Subduction-related Volatile Recycling and Magma Generation beneath Central Mexico: Insights from Melt Inclusions, Oxygen Isotopes and Geodynamic Models

The subduction-related Michoacán–Guanajuato Volcanic Field (MGVF) in central Mexico contains ∼900 cinder cones and numerous larger shield volcanoes of Late Pliocene to Holocene age. We present data for major, trace and volatile (H2O, CO2, S, Cl) elements in olivine-hosted melt inclusions from eight calc-alkaline cinder cones with primitive magma characteristics and one more evolved alkali basalt tuff ring. The samples span a region extending from the volcanic front to ∼175 km behind the front. Relationships between H2O and incompatible trace elements are used to estimate magmatic H2O contents for 269 additional volcanic centers across the MGVF and central Mexico. The results show that magmatic H2O remains high (3–5·75 wt %) for large distances (∼150 km) behind the front. Chlorine and S concentrations are strongly correlated with melt H2O and are also high across most of the arc (700–1350 ppm Cl, 1500–2000 ppm S). The alkali basalt, located far behind the front (∼175 km), has much lower volatile contents (