Fast 3D inversion of transient electromagnetic (TEM) resistive limit data

Fullagar, Peter K.; Schaa, Ralf

doi:10.1190/segam2014-1157.1

Cited by 7 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another indicator of good conductors is the resistive limit, which limit is directly proportional to target conductance and response amplitude (Fullagar and Schaa ). This parameter is much larger for shallow targets than deep targets.…”

Section: Methodsmentioning

confidence: 99%

Definitive superparamagnetic source identification through spatial, temporal, and amplitude analysis of airborne electromagnetic data

Macnae

2016

Geophysical Prospecting

View full text Add to dashboard Cite

The aim of this paper is to add confidence to existing methods using decay shape analysis to detect superparamagnetic responses in airborne electromagnetic data. While expensive to acquire, vertical spatial gradient measurements of the electromagnetic signals can discriminate near‐surface superparamagnetic sources. This research investigated the use of horizontal spatial gradients and amplitude information as further indicators of superparamagnetic. High horizontal gradients were shown both theoretically and in field data to help discriminate superparamagnetic from deep mineral targets. Further, superparamagnetic responses have characteristically small amplitudes inconsistent with realistic mineral exploration targets at shallow depths.

show abstract

Section: Methodsmentioning

confidence: 99%

Definitive superparamagnetic source identification through spatial, temporal, and amplitude analysis of airborne electromagnetic data

Macnae

2016

Geophysical Prospecting

View full text Add to dashboard Cite

show abstract

“…For the 3D inversion of this VTEM data set, we used VPem3D, which is an approximate 3D modeling and inversion routine for transient electromagnetic (TEM) data collected with a variety of common system configurations (Fullagar and Schaa, 2014). It can be used for airborne, ground, or borehole data.…”

Section: Aem Datamentioning

confidence: 99%

Forward modeling and 3D inversion of electromagnetic data collected over the McArthur River uranium deposit in the Athabasca Basin, Canada

Mir

Fullagar²,

Darijani

et al. 2022

GEOPHYSICS

View full text Add to dashboard Cite

Detection and assessment of the deeply buried high-grade uranium deposits in the Athabasca Basin rely on geophysical methods to map conductive rocks. Variable Quaternary surface cover can mask the anomalous signals from depth and affect interpretation of inverted conductivity models. We present the analysis of a number of EM modeling studies and two field data sets, to demonstrate the effects of varying Quaternary cover resistivity and thickness, on the ability to resolve the parameters of underlying sandstone, alteration, and basement conductors. Synthetic data, assuming a typical shallow EM sounding system and realistic resistivities found in the Athabasca Basin, show that resistivity and thickness parameters of the Quaternary cover can be separately recovered in cases where this cover is more conductive than the underlying sandstone, but not when the cover is significantly more resistive. A 3D modeling study shows that using airborne EM data, it is possible to detect a basement conductor of 20 S at a depth of at least 600 m below surface, even in the presence of Quaternary cover thickness variations of the up to 20% (40 m to 60 m). Furthermore, while Quaternary cover variations and deeper sandstone alteration can produce comparable anomalous signal amplitudes in a time-domain EM response, their effects are most visible in distinctly separate time windows. Analysis of a GPR field data set to map the thickness of Quaternary cover in the McArthur River area, indicates that this cover consists mostly of sandy tills and ranges in thickness from 0 to 117 m. Constrained 3D inversion of an airborne EM data set from the same area shows basement conductors consistent with the depth and location of a known fault. Elevated conductivity in the sandstone by up to a factor of two over the background values could indicate possible alteration.

show abstract

“…The 2/2.5D inversion tools e.g. ArjunaAir, PArjuna [265] are today mainly replaced by 3D inversions such as M3Dinv, PMoving Footprint, PLoki/LokiAir, PEMIGMA [261] and others [266]. Today's powerful computational hardware will, in future, allow inversions of more complex scenarios using finite element tools such as custEM [267].…”

Section: Performance Of Squid-based Temmentioning

confidence: 99%

Superconducting sensors and methods in geophysical applications

Stolz

Schmelz

Zakosarenko³

et al. 2021

Supercond. Sci. Technol.

View full text Add to dashboard Cite

More than 50 years ago superconducting quantum interference devices (SQUIDs) were invented. Since then many applications opened up. Already in a 1980 workshop (Weinstock and Overton 1981 SQUID Applications to Geophysics (Society of Exploration Geophysicists)) the application of SQUIDs in geosciences was reviewed. The fabrication and cooling technologies, electronics and other SQUID system components underwent significant improvement within the past years. Thus, SQUIDs are today better suited, more sensitive and effective as well as robust and reliable in operation for geophysical measurements. Many successful application examples, demonstrations and discoveries of mineral resources have been made using them in laboratory devices for investigation of magnetic properties, magnetic exploration, transient electromagnetics and for superconducting gravimeters as well as gravity gradiometers. Therefore, this article intends to review the past, present, and some future aspects of SQUIDs in geo-scientific applications such as e.g. mineral exploration. Since this field is still very active and quite a number of developments are ongoing, this review cannot be comprehensive.

show abstract

Fast 3D inversion of transient electromagnetic (TEM) resistive limit data

Cited by 7 publications

References 10 publications

Definitive superparamagnetic source identification through spatial, temporal, and amplitude analysis of airborne electromagnetic data

Definitive superparamagnetic source identification through spatial, temporal, and amplitude analysis of airborne electromagnetic data

Forward modeling and 3D inversion of electromagnetic data collected over the McArthur River uranium deposit in the Athabasca Basin, Canada

Superconducting sensors and methods in geophysical applications

Contact Info

Product

Resources

About