Isotopic Compositions of Plagioclase From Plutonic Xenoliths Reveal Crustal Assimilation Below Martinique, Lesser Antilles Arc

The chemical and isotopic compositions of volcanic arc lavas often show evidence for involvement a sedimentary component during magma genesis. Determining where this is added to magmas vital importance constraining the extent which sediments volatiles are recycled at subduction zones. Lavas from Martinique in Lesser Antilles have wide ranging extending highly radiogenic values (e.g. 87 /Sr/ 86 Sr up ∼0.710) that could, principle, be explained by sediment addition mantle source or crustal assimilation upper plate. We use plagioclase plutonic xenoliths provide supporting hypothesis. Plagioclase formed mid-crust (∼12 km) restricted range unradiogenic isotope ratios ( Sr/ = 0.7041–0.7042) whereas (∼6 greater intra-sample variation more 0.7047. This trend also observed xenolith whole rock Sr. Combined, these results indicate becomes larger as result shallow levels. supported Assimilation-Fractional Crystallization modeling, shows chemically isotopically heterogenous can produce lavas. Our highlight contributions plate before using lava geochemistry quantify volatile recycling zones assessing potential heterogeneity sources.