Journal article
Major zircon megacryst suites of the Indo-Pacific lithospheric margin (ZIP) and their petrogenetic and regional implications
L Sutherland, I Graham, G Yaxley, R Armstrong, G Giuliani, P Hoskin, V Nechaev, J Woodhead
Mineralogy and Petrology | Published : 2016
Abstract
Zircon megacrysts (± gem corundum) appear in basalt fields of Indo-Pacific origin over a 12,000 km zone (ZIP) along West Pacific continental margins. Age-dating, trace element, oxygen and hafnium isotope studies on representative zircons (East Australia–Asia) indicate diverse magmatic sources. The U–Pb (249 to 1 Ma) and zircon fission track (ZFT) ages (65 to 1 Ma) suggest thermal annealing during later basalt transport, with < 1 to 203 Ma gaps between the U–Pb and ZFT ages. Magmatic growth zonation and Zr/Hf ratios (0.01–0.02) suggest alkaline magmatic sources, while Ti—in—zircon thermometry suggests that most zircons crystallized within ranges between 550 and 830 °C. Chondrite-normalised mu..
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Funding Acknowledgements
The project was supported by Australian Museum Geodiversity Research Centre funding, SEM imaging was facilitated by Sue Lindsay, Australian Museum, SHRIMP age dating and LA-ICP-MS facilities at Research School of Earth Sciences, Australian National University, Canberra, assisted by Chuck Magee, Charlotte Allen and Steve Eggins, ZFT dating guided by Paul Green, Geotrack International, Melbourne, EMP analyses at School of Sciences, University of Western Sydney, guided by Adam McKinnon, and Hf-Lu isotope analytical facilities at Earth Sciences, University of Melbourne. Ion-microprobe O isotope analysis used facilities in Centre National de la Recherche Scientifique, University of Lorraine, Nancy, France. Data calculations were assisted by Elena Belousova, Earth Sciences, Macquarie University, Sydney, and plate motion reconstructions for East Australia and East Asia benefitted from support by Sabin Zaharovic, Maria Seton and Dietmar Muller, EarthByte Group, School of Geosciences, University of Sydney.