A low-Li geochemical province in the NE Atlantic |
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| Authors: | JC Bailey R Gwozdz |
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| Institution: | Institute for Petrology, University of Copenhagen, Øster Voldgade 10, Copenhagen K, Denmark |
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| Abstract: | Lithium was analysed in 392 basalts and related igneous rocks from the North Atlantic Tertiary-Recent province using activation analysis and ?erenkov counting.Monotonous Li values of 5.5±2 ppm in NE Atlantic basalts define a low-Li geochemical province which has persisted for 60 million years, over 20° of latitude and regardless of basalt type and chemistry. This low-Li province and the increasing Li contents of ocean-ridge tholeiites into the S Atlantic are believed to monitor Li heterogeneity in the underlying mantle.Li, like Na, increases gently during the differentiation of several basalt series. No whole-rock coherence is observed between Li and Mg, K, Rb or Ca. Mantle phlogopite is considered to play an insignificant rôle in controlling the Li levels of NE Atlantic basalts. |
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