The Geochemistry and Cosmochemistry Group uses experimental and analytical equipment to characterise Earth materials throughout geologic history in order to understand the processes that have been active in making a habitable planet. Much of our work is based around laboratories and facilities, particularly related to analytical mass spectrometers (Noble Gas, SHRIMP, TIMS), but we also carry out experiments including the SPEC-E lab.
G&C has a close association with the ‘Origins: Stars, Planets and Life’ research theme, where much of our work is applied. The origin and evolution of Earth as a planet is a key element of our research, and much of that research is based on the measurements we can make.
This year has seen developments in all the laboratories. The SHRIMP Facility continues to improve in the measurement of minor stable isotopes and particularly in the abundances of 17O, 33S, and 36S. In the PhD work of Liane Loisell, resolution in 17O has been demonstrated at the 0.1 permil level for Martian meteorites. Techniques have been developed for the precise analysis of O isotopes in 40 mm thin sections of biophosphate. In a collaborative study with representatives from the Chinese National Institute of Metrology, as a contribution to the Avogadro Project, the isotopic composition of enriched Si has been measured in both negative and positive ion mode, achieving sub-percent precision on isotopic ratios as small as 3 x 10-7.
The SPIDE2R lab (isotope geochemistry clean laboratory and Triton plus and MAT 261 mass spectrometers) continues in full production. A sampling of the highlights for 2017 include: improvements on our Triton plus enabling measurement of high precision isotope ratios of extinct nuclides (142Nd) to ± 5 ppm (2 SD). PhD student Pat Carr, as part of his research, developed protocols for measurement of Nd isotopic compositions of low Nd concentration tourmalines for fluid tracing associated with mineralisation. New chemical procedures have been developed enabling the first high precision ID-TIMS U-Pb dating of the mineral cassiterite. Collaborative work with our visitors Mingxing Ling and Weidong Sun, Chinese Academy of Sciences, has led to refined age estimates of the Ordivician-Silurian boundary using single zircon ID-TIMS U-Pb dating. Continued high precision U-Pb age determinations and initial Sr isotope accretion chronology of the oldest achondrite meteorites are leading to a refined chronology of early solar system processes and planetary differentiation timescales.
In the Noble Gas lab, Helix-MC Plus multi-collector noble gas mass spectrometer functions well. During the year, in collaboration with Thermo-Fisher Scientific, we developed a collector automation kit for the mass spectrometer, which is now commercially available. The first one was sold to the University of Oxford. Utilising the mass spectrometer, a post-graduate student, Ms Suzette Timmerman produces high quality noble gas data from minute amounts of well-characterised diamonds. These results are useful to constrain the structure of the mantle and how it has changed since Earth’s formation.
The SPEC-E (Spectroscopy, Characterization and Experiments) Laboratory saw the installation of thermogravimetric analysis, differential scanning calorimeter and differential thermal analysis equipment. The infrared spectrometer with microscope and environmental chambers, plus the handheld infrared spectrometer continue to operate well. New approaches with X-ray diffraction are being pioneered at the Australian Synchrotron and Advanced Light Source.
Cross-section of a basaltic glass reacted with SO2 at 800 °C created by Christian Renggli (PhD student working with Penny King). Brown- silicate glass, red – silicate phases, blue – calcium sulfate, green – magnesium sulfate.
Firstly, congratulations to Vickie Bennett on her promotion to Professor (Level E1) in 2017. An honour well deserved for her tireless efforts in leadership and promoting Earth Chemistry and G&C.
Dr Penny King received the Clare Burton Award from ANU for excellence in Equity and Diversity, and Senior Fellowship of the Higher Education Academy.
We wish to congratulate two of our scientists for success in the recent ARC DP round: Prof. Vickie Bennett was lead CI (with co-CIs Allen Nutman and Dominique Tanner, University of Wollongong) for research into the chemistry of the early Earth “Earth’s coming of age: The global transformation from the Hadean to the geologically modern Earth”, and Dr Mark Kendrick was lead CI (with co-CI Dr Oliver Nebel, Monash University) on a grant “Mantle evolution and the origin of Earth's atmosphere”.
Finally, congratulations to Prof. Ian Williams and Dr Masahiko Honda for deciding to take on retirement. Ian and Honda have been stalwarts of developing the capabilities of mass spectrometers – Ian with SHRIMP, Honda with the Noble Gas Lab. While they aren’t going anywhere, this is a significant event for them and us and we wish to thank them for all they have done, congratulate them on a career well served, but also look forward to working on with them into the future.
