This Record presents data collected in July–August 2020 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia SHRIMP geochronology project under the National Collaboration Framework agreement and Geoscience Australia's Exploring for the Future Program. New U–Pb SHRIMP zircon geochronological results derived from eight sedimentary samples from the western Amadeus Basin in the Northern Territory are presented herein. Detrital zircon U–Pb ages were determined from four samples of the Winnall Group: three samples of the Liddle Formation and one of the Puna Kura Kura Formation. Zircon U–Pb ages were also determined from two samples of the Pertaoorrta Group (Cleland Sandstone and Tempe Formation), one sample of the Larapinta Group (Stairway Sandstone) and one sample of the Mereenie Sandstone. <b>Bibliographic Reference:</b> Kositcin N, Verdel C, Normington VJ and Simmons JM, 2021. Summary of results. Joint NTGS–GA geochronology project: western Amadeus Basin, July–August 2020. <i>Northern Territory Geological Survey, Record</i> <b>2021-002</b>.

The Middle Ordovician Stairway Sandstone consists of a succession of siliciclastic shallow marine sediments, stratigraphically positioned between the dark organic-rich siltstones of the Horn Valley Siltstone, and the regressive siltstones and shales of the overlying Stokes Siltstone, in the Amadeus Basin. The Stairway Sandstone is notable for containing early arandaspid fish fossils, and is a prospective reservoir for Larapinta Petroleum System hydrocarbons. The unit has not been directly dated, but a field sample from the uppermost Stairway Sandstone has yielded an abundant and well-preserved fauna, including micro-vertebrate and conodont fossils that enable correlation to high resolution international conodont biozonation schemes.