Products of voluminous pyroclastic eruptions with eruptive draw-down of several kilometers provide a snap-shot view of batholith-scale magma chambers, and quench pre-eruptive isotopic fractionations (i.e., temperatures) between minerals. We report analyses of oxygen isotope ratio in individual quartz phenocrysts and concentrates of magnetite, pyroxene, and zircon from individual pumice clasts o...

We examine the implications of new 182W and 142Nd data for Mars and the Moon for the early evolution of the Earth. The similarity of 182W in the terrestrial and lunar mantles and their apparently differing Hf/W ratios indicate that the Moon-forming giant impact most probably took place more than 60Ma after the formation of calcium-aluminium-rich inclusions (4.568Gyr). This is not inconsistent w...

Fifteen North Cascade Arc basalts and andesites were analyzed for Mg isotopes to investigate the extent and manner of crustal contributions to this magmatic system. The δ 26Mg of these samples vary from within the range of ocean island basalts (the lightest being −0.33 ± 0.07‰) to heavier compositions (as heavy as −0.15 ± 0.06‰). The observed range in chemical and isotopic composition is simila...

An integrated study involving whole-rock and Sr–Nd–Hf isotope geochemistry and zircon geochronology and trace element combined with detailed field investigation was carried out for the composite Meiwu batholith in the West Qinling orogenic belt of central China to probe the origins of its compositional diversity and its emplacement history. The batholith is composed of quartz diorite, granodior...

Melt inclusions from Oligocene continental flood basalts (CFB) erupted in Yemen provide unique insight into the timing and nature of the processes that lead to crustal contamination and melt aggregation in CFB magmas. Large variations in trace element indices that are sensitive to the degree and composition of assimilated crustal material (e.g. K2O=0.20^1.94 wt%, Ba= 13^543 ppm, K/Nb=128^1603, ...