Do extrusion ages reflect magma generation processes at depth? An example from the Neogene Volcanic Province of SE Spain |
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| Authors: | Bernardo Cesare Daniela Rubatto María Teresa Gómez-Pugnaire |
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| Institution: | 1.Dipartimento di Geoscienze,Università di Padova,Padua,Italy;2.C.N.R. Istituto di Geoscienze e Georisorse,Padua,Italy;3.Research School of Earth Sciences,The Australian National University,Canberra,Australia;4.Departamento de Mineralogía y Petrología, Facultad de Ciencias,Universidad de Granada,Granada,Spain;5.Instituto Andaluz de Ciencias de la Tierra (CSIC), Facultad de Ciencias,Universidad de Granada,Granada,Spain |
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| Abstract: | The high-K calc-alkaline volcanic rocks along the Neogene Volcanic Province of SE Spain represent crustal anatectic melts
mixed with mantle components during the opening of the Alborán Sea. Partially melted metapelitic enclaves, along with the
geochemical signature, provide evidence of their crustal source. U–Pb SHRIMP geochronology on monazite and zircon from enclaves
and their hosting lavas in the localities of El Hoyazo, Mazarrón and Mar Menor reveals variable delays between the melting
at depth and the eruption of the volcanics. These data indicate that: (1) the most important event of anatexis in the Neogene
spanned at least the 3 m.y. interval between 12 and 9 Ma; (2) there is no trend in age of crustal melting; and (3) the delay
between magma generation and extrusion varies from more than 3 m.y. at El Hoyazo to ~0.5 m.y. and possibly 2.5 m.y. at Mar
Menor, with no significant delay measurable at Mazarrón. The variable time delay between anatexis and lava extrusion indicates
that radiometric ages of volcanics may provide misleading information on the timing of magma genesis occurring at depth. This
highlights the pitfall of basing detailed geodynamic models on volcanic extrusion ages alone.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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| Keywords: | Anatexis Geochronology Monazite SHRIMP Southern Spain Volcanism Zircon |
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