The geology of the Gréixer area (La Cerdanya, Eastern Pyrenees): Sardic, Variscan, and Alpine imprints
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Palabras clave

structural analysis, giant quartz vein, Cambrian-Ordovician, Upper Ordovician, Eastern Pyrenees análisis estructural; vena gigante de cuarzo; Cambro-Ordovícico; Ordovícico Superior; Pirineo Oriental

Cómo citar

González-Esvertit, E., Molins-Vigatà, J., Canals, Àngels, & Maria Casas, J. (2023). The geology of the Gréixer area (La Cerdanya, Eastern Pyrenees): Sardic, Variscan, and Alpine imprints. Trabajos De Geología, 37(37), 81–95. https://doi.org/10.17811/tdg.37.2023.81-95

Resumen

We present new data of the pre-Variscan, Variscan, and Alpine evolution of the pre-Silurian rocks from the Gréixer sector (La Cerdanya area, Eastern Pyrenees). Structural analysis and detailed mapping of Cambrian-Ordovician and Upper Ordovician low-grade metasediments suggest the existence of three deformational events, together with the emplacement of an hectometric-sized quartz vein and the development of thrusts zones. We compare the results with other sectors close to the study area, and suggest that they form the southern (reverse) limb of a kilometre-sized E-W-trending south-verging “D2” antiform of Variscan age. This fold was deformed by open NW-SE-trending south-verging “D3” folds with gently north-dipping limbs of unknown age—Variscan or Alpine. Moreover, microstructural analysis and the structural attitude of the D2 mesostructures suggest the existence of a pre-Upper Ordovician “D1” deformational event that only affects the Cambrian-Ordovician metasediments. By comparison with neighbouring areas, an Alpine age for quartz vein emplacement and the development of thrust zones is suggested.

https://doi.org/10.17811/tdg.37.2023.81-95
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Citas

AYORA, C. and CASAS, J. M. (1983): Estudi microtermomètric dels filons de quars de les Esquerdes de Rojà, Massís de Canigó, Pirineu Oriental. Acta Geologica Hispanica, 18(1): 35–46.

AYORA, C., CARRERAS, J., CASAS, J. M. and LIESA, M. (1984): Informe quarsos. Internal report of the University of Barcelona (available under request). Barcelona, Universitat de Barcelona.

CAPELLÀ, I. and BOU, O. (1997): La estructura del domo de la Rabassa y del sector oriental del sinclinal de Llavorsí (Pirineo Central). Estudios Geológicos, 53(3-4): 121–133. https://doi.org/10.3989/egeol.97533-4237

CASAS, J. M. (2010): Ordovician deformations in the Pyrenees: New insights into the significance of pre-Variscan (‘sardic’) tectonics. Geological Magazine, 147(5): 674–689. https://doi.org/10.1017/S0016756809990756

CASAS, J. M. and FERNÁNDEZ, O. (2007): On the Upper Ordovician unconformity in the Pyrenees: New evidence from the La Cerdanya area. Geologica Acta, 5(2), 193–198.

CASAS, J. M. and PALACIOS, T. (2012): First biostratigraphical constraints on the pre-Upper Ordovician sequences of the Pyrenees based on organic-walled microfossils. Comptes Rendus Geoscience, 344(1): 50–56. https://doi.org/10.1016/j.crte.2011.12.003

CASAS, J. M., PARÉS, J. M. and MEGÍAS, L. (1998): La fábrica magnética de los materiales cambroordovícicos del Anticlinal de la Massana (Andorra, Pirineo Central). Revista de La Sociedad Geológica de España, 11: 317–329.

CASAS, J. M., QUERALT, P., MENCOS, J. and GRATACÓS, O. (2012): Distribution of linear mesostructures in oblique folded surfaces: Unravelling superposed Ordovician and Variscan folds in the Pyrenees. Journal of Structural Geology, 44: 141–150. https://doi.org/10.1016/j.jsg.2012.08.013

CAVET, P. (1957): Le Paléozoïque de la zone axiale des Pyrénées orientales françaises entre le Roussillon et l’Andorre. Bulletin Service Carte Géologique France, 55: 303–309.

CIRÉS, J., DOMINGO, D., SIRVENT, J. C., SANTANACH, P., ROCA, E. and ESCUER, J. (1994): Mapa Geológico de España a escala 1:50.000, Hoja 217-Puigcerdà. Instituto Geológico y Minero de España (IGME).

