Header_geotransfer

Líneas de Investigación:

TECTÓNICA

El principal objetivo de esta línea es el reconocimiento geológico del terreno, esencialmente en el marco de las grandes unidades estructurales del NE peninsular (Pirineos, Cordillera Ibérica y cuencas terciarias circundantes).

Este objetivo se aborda tanto desde un punto de vista teórico (contribución al conocimiento detallado de la historia deformacional de la placa ibérica) como práctico; este último con la doble vertiente del reconocimiento de las propiedades geotécnicas de los suelos y cuerpos rocosos, con especial atención a las discontinuidades que les afectan, por una parte, y por otra, la identificación y delimitación de materiales de interés aplicado.

Las investigaciones actualmente en desarrollo son:

  • Desarrollo metodológico de análisis de poblaciones de fallas.
  • Paleosismología y neotectónica.
  • Análisis de tensores de paleoesfuerzos en el NE peninsular.
  • Datación de la deformación en relación con los depósitos sintectónicos, tanto en extensión como en compresión.
  • Análisis de cuencas extensionales invertidas por métodos paleomagnéticos.
  • Análisis de fábricas magnéticas en rocas sedimentarias e ígneas.
  • Modelización de cuerpos geológicos por métodos gravimétricos y magnéticos.
  • Detección de cavidades mediante prospección geofísica.
  • Caracterización de las propiedades geotécnicas de suelos y rocas.
  • Modelización a escala de estructuras y mecanismos de deformación.

Resultados destacados:

Multidisciplinary approach to an extensional syncline model for the Mesozoic Cameros Basin (N Spain). A.M. Casas, J.J. Villalaín, R. Soto, A. Gil-Imaz, P. del Río and G. Fernández. Tectonophysics (en prensa).

Abstract: In this paper we explore the possibility of reconstructing the initial geometry of inverted basins using combined geophysical and geological methods: seismic reflection profiles, paleomagnetism, analogue modelling and 3D geometrical analysis. These techniques allow for some unknowns in the geometry and evolution of extensional sedimentary basins (mainly the normal drag–reverse drag geometrical problem) to be solved. The example chosen for checking these techniques is the Cameros Basin (northern Iberian Chain), formed during the Late Jurassic–Early Cretaceous, and inverted during the Tertiary compressional stage. According to the reconstruction proposed, the Cameros Basin can be characterised as a lens-shaped, syncline basin with maximum thickness of deposits of about 8000 m in its depocenter, gradually diminishing toward the North and South.

The extensional geometry of the Cameros Basin is defined by: 1) a large-scale growth syncline over the major basement fault, with southward-dipping beds in the northern basin margin, forming a southward-opening sedimentary wedge, with upward-decreasing dip values (large-scale normal drag geometry); 2) roll-over anticlines at the contact between the pre-rift series against the normal fault limiting the basin (smaller-scale reverse drag geometry). The combined syncline–anticline syn-extensional structures were characterised by means of paleomagnetic analysis of a remagnetization acquired at the time of extension. Analogue models indicate that the development of syncline basin geometries in extensional settings, as the one interpreted for the Cameros Basin, is closely related to the presence of a detachment level in the pre-rift sequence above the main basement faults. (-> artículo completo)

Folded onlap geometries: implications for recognition of syn-sedimentary folds: A.M. Casas, R. Soto, A. González and J.J. Villalaín. Journal of Structural Geology, 27: 1644-1657 (2005).

Abstract: Growth strata are usually analysed from geological maps, outcrop geometry or seismic sections. Many growth folds have been defined from geological maps, especially in areas where plunging structures allow the syn-tectonic sequence to be displayed at the surface.

The geometrical arrangement of these syn-tectonic sequences can also be defined from the relationships between pre-growth and growth strata, as obtained from geological maps.

In this paper, from theoretical models and natural examples from the southern Pyrenees, we argue that some cartographic patterns of strata associated with variably plunging folds, traditionally ascribed to syn-tectonic sedimentation with thinning of sedimentary units toward the anticlinal hinge zone, can be explained as completely post-sedimentary folds of sedimentary units lapping onto an inclined bedding surface, and linked to basin margin, or downlap geometries on the basin floor.

We conclude that 3-D analysis of syn-tectonic structures, combining data from independent sources (i.e. geological maps and seismic reflection profiles) is essential to determine relationships between sedimentary units and structures. (-> artículo completo)

Tambien puede consultar otros resultados