New Roman" size="-1" color="#000000">Title:
Geophysical evidence for mantle heterogeneity<br>
Convener:<br>
Co-convenors:<br>
R. van der Hilst (hilst@mit.edu)<br>
H. Thybo (<u>thybo@geol.ku.dk</u>)<br>
A. Levander (alan@rice.edu)<br>
<br>
<br>
<br>
Significant mantle heterogeneity has been documented on all scale
lengths, primarily by application of seismological methods, but also
in exposures of upper mantle rocks. Recent studies provide new insight
into the origin of the heterogeniety by use of a variety of methods.
Seismic tomography very early demonstrated significant long wavelength
heterogeniety, which has been interpreted successfully in terms of
subduction and plume structure. In places controlled source
seismological methods have further increased the resolution of
heterogeneity in the upper mantle, and recently receiver function and
other direct imaging techniques have proven promising for improvements
in resolution. High resolution teleseismic migration methods
have shown that certain depth intervals may be very heterogeneous, in
particular the lithosphere and the D'' region at the base of the
mantle. There is considerable debate on the origin of the mantle
heterogeneity in terms of chemical-mineralogical variations and
physical properties.<br>
<br>
We invite contributions on documentation and interpretation of mantle
heterogeneity at any scale length, from outcrop to global, and
particularly encourage contributions that relate seismic velocity to
thermal state or chemical/mineralogical variation.<br>
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<div>Alan Levander<br>
Carey Croneis Professor and Chair<br>
<br>
Department of Earth Science<br>
Rice University<br>
6100 Main Street<br>
Houston, TX 77005<br>
<br>
713-348-6064<br>
713-348-5214 Fax<br>
<br>
http://earthscience.rice.edu<br>
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