The seismic crustal structure of the Ossa-Morena Zone and its geological interpretation
2004 (English)In: Journal of Iberian Geology, ISSN 1698-6180, E-ISSN 1886-7995, Vol. 30, 133-142 p.Article in journal (Refereed) Published
The IBERSEIS deep reflection seismic experiment has provided a crustal image of the Variscan orogen of southwest Iberia. A brief presentation of the entire seismic profile is given, and then the Ossa-Morena Zone (OMZ) and its boundaries are considered. The crust of the OMZ is shown to be divided into an upper crust, characterized by dominantly NE-dipping reflectivity, and a poorly reflective lower crust. The reflectivity of the upper crust has good correlation with the geological cross-section constructed from surface mapping. In the seismic image, the upper crustal geological structures are seen to merge in the middle crust. Nevertheless, the OMZ middle crust is not a mere detachment level, as it shows very unusual features: it appears as a band of strong reflectivity and irregular thickness (the Iberian Reflective Body, IRB) that we interpret as a great sill-like intrusion of basic rocks. The boundaries of the OMZ are considered sutures of the orogen, and their geometrical features, as deduced from geological mapping and the seismic image, are in accordance with the transpressional character of the Variscan collision recorded in SW Iberia. The present Moho is flat, obliterating the root of the orogen.
Place, publisher, year, edition, pages
2004. Vol. 30, 133-142 p.
Deep seismic reflection, structure of the crust, Variscan orogen, Ossa-Morena Zone
IdentifiersURN: urn:nbn:se:uu:diva-14468OAI: oai:DiVA.org:uu-14468DiVA: diva2:42238