Factors controlling the Alpine evolution of the central Pyrenees inferred from a comparison of observations and geodynamical models
Tóm tắt
Geodynamical numerical modeling has been combined with crustal structural restoration of the central Pyrenees in order to gain insight into fundamental processes that control the evolution of collisional orogens. Models are based on deformation of the crust by stresses transmitted upward from kinematic basal boundary conditions corresponding to the subduction of part of the lithosphere. The influence of inherited crustal heterogeneities, denudation, subcrustal loads, and crustal mechanical properties, consistent with well‐constrained crustal partial restored cross sections of the central Pyrenees, is investigated by progressively incorporating them into model experiments. The primary result inferred from the modeling is that the asymmetry of the central Pyrenees double‐wedge, seen as strain partitioning and in the morphological evolution, is a consequence of the asymmetric distribution of inherited crustal heterogeneity. The tectonic style of the central Pyrenees is the result of the inversion of the Early Cretaceous extensional fault system, during the early stages of the collision, and the reactivation of Hercynian heterogeneities during the late stages. Most of the upper crustal mass that entered the orogen during the calculated 165 km of convergence was accommodated by an increase of upper crustal cross sectional area or lost by denudation. To explain the upper crustal mass partitioning, as well as the geometry of the foreland basins and the preservation of synorogenic deposits in piggyback basins, a subduction load has to be applied to the models. Lower crust and mantle lithosphere were consumed by the mantle.
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Tài liệu tham khảo
Baby P., 1988, Rôle des paléostructures albo‐cénomaniennes dans la géométrie des chevauchements frontaux nord‐pyrénéens, C. R. Acad. Sci. Paris, Sér. II, 306, 307
Berastegui X., 1993, Tall geològic del Pirineu central 1/200.000
Buis M. G., 1975, Une évolution sédimentaire de type deltaique: Le passage du Tertiaire marin au Tertiaire continental entre l'Ariège et le Douctouyre (Pyrénées Ariégeoises), Bull. Soc. Hist. Nat. Toulouse, 111, 80
Casas J. M., 1989, Essai de restitution de la déformation dans une zone avec plis et chevauchements: Le synclinal de Llavorsi dans les Pyrénées centrales (Espagne), C. R. Acad. Sci. Paris, 308, 427
Cazes M., 1988, Etude de la Croûte Terrestre par Sismique Profonde: Profil Nord de la France: Structure Hercynienne
Choukroune P. Structure et Evolution Tectonique de la Zone Nord Pyreneenne: Analyse de la Deformation Dans une Partie de Chaine à Schistosité Sub‐verticale Mem. Soc. Geol. Fr. LV 127 116 1976.
Daignières M., 1994, The Arzacq‐Western Pyrenees ECORS deep seismic profile, Publ. Eur. Assoc. Pet. Geol. Mem., 4, 199
Garwin L. J. Fission track dating and tectonics in the eastern Pyrenees 218 pp. PhD thesis Cambridge Univ. Cambridge England 1985.
Goldberg J. M., 1988, Données nouvelles et mise au point sur l'âge du métamorphisme pyrénéen, C. R. Acad. Sci. Paris, 306, 429
Ledo J. J. Apliacacion del metodo magnetotelunco al estudio de la estructura litosfenca de los Pirineos Ph.D. thesis 196 pp. Univ. of Barcelona Barcelona 1996.
López Blanco M., 1999, Tectonic and climatic controls on the development of large, foreland fan deltas: Montserrat and Sant Llorenç del Munt systems (middle Eocene, Ebro basin, NE Spain, Sediment. Geol.
Mellere D., 1993, Tectonic Control and Signatures in Sedimentary Successions, 259
Olivet J.‐L., 1996, La cinématique de la plaque Ibérique, Bull. Cent. Rech. Explor. Prod. Elf Aquitaine, 20, 131
Sàbat F., 1997, Role of extension and compression in the evolution of the eastern margin of Iberia: The ESCI‐València Trough seismic profile, Rev. Soc. Geol. España, 8, 431
Shelton G., 1981, Experimental flow laws for crustal rocks, Eos Trans. AGU, 62, 396
Vergés J. Estudi geologic del vessant sud del Pirineu oriental i central: Evolucio cinematica en 3D 203 pp. Ph.D. thesis Univ. Barcelona Barcelona 1993.
Vergés J., 1995, Eastern Pyrenees and related foreland basins: Pre‐, syn‐ and post‐collisional crustal‐scale cross sections, Mar. Pet. Geol., 12, 893, 10.1016/0264-8172(95)98854-X