Extreme 230 Th excesses in magnesian andesites from Baja California
作者: François NauretChristophe HémondRené C. MauryAlfredo Aguillon-RoblesHervé GuillouAntoine Le Faouder
作者单位: 1Université de Brest; UEB, UMR 6538 Domaines Océaniques; Institut Universitaire Européen de la Mer, Place N. Copernic, 29280 Plouzané, France
2Clermont Université, Université Blaise Pascal, Laboratoire Magmas et Volcans, BP 10448, F-63000 Clermont-Ferrand, France
3CNRS, UMR 6524, LMV, F-63038 Clermont-Ferrand, France
4IRD, R 163, LMV, F-63038 Clermont-Ferrand, France
5CNRS, UMR 6538 Domaines Océaniques, Institut Universitaire Européen de la Mer, Place N. Copernic, 29280 Plouzané, France
6Instituto de Geología, UASLP, Av. Dr. Manuel Nava no. 5, Zona Universitaria, San Luis Potosí, S.L.P., C.P. 78250, Mexico
7UMR 1572 LSCE/CEA-CNRS, Domaine du CNRS, 12 avenue de la Terrasse, 91118 Gif-sur-Yvette, France
刊名: LITHOS, 2012, Vol.146-147 , pp.143-151
来源数据库: Elsevier Journal
DOI: 10.1016/j.lithos.2012.04.003
关键词: Mg-AndesiteBaja CaliforniaRutileU–Th disequilibriumGeochemistry
原始语种摘要: Abstract(#br)Four Late Pleistocene magnesian andesites (locally called “bajaites”) from Baja California have been dated by the unspiked K–Ar method and analyzed for major, trace elements and Sr, Nd, Pb, Th and U isotopes. They display very large 230 Th excesses (50% to 120%) relative to 238 U. They also have very high Ba and Sr contents and Sr/Y and La/Yb ratios, together with suprachondritic Nb/Ta ratios (22 to 26). From correlations between 230 Th excess and major elements, trace element and isotopic ratios, we show that the unusual geochemical signature of these lavas can be ascribed to very low partial melting degrees of a mantle source containing residual rutile. This mantle source derived from interactions between the Baja California lithospheric mantle and older magnesian andesite...
全文获取路径: Elsevier  (合作)
影响因子:3.779 (2012)