Publication GSC6
Deep electromagnetic imaging of the Bathurst No. 12 deposit: 3-D forward modelling,
2-D inversion and sensitivity tests
Queralt, P., A.G. Jones and J. Ledo
Abstract
A detailed three-dimensional (3-D) numerical electrical resistivity model of the
Bathurst No. 12 deposit (New Brunswick) has been constructed using available
geological and geophysical information. This model facilitates studies of the
capabilities of audio-magnetotellurics (AMT) at locating and defining mineral
targets at depth, and of methods of optimizing data acquisition. Different
conditions were analysed: presence of overburden, dimensions and positions of the
orebody, and varying data sampling. The behaviour of 3-D electromagnetic fields
are compared with ones from a body of infinite length extent (a two-dimensional
case). The 3-D and 2-D AMT responses are similar at high frequencies, so 2-D
modelling is sufficient. However, at low frequencies only those responses for
current flow perpendicular to the body (the Transverse Magnetic mode) are
reasonably alike. The sensitivity tests show that an optimized cost-effective
field experiment would be with fixed magnetic sensors and roving electric ones.
Source
Geol. Surv. Canada Current Research, , 2002-D3, 8 p., 2002.
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Alan G Jones / 10 June 2004 /
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