Geological Map of Andorra

This project began in 2000 with the aim of drawing up the geological cartography of Andorra on a scale of 1:25,000. Geological mapping is very useful for all types of studies related to soil and subsoil. Detailed knowledge of the stratigraphy and structure of Andorra's rocks is essential when preparing studies on subjects directly related to geology, such as hydrogeology, geotechnics, engineering, geological risks, mining and geothermal energy. On the other hand, it is also essential in studies in areas as diverse as botany, soil contamination or archaeology, among others.

Today, the whole of Andorra is available at a scale of 1:50,000 and the cartography is available on the SIGMA website.

In 2015 two doctoral theses related to the geological mapping of this project were presented [1] [2]. The results and knowledge obtained from this project are useful for providing geological information to government initiatives. Geological mapping has also been useful for working on international research projects [3].

In collaboration with the Geomodels Research Institute of the Universitat de Barcelona, we are working on the geological cross-sections with the aim of understanding the structure of the rocks of Andorra and their relationship with the structure of the Pyrenees. Several sedimentary rocks and igneous rocks have also been sampled, which will be used to continue advancing in the knowledge of the chronology of the deformations [4].

This September we have published an article related to the project "Variscan and Alpine overlapping deformation in the basement rocks of southern Andorra, central Pyrenees" in which we present some of the results. [5]

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[1] P. Clariana, “Estratigrafía, estructura y su relación con el metamorfismo de la Zona Axial pirenaica en la transversal del Noroeste de Andorra y comarcas del Pallars Sobirà y el Alt Urgell”, 2015.

[2] A. Margalef, “Estudi estructural i estratigràfic del sud d’Andorra”, 2015.

[3] P. Clariana, A. Margalef, J. García – Sansegundo, JM. Casas “Estructura de los materiales prevariscos de la Zona Axial pirenaica en la transversal de Andorra”,  2019.

[4] A. Margalef et al. “Detrital zircons from the Ordovician rocks of the Pyrenees: Geochronological constraints and provenance”, 2016.

[5] A. Margalef et al. "Superimposed Variscan and Alpine deformation in the basement rocks of southern Andorra, central Pyrenees", 2023.