Late Quarternary volcanic activity in the New Ireland Basin

The sedimentology, petrology, and geochemistry of volcanic ash beds in sediment cores recovered during the EDISON II Cruise (SO133) in the New Ireland Basin adjacent to the Tabar-Lihir-Tanga-Feni (TLTF) volcanic chain, east of Papua New Guinea are presented. Age determinations through AMS 14C supplemented by d18O on Globigerinoider ruber assisted the correlation of the tephra. Major and trace element compositions of numerous glass shards and minerals within the ash beds were determined using an electron microprobe and ICP-MS. The shards can be distinctly split into three compositional groups reflecting three different provenances. The first group is composed of shoshonites through phonolites to trachytes, and is characterized by a strong enrichment in K, P, Sr, LILE, LREE, with Ti and HREE depletion relative to MORB, characteristic for TLTF tephras. The second group consists of high-K dacite, rhyolite, and trachyte with similar enrichment in LILE and LREE as the TLTF lavas, but with markedly lower P and Sr concentrations, a negative Eu anomaly, and enrichment in HFSE and HREE. They closely resemble the lavas from Rabaul. The third group consists of medium to low K series andesite and rhyolite, with LILE and REE concentrations typical of island arc lavas, and have strongly depleted HFSE concentrations. They are identical to the active New Britain island arc volcanoes (excluding Rabaul). Surprisingly, only a few thin tephra beds are due to eruptions of the TLTF volcanoes. This suggests that either (i) only small, or non-explosive, eruptions have occurred during the last 333 ka B.P., or (ii) these volcanoes were largely inactive since then. There is a clear distinction, based on geochemistry, between the mantle source of the TLTF volcanoes and that of Rabaul and the other New Britain volcanoes. Glasses from Rabaul in the far northeast of New Britain have a more complicated transitional composition that may reflect a mix of both Solomon and Manus mantle components, and possibly a greater role for fractional crystallization of Ti-rich phases

MPI-Ding reference glasses for in situ microanalysis: New reference values for element concentrations and isotope ratios

We present new analytical data of major and trace elements for the geological MPI-DING glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, GOR132-G, BM90/21-G, T1-G, and ATHO-G. Different analytical methods were used to obtain a large spectrum of major and trace element data, in particular, EPMA, SIMS, LA-ICPMS, and isotope dilution by TIMS and ICPMS. Altogether, more than 60 qualified geochemical laboratories worldwide contributed to the analyses, allowing us to present new reference and information values and their uncertainties (at 95% confidence level) for up to 74 elements. We complied with the recommendations for the certification of geological reference materials by the International Association of Geoanalysts (IAG). The reference values were derived from the results of 16 independent techniques, including definitive (isotope dilution) and comparative bulk (e.g., INAA, ICPMS, SSMS) and microanalytical (e.g., LA-ICPMS, SIMS, EPMA) methods. Agreement between two or more independent methods and the use of definitive methods provided traceability to the fullest extent possible. We also present new and recently published data for the isotopic compositions of H, B, Li, O, Ca, Sr, Nd, Hf, and Pb. The results were mainly obtained by high-precision bulk techniques, such as TIMS and MC-ICPMS. In addition, LA-ICPMS and SIMS isotope data of B, Li, and Pb are presented