Publication 80

Electromagnetic Images of a Stike-Slip Fault: The Tintina Fault Zone-Northern Canadian Cordillera

Ledo, J., A.G. Jones and I.J. Ferguson


Wideband magnetotelluric (MT) data were acquired along three profiles crossing the strike-slip Tintina Fault in northwestern Canada. The two regional profiles were separated by more than 350 km along strike, and were designed to obtain crustal scale electromagnetic images of the fault. A short, higher station density profile, designed to obtain superior resolution of upper crustal features, was located 35 km south of the northern profile. 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.


Geophysical Research Letters, 29 (8), doi: 10.1029/2001GL013408, 2001.

Request reprint of publication 80

MTNet Home Page Alan's Home Page

Alan G Jones / 10 June 2004 /