[Geodynamics] IUGG 2023, Session "Integrating Seismic Tomography with Mineral Physics and Potential Fields to Describe the Crust and Upper Mantle Physical State”

[Ajay Kumar]

Dear colleagues,

We would like to draw your attention to the *28th IUGG General 
Assembly*, *11-20 July 2023, Berlin* and our session *S18 *titled*  
“Integrating Seismic Tomography with Mineral Physics and Potential 
Fields to Describe the Crust and Upper Mantle Physical State”*.

We welcome your contributions that discuss advances, challenges, and 
applications in the interpretation of seismic tomography by using 
seismology independent observations to understand the dynamics of the 
lithosphere (details below).

The *abstract submission deadline is 14 February, 2023*. For more 
information, please visit 
https://protect-au.mimecast.com/s/VTJ4Cr81nytAvA269C7mhTC?domain=iugg2023berlin.org 
<https://protect-au.mimecast.com/s/VTJ4Cr81nytAvA269C7mhTC?domain=iugg2023berlin.org/>.

Best wishes from the conveners

Judith Bott, Ajay Kumar, Magdalena Scheck-Wenderoth, Ulrich Achauer

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*

/Session description /

/To understand plate tectonics as driven by mantle thermodynamics and 
gravitational forces at interplay with rock rheology, we need 
comprehensive images of the in-situ physical properties (density, 
viscosity) and underlying state conditions (pressure, temperature) of 
the lithospheric plate and its transition into the upper mantle. Once 
the present-day physical state of such a system is defined, the 
intrinsic deviatoric stress field and the mantle sources of heat 
contributing to active plate deformation can be calculated. One key 
insight into the crust and upper mantle physical state is provided by 
seismology, namely tomography imaging of seismic velocity perturbations. 
Their interpretation in terms of composition and temperature conditions, 
however, is highly non-unique. Despite an ever-growing amount of 
laboratory-derived relationships between the seismic velocity of mantle 
minerals and their pressure and temperature derivatives of density and 
elastic constants, inversion of seismological information for in-situ 
bulk rock temperature is an ill-posed problem. In addition, effects of 
anelasticity, e.g., frequency-dependent wave velocity, grain size and 
fluid content, are important, but less well explored. To reduce the 
number of potential solutions, additional independent information on 
crustal configuration and mantle composition, temperature, pressure and 
density can help. As alternative to thermodynamics-based inversions, 
empirical approaches to calculate mantle temperature from seismic 
tomography models implicitly assume some fixed mantle composition or 
calibrate tomography models with respect to thermal models of the 
lithosphere and/or pressure-temperature estimates from mantle xenoliths. 
With this session, we intend to resume an open discussion on how to best 
exploit mantle seismic velocity models to derive conclusions on the 
composition and pressure-temperature conditions within the upper 
(including lithospheric) mantle. We invite contributions integrating 
multidisciplinary data on the crust and mantle (geological, seismic, 
heat flow, potential fields, xenoliths) with tomographic models to 
identify rheological variability exerting the most significant impacts 
on crustal and surface deformation./

-- 
Dr. Ajay Kumar
Section 4.5, Basin Modelling
Phone: +49 (0)331/2882828
Fax: +49 (0)331/2882828
Email:kumar at gfz-potsdam.de
___________________________________

Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Foundation under public law of the federal state
of Brandenburg
Telegrafenberg, D-14473 Potsdam
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