Geochronology
Type of resources
Keywords
Publication year
Service types
Topics
-
This Record presents data collected in April 2019 as part of the ongoing Northern Territory Geological Survey–Geoscience Australia (NTGS–GA) SHRIMP geochronology project under the National Collaborative Framework (NCF) agreement and Geoscience Australia's Exploring for the Future Program. Two new U–Pb SHRIMP zircon geochronological results derived from two samples of meta-igneous and metasedimentary rocks from the Aileron and Irindina provinces in JINKA and DNEIPER (HUCKITTA) in the Northern Territory are presented herein. <b>Bibliographic Reference:</b> Kositcin N, and Reno BL, 2020. Summary of results. Joint NTGS–GA geochronology project: Aileron and Irindina provinces, Jinka and Dneiper 1:100 000 mapsheets, 2019. <i>Northern Territory Geological Survey</i>, <b>Record 2020-001</b>.
-
This report presents new Sensitive High Resolution Ion Micro Probe (SHRIMP) U-Pb geochronological results obtained during the Geological Survey of Queensland-Geoscience Australia (GSQ-GA) Geochronology project between July 2010 and June 2012. A total of 24 samples were analysed, in support of ongoing regional geoscientific investigations and mapping programs by the GSQ. This report documents detailed results for each sample individually, encompassing sample location and geological context, a description of the target mineral for geochronology, the relevant analytical data, and a brief geochronological interpretation. A summary of all results from this study is presented in Table i, and the sample locations are shown in Figure i. The analysed samples are from regions extending from the Eulo Ridge, an exposed part of the mainly concealed Thomson Orogen in south-western Queensland, to the Charters Towers and Greenvale regions in the north and the Mount Isa region in the north-west (Figure i). The work was carried out to provide an improved time framework for updated interpretations of the geology of selected parts of the state.
-
NDI Carrara 1 is a deep stratigraphic drill hole (~1751m) completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. This report presents the Pb isotopes analyses conducted on 22 selected whole rock samples of NDI Carrara 1 undertaken by University of Melbourne.
-
The Exploring for the Future Program (EFTF) is a $100.5 million four year, federally funded initiative to better characterise the mineral, energy and groundwater potential of northern Australia. A key focus area of the initiative is the South Nicholson region, situated across the Northern Territory and Queensland border. The South Nicholson region is located between two highly prospective provinces, the greater McArthur Basin in the Northern Territory, the Lawn Hill Platform and the Mount Isa Province in Queensland–Northern Territory, which both have demonstrated hydrocarbon and base metal resources. In contrast, the South Nicholson region is not well understood geologically, is mostly undercover with limited well data, and prior to EFTF contained limited seismic coverage. Re–Os analyses in this study were undertaken to complement seismic data, U–Pb geochronology and geochemistry data to better understand the geological evolution and resource potential of the South Nicholson region. Five organic carbon bearing sedimentary samples from drillholes BMR Ranken 1, NTGS00/1, DDH 83/1 and DDH 83/4 located across the South Nicholson region were analysed for whole rock Re–Os. The aim of the analyses was to better constrain the depositional age of basin units in the region, and to potentially provide insights into the timing of post-depositional processes such as fluid events and hydrocarbon generation and/or migration. Samples belong to the Mesoproterozoic South Nicholson Group, Paleoproterozoic Fickling and McNamara groups, and the Neoproterozoic to Devonian Georgina Basin. Samples were analysed at the University of Alberta, Canada.
-
The late Permian Wandsworth Volcanic Group (WVG) in the southern New England Orogen (SNEO) is dominated by a monotonous series of amalgamated rhyodacitic to felsic eruptives, with minor interbedded flows, intrusives and sediments. The area enclosing known exposures of the WVG cover more than 30,000 km2, with a minimum thickness of 2 km. The top of the succession, as well as the vast majority of the pile representing non-welded material, has not been preserved. Field relationships indicate a broadly contemporaneous (though not necessarily genetic) relationship with late Permian granite magmatism, while Triassic plutons (typically in the range 246-243 Ma) intrude the WVG. SHRIMP U-Pb zircon dating indicates ages around 256.4 ± 1.6 Ma for basal units of the WVG, and 254.1 ± 2.2 Ma for the youngest preserved member of the WVG (Dundee Rhyodacite), defining a short period of substantial intermediate to acid eruptive volcanism. The compositionally unevolved Drake Volcanics to the northeast are older (264.4 ± 2.5 Ma) while those at Halls Peak are older still (Early Permian). Granites of the I-type Moonbi and Uralla Supersuites are dominantly 256-251 Ma and thus overlap in timing (and space) with the WVG event. Interestingly, many mineralized leucogranites (e.g. Parlour Mountain, Oban River, Gilgai) which were formerly regarded as Triassic are now established as synchronous with the Moonbi and Uralla Supersuites and the WVG. The age range of eruption of the WVG permitted by the SHRIMP results (~6 Ma) has been further constrained by CA-ID-TIMS U-Pb zircon analysis which yielded oldest and youngest ages of 255.54 ± 0.16 Ma and 253.26 ± 0.15 Ma respectively, indicating a maximum eruptive time range of ~2 Ma for the preserved pile. Our new results coincide with those determined from CA-ID-TIMS dating of tuffs in the Sydney and Gunnedah Basins. WVG exposures at Attunga are exactly (within ~0.1 Ma) coincident with the age of tuffs within the Trinkey Formation located in the Gunnedah Basin to the west, and the Dundee Rhyodacite is similarly closely matched to the thick Awaba Tuff in the Sydney Basin. Notably, much of the late Permian volcanic and plutonic magmatism in the SNEO is restricted to a remarkably small time range, which coincides exactly with the range of ash fall events in the Sydney and Gunnedah Basins, and possibly further afield. This suggests the SNEO, and the WVG in particular, was the dominant source of volcanic material erupted into these adjacent basins. Further, the adjacent basins may provide a more complete record of Permo-Triassic magmatism in the SNEO than currently preserved within the orogen itself.
