Major element data of pyroclastic glasses from push cores taken in the center of the Axial Seamount caldera.

Sediment push core samples contain pyroclastic glassy shards up to ∼1 cm. Two cores (D75-PC43 and D75-PC58) were collected above plagioclase-phyric Group 2 lava (see Dreyer et al., 2013 for definition). They are separated by ∼0.3 km on the central portion of the summit caldera floor of Axial Seamount. These cores were divided into thirteen 2 cm thick depth-horizons and provide stratigraphic and absolute age-constrained glass chemistry (see also Clague et al. 2013). Electron microprobe major element analyses were performed on 256 stratigraphically controlled fluidal pyroclastic glass fragments, each an average of four spots on the analyzed glass shard (EMPA at UC Davis following methods of Clague et al., 2013).