Two dimensional cross-gradient joint inversion of gravity and magnetic data sets constrained by airborne electromagnetic resistivity in the Capricorn Orogen, Western Australia
Adrián Misael León-Sánchez 1 3 Luis A. Gallardo 1 Alan Yusen Ley-Cooper 2
+ Author Affiliations
- Author Affiliations
1 Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California (CICESE), Carretera Ensenada-Tijuana 3918, Zona Playitas, Baja California 22860, México.
2 Geoscience Australia, Corner of Jerrabomberra Avenue and Hindmarsh Drive, Symonston, ACT 2609, Australia.
3 Corresponding author. Email: aleon@cicese.edu.mx
Exploration Geophysics 49(6) 940-951 https://doi.org/10.1071/EG16069
Submitted: 16 June 2016 Accepted: 24 January 2018 Published: 3 April 2018
Abstract
In many geological scenarios, the interpretation of multiple geophysical datasets through the use of joint inversion has become a common practice provided all data share compatible spatial resolution. Unfortunately, this requirement has also limited the application of airborne electromagnetic (AEM) data in joint inversion. For instance, we commonly assume that airborne gravity and magnetic datasets largely originate at a depth of a few kilometres, whereas co-located AEM signals can only penetrate a few hundred metres, thus rendering spatially incompatible datasets. We believe, however, that a fraction of these datasets originate from the same structures and provide a common ground for structural joint inversion strategies. We aim to explore the viability of jointly inverting such datasets using potential and AEM field data acquired in Western Australia with three comparative experiments. First, we generate conventional 2D separated models for each dataset to gauge their individual resolution capability. We then perform the 2D cross-gradient joint inversion of gravity and magnetic datasets. Finally, we adapt the structural joint inversion to include the AEM resistivity model as a constraint. We show that there is an area commonly sensed by the three datasets and that the coupled resolution influences both shallow and deep structures of the joint models. This yields a coherent integrated interpretation of shallow and deep structures of the studied section, which is validated when compared to a nearby seismic traverse section.
Key words: airborne electromagnetics, Australia, gravity, inversion, magnetics.
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