Zircon inheritance, sources of Devonian granitic magmas and crustal structure in central Victoria

In central Victoria, inherited zircon in Devonian igneous rocks and detrital metasedimentary country an amphibolite-facies xenolith show that Mesoproterozoic parts of the underlying Selwyn Block cannot be source for all silicic magmas. Zircon inheritance S-type samples reveals significant thermal events at 525–425 Ma 1200–1100 Ma. Both S- I-type have prominent age peaks 420–410 Ma, which record high-grade metamorphism deep crust during terminal phases Benambran Bindian orogenies. All 650–500 peaks, suggesting derivation from arc-related metavolcanic upper Block. Protoliths greenschist-facies Ordovician metasediments Cambrian were deposited distal backarc settings. Most cores are metamorphic, strongest occurs hornblende-bearing rocks, highlighting their largely crustal origin. populations ca 1400 thought to signal sediment East Antarctica Rodinia-Nuna, mostly absent some S-types. The probably applies upper, Block, so magmas sourced mainly deeper sections. was not influenced by exposed rocks. Two one smaller plutons contrasting patterns inheritance, relatively small-scale heterogeneity. Many rounded corroded crystals yield same ages as crystallisation dates thus antecrysts. Higher whole-rock Zr contents generally correlate with higher proportions zircon, differentiation does affect this relationship. degree partial melting a magma efficiency crystal entrainment critical governing inheritance.