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The eclogitized pillows of the Betic Ophiolitic Association: relics of the Tethys Ocean floor incorporated in the Alpine chain after subduction
Author(s) -
Puga E.,
Federico A. Diaz,
Demant A.
Publication year - 1995
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1995.tb00665.x
Subject(s) - geology , ophiolite , subduction , basalt , magmatism , metamorphism , geochemistry , tethys ocean , phenocryst , outcrop , lava , paleontology , cretaceous , flood basalt , volcano , pillow lava , rift , volcanic rock , volcanism , tectonics
In the volcanic sequence of the Betic Ophiolitic Association (BOA) volcanic structures and textures are preserved in spite of being metamorphosed to the edogite facies. The original quenched glassy margins of the pillows and lava flows are still recognizable by the darker colour, fine‐grained textures and scarcity of phenocrysts. The BOA eclogitized pillows have chemical compositions very similar to the basalts enriched in LIL elements erupted nowadays at the mid‐oceanic ridges. Magmatism which generated the BOA most likely began under continental rift conditions at the Triassic‐Jurassic boundary and continued under ocean‐floor extensional conditions during the lower and middle Jurassic. In age and petrological characteristics this magmatism is equivalent to that of the western Tethys ophiolites. During the Late Cretaceous, due to the collision of African and Iberian Plates, the BOA ophiolites were subducted and underwent a metamorphism in the eclogite fades whose climax in the Lugros outcrop can be estimated at 650–700°C and about 20 kb.