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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., &delta;<sup>13</sup>C and &delta;<sup>18</sup>O) in parts per mil (‰) relative to the Vienna Peedee Belemnite (VPDB) standard, with the &delta;<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 (&delta;<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 (&delta;<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 (&delta;<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>

  • The Coompana Project is a collaborative project between Geoscience Australia and the Geological Survey of South Australia, co-funded by Geoscience Australia’s Exploring for the Future Programme and the South Australian Government’s PACE Copper Initiative. The Coompana Project aims to provide new precompetitive geological, geophysical and geochemical data in the under-explored Coompana Province in South Australia. The pre-drilling geophysics program was undertaken to assist the drilling process by reducing the uncertainty associated with intersecting the targeted stratigraphy. Seismic data were acquired at eight proposed drilling sites for the Coompana Drilling Program in February 2017. Seismic data were collected using vertical and horizontal geophones. An accelerated weight-drop source was tested with metal and plastic strike plates. The plastic strike plate was preferred and used for all sites. P-wave reflection images were used to images subsurface layers and estimate bedrock depth at each drill site. Horizontal geophone data indicated S-wave data had higher resolution than the vertical geophone P-wave data, but initial testing did not provide good bedrock imaging. Fan shots can indicate zones of low velocity weathering at the near surface. Multichannel Analysis of Surface Waves provided near surface weathering profiles. Near surface weathering can be an indication of caves in this limestone environment. The S-wave shot records may indicate the presence of caves with S-wave signal degradation at cave locations, as S-waves do not travel through voids, not noticed at these sites. The seismic reflection method can be used to show subsurface variations and provide bedrock depth estimates, though the bedrock can be difficult to identify. The data is very noisy and data quality changes at different locations. Seismic data quality can be improved with a higher energy source.