Sr and Nd isotope composition of the metamorphic, sedimentary and ultramafic xenoliths of Lanzarote (Canary Islands): Implications for magma sources
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2010
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Resumo |
The lavas produced by the Timanfaya eruption of 1730-1736 (Lanzarote, Canary Islands) contain a great many sedimentary and metamorphic (metasedimentary), and mafic and ultramafic plutonic xenoliths. Among the metamorphosed carbonate rocks (calc-silicate rocks [CSRs]) are monomineral rocks with forsterite or wollastonite, as well as rocks containing olivine +/- orthopyroxene +/- clinopyroxene +/- plagioclase: their mineralogical compositions are identical to those of the mafic (gabbros) and ultramafic (dunite, wherlite and lherzolite) xenoliths. The (87)Sr/(16)Sr (around 0.703) and (143)Nd/(144)Nd (around 0.512) isotope ratios of the ultramafic and metasedimentary xenoliths are similar, while the (147)Sm/(144)Nd ratios show crustal values (0.13-0.16) in the ultramafic xenoliths and mantle values (0.18-0.25) in some CSRs. The apparent isotopic anomaly of the metamorphic xenoliths can be explained in terms of the heat source (basaltic intrusion) inducing strong isotopic exchange ((87)Sr/(86)Sr and (143)Nd/(144)Nd) between metasedimentary and basaltic rocks. Petrofabric analysis also showed a possible relationship between the ultramafic and metamorphic xenoliths. (C) 2009 Elsevier B.V. All rights reserved. Spanish Ministry of the Environment Spanish Ministry of the Environment[MMA-112/2003] Ministry of Education and Science GEOMOD Ministry of Education and Science GEOMOD[CGL 2005-05500-CO2] Ministry of Education and Science GEOMOD Ministry of Education and Science GEOMOD[CGL 2008-05584-CO2-01] |
Identificador |
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, v.189, n.1/Fev, p.143-150, 2010 0377-0273 http://producao.usp.br/handle/BDPI/30245 10.1016/j.jvolgeores.2009.10.017 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCIENCE BV |
Relação |
Journal of Volcanology and Geothermal Research |
Direitos |
restrictedAccess Copyright ELSEVIER SCIENCE BV |
Palavras-Chave | #ultramafic-metamorphic xenoliths #contact metamorphism #Nd and Sr isotopic anomalies #Lanzarote #LOWER CONTINENTAL-CRUST #GRAN-CANARIA #MANTLE BENEATH #EVOLUTION #CONSTRAINTS #ERUPTION #ASCENT #LAVAS #CLINOPYROXENES #GEOCHRONOLOGY #Geosciences, Multidisciplinary |
Tipo |
article original article publishedVersion |