02603nas a2200313   4500000000100000008004100001653002000042653003200062653001600094653001500110653002000125653001000145653001500155653001600170653003600186653002000222653003000242100001400272700001300286700001300299700001300312700001500325700001600340245014100356856006500497300001900562490000700581520170100588       2012                            d10agalapagos plume10agenesis and partial melting10aindex terms10aisland arc10aLesser Antilles10amagma10aMontserrat10apb isotopes10aradiogenic isotope geochemistry10asubduction zone10asubduction zone processes1 aM Cassidy1 aR Taylor1 aM Palmer1 aR Cooper1 aC Stenlake1 aJ Trofimovs00aTracking the magmatic evolution of island arc volcanism: Insights from a high-precision Pb isotope record of Montserrat, Lesser Antilles  uhttp://onlinelibrary.wiley.com/doi/10.1029/2012GC004064/full  a1\textendash190 v133 a<p>The volcanic succession on Montserrat provides an opportunity to examine the magmatic evolution of island arc volcanism over a \~2.5 Ma period, extending from the andesites of the Silver Hills center, to the currently active Soufrière Hills volcano (February 2010). Here we present high-precision double-spike Pb isotope data, combined with trace element and Sr-Nd isotope data throughout this period of Montserrat\textquoterights volcanic evolution. We demonstrate that each volcanic center; South Soufrière Hills, Soufrière Hills, Centre Hills and Silver Hills, can be clearly discriminated using trace element and isotopic parameters. Variations in these parameters suggest there have been systematic and episodic changes in the subduction input. The SSH center, in particular, has a greater slab fluid signature, as indicated by low Ce/Pb, but less sediment addition than the other volcanic centers, which have higher Th/Ce. Pb isotope data from Montserrat fall along two trends, the Silver Hills, Centre Hills and Soufrière Hills lie on a general trend of the Lesser Antilles volcanics, whereas SSH volcanics define a separate trend. The Soufrière Hills and SSH volcanic centers were erupted at approximately the same time, but retain distinctive isotopic signatures, suggesting that the SSH magmas have a different source to the other volcanic centers. We hypothesize that this rapid magmatic source change is controlled by the regional transtensional regime, which allowed the SSH magma to be extracted from a shallower source. The Pb isotopes indicate an interplay between subduction derived components and a MORB-like mantle wedge influenced by a Galapagos plume-like source.</p>