Propiedades físicas de la litosfera en la Zona Centro Ibérica (Península Ibérica)
The lithosphere beneath the Central Iberian Zone (CIZ) features different character and nature than the lithosphere beneath the southwestern part of the Iberian Peninsula (Ossa Morena and South-Portuguese Zones, OMZ and SPZ).
Both lithospheres are separated by an identified suture zone. The ALCUDIA deep seismic reflection transect (CIZ) produced an image that extended the knowledge acquired by the IBERSEIS transect (OMZ and SPZ) towards the north up to Toledo. Thus we have for the first time an approximately 600 km long crustal image of SW-Iberia. One of the most relevant outcomes of these transect is that the crust in southern Iberia featured a singular evolution mainly as a result of the activity of a mantle plume. This may have caused a relatively large amount of predominantly mafic intrusions, into the mid-to-lower crust. Therefore, the crust of SW-Iberia is the result of the evolution of singular lithospheric processes.
Although the existing data provides relatively good constraints on the geometry and internal architecture of the continental crust, little knowledge is currently available on the upper mantic beneath Iberia. The geophysical data available up to date evidences relevant upper mantle structures, like a possible discontinuity at 60 km depth: the seismic record sections of the wide-angle IBERSEIS (IBERSElS-WA) recordings and, the preliminary interpretations of the receiver functions estimated from the newly acquired natural source seismic data by the TOPOIBERIA project suggest the existence of an important discontinuity in the upper mantle.
The ALCUDIA-WA project aims to place strong constraints in the distribution of the physical properties (P and S seismic wave velocities) in the upper mantle beneath the ClZ. To achieve those high resolution constraints we propose to acquire a 500 km long wide-angle seismic reflection transect with an unprecedented level of lateral resolution (tracepacing/instrument spacing=500 m). Accordingly we plan to distribute 1000 seismic recording instruments along the profile. With this design, the existing data from other similar experiments (IBERSEIS-WA) can be easily integrated. Furthermore, different processing approaches can be the design to be used in the interpretation and modclling of these data. Low fold stacks and/or depth migrated images can be achieved because of the close spacing. A low fold stack would be attempted to image the upper mantle from south of Toledo to south of Rio Tinto. Also this type of data can be used as input for tomographic algorithms. Finally it can be also a catalyser for the development of more mathematically elaborated inversion schemes such as full-wave-form approximations. Thus this Project aims to provide new constraints on the upper mantle beneath the CIZ and in SW Iberia and to push forward new approaches to the interpretation and modelling of seismic reflection data.
- Ramon Carbonell Bertran, ICTJA-CSIC, Barcelona, Spain, Project Leader
- Alcinoe Calahorrano Betancourt, ICTJA-CSIC, Barcelona, Spain
- Juan Alcalde Martin, ICTJA-CSIC, Barcelona, Spain
- Antonio Pérez Azor, Universidad de Granada, Spain
- Luis Miguel Martín Parra, IGME, Spain
- David Marti Linares, ICTJA-CSIC, Barcelona, Spain
- Fernando Simancas Cabrera, Universidad de Granada, Spain
- Jerónimo Matas Gonzalez, IGME, Spain
- Andrés Pérez Estaun, ICTJA-CSIC, Barcelona, Spain
- Puy Ayarza Arribas, Universidad de Salamanca, Spain
- José Luis García Lobón, IGME, Spain
- José Luis Gallardo Millán, Universidad de Castilla-La Mancha, Spain
- Luis Mansilla Plaza, Universidad de Castilla-La Mancha, Spain
Project Leader: Ramon Carbonell Bertran
Project Financed by PNIDI-CGL - CGL2010-17280R