NTGS Record 2025-007 presents new LA–ICP–MS U–Pb zircon age data from Neoproterozoic sandstones of the Kiana Group of the northern Georgina Basin, south of Katherine, Northern Territory. The study analysed detrital zircons from two sandstone samples collected from adjacent groundwater bores RN041447 and RN041448, drilled in 2020 as part of regional groundwater investigations by the Northern Territory Department of Environment, Parks and Water Security.
The results reveal complex zircon age populations and provide important new constraints on the depositional history of the Kiana Group. One sample yielded a maximum depositional age of 707 ± 11 Ma, significantly younger than previously reported estimates (ca 960 Ma) and consistent with early Cryogenian deposition during the initial stages of the Sturtian glaciation. The age spectrum suggests possible correlations with upper Kiana Group sandstones to the east (informally named the Inacumba unit) and with Neoproterozoic sandstone units of either the upper Victoria or Wolfe basins to the west. It also suggests that Cryogenian-aged strata might have a wider distribution across the northern NT than previously thought.
The second sample records a maximum depositional age of 1156 ± 7 Ma and displays a detrital zircon age signature indistinguishable from that of the Bukalara Sandstone at the base of the Kiana Group, supporting its assignment to that unit, and further extending its distribution within the western Beetaloo Sub-basin.
Elements of the Kiana Group, including the fine-grained Cox Formation, are missing from the water bore sections, suggesting a complex history of deposition and erosion in this area.
The new geochronological data reported in Record 2025-007 improve understanding of Neoproterozoic basin evolution in northern Australia and provide a valuable framework for regional stratigraphic correlation and tectonic interpretation.
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