Evolution of a salt-rich transtensional rifted margin, eastern North Pyrenees, France

• Published in: Journal of the Geological Society
• Main Authors: Ford, Mary, Vergés, Jaume
• Other Authors: Ministerio de Economía y Competitividad (España), Agence Nationale de la Recherche (France), Generalitat de Catalunya, Centre National de la Recherche Scientifique (France)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of London 2020
• Subjects: Western Pyrenees; Basement Blocks; Mesozoic Evolution; Mantle exhumation; Southern Corbieres; Alkaline magmatism; Cretaceous Albitization; Iberia-newfoundland; Central High-Atlas; Fold-thrust belt; Pyramid; Pyramid The; Newfoundland
• Online Access: http://hdl.handle.net/10261/222554; https://doi.org/10.1144/jgs2019-157; https://doi.org/10.13039/501100001665; https://doi.org/10.13039/501100004794; https://doi.org/10.13039/501100002809; https://doi.org/10.13039/501100003329

In this field study we reinterpret the narrow eastern North Pyrenean Zone, France, as an inverted salt-rich transtensional rift system based on identification of halokinetic depositional sequences across rift platform to distal rift margin domains with a cumulative throw of >2.8 km on steep Cretaceous faults. The rift platform records extension on detached rotational faults above Triassic evaporites from Jurassic to Aptian with uplift and erosion during the Albian. Transtensional Aptian–Albian minibasins align along the salt-rich rift margin fault zone. In the Aptian–Albian main rift large en echelon synclinal minibasins developed between salt walls, although Jurassic diapiric evolution is likely. Upper Cretaceous units locally record continuing diapirism. The Boucheville and Bas Agly depocentres, altered by synrift HT metamorphism, form the distal rift domain terminating south against the North Pyrenean Fault. The narrowness of the Pyrenean rift, shape of minibasins, en echelon oblique synclinal depocentres and folds coupled with a discontinuous distribution and intensity of HT metamorphism support a transtensional regime along the Iberia–Europe plate margin during late Early and early Late Cretaceous. In this model, the distal European margin comprises deep faults limiting laterally discontinuous crustal domains and ‘hot’ pull-apart basins with mantle rocks directly beneath sedimentary cover. This work was funded by the French ANR project PYRAMID; the OROGEN project financed by Total, BRGM and the CNRS; the Spanish Ministry of Economy and Competitiveness, Grant/Award Number SUBTETIS (PIE-CSIC-201830E039); and Generalitat de Catalunya, Grant/Award Number AGAUR 2017 SGR 847. Peer reviewed