New magnetotelluric data through the boundary between the Ossa Morena and Centroiberian Zones
Muñoz, G. (Universitat de Barcelona. Departament de Geodinàmica i Geofísica)
Heise, W. (Geological and Nuclear Sciences)
Paz, C. (Universidade de Lisboa. Centro de Geofísica)
Almeida, E. (Instituto Politécnico de Tomar and Escola Superior de Abrantes)
Monteiro Santos, F. (Universidade de Lisboa. Centro de Geofísica)
Pous, J. (Universitat de Barcelona. Departament de Geodinàmica i Geofísica)

Data:	2005
Resum:	The south-western part of the Iberian Peninsula, including the southern branch of the Iberian Massif, has recently been the subject of several magnetotelluric (MT) studies. This area is made up of three different tectonic terranes: the South Portuguese Zone (SPZ), the Ossa Morena Zone (OMZ) and the Central Iberian Zone (CIZ). The boundaries between these zones are considered to be sutures, which appear as high electrical conductivity anomalies in the MT surveys. The OMZ is characterised by a conductive layer at middle-lower crustal levels. To investigate the continuity of this conductive layer into the CIZ, a new MT profile was carried out. This 75-km long ENE profile goes through the boundary between the OMZ and the CIZ. The results of a two-dimensional magnetotelluric inversion revealed a high-conductivity anomaly in the transition OMZ/CIZ (the so-called Central Unit), which is interpreted as due to interconnected graphite along shear planes. High-conductivity anomalies appeared in the middle crust of the CIZ, whose geometry and location are consistent with the conductive layer previously found in the OMZ, thus confirming the prolongation of the conductive layer into the CIZ. The top of this layer correlated spatially with a broad reflector detected by a seismic profile previously acquired in the same area. This, together with other geological and petrological evidence, points to a common origin for both features.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Variscan ; SW Iberia ; Crustal structure ; Graphite ; Magnetotellurics
Publicat a:	Geologica acta, Vol. 3, Núm. 3 (2005) , p. 215-223, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/82304
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000001392
DOI: 10.1344/105.000001392

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