Seismic structure and composition of the southern central Iberian crust: The ALCUDIA wide angle seismic reflection transect Palomeras, Inma Martínez Poyatos, David Jesús Azor Pérez, Antonio Wide-angle reflection/refraction profile Central Iberian Zone (Spain) P- and S-wave velocity model Poisson's ratio model Crustal lithologies The authors thank the Associated Editor and the anonymous reviewers for their thoroughly valuable suggestions and comments that improved the manuscript. Seismic data were collected in 2012 with funding provided by the Spanish Ministry of Science and Innovation (grants: CGL2004-04623/BTE, CGL2007-63101/BTE, CGL2011-24101, CSD2006-00041). Instrumentation was provided by the IRIS-PASSCAL instrument center, Socorro, New Mexico, USA. The seismic data, including experiment geometry are stored in the IRIS-PASSCAL facilities and can be accessed through the IRIS-PASSCAL data management center. I.P. is funded by the Spanish Government and the Universidad de Salamanca with a Beatriz Galindo grant (BEGAL 18/00090). S.A. Ehsan is funded by the European Commission grant Marie Curie Actions (264517-TOPOMOD-FP7-PEOPLE-2010-ITN). We thank Instituto Geologico y Minero de Espana for providing the logistic help and an academic crew for data acquisition. GMT was used to prepare some of the figures shown in the paper. The nature of the crust beneath central Iberia was estimated by a wide-angle seismic reflection/refraction transect, ALCUDIA-WA, which sampled the southern half of the Variscan Central Iberian Zone, covered in the north by the Cenozoic Tajo Basin. The shot gathers recorded by vertical component sensors revealed well defined P- and S-wave phases. These arrivals were modeled by an iterative forward approach providing 2D crustal models showing variations in the velocity distribution with upper crustal P- and S-wave velocities increasing northwards. The lower crust P-wave velocities are homogeneous along the profile while the S-wave velocities slightly increase northwards. The Moho is placed at 32 km depth in the southern edge of the profile, deepening northward down to 35 km beneath the Tajo Basin. The Poisson's ratio, calculated from P- and S-wave velocities, varies along the profile at upper crustal depths. The highest values are located below the Mora and Pedroches batholiths. These resulting physical properties can serve to constrain the crustal composition by comparing them with laboratory measurements on rock samples. Our results suggest that the upper crust in the southern and central segments of the ALCUDIA profile is made up of low-grade metasedimentary rocks, while the northern segment is dominated by igneous rocks, in agreement with the surface geology. Separated by a sharp boundary located between 12 km (south) and 18 km (north) depth, the lower crust is more homogeneous and shows low Poisson’ ratios compatible with a rather felsic composition. However, outstanding lamination described in coincident vertical incidence data indicates some degree of intercalation with mafic components. 2021-11-29T12:10:14Z 2021-11-29T12:10:14Z 2021-10-23 journal article Imma Palomeras... [et al.]. Seismic structure and composition of the southern central Iberian crust: The ALCUDIA wide angle seismic reflection transect, Tectonophysics, Volume 820, 2021, 229114, ISSN 0040-1951, [https://doi.org/10.1016/j.tecto.2021.229114] http://hdl.handle.net/10481/71815 10.1016/j.tecto.2021.229114 eng info:eu-repo/grantAgreement/EC/FP7/264517 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access Atribución-NoComercial-SinDerivadas 3.0 España Elsevier