Summary of results. Joint NTGS-GA geochronology project: Tanami region 2001-2002

SHRIMP U-Pb zircon geochronology results are presented for nine samples collected in the Tanami Region during the GA1-NTGS geochronology field sampling trip in July 2001. The Dead Bullock Formation (2001082513) is assigned a maximum depositional age of 1865 ± 12 Ma (2σ). Previously, this unit was assigned to the MacFarlane Peak Group of Hendrickx et al (2000) and was thought to have been deposited between 1880 Ma and 1910 Ma. Results for four samples of the Killi Killi Formation have confirmed the widespread occurrence of this unit, its characteristic detrital zircon provenance signature and consistent maximum deposition age of 1840 Ma. The maximum deposition age of the Wilson Formation (Ware Group) is determined to be 1800 ± 31 Ma. The Pargee Sandstone was previously interpreted as a syn-orogenic molasse, deposited during the Tanami Orogenic Event (1848 Ma-1825 Ma). SHRIMP U-Pb detrital zircon results for sample 2001082517 prove this to be incorrect, as the youngest group of seven zircons from this sample records ages between 1735 Ma and 1770 Ma. Bibliographic Reference: Cross A, Claoué-Long JC and Crispe AJ, 2003. Summary of results. Joint NTGS-GA geochronology project: Tanami Region 2001-2002. Northern Territory Geological Survey, Record 2003-006.