Integrated interpretation of overlapping AEM datasets achieved through standardisation
Camilla C. Sørensen 1 3 Tim Munday 2 Graham Heinson 1
+ Author Affiliations
- Author Affiliations
1 Geology & Geophysics, University of Adelaide, North Terrace, SA 5005, Australia.
2 CSIRO, 26 Dick Perry Avenue, Kensington, WA 6151, Australia.
3 Corresponding author. Email: Camilla.Sorensen@gmail.com
Exploration Geophysics 46(4) 309-319 https://doi.org/10.1071/EG14066
Submitted: 4 July 2014 Accepted: 6 November 2014 Published: 24 December 2014
Abstract
Numerous airborne electromagnetic surveys have been acquired in Australia using a variety of systems. It is not uncommon to find two or more surveys covering the same ground, but acquired using different systems and at different times. Being able to combine overlapping datasets and get a spatially coherent resistivity-depth image of the ground can assist geological interpretation, particularly when more subtle geophysical responses are important. Combining resistivity-depth models obtained from the inversion of airborne electromagnetic (AEM) data can be challenging, given differences in system configuration, geometry, flying height and preservation or monitoring of system acquisition parameters such as waveform. In this study, we define and apply an approach to overlapping AEM surveys, acquired by fixed wing and helicopter time domain electromagnetic (EM) systems flown in the vicinity of the Goulds Dam uranium deposit in the Frome Embayment, South Australia, with the aim of mapping the basement geometry and the extent of the Billeroo palaeovalley. Ground EM soundings were used to standardise the AEM data, although results indicated that only data from the REPTEM system needed to be corrected to bring the two surveys into agreement and to achieve coherent spatial resistivity-depth intervals.
Key words: AEM, calibration, Goulds Dam uranium deposit, REPTEM, standardisation, TEMPEST, WalkTEM.
References
Auken, E., and Christiansen, A. V., 2004, Layered and laterally constrained 2D inversion of resistivity data: Geophysics, 69, 752–761| Layered and laterally constrained 2D inversion of resistivity data:Crossref | GoogleScholarGoogle Scholar |
Auken, E., Christiansen, A., Kirkegaard, C., Fiandaca, G., Schamper, C., Behroozmand, A., Binley, A., Nielsen, E., Effersø, F., Christensen, N., Sørensen, K., Foged, N., and Vignoli, G., 2014, An overview of a highly versatile forward and stable inverse algorithm for airborne, ground-based and borehole electromagnetic and electric data: Exploration Geophysics, ,
| An overview of a highly versatile forward and stable inverse algorithm for airborne, ground-based and borehole electromagnetic and electric data:Crossref | GoogleScholarGoogle Scholar |
Beckitt, G., 2003, Exploration for unconformity uranium in Arnhem Land (NT): Exploration Geophysics, 34, 137–142
| Exploration for unconformity uranium in Arnhem Land (NT):Crossref | GoogleScholarGoogle Scholar |
Boyd, G. W., 2004, HoisTEM – a new airborne electromagnetic system: PACRIM Proceedings, Adelaide, 211–218.
Boyd, G. W., and Vrbancich, J., 2007, A new helicopter time domain AEM system for shallow seawater geophysical surveying – static trials: ASEG Extended Abstracts 2007, 1 .
Christensen, N. B., 2002, A generic 1-D imaging method for transient electromagnetic data: Geophysics, 67, 438–447
| A generic 1-D imaging method for transient electromagnetic data:Crossref | GoogleScholarGoogle Scholar |
Christiansen, A. V., and Auken, E., 2012, A global measure for depth of investigation: Geophysics, 77, WB171–WB177
| A global measure for depth of investigation:Crossref | GoogleScholarGoogle Scholar |
Christiansen, A. V., Auken, E., and Viezzoli, A., 2011, Quantification of modeling errors in airborne TEM caused by inaccurate system description: Geophysics, 76, F43–F52
| Quantification of modeling errors in airborne TEM caused by inaccurate system description:Crossref | GoogleScholarGoogle Scholar |
Craig, M. A., ed., 2011, Geological and energy implications of the Pine Creek region airborne electromagnetic (AEM) survey, Northern Territory, Australia: Geoscience Australia Record 2011/18, 292 pp.
Dentith, M., and Randell, M., 2003, Sandstone-type uranium deposits in South Australia and North America: a comparison of their geophysical characteristics: ASEG Extended Abstracts 2003, 233–247.
Deszcz-Pan, M., Fitterman, D. V., and Labson, V. F., 1998, Reduction of inversion errors in helicopter EM data using auxiliary information: Exploration Geophysics, 29, 142–146
| Reduction of inversion errors in helicopter EM data using auxiliary information:Crossref | GoogleScholarGoogle Scholar |
Ellis, G. K., 1980, Distribution and genesis of sedimentary uranium near Curnamona, Lake Frome region, South Australia: AAPG Bulletin, 64, 1643–1657
| 1:CAS:528:DyaL3cXmsVaqu7o%3D&md5=8685cc2d79aeee63b03ee62b221b2213CAS |
Fitzpatrick, A., 2013, Maximising the benefit of historic airborne EM through new modelling – 36 surveys over a decade for building a basin-wide conductivity model for uranium exploration: 13th SAGA Biennial Conference and Exhibition, Extended Abstracts, 1–5.
