b'AEGC 2021Short abstractsPorphyritic intrusions utilising pre-existing planes ofwith no means to separate what reliable information there weakness created by the faults and/or within likely beddingis from apparent detail which non-uniqueness reduces to be planes. worthless or even worse, misleading. Parametric modelling safely produces geometrical property distributions that are We will also show how the seismic data very clearly showsin most cases clearly not geologically acceptable, but voxel the presence of a large, previously unknown intrusive body atinversions report property values across a three-dimensional 1.2km depth which may be aa critical component of the mineralmatrix of subsurface addresses with often seductive apparent system at Yaour. detail possibly suggestive of a particular geological preference. Well-run gravity and magnetic inversions (both parametric and 151: Petroleum source rocks, generation and primaryvoxel) can provide valuable and reasonably reliable information, migration: Insights using new direct nano-scale Tof- but to maximise the value of that information it must be separated from misleading aspects of the models. The reliable Sims SEM analysis and Re-Os radiometric dating information is the centre location and total anomalous mass Prof Gregory Smith 1, Dr William Rickard1, Mr Zhen Li1 and Msor magnetization for anomalies confidently separated from Svetlana Tessalina1 a background field. We propose that these statistics should be extracted and presented as inversion results. The models 1 Curtin University themselves or any subsequent derivatives from them can then be separately presented as interpretations without the The literature is full of countless papers discussing theimplication that the inversion favours or justifies that model. It is maturation, generation and primary migration of hydrocarbonsbecoming increasingly important to address these issues as the from organic matter. Yet no one has actually seen how thisease of running an inversion is increased, as critical evaluation works under the microscope. The theory is based on destructiveof computer output is relaxed, and as methodologies such as AI organic geochemical studies derived by pulverising, dissolvingand machine learning further distance computer output from or pyrolysing organic matter and then trying to recombine thethe fundamental physics that is the foundation of geophysical organic geochemical fragments into entities that can be typedmethods. We present case studies to illustrate our proposed to possible starting components. process and highlight variation in the confidence of information The latest generation of Tof-SIMS electron microscopes are nowderived from gravity and magnetic field inversions.capable of producing mass-spectrometry of elements, isotopes and molecules across the full range of atomic numbers from157: Airborne geophysical surveys uploaded to SARIG the light elements upwards including Carbon and Oxygen. Importantly, this means for the first time organic matter canin 2020: Industry focusbe analysed down to the nano-scale under the microscope without disintegrating the component macerals and canDr Philip Heath 1simulataneously analyse the associated inorganics. 1 Geological Survey of South AustraliaSamples of typical organic source rocks have been analysedThe Covid-19 pandemic has given the geophysicists at the using the new IONTOF machine at Curtin University withGeological Survey of South Australia the opportunity to revisit startling results across a range of source rocks. Somehistorical geophysical data that had not yet been uploaded examples will be shown demonstrating maturation and actualonto the South Australian geoserver web portal: SARIG (South primary migration for the first time. Other examples showAustralian Resources Information Gateway). Since April 2020, how the various organic matter types can be distinguishedover 30GB of data have been uploaded to the portal and are from each other by their mass spectral fingerprints directlynow available for free download. This poster summarises all in the sample (eg acritarchs, spores, G. prisca, Tasmanites,these data released in 2020 via SARIG (excluding survey data vitrinite, inertinite, bitumen) and how Carbon, Sulphur andacquired as part of the Gawler Craton Airborne Survey (GCAS)). Oxygen isotopes can be done at the nano-scale including forInstructions for how to locate and download geophysical datareservoir cementation. including data not yet uploaded to SARIG as ASCII and gridded This analytical technology is revolutionary and truly sets a newdatasetsare included.paradigm for source and reservoir petrology that has profound implications for petroleum exploration and development. 158: Stratigraphic drilling in the era of EFTF: The Barnicarndy 1 and NDI Carrara 1 wells153: Why we should not report unconstrained inversionDr Adam Bailey, Dr Emmanuelle Grosjean1, Dr Amber Jarrett1, output in densities or magnetic susceptibilities Dr Chris Boreham1, Ms Lidena Carr1, Dr Dianne Edwards1, Dr Liuqi Wang1, Dr Susannah MacFarlane1, Dr Chris Carson1, Mr Dr Clive Foss 1 and Dr James Austin2 Chris Southby1, Dr Jade Anderson1, Dr Kamal Khider1 and Dr Paul Henson11 CSIRO2 CSIRO Mineral Resources 1 Geoscience AustraliaMany gravity and magnetic inversions are of far-field dataExploring for the Future (EFTF) is an Australian Government acquired at an elevation above the property distribution atinitiative that gathers new data and information about potential which there is little or no information about the details ofmineral, energy and groundwater resources. Commencing its distribution. Despite this the current practice is to reportin 2016 with a focus on northern Australia, an extension was inversion results which purport to illustrate that distributionrecently announced extending EFTF though to 2024 and 89 PREVIEW AUGUST 2021'