We congratulate completing students who have fought and persevered through their programs of endeavour:
Thomas Haber was awarded the PhD degree for his thesis “Constraining the bombardment history of the Moon with a set of Apollo 14, 16 and 17 impact melt rocks” (Supervisors Prof. V. Bennett and Dr M. Norman). Thomas is now a postdoctoral fellow at the University of Münster continuing his research on lunar and meteorite samples.
Piers Koeford has completed the requirements for his PhD (Supervisor Dr Y. Amelin), for his thesis titled “Sequencing planetary accretion using chronology of ungrouped achondrites”. Piers is heading to Washington University in St Louis for a post doc position.
Darren Laker was awarded a first class Honours degree for his thesis “Source Material of the Fractionated Mole Granite: Whole Rock and Zircon Analysis” (supervisors Prof. V. Bennett and Dr. M. Norman).
Geoff Bonning was awarded a first class Honours degree with his thesis titled “Oxygen isotope compositions of chondrules from carbonaceous chondrites” (supervisor Prof. T. Ireland). Geoff has commenced his PhD studies with us.
Callum MacFarlane was awarded a first class Honours degree with his thesis titled “Biogenic Sulfur isotopic Fractionation on SHRIMP SI” (supervisor Prof. T. Ireland). Callum has taken a position with an Australian Government Department.
This year saw the start of the research programs of the following new students:
Geoff Bonning (PhD with supervisor Prof. T. Ireland): Experimental cosmochemistry and the origin of high temperature fractionations in the early solar system.
Evgenii Krestianinov (PhD with supervisor Dr Y. Amelin) will study chronology of accretion and differentiation of asteroids using isotope systematics of ungrouped achondrites.
Emeritus, Honorary staff and Visitors
Dr Marc Norman continues his research on the bombardment history of the Earth and Moon and is the Executive Editor of Geochimica et Cosmochimica Acta.
Dr George Gibson led a 6-day post-conference field excursion in the Mount Isa region as part of Rodinia 2017, one of two major meetings for IGCP 648: Supercontinent cycle and global geodynamics.
Extended travel and outcomes
Prof. Vickie Bennett spent 3 weeks in the Isua region, southwest Greenland as part of ARC funded fieldwork to investigate the origins of habitability as preserved in the oldest (>3,600 million year old) rock record.
Dr M. Honda attended a Geochronology Workshop held at New Mexico Tech, Socorro in June.
Prof. Trevor Ireland visited Professor Weidong Sun at the Qingdao Institute of Oceanology for three weeks as well as attending two conferences: 3rd Beijing International Forum on Lunar and Deep Space Exploration, and the Meteorites in China Symposium in Kunshan.
Prof. Ian Williams spent two weeks collecting zircon samples in the Galapagos Islands. During two weeks in China he visited geological sites in Yunnan and worked in the Beijing SHRIMP Laboratory. He was a guest speaker at the Granites2017@benalla conference.
Dr Penny King spent time at Tokyo Institute of Technology as an invited speaker and guest of the ELSI Origins Network, Cosmic Perspectives of Earth workshop series.
Outreach activities & Service roles external to ANU
Prof. Trevor Ireland continues as President of The Meteoritical Society, and as an Associate editor of Geochimica et Cosmochimica Acta.
Dr Y. Amelin participated as a panel member in the NASA Emerging Worlds program, and continues as an Associate Editor of Geochimica et Cosmochimica Acta and as a member of the Editorial Board of Chemical Geology.
Dr Mark Kendrick continues as a member of the Editorial Board of Chemical Geology.
Prof. Ian Williams, continuing his work with Australian Scientific Instruments, spent a week in India progressing the purchase of a SHRIMP by the Geological Survey of India, and four weeks in Russia helping to upgrade the St Petersburg SHRIMP. He also spent two weeks at IIT Roorkee, where he presented the entire second semester isotope geochemistry course in one week to a group of HDR students selected from top Indian universities.
Dr Penny King was Chair of the Mineralogical Society of America Short Course Committee, member of the Geochemical Society – European Association Geochemists Fellows Awards Committee, Past-Head, Treasurer and Member of the Australasian University Geoscience Educators’ Network. She finished up her role as Contributing Editor for Elements magazine “A Life in Science” column.