-
This Record contains new zircon U-Pb geochronological data obtained via Sensitive High-Resolution Ion Micro Probe (SHRIMP) from 15 samples of volcanic and plutonic igneous rocks of the Lachlan Orogen, the Thomson Orogen, and the Delamerian Orogen, New South Wales. These data were obtained during the reporting period July 2009-June 2010, under the auspices of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA), which is part of the National Geoscience Accord.
-
In this Record new U-Pb SHRIMP zircon results are presented from nine samples from western South Australia and eastern Western Australia. This geochronological study was undertaken to provide temporal constraints on the crystalline basement geology beneath the Nullarbor Plain, to assist in geological interpretation of a reflection seismic transect (13GA-EG1) between the Albany-Fraser Province in the west and the central Gawler Craton in the east. This seismic line transects a region in which the crystalline basement geology is entirely buried beneath Neoproterozoic to Cenozoic sedimentary rocks. Consequently, the age, tectonic evolution and mineral potential of the crystalline basement in this region is very poorly understood. The new results complement the very limited pre-existing geochronology data from the Coompana Province and Madura Province, and provide a basis for comparison of geological ages in these provinces with the geological histories reconstructed for the adjacent provinces of the Gawler Craton to the east and the Albany-Fraser Province to the west.
-
Geoscience Australia has compiled U-Pb datasets from disparate sources into a single, standardised and publicly-available U–Pb geochronology compilation for all Australia. The national maps presented in this poster expand upon the data coverage previously compiled by Anderson et al. (2017) and Jones et al. (2018), which covered northern and western Australia only. This extension of a national coverage has been achieved through the development of Geoscience Australia’s Interpreted Ages database. In this database, there are now >4000 U–Pb sample points compiled from across Australia, with significant datasets to come from the southern Australia regions. These will be available to the public in the coming months through the Exploring for the Future Data Discovery Portal (eftf.ga.gov.au).
-
This Record presents new zircon U-Pb geochronological data, obtained using a Sensitive High Resolution Ion MicroProbe (SHRIMP) for five samples of plutonic and volcanic rocks from the central Lachlan Orogen and the Thomson Orogen, New South Wales. The work was carried out under the auspices of the National Geoscience Accord, as a component of the collaborative Geochronology Project between the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) during the reporting periods 2011-2012.
-
The fundamental geological framework of the concealed Paleoproterozoic East Tennant area of northern Australia is very poorly understood, despite its relatively thin veneer of Phanerozoic cover and its position along strike from significant Au–Cu–Bi mineralisation of the Tennant Creek mining district within the outcropping Warramunga Province. We present 18 new U–Pb dates, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), constraining the geological evolution of predominantly Paleoproterozoic metasedimentary and igneous rocks intersected by 10 stratigraphic holes drilled in the East Tennant area. The oldest rocks identified in the East Tennant area are two metasedimentary units with maximum depositional ages of ca. 1970 Ma and ca. 1895 Ma respectively, plus ca. 1870 Ma metagranitic gneiss. These units, which are unknown in the nearby Murphy Province and outcropping Warramunga Province, underlie widespread metasedimentary rocks of the Alroy Formation, which yield maximum depositional ages of 1873–1864 Ma. While parts of this unit appear to be correlative with the ca. 1860 Ma Warramunga Formation of the Warramunga Province, our data suggest that the bulk of the Alroy Formation in the East Tennant area is slightly older, reflecting widespread sedimentation at ca. 1870 Ma. Throughout the East Tennant area, the Alroy Formation was intruded by voluminous 1854–1845 Ma granites, contemporaneous with similar felsic magmatism in the outcropping Warramunga Province (Tennant Creek Supersuite) and Murphy Province (Nicholson Granite Complex). In contrast with the outcropping Warramunga Province, supracrustal rocks equivalent to the 1845–1810 Ma Ooradidgee Group are rare in the East Tennant area. Detrital zircon data from younger sedimentary successions corroborate seismic evidence that at least some of the thick sedimentary sequences intersected along the southern margin of the recently defined Brunette Downs rift corridor are possible age equivalents of the ca. 1670–1600 Ma Isa Superbasin. Our new results strengthen ca. 1870–1860 Ma stratigraphic and ca. 1850 Ma tectono-magmatic affinities between the East Tennant area, the Murphy Province, and the mineralised Warramunga Province around Tennant Creek, with important implications for mineral prospectivity of the East Tennant area. Appeared in Precambrian Research Volume 383, December 2022.