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RSES SITE SEARCH
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Research Activities 2006

PRISE

 

Click on the links below to read
the 2006 PRISE research highlights
Or download the 2006 PRISE Research Highlights in PDF format HERE 223Kb

Introduction

PRISE operates as a unique entity within the Research School of Earth Sciences, with the principal charter being to provide external access to the Research School 's specialised equipment and expertise in areas of geochronology, isotope geochemistry and trace- and major element geochemistry. It is thus the Research School 's preferred vehicle for commercial and “commercial collaborative” projects in these areas.

The specialised expertise of the PRISE staff sees them involved in wide ranging collaborative research projects with academic colleagues throughout the world, as well as providing their research and analytical expertise to industry and Government agencies on a commercial basis. During 2006 PRISE hosted 23 visitors from Australia and overseas. Most undertook collaborative projects utilising the SHRIMP, Laser ablation- and solution ICPMS, electron microprobe and TIMS analytical facilities. PRISE staff also participated in, and led, a number of field-orientated studies in Australia , Africa , South America and Norway .

As members of a self-funded research group, PRISE scientists also undertake their own research projects and have been involved in successful Australian and international research grant proposals. During 2006 Dr Greg Yaxley was awarded an ARC Linkage grant with industry partner AMIRA International to develop new tools for the interpretation of diamond indicator minerals. The PRISE group maintains a high publication record and 2006 was no exception, with 42 papers being published in international journals and books ( http://rses.anu.edu.au/prise/pubs_2006.htm ).

Some areas of current research activity

  • A new high pressure empirical calibration of the exchange reaction for Ni and Mg between olivine and pyrope garnet at mantle pressures (3.0-4.5 GPa) was determined using the piston-cylinder apparatuses at RSES. This reaction is the basis of "Ni-in-garnet" thermometry, an important exploration tool used by the diamond industry in estimating thermal conditions and probable diamond stability in the lithospheric upper mantle. The key finding was that, as well as being temperature dependent, the reaction is also pressure dependent, casting doubt on previous calibrations which did not include any pressure dependence. This research is kindly funded by de Beers.
  • The ultimate test of the Neoproterozoic “Snowball Earth” hypothesis is to accurately determine the ages of the various glaciogenic deposits around the world. This is possible by U-Pb dating of zircons from volcanic ashes from within these deposits, but complications caused by inheritance and mixed populations of zircons make this a difficult exercise. A sampling and analytical strategy (using the SHRIMP) has been developed to maximise the chances of successfully dating the correct material. This procedure is being applied to better constrain the timing of world-wide glacigene events.
  • Sulphur isotope studies are fundamental to the understanding the origin and conditions of formation of the metal sulphides. One of the keys to discovering and deciphering complex histories within sulphide minerals is to use the spatial resolving power of the SHRIMP. Together with the Earth Chemistry group, analytical protocols for sulphur isotope analyses have been developed using the multi-collectors of the SHRIMP II. Testing of various potential standards has been successfully completed and reconnaissance studies on two ore deposits have been carried out.
  • Sedimentary basin evolution is being studied through combined studies of oxygen isotopes and fluid inclusions in quartz cements, K-Ar ages of diagenetic illite, and Re-Os isotopes and trace elements in late-stage sulfides. The work has direct application to understanding the quality of petroleum reservoirs. In the next phase of the project the geochemical and petrographic data will be linked with regional tectonic models to improve predictive capabilities of the geochemical and geophysical datasets.
  • Field work was conducted on the Almklovdalen peridotite-dominated body in the Western Gneiss Region, Norway . This is a large slice of upper mantle material, tectonically emplaced into the crust, which largely consists of fertile peridotite with abundant relatively refractory garnet clinopyroxenite and eclogite layers. All lithologies were extensively sampled for future petrological and geochemical studies aimed at investigating high pressure interactions between partial melts of eclogite or pyroxenite, and peridotite. These field based studies complement on-going high pressure experimental investigations of melting of heterogeneous upper mantle.

Research Projects