Detrital zircon age structure within ca. 3 Ga metasedimentary rocks, Yilgarn Craton : elucidation of Hadean source terranes by principal component analysis

A multivariate approach using a similarity matrix derived from >5500 U-Pb zircon analyses was used to investigate the complex and overlapping detrital zircon age structure within ca. 3Ga metasedimentary rocks from the Yilgarn Craton, Western Australia. Detrital zircon analyses were grouped by their 207Pb/206Pb dates using a robust Chi-square grouping method which produced 74 Yilgarn-wide age groups from a pool of >3500 analyses and that were correlated between different metasedimentary rocks. Principal component analysis (PCA) was then used on a calculated similarity matrix of >65 samples which contained these age groups. PCA indicates that the main age populations of the detrital zircons in the ca. 3Ga metasedimentary rocks were derived in varying portions from the Narryer and Yarlarweelor Gneiss Complexes. Differences between the age structure of >3.9Ga zircon populations within the Mt. Alfred metasedimentary rocks with those from Mt. Narryer, Jack Hills and Maynard Hills localities is best explained by their derivation from two Hadean terranes which were joined by ca. 3.7Ga.