On the Upper Ordovician unconformity in the Pyrenees: New evidence from the La Cerdanya area
DOI:
https://doi.org/10.1344/105.000000304Keywords:
Upper Ordovician, Angular unconformity, Variscan, PyreneesAbstract
In recent years, contradictory reports about whether or not an unconformity exists at the base of the Upper Ordovician succession of the Pyrenees have been made. In the Cerdanya area (Central Pyrenees), good outcrop evidence for this unconformity is displayed at the base of the Rabassa conglomerates. In this area, the Upper Ordovician rocks overlie a tilted Cambro-Ordovician sequence, displaying an angular unconformity and indicating a break in the stratigraphic series. Moreover, the existence of such an unconformity is supported by the distribution of Variscan minor structures, suggesting that the Cambro-Ordovician and the Upper Ordovician strata initially had different orientations before the main Variscan folding.
References
Abad, A., 1987. Primera cita de Arqueociátidos en Cataluña. Barcelona, Trabajos Museo Geología. Seminario Barcelona, 222, 10 pp.
Abad, A., 1988. El Cámbrico inferior de Terrades (Gerona). Estratigrafía, Facies y Paleontología. Batalleria, 2, 47-56.
Barnolas, A., García-Sansegundo, J., 1992. Caracterización estratigráfica y estructural del Paleozoico de Les Gavarres (Cadenas Costero Catalanas, NE de España). Boletín Geológico y Minero, 103(1), 94-108.
Capellà, I., Bou, O., 1997. La estructura del domo de la Rabassa y del sector oriental del sinclinal de Llavorsi (Pirineo central). Estudios Geológicos, 53(3-4), 121-133.
Casas, J.M., Cirés, J., Domingo, F., Fernández, O., Picart, J., 2004. Evolución estructural paleozoica de los materiales de la Cerdanya y del Alt Urgell. Geo-Temas, 6(3), 259-262.
Cavet, P., 1957. Le Paléozoïque de la zone axiale des Pyrénées orientales françaises entre le Roussillon et l’Andorre. Service Carte Géologique de France, Bulletin, 55(254), 303-518.
Cirés, J., Alías, G., Poblet, J., Casas, J.M., 1990. La estructura del anticlinal de la Massana (Hercinico del Pirineo Central). Geogaceta, 8, 42-44.
Den Brok, S.W.J., 1989. Evidence for pre-Variscan deformation in the Lys Caillaouas area, Central Pyrenees, France. Geologie en Mijnbouw, 68, 377-380.
Gil-Peña, I., Barnolas, A., Sanz-López, J., García-Sansegundo, J., Palau, J., 2001. Discontinuidad sedimentaria del Ordovícico terminal en los Pirineos centrales. Geogaceta, 29, 57-60.
García-Sansegundo, J., Alonso, J.L., 1989. Stratigraphy and structure of the southeastern Garona Dome. Geodinamica Acta, 3(2), 127-134.
García-Sansegundo, J., Gavaldà, J., Alonso, J.L., 2004. Preuves de la discordance de l’Ordovicien supérieur dans la zone axiale des Pyrénées: exemple de dôme de la Garonne (Espagne, France). Compte Rendu Geosciences, 336, 1035-1040.
Guitard G., Laumonier B., Autran A., Bandet Y., Berger G.M., 1998. Notice explicative, Carte géologique de France (1:50.000), feuille Prades (1095). Orléans, BRGM, 198 pp.
Hartevelt, J.J.A., 1970. Geology of the upper Segre and Valira valleys, central Pyrenees, Andorra/Spain. Leidse Geologische Mededelingen, 45, 167-236.
Laumonier, B., 1988. Les groupes de Canaveilles et de Jujols (“Paléozoïque inférieur”) des Pyrénées orientales arguments en faveur de l’age essentiellment cambrien de ces séries. Hercynica, IV(1), 25-38.
Laumonier, B., 2004. Pliegues y cabalgamientos hercínicos precoces en los Pirineos orientales: el ejemplo del sinclinal de Villefranche. Geo-Temas, 6(3), 271-274.
Llopis Lladó, N., 1965. Sur le Paléozoïque inférieur de l’Andorre. Bulletin Societé géologique de France, (7)VII, 652-659.
Martí, J., Muñoz, J.A., Vaquer, J., 1986. Les roches volcaniques de l’Ordovicien supérieur de la région de Ribes de Freser Rocabruna (Pyrénées catalanes): caractères et signification. Comptes rendus de l’Académie des Sciences de Paris, ser. II, 302(20), 1237-1242.
Muñoz, J.A., Casas, J.M., 1996. Tectonique préhercynienne. In: Carreras, J., Debat, P. (coords.). Tectonique Hercynienne. Synthèse géologique et géophysique des Pyrénées. Vol.1
Cycle Hercynien. Orléans et Madrid, BRGM-ITGE, 587-589. Poblet, J., 1991. Estructura herciniana i alpina del vessant sud de la zona axial del Pirineu central. Doctoral thesis. Universitat de Barcelona, 604 pp.
Robert, J.F., Thiebaut, J., 1976. Découverte d’un volcanisme acide dans le Caradoc de la région de Ribes de Freser (Prov. de Gerone). Comptes rendus de l’Académie des Sciences de Paris, ser. D, 282, 2050-2079.
Santanach, P., 1972. Sobre una discordancia en el Paleozoico inferior de los Pirineos orientales. Acta Geologica. Hispanica, 7(5), 129-132.
Speksnijder, A., 1986. Geological analysis of Paleozoic largescale faulting in the south-central Pyrenees. Geologica Ultraiectina, 43, 211 pp.
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