CLARIANA, P. AND GARCÍA-SANSEGUNDO, J. (2009): Variscan structure in the eastern part of the Pallaresa massif, Axial Zone of the Pyrenees (NW Andorra). Tectonic implications. Bulletin de La Société Géologique de France, 180(6): 501–511. https://doi.org/10.2113/gssgfbull.180.6.501

COCCO, F. and FUNEDDA, A. (2019): The Sardic Phase: Field evidence of Ordovician tectonics in SE Sardinia, Italy. Geological Magazine, 156(1): 25–38. https://doi.org/10.1017/S0016756817000723

DEN BROK, D. W. I. (1989): Evidence for pre-Variscan deformation in the Lys Caillaouas area, Central Pyrenees, France. Geologie en Mijnbouw, 68: 377–380.

GARCÍA-SANSEGUNDO, J. and ALONSO, J. (1989): Stratigraphy and structure of the southeastern Garona Dome. Geodinamica Acta, 3(2): 127–134. https://doi.org/10.1080/09853111.1989.11105180

GARCÍA-SANSEGUNDO, J., GAVALDÁ, J. and LUIS ALONSO, J. (2004): Preuves de la discordance de l’Ordovicien supérieur dans la zone axiale des Pyrénées: Exemple du dôme de la Garonne (Espagne, France). Comptes Rendus Geoscience, 336(11): 1035–1040. https://doi.org/10.1016/j.crte.2004.03.009

GIL-PEÑA, I., BARNOLAS, A., VILLAS, E. and SANZ-LÓPEZ, J. (2004): El Ordovícico Superior de la Zona Axial. In: J. A. Vera (ed.): Geología de España, Sociedad Geológica de España and Instituto Geológico y Minero de España (SGE-IGME), Madrid, 247.

GONZÁLEZ-ESVERTIT, E., CANALS, À., CASAS, J. M. and NIETO, F. (2020): Insights into the structural evolution of the pre-Variscan rocks of the Eastern Pyrenees from La Molina quartz veins; constraints on chlorite and fluid inclusion thermometry. Geologica Acta, 18: 1–XXIV. https://doi.org/10.1344/GeologicaActa2020.18.18

GONZÁLEZ-ESVERTIT, E., CANALS, À., CASAS, J. M. and NIETO, F. (2021): Chlorite chemical adjustment in the Gréixer vein: Effects on thermometry. Macla, 25: 32–33.

GONZÁLEZ-ESVERTIT, E., CANALS, À., BONS, P. D., MURTA, H., CASAS, J. M., and GOMEZ-RIVAS, E. (2022a). Geology of giant quartz veins and their host rocks from the Eastern Pyrenees (Southwest Europe). Journal of Maps, 1-13. https://doi.org/10.1080/17445647.2022.2133642

GONZÁLEZ-ESVERTIT, E., CANALS, A., BONS, P. D., CASAS, J. M., and GOMEZ-RIVAS, E. (2022b). Compiling regional structures in geological databases: the Giant Quartz Veins of the Pyrenees as a case study. Journal of Structural Geology, 163, 104705. https://doi.org/10.1016/j.jsg.2022.104705

HARTEVELT, J. A. A. (1970): Geology of the upper Segre and Valira valleys, central Pyrenees, Andorra/Spain. Leidse Geologische Mededelingen, 45: 167–236.

KRIEGSMAN, L. M., AERDEN, D. G. A. M., BAKKER, R. J., DEN BROK, D. W. I. and SCHUTJENS, P. M. T. M. (1989): Variscan tectonometamorphic evolution of the eastern Lys-Caillaouas massif, Central Pyrenees-evidence for late orogenic extension prior to peak metamorphism. Geologie en Mijnbouw, 68: 323–333.

LAUMONIER, B. (1988): Les groupes de Canaveilles et de Jujols (‘“Paléozoïque inférieur”’) des Pyrénées orientales – arguments en faveur de l’âge essentiellement Cambrien de ces séries. Hercynica, 4: 25–38.

MARGALEF, A. (2015): Estudi estructural i estratigràfic del sud d’Andorra. PhD Thesis, Universitat de Barcelona, 172 p.

MARGALEF, A. and CASAS, J. M. (2016): Corte geológico compensado del sur de Andorra: Aportaciones a la estructura varisca del Pirineo central. Geo-Temas, 16: 61–63.

