Electromagnetic images of a strike-slip fault: the Tintina fault - Northern Canadian

Wideband magnetotelluric (MT) data were acquired along three profiles crossing the strike-slip Tintina Fault in northwestern Canada. The MT responses obtained exhibit remarkable similarity from all three profiles, implying similar two-dimensional (2-D) electromagnetic behavior of the fault zone over a strike length of at least 350 km. Analyses of the MT responses for dimensionality corroborate the validity of assuming regional 2-D structures in interpretation. Several high conductivity anomalies at different depth scales are present in the models obtained, and we suggest that both the shallow structures and the deep crustal scale anomalies are caused by electronic conduction mechanisms in interconnected mineralized zones. Intriguingly, the middle and lower crust beneath the surface expression of the Tintina Fault is highly resistive, in contrast to some other large-scale strike-slip faults. This implies that fault zone processes that result in interconnected conducting phases are not generic in nature but are controlled by local conditions.