Fig. 2: Geochronology of the Sylvania amphibolites and tonalites.
From: Incipient continent formation by shallow melting of an altered mafic protocrust
a High-resolution BSE and cathodoluminescence (CL) image of a zircon crystal from the amphibolite showing primary anatectic zircon crosscut by recrystallisation fronts and mottle-texture zircon. Red ellipses denote SHIRMP U-Pb analysis spots with corresponding common-Pb corrected 207Pb/206Pb dates, and white ellipses denote SIMS oxygen isotope analyses spots and δ18O (VSMOW) composition. b BSE image of titanite-ilmenite corona showing granular titanite texture and relic inclusions of ilmenite in titanite. c, d Stacked Tera-Wasserburg concordia diagram and box diagram showing U-Pb isotope composition of titanite(red) and zircon (green) in the amphibolite, and the weighted average U-Pb dates for each mineral respectively. e. Plane polarised light photomicrograph of garnet in the metatonalite. f Inverse Lu-Hf isochron diagram for garnet from the metatonalite showing that garnet in the metatonalite is the same age as zircon and titanite in the amphibolite. g. Kernel density estimate for a compilation of detrital and inherited zircon in rocks from the Pilbara Craton showing that partial melting in the rocks from the Sylvania Inlier occurred during an inferred major period of felsic crust production.
