2026-06-28T10:14:27Zhttps://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
Docta Complutense author Pujol Solà, Núria author Casas Tuset, Josep María author Proenza, Joaquín A. author Blanco Quintero, Idael Francisco author Druguet, Elena author Liesa Torre Marín, Montserrat author Román Alpiste, M.J. author Álvaro, J.J. 2023-06-22T12:35:07Z 2023-06-22T12:35:07Z 2022-11-25 1695-6133 10.1344/GeologicaActa2022.20.13 https://hdl.handle.net/20.500.14352/72878 https://doi.org/10.1344/GeologicaActa2022.20.13 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. eng Atribución-CompartirIgual 3.0 España Cadomian metabasites of the Eastern Pyrenees revisited journal article URL https://docta.ucm.es/bitstreams/00063289-defa-4926-9640-9aed1eadb97e/download File MD5 b5e00515aa0b344f4ca303cf8c208daf 7892705 application/pdf Cadomian metabasites of the Eastern Pyrenees revisited.pdf URL https://docta.ucm.es/bitstreams/b880e9c3-ca24-4f65-8468-a589ab1c38cd/download File MD5 e9c5417a347b066fa6eef796b100ba40 120335 text/plain Cadomian metabasites of the Eastern Pyrenees revisited.pdf.txt