The aim of this project is to study the present lithospheric structure of three anomalous regions along the

Alpine-Himalayan belt: The Atlas, Tibet and the Zagros mountains. Although these three zones have a

different geological history, with continental collision in the Himalaya and Zagros, and intra plate tectonic

inversion in the Atlas, they show similar unusual characteristics: low seismic velocities, basic volcanism,

an important dynamic topography component, and subcrustal mass deficit attributed to thinning of the

lithospheric mantle.

Recent works in petrology have shown the dependence of the density of the mantle on its composition,

temperature and tectonic evolution. With this project we aim to revise critically the mantle characteristics,

the mineralogical composition, and its effect on density, and quantify the thickness variations of the three

belts. This will permit us to characterize the mantle structure, evaluate the dynamic topography and its

stage of evolution, and estimate the mechanical processes responsible for lithospheric mantle thinning

(delamination, convective removal, slab break off, etc.).

To this end, we will use a combination of numerical techniques which integrate potential field equations

(gravity and geoid) with isostatic (elevation), thermal (heat flow and temperature distribution), and

petrophysical models. This novel use of petrophysical data will permit us to compare calculated seismic

waves velocities (Vp, Vs), from the pressure, temperature and mineralogical composition, with existing

seismic tomographic data.

Improving the understanding of the lithospheric structure beneath these orogens with a unified method will

enable us to critically evaluate the various geodynamic models that have been proposed for these three

mountain regions.

The candidate will apply existing numerical models that combine potential field equations with isostatic,

thermal and petrophysical models. This technique will permit to characterize the upper mantle beneath

one of these orogens, to contrast with the seismic velocities predicted by the tomography and to evaluate

the possible geodynamic processes that caused the actual situation.

Basic knowledge of computer programming, petrology and tectonophysics will be positively valued.

For more information contact with:

Ivone Jiménez-Munt and Manel Fernàndez

Instituto de Ciencias de la Tierra ‘Jaume Almera’ (ICTJA), CSIC

Lluís Solé i Sabarís s/n, 08028 Barcelona. Spain

Tel: +34 - 93 4095410