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MT can be used in an overthrust environment to delineate conductive sediments beneath a resistive thrust plate. It is often difficult to acquire good-quality seismic data in an overthrust area where high-velocity (high-resistivity) rocks overlie low-velocity (low-resistivity) sediments.

Magnetotellurics (MT) can be used in an [[overthrust]] environment to delineate conductive sediments beneath a resistive thrust plate. It is often difficult to acquire good-quality [[seismic data]] in an overthrust area where high-velocity (high-resistivity, low-conductivity) rocks overlie low-velocity (low-resistivity, high-conductivity) sediments.

The Precambrian overthrust in the Bear Springs area of northwestern Colorado is an example.<ref name=ch16r5>Mills, A., 1994, Zephyr Geophysical Services, personal communication.</ref>

The [[Precambrian]] overthrust in the Bear Springs area of northwestern Colorado is an example.<ref name=ch16r5>Mills, A., 1994, Zephyr Geophysical Services, personal communication.</ref>

==Survey results==

==Survey results==

[[file:applying-magnetotellurics_fig16-7.png|thumb|500px|{{figure number|1}}An 11-station MT profile across the thrust. Drafted from data from Mills.<ref name=ch16r5 />]]

[[file:applying-magnetotellurics_fig16-7.png|thumb|500px|{{figure number|1}}An 11-station MT profile across the thrust. Drafted from data from Mills.<ref name=ch16r5 />]]

The MT station near the drill hole (see diagram [[:file:applying-magnetotellurics_fig16-7.png|Figure 1]]) shows a thin, near-surface conductor on top of the resistive Precambrian thrust sheet. This is a wedge of Quaternary and [[Tertiary]] sediments. Beneath the thrust, a thick conductive section of Cretaceous sediments is observed.

The MT station near the drill hole (see diagram [[:file:applying-magnetotellurics_fig16-7.png|Figure 1]]) shows a thin, near-surface conductor on top of the resistive Precambrian thrust sheet. This is a wedge of [[Quaternary]] and [[Tertiary]] sediments. Beneath the thrust, a thick conductive section of [[Cretaceous]] sediments is observed.

[[:file:applying-magnetotellurics_fig16-7.png|Figure 1]] is an 11-station MT profile across the thrust.

[[:file:applying-magnetotellurics_fig16-7.png|Figure 1]] is an 11-station MT profile across the thrust.