The petroleum exploration wells Kutjara 1 and Mulyawara 1, drilled by Rodinia Oil (Australia) Pty. Ltd in the Officer Basin in northwestern South Australia, each intersected granitic basement at depths exceeding 2400 m. Zircons from both granites were isolated for U-Pb dating via Sensitive High-Resolution Ion Micro Probe (SHRIMP), with the aim of determining magmatic crystallisation ages, and constraining the ages of any subsequent high-grade metamorphic events. The sample from the Kutjara 1 well yielded a magmatic crystallisation age of 1591 ± 11 Ma (all uncertainties quoted at 95% confidence), and the zircons feature low-Th/U rims recording subsequent high-grade metamorphism at 1167 ± 7 Ma. The adamellite from Mulyawara 1 records a magmatic crystallisation age of 1168 ± 6 Ma, and contains a small number 1615-1530 Ma inherited grains.