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Electric resistivity structure of the Siljan impact region

1988; American Geophysical Union; Volume: 93; Issue: B6 Linguagem: Inglês

10.1029/jb093ib06p06485

2156-2202

Ping Zhang, Thorkild M. Rasmussen, Laust B. Pedersen,

Geophysical Methods and Applications

Based on 65 magnetotelluric (MT) measuring stations, a cross section of the electric conductivity structure in the Siljan impact area, located in the central part of Sweden, is presented. Static shift effects due to local near‐surface inhomogeneities are present in nearly all of the MT soundings. In an attempt to correct for near‐surface distortions, average impedance data and distortion parameters were interpreted. Derived two‐dimensional models show some coincidence with seismic reflection results and support an impact origin of the Siljan area. Fluid migration through the fractures generated by the impact is one possible explanation for the anomalously high conductivity within the upper crust.