The research activities within the Isotope Geochemistry group span the extremes of the geologic timescale, from the study of rare pre-solar grains preserved in meteorites pre-dating the beginning of the solar system more than 4.5 billion through to high precision age determinations of young volcanoes, and in scale from planetary systems to individual molecules. Active areas of research within the Isotope Geochemistry area include planetary and early Earth studies, metamorphic and igneous geochemistry, the role of fluids in crustal processes and the elemental cycling from atmosphere to the deep Earth interior. The diverse faculty and research activities under the Isotope Geochemistry banner are linked through reliance on the development and application of novel analytical methods and instrumentation for isotopic measurements, with a strong network of collaborations and student co-supervision throughout the group.
2015 was another exciting and productive year. Notable advances for instrument development were the installation on the multi-collector noble gas mass spectrometer Helix-MC of a new source assembly and high gain Faraday amplifier with 1E13 ohm feedback resistor. These upgrades improved accuracies of noble gas analyses significantly in M. Honda’s lab and are leading to new types of investigations. Under the direction of Trevor Ireland, the SHRIMP SI is continuing to make good progress measuring minor stable isotope abundances, including the rare isotopes 17O in meteoritic materials and 36S in Archean sulphides. Central to work has been the development of a new detection system by the RSES Electronics Group based on charge accumulation.
Isotope Geochemistry faculty and students continue high rates of publication in international journals. Highlights of the past year include the work of Ian Williams to produce and publish over 2,500 conodont oxygen analyses from over 160 rock samples to define in more detail than ever before the rise and fall of global sea surface temperatures throughout the Silurian (J. A. Trotter, I. S. Williams, et al., New conodont δ18O records of Silurian climate change: Implications for environmental and biological events, Palaeogeography, Palaeoclimatology, Palaeoecology 443 (2016) 34–48).
Marc Norman’s work showed that the petrology, mineral chemistry, and well-defined crystallization age of a noritic anorthosite impact melt rock from the Moon shows that a basin-scale impact occurred on the Moon at 4.2 Ga. This shows that that the late heavy bombardment on the Moon was more prolonged than a single episode at 3.9 Ga (M. D. Norman, et al., (2015) Crystal accumulation in a 4.2 Ga lunar impact melt. Geochimica et Cosmochimica Acta, vol. 172, pp. 410-429. DOI: 10.1016/j.gca.2015.09.021).
Vickie Bennett was part of a team synthesizing observations from the oldest rocks worldwide to put together a new model for an early supercontinent (Nutman, A.P., Bennett, V.C., and Friend, C.R.L.F., Proposal for the continent Itsaqia amalgamated at 3.66 Ga and rifting apart from 3.45 Ga: Evidence and mechanism for a Wilson cycle at the start of the rock record. (2015) American Journal of Science 315 (6), 509-536.)
Group members maintained high levels of international professional service with notable examples being Marc Norman continuing as Executive Editor of the leading geochemistry journal Geochimica et Cosmochimica Acta, overseeing 90 associate editors and 1000 new manuscript submissions per year; Trevor Ireland as Vice-President of the Meteoritical Society; Vickie Bennett is the Early Earth theme chair for the 2016 Goldschmidt conference, Yokohama Japan and the Chair of the Awards Nomination Committee of the Geochemical Society.
Faculty and students of Isotope Geochemistry area are active in the newly formed SSERVI Australia, which is a node of the NASA Solar System Exploration Research Virtual Institute and contributed to the Planetary Science Workshop held at RSES on 28 September. SSERVI Australian aims to strengthen national planetary research and extend collaborations with the international community through SSERVI and NASA (www.sserviaustralia.org).
PhD student Suzette Timmerman (Supervisor M. Honda) presented an invited talk on multiple inclusion ages in diamonds at the Goldschmidt Geochemistry conference in Prague. Our PhD students excelled at the ANU-wide “3 Minute Thesis” competition Hannah James reaching the finals and with Kelsie Long winning second place (both supervised by Ian Williams).
Isotope Geochemistry faculty continue to increase their teaching profiles with Ian Williams taking over as convener of the 2nd year course EMSC 2015 “Chemistry of Planet Earth” and with new faculty member Mark Kendrick contributing 50% of the lectures to a highly revised course. Vickie Bennett and Yuri Amelin prepared and delivered the new Master’s level course EMSC 8022, “Analytical Geochemistry” in 2nd semester.
We welcomed new PhD students Suzette Timmerman (Supervisor M. Honda), Li Liu and Lianne Loiselle (Supervisor Trevor Ireland).
We congratulate Marian Sampah on submission of her PhD thesis (Supervisors Trevor Ireland and Yuri Amelin).
On a sad note, in July we said farewell to Daniela Rubatto after 17 years as part of the SHRIMP group at RSES. Daniela leaves us to take up a Professorship at the University of Bern, Switzerland. Her research and administrative leadership will be greatly missed, as will her energy and enthusiasm, but we look forward to visiting our new “international” colleague and working with her in the future.