The lithospheric/sub-lithospheric upper mantle system: Advances and limitations from recent multidisciplinary studies

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Afonso, Juan Carlos; Fernandez, Manel; Fullea, Javier; Zlotnik, Sergio
Holding Date 16 September 2008

There have been significant advances over the past decade in the determination of the thermal and compositional structure of the upper mantle. The improvement and integration of geophysical, petrological, mineral physics, and geochemical data into self-consistent models have opened new promising approaches to study the mechanical and chemical interaction between the lithospheric and sub-lithospheric upper mantle. Such models provide the necessary information to link geophysical and geological data with evolutionary models of the lithospheric/sub-lithospheric upper mantle system.
In this talk, we will review recent results from such interdisciplinary studies, and their implications for the interpretation of geophysical and petrological data. Firstly, we will evaluate recent seismological models and their capability to distinguish thermal vs compositional signatures. For this, we present the results of a systematic exploration of the effects of thermal and compositional heterogeneities in seismic velocities applying 1) both thermodynamically self-consistent and hybrid methods, 2) the latest mineral physics databases, and 3) recent anelasticity measurements on olivine aggregates at seismic frequencies.
Secondly, we present results from 2D and 3D forward, inverse, and dynamic models based on a self-consistent combination of petrological, mineral physics, and geophysical information. Using this approach we obtain lithospheric/sublithospheric thermal and compositional models that simultaneously fits all available geophysical and petrological observables, which reduce the uncertainties associated with the modelling of these observables alone or in pairs.
Finally, we discuss future technical and observational advances that will be required to further expand our understanding of the lithosphere-sublithospheric upper mantle system.