U-Pb zircon studies of mid-crustal metasedimentary enclaves from the S-type Deddick Granodiorite, Lachlan Fold Belt, SE Australia

Abstract

High-grade metasedimentary enclaves in granites can be used to directly characterize the lower and mid crust. Enclaves in the Silurian S-type Deddick Granodiorite, SE Australia, have chemical and Nd-Sr isotopic compositions broadly similar to Ordovician-Silurian clastic sedimentary rocks throughout the fold belt. SHRIMP U-Pb ages of detrital zircons in the enclaves indicate Early Ordovician maximum depositional ages for their psammitic-pelitic precursors. Patterns of zircon inheritance show the same ~ 500 and 1100-1200 Ma peaks commonly observed in Palaeozoic Gondwana margin sedimentary sequences in eastern Australia, New Zealand and East Antarctica. U-Pb ages for metamorphic zircon rims and..