Investigation of inclusions in 3.0-4.4 Gyr old zircon from the Mt. Narryer terrane, Western Australia

• Applicant: Professor Dr. Andrew Putnis, since 1/2012
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 83350698

The project aims to establish a systematic study of inclusions found in detrital zircons from Jack Hills and Mt. Narrier, Western Australia. Some of these grains are older than 4.0 Ga and along with their mineral inclusions they represent the oldest material preserved on Earth and thus a unique inventory for obtaining geochemical and petrological information about the very early history of the planet. The present project aims (i) to characterise inclusions with respect to their mineral parageneses and quantity, (ii) to unravel petrological and geochemical information stored in these inclusions and (iii) to relate these features to the ages and isotopic and chemical characteristics of the host zircons by using a wide range of micro-analytical techniques. Particularly relevant is further research on recently discovered diamond and graphite inclusions in up to 4.25 Ga old zircons (Menneken et al. 2007, Nature 448, 917), which have unusually low (13C values with a median of -31‰ (Nemchin et al. 2008, Nature, in review). It is planned to analyse the carbon isotope composition and the nitrogen concentration of these diamonds by ion microprobe, their nitrogen aggregation state by synchrotron infrared spectroscopy, and their microtexture, their structural relationship with graphite, as well as the possibility of nano-inclusions by transmission electron microscopy. Additional information on the origin of the diamonds will be explored by cathodoluminescence spectroscopy. The results of these investigations will greatly improve current knowledge of the early evolution of Earth. This research also addresses a number of other issues that are intimately linked to the early history of the planet, such as (i) the origin of life, (ii) the evolution of hydrosphere and atmosphere, (iii) the early formation of some ore deposits, and (iv) the onset of plate tectonics.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr. Thorsten Geisler-Wierwille, until 1/2012