isotope stratigraphy
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<div>The bulk rock stable isotopes database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for the stable isotopic composition of sedimentary rocks with an emphasis on calcareous rocks and minerals sampled from boreholes and field sites. The stable isotopes of carbon, oxygen, strontium, hydrogen, nitrogen, and sulfur are measured by various laboratories in service and exploration companies, Australian government institutions, and universities, using a range of instruments. Data includes the borehole or field site location, sample depth, stratigraphy, analytical methods, other relevant metadata, and the stable isotopes ratios. The carbon (<sup>13</sup>C/<sup>12</sup>C) and oxygen (<sup>18</sup>O/<sup>16</sup>O) isotope ratios of calcareous rocks are expressed in delta notation (i.e., δ<sup>13</sup>C and δ<sup>18</sup>O) in parts per mil (‰) relative to the Vienna Peedee Belemnite (VPDB) standard, with the δ<sup>18</sup>O values also reported relative to the Vienna Standard Mean Ocean Water (VSMOW) standard. Likewise, the stable isotope ratio of hydrogen (<sup> 2</sup>H/<sup> 1</sup>H) is presented in delta notation (δ<sup> 2</sup>H) in parts per mil (‰) relative to the VSMOW standard, the stable isotope ratio of nitrogen (<sup> 15</sup>N/<sup>14</sup>N) is presented in delta notation (δ<sup>15</sup>N) in parts per mil (‰) relative to the atmospheric air (AIR) standard, and the stable isotope ratio of sulfur (<sup> 34</sup>S/<sup> 32</sup>S) is presented in delta notation (δ<sup> 34</sup>S) relative to the Vienna Canyon Diablo Troilite (VCDT) standard. For carbonates, the strontium (<sup>87</sup>Sr/<sup>86</sup>Sr) isotope ratios are also provided.</div><div><br></div><div>These data are used to determine the isotopic compositions of sedimentary rock with emphasis on the carbonate within rocks, either as minerals, the mineral matrix or cements. The results for the carbonate rocks are used to determine paleotemperature, paleoenvironment and paleoclimate, and establish regional- and global-scale stratigraphic correlations. These data are collated from Geoscience Australia records, destructive analysis reports (DARs), well completion reports (WCRs), and literature. The stable isotope data for sedimentary rocks are delivered in the Stable Isotopes of Carbonates web services on the Geoscience Australia Data Discovery Portal at https://portal.ga.gov.au which will be periodically updated.</div>
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<div>As part of the Data Driven Discoveries program, Geoscience Australia and the Geological Survey of Queensland collaborated to re-examine legacy well cuttings for a chemostratigraphic study. The aim was to identify opportunities for resource discovery in the Devonian-aged Adavale Basin in south-central Queensland by conducting a chemostratigraphic study to define regional stratigraphic correlations in a structurally complex basin with limited well penetrations. A total of 1,489 cutting samples were analysed for whole-rock geochemistry, as well as subsets of samples for whole-rock mineralogy and/or carbonate carbon and oxygen isotopes, from a whole-rock sample. The purpose was to establish new chemostratigraphic correlations across the basin independently, using data from 10 wells that sampled the Adavale Basin.</div>
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<div>Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources.</div><div><br></div><div>In order to gain insights into the resource potential of the South Nicholson region, a key region of focus for EFTF, National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS), and the MinEx CRC. NDI Carrara 1 is the first drill hole to intersect the, as yet, undifferentiated Proterozoic rocks of the newly defined Carrara Sub-Basin within the South Nicholson region. NDI Carrara 1 is located on the western flank of the Carrara Sub-basin, reaching a total depth of 1751 m, intersecting ca. 630 m of Cambrian Georgina Basin overlying ca. 1100 m of Proterozoic carbonates, black shales and minor siliciclastics.</div><div><br></div><div>Geoscience Australia is undertaking a range of investigations on the lithology, stratigraphy and geotechnical properties of NDI Carrara 1 based on wireline data, as well as undertaking a range of analyses of over 400 physical samples recovered through the entire core. These analyses include geochronology, isotopic studies, mineralogy, inorganic and organic geochemistry, petrophysics, geomechanics, thermal maturity, and petroleum systems investigations. Hylogger™ data is available at the NTGS Geoscience Exploration and Mining Information System (GEMIS) webpage.</div><div><br></div><div>This data release presents results for analyses on selected rock samples from NDI Carrara 1, conducted by the Mawson Analytical Spectrometry Services, University of Adelaide, under contract to Geoscience Australia. These results include:</div><div><br></div><div>1. Carbon (δ13C), oxygen (δ18O) and strontium (87Sr/86Sr) isotopes on carbonate bearing samples, and</div><div>2. Trace element data on the leachates prepared for 87Sr/86Sr ratio analyses.</div><div><br></div>