Authors / CoAuthors
Bonnardot, M. | Wilford, J. | Rollet, N. | Moushall, B. | Czarnota, K. | Wong, S.C.T. | Nicoll, M.G.
Abstract
To meet the increasing demand for natural resources globally, industry faces the challenge of exploring new frontier areas that lie deeper undercover. Here, we present an approach to, and initial results of, modelling the depth of four key chronostratigraphic packages that obscure or host mineral, energy and groundwater resources. Our models are underpinned by the compilation and integration of ~200 000 estimates of the depth of these interfaces. Estimates are derived from interpretations of newly acquired airborne electromagnetic and seismic reflection data, along with boreholes, surface and solid geology, and depth to magnetic source investigations. Our curated estimates are stored in a consistent subsurface data repository. We use interpolation and machine learning algorithms to predict the distribution of these four packages away from the control points. Specifically, we focus on modelling the distribution of the base of Cenozoic-, Mesozoic-, Paleozoic- and Neoproterozoic-age stratigraphic units across an area of ~1.5 million km2 spanning the Queensland and Northern Territory border. Our repeatable and updatable approach to mapping these surfaces, together with the underlying datasets and resulting models, provides a semi-national geometric framework for resource assessment and exploration. <b>Citation:</b> Bonnardot, M.-A., Wilford, J., Rollet, N., Moushall, B., Czarnota, K., Wong, S.C.T. and Nicoll, M.G., 2020. Mapping the cover in northern Australia: towards a unified national 3D geological model. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.
Product Type
document
eCat Id
134507
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
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Keywords
- theme.ANZRC Fields of Research.rdf
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- EARTH SCIENCES
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- Cover thickness
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- Depth to basement
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- North Australian Craton
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- Northern Territory
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- Queensland
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- Cenozoic
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- Mesozoic
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- Paleozoic
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- Neoproterozoic
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- Exploring for the Future
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- EftF
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- AusAEM1 survey
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- UncoverML
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- Basins
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- Published_External
Publication Date
2020-06-30T02:44:52
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completed
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EFTF Extended Abstract
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asNeeded
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geoscientificInformation
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The cover model provides depth estimates to chronostratigraphic layers, including: Base Cenozoic, Base Mesozoic, Base Paleozoic and Base Neoproterozoic. The depth estimates are based on the interpretation, compilation and integration of multiple sources: 1) horizon interpretation of open file AusAEM1 airborne electromagnetic (Wong et al., 2020), 2) South Nicholson seismic reflection surveys (Carr et al., 2020) acquired as part of the Exploring for the Future (EFTF) program, 3) boreholes markers interpretation extracted from well completion reports, 4) outcropping geology extracted from the GA’s 1:1M scale surface geology (Raymond et al., 2012) and 5) depth to magnetic source estimates with inferred chronostratigraphic surface attributes derived from solid geology maps (Meixner et al., 2016; Stewart et al., 2020). All depth estimates are consistently stored as points in the Estimates of Geophysical and Geological Surfaces (EGGS) database (Matthews et al., 2020). The data points used to compile the cover model were extracted from the EGGS database. Preferred depth estimates were selected to ensure regional data consistency and aid the gridding. Two sets of cover depth surfaces (Bonnardot et al., 2020) were generated using different approaches to map megasequence boundaries associated with the Era unconformities: 1) standard interpolation using a cell size of 4000 m and a minimum-curvature algorithm and 2) machine learning approach (Uncover ML, Wilford et al., 2020) that allows to learn relationship between datasets and therefore, can provide a better depth estimates in areas of sparse data points distribution and assess uncertainties.
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[-24.50, -13.50, 131.50, 145.00]
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