THE BC87 DATASET - TECTONIC SETTING, PREVIOUS EM RESULTS, AND RECORDED MT DATA

As part of project LITHOPROBE, magnetotelluric data were acquired at t wenty-seven sites along a 150 km east-west profile in southeastern Bri tish Columbia straddling the complex tectonic boundary between ancestr al North American rocks and those of the easternmost accreted terranes . These data, named the BC87 dataset, display complex effects due to b oth three-dimensional induction and galvanic scattering at virtually a ll scale sizes, from that of the electrode array (<50 m) to that of th e large plutonic Nelson batholith (150 x 50 km surface extent). The da taset was distributed widely in order to compare and contrast differen t schemes for extracting the underlying predominant two-dimensional st ructure, and to test differing interpretational algorithms on data fro m a complex crystalline terrane. The MT data are shown, and the tecton ic setting described. Also, seismic and previous EM studies of the reg ion are described.