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Conductivity discontinuities in the upper mantle beneath a stable craton
Author(s) -
Schultz A.,
Kurtz R. D.,
Chave A. D.,
Jones A. G.
Publication year - 1993
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl02833
Subject(s) - classification of discontinuities , magnetotellurics , geology , depth sounding , geophysics , mantle (geology) , nonlinear system , inversion (geology) , conductivity , craton , seismology , electrical resistivity and conductivity , geodesy , tectonics , physics , mathematics , mathematical analysis , oceanography , quantum mechanics
We present evidence for approximate collocation of seismic and electrical transitions in the upper mantle. More than two years of very long period magnetotelluric (MT) data were recorded at a lakebottom observatory in the central Canadian Shield. After processing to contend with non‐stationary source effects, and removal of galvanic distortion, the underlying structure is 1D for periods of one hour to four days. The response was extended to periods of 100 days by appending Geomagnetic Depth Sounding data to the MT curves. Minimum structure linearised inversion, nonlinear extremal inversion, and a new genetic algorithm for nonlinear hypothesis testing, reveal discrete jumps in conductivity at depths near the major upper mantle seismic discontinuities. The jumps occur over limited depth ranges.