A detailed crust to upper mantle structure: Comparison between Algerian
and Alboran domains in the Western Mediterranean
Abstract
We present a comparison of the detailed present-day crust to
upper-mantle (400km) structure in the Western Mediterranean along two
transects in Alboran and Algerian domains. The transect across the
Alboran domain is NW-SE oriented crossing the Betics and the Alboran
Basin and the northern margin of Africa between the Tell and Rif
mountains. The Algerian domain transect is also NW-SE oriented crossing
the Valencia Trough, the Balearic Promontory, the Algerian basin and
ending in the Tell-Atlas Mountains in the northern margin of Africa. The
structure is computed using integrated geophysical-petrological
modelling tool (LitMod2D) which combines petrological, geochemical and
geophysical dataset in a self-consistent framework. We model thermal,
compositional, density and seismological structure, also incorporating
slabs imaged by seismic tomography, constrained by simultaneously
fitting elevation, gravity, geoid, surface heat flow and seismic
tomography models to reduce the uncertainties in the modelling.
Preliminary results suggest that crust is thickest beneath the Betics
and thins beneath the Alboran basin within a distance of
~100 km. Farther SE, crust gradually thickens beneath
the north margin of Africa, between Tell and Rif mountains over
~300 km distance. The LAB shows a similar trend though
it is affected by the presence of the slab underneath Betics. For the
Algerian domain transect, maximum crustal thickness occurs beneath the
Tell-Atlas Mountains with noticeable variations across the Algerian
basin, Balearic Promontory and Valencia Trough, the LAB showing a
similar tendency. Comparing the modelled geometries suggests that both
transects have opposite trends with the deepest Moho and LAB in the NW
side of the Alboran transect and in the SE side of the Algerian
transect, imposing important restrictions on the geodynamic evolution of
the Western Mediterranean.