Dating metasomatic events in the lithospheric mantle beneath the Calatrava volcanic field (central Spain)

Abstract

We report the first attempt to date metasomatic events in peridotite xenoliths from the Subcontinental Lithospheric Mantle (SCLM) beneath the Cenozoic Calatrava volcanic field of central Spain. The most metasomatized xenoliths of the El Aprisco olivine melilitite maar were selected to perform a geochronological study on metasomatic apatite (U-Pb method) and amphibole (Ar-Ar), integrated with an enlarged chemical data set on these minerals. The metasomatic agents in studied samples are mainly carbonate-rich ultra-alkaline melts of probable asthenospheric derivation. Some samples have been overprinted by more than one metasomatic event. The geochronological data confirm three metasomatic events that occurred within the SCLM beneath central Spain in Cretaceous (118 Ma), Oligocene (29 Ma), and Miocene (16–4 Ma) times, much earlier than the host volcanic magmatism. To date, no magmatic events of those ages have been recorded in central Spain. However, a correlation with several cycles of sporadic intraplate magmatism of alkaline affinity in the Iberian microplate is suggested. This study illustrates that the SCLM preserves the memory of a complex history of melt and/or fluid percolation processes in a metasomatic record that is generally unrelated to shallower crustal magmatic events.