28 May, 2009 (16:00 GMT), 5 Merrion Square, Dublin 2.

Speaker: Dr. Juan Carlos Afonso (Macquarie University NSW, Australia).
Title: Internally consistent petrological-geophysical-geochemical models of the mantle: the next step.

Abstract:

One of the main challenges concerning the Earths upper mantle is the determination of its present-day thermal and compositional structure. This information represents the basis for any evolutionary model of the Earth, as well as for understanding the relationships between geophysical observables (e.g. electrical conductivity, seismic velocity, etc) and the physical state of the Earths interior. In this context, there have been signi¯cant advances over the past decade in the improvement and integration of geophysical, petrological, mineral physics, and geochemical data into self-consistent models of the Earth’s mantle. This has opened new promising approaches to study the mechanical and chemical interaction between the lithospheric and sub-lithospheric upper mantle. In this talk, I will review recent results from such interdisciplinary studies, and their implications for the interpretation of geophysical and petrological data. Firstly, I will brie°y evaluate some classic methods and their capability to distinguish thermal vs compositional signatures. Secondly, I will 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 ¯ts 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 lithospheresublithospheric upper mantle system.