Argon-lead isotopic correlation in mid-atlantic ridge basalts.

Sarda, P; Moreira, M; Staudacher, T · Science · 1999

basic_science · Level V

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Abstract

Step-heating analyses for Mid-Atlantic Ridge glass samples show that maximum 40Ar/36Ar values correlate with 206,207,208Pb/204Pb. These correlations hold for the whole Atlantic Ocean and therefore are unlikely to result from shallow-level contamination processes. Instead, they are taken as mixing hyperbolae between the degassed-depleted upper mantle and a recycled component characterized by high 206Pb/204Pb ratios (19 to 21) and low 40Ar/36Ar ratios (300 to 1000). These relations imply that argon may also be a tracer of mantle recycling.