EUROPROBE projects: SW IBERIA

The Variscan orogen in southwestern Iberia offers a unique opportunity to image and study a transpressional orogen and to examine the partitioning of deformation in 3-dimensional space and time. The region consists of a series of zones representing different tectonostratigraphic units exposed at a variety of structural levels. Varying components of shortening and left-lateral strike-slip deformation have been recognised from field studies and from geodynamic models. Studies of the structure, stratigraphy, metamorphism, magmatism and palaeogeography will allow a reconstruction of the geometry and history of this important class of orogens produced by oblique collision of lithospheric plates.

The principal aim of this multidisciplinary project is to better understand orogeny resulting from oblique collision. This will be achieved by imaging the crust at different structural levels through collaborative work on existing data, geological and geophysical investigations of critical areas and acquisition of new seismic reflection profiles through the orogen. The seismic profiles will be fully integrated with the surface geology and provide images deep into the mantle, thus, providing a critical ‘missing link’ in the imaging of the Variscan orogen in Europe.

Within the Variscan of SW-IBERIA are some of Europe’s most important Volcanic Massive Sulphide ore deposits (Rio Tinto, Neves-Corvo, etc.). The tectonic setting and reconstruction of the ore bodies requires detailed stratigraphical and structural studies; this project will provide new concepts for further exploration.

The SW-IBERIA project developed from the Uralides. Geoscientists from Bulgaria, France, Germany, Ireland, Italy, Morocco, the Netherlands, Norway, Portugal, Russia, Spain, Sweden and United Kingdom have attended the project meetings. The project now involves research institutes from 15 countries.

The SW-IBERIA project will focus on the following main goals:

Imaging of the lithosphere using deep seismic reflection profiling, wide-angle studies, magnetotelluric and other geophysical experiments.
Testing of transpressional models through mapping of strain variation through the different structural zones. This, together with the geophysical imaging will allow testing of thick-skinned versus thin-skinned models of deformation, and constrain estimates of shortening and displacement at crustal and lithospheric scales.
Reconstruction of the pre-collisional (North Gondwanan) and syn-collisional palaeogeography of the crustal units using sedimentary, faunal and palaeomagnetic studies to constrain the timing and position of orogenic processes.
Examination of the boundaries (sutures) and associated rocks (high grade metamorphics and ophiolites), in order to constrain the processes of continental collision.
Examination of the origin, setting and timing of magmatism and metallogenesis to constrain emplacement mechanisms and crustal evolution.

Get the SW-IBERIA text and figures out of the EUROPROBE 1996 publication by clicking on the corresponding text. Click on the figure and see the image enlarged

PDF-viewers can be obtained through the net for different operating systems.

Text (PDF file, 320 kb)

Fig. 8.1. Paleozoic peri-Atlantic orogens in Permian. EPS (100 kB) PDF (45 kB)	Fig. 8.2. Main structural elements of the Variscides during the early Carboniferous. EPS (95 kB) PDF (50 kB)	Fig. 8.3. Simplified cross-sections of the Iberian Vadiscide Belt. EPS (80 kB) PDF (30 kB)

For more information please contact the project leader:

Prof. António A. R. Ribeiro
Dep. Geologia, Fac. Cièncias
Universidade de Lisboa
58, Rua Escola Politécnica, Edifício C2 - 5 piso
P-1250 LISBOA
PORTUGAL

Tel: +351-1/757 31 41, /396 15 21
Fax: +351-1/759 77 16, /60 58 50
E-mail: gtecanri@cc.fc.ul.pt

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