2026-06-29T07:44:43Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/728782023-07-14T04:23:46Zcom_20.500.14352_14col_20.500.14352_15

Cadomian metabasites of the Eastern Pyrenees revisited Pujol Solà, Núria Casas Tuset, Josep María Proenza, Joaquín A. Blanco Quintero, Idael Francisco Druguet, Elena Liesa Torre Marín, Montserrat Román Alpiste, M.J. Álvaro, J.J. 552.4(234.12) Pan-African Cadomian Inherited zircon Peri-Gondwanan Iberian Massif Petrología This study presents a new geochemical, petrological, and geochronological U–Pb dataset from Ediacaran metabasites of the Canigó and Cap de Creus massifs, Eastern Pyrenees. The rocks are composed of calcic amphibole + plagioclase + chlorite + epidote ± quartz plus titanite + apatite + ilmenite ± biotite ± rutile as accessory phases and show relict igneous textures. Peak pressure-temperature determinations share common conditions, ranging 452–482ºC and 5.2–7.7kbar. These intermediate P-T conditions suggest Barrovian-type metamorphism, most likely related to a collisional setting. The metabasites correspond to evolved basaltic rocks (Mg#<0.55) with moderate TiO2 content (up to 2.08wt.%) and relatively low Cr (43–416ppm). The rocks are moderately enriched in light rare earth elements (LREE) relative to heavy rare earth elements (HREE) (average (La/Lu)n of 2.7) and the N-MORB normalized multi-element patterns show negative slopes, with prominent negative Nb anomalies ((Nb/La)NMORB=0.33–0.78). These variations are akin to island arc tholeiites generated in back-arc basins and to other metabasites described in the Eastern Pyrenees with a putative Ediacaran age, and they differ from the Ordovician tholeiitic metabasites from the Canigó massif, which derived from a contaminated E-MORB source. The positive ƐNd(T) values (0.82–3.05) of the studied metabasites preclude a notable contribution from an older continental crust. U-Pb dating (LA-ICP-MS) of one chlorite-rich schist sample in contact with the metabasites from the Canigó massif yielded a main peak at ca. 632Ma. We argue that the Cadomian metabasites from the Pyrenees formed during back-arc extension in the continental margin of Gondwana and were later affected by (probably early Variscan) medium-P metamorphism before the HT-LP metamorphism classically described in the Pyrenees. Ministerio de Ciencia, Innovación y Universidades Agencia Estatal de Investigación Fondo Europeo de Desarrollo Regional, Unión Europea Universitat de Barcelona Ministerio de Universidades/ Depto. de Geodinámica, Estratigrafía y Paleontología Fac. de Ciencias Geológicas TRUE pub 2023-06-22T12:35:07Z 2023-06-22T12:35:07Z 2022-11-25 journal article https://hdl.handle.net/20.500.14352/72878 1695-6133 10.1344/GeologicaActa2022.20.13 eng CGL2017-87631-P PGC2018-093903-B-C22 Atribución-CompartirIgual 3.0 España https://creativecommons.org/licenses/by-sa/3.0/es/ open access application/pdf Instituto de Ciencias de la Tierra "Jaume Almera" (Barcelona)