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<p>Dear colleagues, <br>
</p>
<p>we want to draw your attention and invite you to contribute to
our EGU-2022 session <br>
</p>
<p><font size="5" color="#00589c">GD7.5 Physical state of the
lithosphere-asthenosphere system: challenges and insights from
integration of seismic tomography with potential field and
mineral physics data </font><br>
</p>
<div align="center"><a class="moz-txt-link-freetext" href="https://protect-au.mimecast.com/s/dVVNCgZ0N1iAQBBEXuNtDuR?domain=meetingorganizer.copernicus.org">https://meetingorganizer.copernicus.org/EGU22/sessionprogramme#GD7</a>
<br>
<a class="moz-txt-link-freetext" href="https://protect-au.mimecast.com/s/xpweCjZ1N7inNOOoLFRf26N?domain=meetingorganizer.copernicus.org">https://meetingorganizer.copernicus.org/EGU22/session/42017</a></div>
<div align="center"> <br>
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<b><font color="#00589c">Session description</font></b>: The
original theory of plate tectonics is a kinematic model with forces
only representing qualitative measures. To understand inter- and
intraplate dynamics driven by mantle thermodynamics and
gravitational forces at interplay with rock rheology, we need
comprehensive images of the in-situ material properties (density,
viscosity) and underlying state conditions (temperature T, pressure
P) of the lithospheric plate and its transition into the upper
mantle.<br>
One key insight into the mantle physical configuration is provided
by seismology, namely tomography imaging of seismic velocity
perturbations. The interpretation of seismic velocity in terms of
mantle composition and T and P conditions, however, is highly
non-unique. Despite an ever-growing data pool of laboratory-derived
relations between seismic velocity of mantle minerals and their T
and P derivatives of density and elastic constants, inversion of
seismological information for in-situ bulk rock T is an ill-posed
problem. To reduce the number of potential solutions, we rely on
additional independent information on mantle composition, T and P
(such as from xenoliths) and mantle density (such as from gravity
field data). In addition, effects of anelasticity (e.g., frequency
dependent wave velocity), grain size and fluid content should be
considered, but these material behaviors are currently less well
explored. An alternative to thermodynamics-based inversions is
provided by empirical approaches to calculate mantle temperature
from seismic tomography models. Finally, the diversity and
inconsistency of seismic tomography models for any specific region
can result in a correspondingly wide spectrum of derived mantle
temperature configurations.<br>
With this session we intend to resume open discussions on how to
exploit mantle seismic velocity models to derive valuable
conclusions on the composition and temperature-pressure conditions
within the upper and lithospheric mantle. Thus, we want to focus on
those mantle domains revealing the largest rheological variability
and exerting strongest impacts on crustal and surface deformation.
The session is intended to cover the multi-disciplinary spectrum of
observations and interpretations for the upper mantle configuration.
We invite contributions addressing state-of-the-art techniques, case
studies that combine mantle seismic velocities with
seismology-independent observations as well as presentations that
highlight the challenges and inconsistencies in the field.<br>
<br>
<font color="#00589c"><b>Solicited author</b></font>: Saskia Goes<br>
<br>
Kind regards, <br>
<br>
Your conveners: Judith Bott, Constanza Rodriguez Piceda, Ajay Kumar,
Javier Fullea, Stewart Fishwick
<pre class="moz-signature" cols="72">--
Dr Judith Bott
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Section 4.5 Basin Modelling
Telegrafenberg
14473 Potsdam
Phone +49 (0)331 288 1342 </pre>
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