Petrogenesis of Permian alkaline lamprophyres and diabases from the Spanish Central System and their geodynamic context within western Europe

• Published in: Contributions to mineralogy and petrology Vol. 156; no. 4; pp. 477 - 500
• Main Authors: Orejana, D., Villaseca, C., Billström, K., Paterson, B. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-10-2008; Springer Nature B.V
• Subjects: Carboniferous; Earth and Environmental Science; Earth Sciences; Geochemistry; Geology; Isotopes; Magma; Mineral Resources; Mineralogy; Original Paper; Permian; Petrology; Rifting; Upwelling; Europe; Permian rifting; Lamprophyres; Alkaline magmatism; Asthenospheric mantle; Western Europe
• ISSN: 0010-7999; 1432-0967
• DOI: 10.1007/s00410-008-0297-x

Basic to ultrabasic alkaline lamprophyres and diabases intruded within the Spanish Central System (SCS) during Upper Permian. Their high LREE, LILE and HFSE contents, together with positive Nb–Ta anomalies, link their origin with the infiltration of sublithospheric K-rich fluids. These alkaline dykes may be classified in two distinct groups according to the Sr–Nd isotope ratios: (1) a depleted PREMA-like asthenospheric component, and (2) a BSE-like lithospheric component. A slight enrichment in radiogenic
207
Pb and
208
Pb allows the contribution of a recycled crustal or lithospheric component in the mantle sources. The intrusion of this alkaline magmatism is likely to have occurred due to adiabatic decompression and mantle upwelling in the context of the widespread rifting developed from Carboniferous to Permian in western Europe. The clear differences in the geochemical affinity of Lower Permian basic magmas from north-western and south-western Europe might be interpreted in terms of a more extensive separation of both regions during that period, until they were assembled during Upper Permian.