Fig. 1: Petrology and geochemistry of amphibolites and metatonalites from the Sylvania Inlier.
From: Incipient continent formation by shallow melting of an altered mafic protocrust
Photomicrographs of amphibolites from the Sylvania Inlier showing their bulk mineralogy (a), evidence for partial melting including former melt pockets (b) and crystallised melt with idiomorphic plagioclase crystals and graphic texture (c), and titanite forming coronae around ilmenite. hbl = hornblende, ilm = ilmenite, ttn = titanite, ep =epidote, pl = plagioclase and q = quartz (d). e. Ternary diagram comparing the major element chemistry of the amphibolites and ‘metatonalites’ to Hadean-Eoarchean rocks in the Acasta Gneiss complex, mafic rocks from the Pilbara Craton and a global compilation of Archean TTG series rock (all normalized to 100% in the NCKFMASTO chemical system after ref. 10). f Chondrite normalised rare earth element (REE) distribution diagram comparing rocks from the Sylvania Inlier to a selection of other mafic rocks from the Pilbara Craton18,28. The average Apex and CF-2 compositions denote a typical tholeiitic and enriched basalt respectively (following Smithies et al.28), which are similar to the high TiO2 and intermediate TiO2 groups of the Mt Ada Basalt from Murphy et al.18.
