SNORCLE - NORTHERN CORDILLERA MT EXPERIMENT: 
ELECTRICAL CONDUCTIVITY DISTRIBUTION OF THE TINTINA FAULT

Juanjo Ledo(1), Alan G. Jones(1), Ian Ferguson(2)
(1) Geological Survey of Canada
    615 Booth St., Ottawa, Ontario, K1A 0E9, Canada
(2) Department of Geological Sciences
    University of Manitoba, Winnipeg MB R3T 2N2, Canada
ledo@cg.nrcan.gc.ca
   
The northern Rocky Mountain Trench-Tintina strike-slip fault -TTF- is 
a 2000 km-long transcurrent fault along which an estimated 450-km or 
more of Cretaceous-Tertiary dextral displacement occurred. Rocks to 
the northeast of the TTF are mainly sedimentary and represent the 
ancient North American Margin. Rocks to the southwest of the TTF are 
mostly young, mainly igneous and metamorphic, and represent numerous 
accreted terranes. Tectonic forces caused the block of rocks southwest 
of the fault to grind up against the stable North American block and, 
during a history of innumerable earthquakes, moved the southwestern 
block northwest to Alaska. To determine the subsurface geometry and 
character of the TTF zone, one dense AMT and three regional MT surveys 
have been carried out as part of the SNORCLE transect investigations. 
The study of the fault had been done at three different length scales. 
First of all a high density AMT profile to study the local structure 
of the upper few kilometres of the fault. Secondly, three MT broadband 
profiles crossing the fault at different locations, which allows us to 
obtain the image of the fault at crustal and upper mantle scale. 
Finally the integration of the three MT models together with different 
geological and geophysical information to produce a 3D image of the 
fault.