Wed 22nd November @ noon, Rm 407.208
Abstract:
Following publication of the first reliable Hadean age from Earth in 1983, the inventory of Hadean zircon grains has grown dramatically in recent years. Initially a preserve of Western Australia, there are now at least sixteen locations globally where Hadean zircon has been recorded. However, the Jack Hills remains the only place on Earth where such grains are abundant, and by far the majority have come from a single location – the W74 conglomerate site on Eranondoo Hill. Mount Narryer is the second most abundant site, but elsewhere Hadean zircon is generally present as just solitary grains within igneous, metamorphic or sedimentary rocks that range from Archean to Cenozoic in age. All locations for which published data are available will be reviewed and, where available their chemical and isotopic characteristics will be evaluated. Since these grains are the only tangible record on Earth of the first 500 Ma of our planet’s history, it is imperative that we glean as much information as possible from these crystals. Of particular importance – and great controversy – is what they tell us about conditions on the early Earth and the evolution of its continental crust. The various viewpoints will be discussed and an attempt made to trace key events during the Hadean and its transition into the Archean.
Short bio:
Simon Wilde has been around for a long time! He joined the Geological Survey of Western Australia in 1972 where he mapped >50,000km2 of southwestern Australia on the Perth, Pinjarra, Collie and Pemberton-Irwin Inlet 1:250,000 sheets. He joined Curtin University in mid-1981, was the inaugural Head of the School of Applied Geology from 1991-1997 and established The Institute for Geoscience Research (TIGeR) in 2006, being its Director until 2014. Besides chasing old zircons around the world, he has worked extensively in China for the past 25 years, especially in the North China Craton and the Central Asian Orogenic Belt, and more recently in Tibet. Although primarily focussing on the Precambrian, he has also studied Phanerozoic crustal evolution in several cratons, principally through field, petrological, geochemical and isotopic studies of granitoids.
