Isotope geochemistry and FOZO mantle component of the alkaline-carbonatitic association of Fuerteventura, Canary Islands, Spain

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doi: 10.1016/j.chemgeo.2006.02.009
Authors:de Ignacio, Cristina; Muñoz, Mercedes; Sagredo, Juana; Fernández-Santín, Soledad; Johansson, Ake
Author Affiliations:Primary:
Universidad Rey Juan Carlos, Departamento de Matemáticas, Física Aplicada y Ciencias de la Naturaleza, Madrid, Spain
Universidad Complutense de Madrid, Spain
Swedish Museum of Natural History, Sweden
Volume Title:Chemical Geology
Source:Chemical Geology, 232(3-4), p.99-113. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0009-2541
Publication Date:2006
Note:In English. 53 refs.; illus., incl. 4 tables, sketch map
Summary:Carbonatites are very rare in oceanic environments, where they have been reported only at the Canary and Cape Verde islands in the Atlantic Ocean. In the Canary archipelago, calciocarbonatites occur only on the island of Fuerteventura, in clear spatial and temporal association to alkaline silicate rocks, ranging from ultramafic to salic, and comprising alkaline clinopyroxenites, melteigites-ijolites-urtites, nepheline-bearing gabbros and nepheline-syenites, together with their volcanic equivalents. Selected isotopic (Sr, Nd and Pb) data from representative samples of this alkaline-carbonatitic association show a very restricted range of isotopic compositions, with those of the calciocarbonatites overlapping those of the alkaline silicate rocks. Despite the fact that all these rocks display cumulate textures and cover a wide range of SiO2 and Sr, Nd, Pb contents, initial isotopic compositions are approximately constant and mantle-like, indicating that evolution of the alkaline-carbonatitic association of Fuerteventura must have taken place in the absence of crustal contamination processes. Regarding the mantle source for the alkaline-carbonatitic association, its depleted initial Sr (87Sr/86Sr = 0.7032-0.7036) and Nd (143Nd/144Nd = 0.5128-0.5129) compositions, fall on the same trend as the East African young (<40 Ma) carbonatites. In 143Nd/144Nd and 87Sr/86Sr vs. 206Pb/204Pb diagrams, the alkaline-carbonatitic association of Fuerteventura shows FOZO compositions for Sr and Nd, and slightly higher (towards HIMU) Pb compositions. Furthermore, these data fit the projection of the mantle plane defined by Sr, Nd and Pb isotopic compositions of the DMM, HIMU and EMI components, this fit not being found in sources containing crustal components. In view of this, we propose that the alkaline-carbonatitic association of Fuerteventura was derived mainly from a heterogeneous mantle plume with a deep-seated (FOZO) signature, mixed with HIMU component. Abstract Copyright (2006) Elsevier, B.V.
Sections:Geochemistry; Petrology
Subsections:Igneous petrology; Igneous rocks
Subjects:Alkalic composition; Alkaline earth metals; Carbonatites; Chemical composition; Geochemistry; Igneous rocks; Isotope ratios; Isotopes; Lead; Magmas; Mantle; Metals; Nd-144/Nd-143; Neodymium; Pb-206/Pb-204; Plutonic rocks; Provenance; Radioactive isotopes; Rare earths; Sr-87/Sr-86; Stable isotopes; Strontium; Volcanic rocks; Volcanism; Africa; Atlantic Ocean Islands; Canary Islands; Cape Verde Islands; Fuerteventura
Coordinates:N282500 N282500 W0140000 W0140000
Abstract Numbers:06M/4523
Record ID:2007074873
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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