[1] The abundances of 60 elements in 616 Ocean Floor Basaltic (OFB) glasses from the Abyssal Volcanic Glass Data File (AVGDF) of the Smithsonian Institution have been determined by laser-ablation (LA)-ICP-MS and electron microprobe analysis (EMPA). The elements analyzed include all 28 of the refractory lithophile elements, which provide the framework for establishing the geochemical behavior and source abundances of volatile, chalcophile and siderophile elements. In addition to the traditionally analyzed elements (rare earth elements (REE), high field strength elements (HFSE), large ion lithophile elements (LILE) and first row transition elements (FRTE)), we report analyses for lesser-analyzed elements (Li, Be, Ga, Ge, As, Se, Mo, Ag, Cd, In, Sn, Sb, W, Tl and Bi). The precision of the method for most elements is between 2 and 4%, one standard deviation, although ratios of elements determined simultaneously are more precise (e.g., REE, Zr/Hf). Subsets of 329 glasses were analyzed by electron microprobe for S and 154 glasses for Cl. The results define a representative trace element geochemistry of OFB, against which local variations resulting from differences in basalt petrogenesis in a range of tectonic settings or different styles of magmatic differentiation may be compared.Components: 4600 words, 8 figures.

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[1] Chemical analysis by laser-ablation ICP-MS can determine a large number of trace elements with a precision approaching traditional whole-rock analysis, but on a scale approaching that achieved by the electron microprobe. These characteristics make it a particularly attractive method for the analysis of volcanic glasses, but at present little is known about systematic errors, especially those from matrix effects. Here we investigate the precision and accuracy of LA-ICP-MS analysis of basaltic glasses for 60 elements, including rare earth elements (REE), large ion lithophile elements (LILE), high field strength elements (HFSE), the first row transition elements (FRTE), as well as less commonly analyzed elements such as Li, Be, Ge, Ga, W, Mo, As, Sb, Sn, Se, Ag, Tl, Bi, Cd and In. The rate of signal decline during ablation was found to vary systematically with the electronic structure of the element, in both calibration material (NIST SRM 612) and unknowns (natural basaltic glass VG-2 and vitrified basalt BCR-2G). These observations allow optimal analytical conditions with the available instrumentation and standards to be established. Analyses of VG-2 and seven of the MPI-DING vitrified rocks, commonly used as secondary standards, obtained under these conditions, are presented.Components: 9300 words, 7 figures.

Olivine-hosted melt inclusions are commonly used to determine pre-eruptive storage conditions. However, this approach relies on the assumption that co-erupted olivines have a simple association with their carrier melts. We show that primitive olivine crystal cargoes and their melt inclusions display a high degree of geochemical disequilibrium with their carrier melts at Kīlauea Volcano, Hawai’i. Within a given eruption, melt inclusions trapped in primitive olivine crystals exhibit compositional diversity exceeding that in erupted lava compositions since 1790 CE. This demonstrates that erupting liquids scavenge crystal cargoes from mush piles accumulating diverse melt inclusion populations over timescales of centuries or longer. Entrainment of hot primitive olivines into cooler, evolved carrier melts drives post-entrapment crystallization and sequestration of CO2 into vapour bubbles, producing spurious barometric estimates. While scavenged melt inclusion records may not be suitable for the investigation of eruption-specific processes, they record timescales of crystal storage and remobilization within magmatic mush piles.