*Revised manuscript with no changes marked Click here to view linked References 1 Geochronology of Hadean zircon grains from the Jack Hills, Western Australia 2 constrained by quantitative scanning ion imaging 3 4 J. J. Bellucci1*, A. A. Nemchin1,2, M. J. Whitehouse1, R.B. Kielman1, J. F. Snape1, and 5 R.T. Pidgeon2 6 7 *Corresponding author, email address:
[email protected] 8 9 1Department of Geosciences, Swedish Museum of Natural History, SE-104 05 10 Stockholm, Sweden 11 2 Department of Applied Geology, Curtin University, Perth, WA 6845, Australia 12 13 Abstract 14 Five Hadean (>4 Ga) aged zircon grains from the Jack Hills metasedimentary belt 15 have been investigated by a secondary ion mass spectrometry scanning ion image 16 technique. This technique has the ability to obtain accurate and precise full U-Pb 17 systematics on a scale <5 mm, as well as document the spatial distribution of U, Th and 18 Pb. All five of the grains investigated here have complex cathodoluminescence patterns 19 that correlate to different U, Th, and Pb concentration domains. The age determinations 20 for these different chemical zones indicate multiple reworking events that are preserved 21 in each grain and have affected the primary crystalized zircon on the scale of <10 mm, 22 smaller than conventional ion microprobe spot analyses. In comparison to the spot 23 analyses performed on these grains, these new scanning ion images and age 24 determinations indicate that almost half of the spot analyses have intersected several age 25 and chemical domains in both fractured and unfractured parts of the individual crystals.