MARGALEF, A., CASTIÑEIRAS, P., CASAS, J. M., NAVIDAD, M., LIESA, M., LINNEMANN, U., HOFMANN, M. and GÄRTNER, A. (2016): Detrital zircons from the Ordovician rocks of the Pyrenees: Geochronological constraints and provenance. Tectonophysics, 681: 124–134. https://doi.org/10.1016/j.tecto.2016.03.015

MCCLELLAND, E. A. and MCCAIG, A. M. (1988): Palaeomagnetic estimates of total rotation in basement thrust sheets, Axial Zone, Southern Pyrenees. Cuadernos de Geología Ibérica, 12: 181-193.

MUÑOZ, J. A. (1992): Evolution of a continental collision belt: ECORS-Pyrenees crustal balanced cross-section. In: K. R. McClay (ed.): Thrust Tectonics, Springer, Netherlands, 235–246. https://doi.org/10.1007/978-94-011-3066-0_21

NAVIDAD, M., CASTIÑEIRAS, P., CASAS, J. M., LIESA, M., BELOUSOVA, E., PROENZA, J. and AIGLSPERGER, T. (2018): Ordovician magmatism in the Eastern Pyrenees: Implications for the geodynamic evolution of northern Gondwana. Lithos, 314–315: 479–496. https://doi.org/10.1016/j.lithos.2018.06.019

PADEL, M., ÁLVARO, J. J., CASAS, J. M., CLAUSEN, S., POUJOL, M. and SÁNCHEZ-GARCÍA, T (2018): Cadomian volcanosedimentary complexes across the Ediacaran–Cambrian transition of the Eastern Pyrenees, southwestern Europe. International Journal of Earth Sciences, 107(5): 1579–1601. https://doi.org/10.1007/s00531-017-1559-5

PADEL, M., CLAUSEN, S., ÁLVARO, J. J. and CASAS, J. M. (2018): Review of the Ediacaran-Lower Ordovician (pre-Sardic) stratigraphic framework of the Eastern Pyrenees, southwestern Europe. Geologica Acta, 16: 339–365.

POBLET, J. (1991): Estructura herciniana i alpina del vessant sud de la zona axial del Pirineu central. PhD Thesis. Barcelona, Universitat de Barcelona, 604 p.

POUS, J., JULIA, R. and SOLE-SUGRANES, L. (1986): Cerdanya basin geometry and its implication on the Neocene evolution of the Eastern Pyrenees. Tectonophysics, 129: 355–365.

PUDDU, C., ÁLVARO, J. J., CARRERA, N. and CASAS, J. M. (2019): Deciphering the Sardic (Ordovician) and Variscan deformations in the Eastern Pyrenees, SW Europe. Journal of the Geological Society, 176(6): 1191–1206. https://doi.org/10.1144/jgs2019-057

ROEST, W. R. and SRIVASTAVA, S. P. (1991): Kinematics of the plate boundaries between Eurasia, Iberia, and Africa in the North Atlantic from the Late Cretaceous to the present. Geology, 19(6): 613–616. https://doi.org/10.1130/0091-7613(1991)019<0613:KOTPBB>2.3.CO;2

ROSENBAUM, G., LISTER, G. S. and DUBOZ, C. (2002): Reconstruction of the tectonic evolution of the western Mediterranean since the Oligocene. Journal of the Virtual Explorer, 8: 107–130. https://doi.org/10.3809/jvirtex.2002.00053

SANTANACH, P. (1972a): Estudio tectónico del Paleozoico inferior del Pirineo entre la Cerdaña y el río Ter. Acta Geologica Hispanica, 7: 44–49.

SANTANACH, P. (1972b): Sobre una discordancia en el Paleozoico inferior de los Pirineos orientales. Acta Geologica Hispanica, 7: 129–132.

SPEKSNIJDER, A. (1986): Geological analysis of Paleozoic large-scale faulting in the south-central Pyrenees. Geologica Ultraiectina, 43: 1–211.

STIPP, M., STÜNITZ, H., HEILBRONNER, R. and SCHMID, S. M. (2002): Dynamic recrystallization of quartz: Correlation between natural and experimental conditions. Geological Society, London, Special Publications, 200(1): 171–190. https://doi.org/10.1144/GSL.SP.2001.200.01.11