Foged, N., Auken, E., Christiansen, A. V., and Sørensen, K. I., 2013, Test site calibration and validation of airborne and ground based TEM systems: Geophysics, 78, E95–E106
| Test site calibration and validation of airborne and ground based TEM systems:Crossref | GoogleScholarGoogle Scholar |
Geofysiksamarbejdet, 2012, Refinement of the national TEM reference model at Lyngby [Web document]. Available at www.gfs.geo.au.dk
Hashemi, A., and Meyers, J., 2004, HoistEM data processing for discovery of high grade manganese ore under regolith cover: ASEG Extended Abstracts 2004, 1–4.
Lane, R., Green, A., Golding, C., Owers, M., Pik, P., Plunkett, C., Sattel, D., and Thorn, B., 2000, An example of 3D conductivity mapping using the TEMPEST airborne electromagnetic system: Exploration Geophysics, 31, 162–172
| An example of 3D conductivity mapping using the TEMPEST airborne electromagnetic system:Crossref | GoogleScholarGoogle Scholar |
Lane, R., Heislers, D., and McDonald, P., 2001, Filling in the gaps - validation and integration of airborne EM data with surface and subsurface observations for catchment management – an example from Bendigo, Victoria, Australia: Exploration Geophysics, 32, 225–235
| Filling in the gaps - validation and integration of airborne EM data with surface and subsurface observations for catchment management – an example from Bendigo, Victoria, Australia:Crossref | GoogleScholarGoogle Scholar |
Macnae, J., 2007, Developments in broadband airborne electromagnetics in the past decade, in B. Milkereit, ed., Exploration in the new millennium – Proceedings of Exploration 07, Toronto: Decennial Mineral Exploration Conferences, 387–398.
Macnae, J., King, A., Stolz, N., Osmakoff, A., and Blaha, A., 1998, Fast AEM data processing and inversion: Exploration Geophysics, 29, 163–169
| Fast AEM data processing and inversion:Crossref | GoogleScholarGoogle Scholar |
McConachy, G., Mcinnes, D., and Paine, J., 2006, Airborne electromagnetic signature of the Beverley Uranium Deposit, South Australia: 76th Annual International Meeting, SEG, Expanded Abstracts, 25, 790–794.
Nyboe, N. S., Jørgensen, F., and Sørensen, K. I., 2010, Integrated inversion of TEM and seismic data facilitated by high penetration depths of a segmented receiver setup: Near Surface Geophysics, 8, 467–473
| Integrated inversion of TEM and seismic data facilitated by high penetration depths of a segmented receiver setup:Crossref | GoogleScholarGoogle Scholar |
Podgorski, J. E., Auken, E., Schamper, C., Christiansen, A. V., Kalscheuer, T., and Green, A. G., 2013, Processing and inversion of commercial helicopter time-domain electromagnetic data for environmental assessments and geologic and hydrologic mapping: Geophysics, 78, E149–E159
| Processing and inversion of commercial helicopter time-domain electromagnetic data for environmental assessments and geologic and hydrologic mapping:Crossref | GoogleScholarGoogle Scholar |
Roach, I. C., ed., 2010, Geological and energy implications of the Paterson Province airborne electromagnetic (AEM) survey, Western Australia: Geoscience Australia Record 2010/12, 318 pp.
Roach, I. C., ed., 2012, The Frome airborne electromagnetic survey, South Australia: Implications for energy, minerals and regional geology: Geoscience Australia Record 2012/40 – DMITRE Report Book 2012/00003, 296 pp.
Roach, I. C., Jaireth, S., and Costelloe, M. T., 2014, Applying regional airborne electromagnetic (AEM) surveying to understand the architecture of sandstone-hosted uranium mineral systems in the Callabonna Sub-basin, Lake Frome region, South Australia: Australian Journal of Earth Sciences, 61, 659–688
| 1:CAS:528:DC%2BC2cXhsVWjurjF&md5=301ea1cf545e2df7188adf57a483dccdCAS |
Sattel, D., 2009, An overview of helicopter time-domain EM systems: ASEG Extended Abstracts 2009, 1–6.
Sattel, D., and Kgotlhang, L., 2003, Groundwater exploration with AEM in the Boteti Area, Botswana: ASEG Extended Abstracts 2003, 1–5.
Stolz, E. M. G., 2005, Regolith mapping in hypersaline environments: a comparison of SAM with helicopter TEM: Exploration Geophysics, 36, 157–162
| Regolith mapping in hypersaline environments: a comparison of SAM with helicopter TEM:Crossref | GoogleScholarGoogle Scholar |
Street, G. J., and Abbott, S., 2007, Study of groundwater flow in sediments and regolith defined by airborne geophysical surveys: ASEG Extended Abstracts 2007, 1–5.
Sykes, M., Wolfgram, P., Hart, J., and Mckinnon-Matthews, J., 2006, Airborne EM surveys over the Barrow Creek Prospect, NT: ASEG Extended Abstracts 2006, 1–10.
Vrbancich, J., 2011, Airborne electromagnetic bathymetry investigations in Port Lincoln, South Australia – comparison with an equivalent floating transient electromagnetic system: Exploration Geophysics, 42, 167–175
| Airborne electromagnetic bathymetry investigations in Port Lincoln, South Australia – comparison with an equivalent floating transient electromagnetic system:Crossref | GoogleScholarGoogle Scholar |
Vrbancich, J., and Fullagar, P. K., 2007, Improved seawater depth determination using corrected helicopter time-domain electromagnetic data: Geophysical Prospecting, 55, 407–420
| Improved seawater depth determination using corrected helicopter time-domain electromagnetic data:Crossref | GoogleScholarGoogle Scholar |