[CIG-ALL] EGU22 | Session GD7.5 Physical state of the lithosphere-asthenosphere system: challenges and insights from integration of seismic tomography with potential field and mineral physics data

[Constanza Rodriguez Piceda]

Dear colleagues,

we want to draw your attention and invite you to contribute to our 
EGU-2022 session

GD7.5 Physical state of the lithosphere-asthenosphere system: challenges 
and insights from integration of seismic tomography with potential field 
and mineral physics data

https://meetingorganizer.copernicus.org/EGU22/sessionprogramme#GD7
https://meetingorganizer.copernicus.org/EGU22/session/42017

*Session description*: 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.
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.
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.

*Solicited author*: Saskia Goes

Kind regards,

Your conveners: Judith Bott, Constanza Rodriguez Piceda, Ajay Kumar, 
Javier Fullea, Stewart Fishwick

-- 
Constanza Rodriguez Piceda
Section 4.5: Basin Modelling
E-Mail: piceda at gfz-potsdam.de
___________________________________

Helmholtz-Zentrum Potsdam
Deutsches GeoForschungsZentrum GFZ
Stiftung des öff. Rechts Land Brandenburg
Telegrafenberg, 14473 Potsdam

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