Book Subtitle: Proceedings of the 3rd Conference of the Arabian Journal of Geosciences (CAJG-3)., Networks of halite veins have been analysed along galleries of the potash Cabanasses mine (Súria anticline, SE Pyrenees). The presence of a shape preferred orientation cross-cut by halite veins suggests that the rocks hosting the veins underwent ductile deformation before fracture formation and healing. The petrographical characteristics of veins and host rocks, as well as the analysis of their bromine content, reveal that the vein-forming fluids likely resulted from pressure-solution and dynamic recrystallisation of the Lower Halite Unit rocks. Fluids at high pressure migrated upwards and were arrested at the Halite-Sylvinite Unit causing fracture formation below the Potash Unit, which acted as a seal and did not experience brittle deformation., This research has been funded by the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I, Projects PID2020-118999GB-I00 and PGC2018-093903-B-C22) and the Consolidated Research Group 2021 SGR 00349 and 2017SGR-824., Peer reviewed

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.