Summary of results. NTGS LA-ICP-MS Hf program: Amadeus Basin, 2015

Abstract

This Record presents new lutetium-hafnium (Lu-Hf) results from detrital zircons collected from 12 Neoproterozoic to Palaeozoic sedimentary rock samples of the central to eastern Amadeus Basin, Northern Territory. The rock samples were originally collected in 2015. Most zircons in this dataset are older than ca 1640 Ma, including a large population centred at ca 1770 Ma with eHf between approximately +10 and -10. Most zircons in the dataset with U-Pb ages ranging from ca 1640 Ma to ca 1300 Ma have eHf between approximately +15 and -5, considerably more radiogenic than the pre-1640 Ma group. The main U-Pb age population occurs at ca 1150 Ma. Most zircons within this population have eHf between +15 and -20, averaging approximately +5. The youngest zircon population has U-Pb ages ranging from ca 700 to ca 500 Ma, centred at ca 580 Ma. These zircons have a particularly wide range of eHf, stretching between approximately +10 and -30. Zircons of this age range with extremely unradiogenic Hf isotope composition have been widely described from other parts of Australia, but this is their first documentation within the Amadeus Basin.