Electrical mantle anisotropy and crustal conductor: a 3-D conductivity model of the Rwenzori Region in western Uganda

摘要: SUMMARY Magnetotelluric measurements were performed east of the Rwenzori Mountains, Uganda. At 23 sites transfer functions between magnetic and telluric fields phase tensor elements estimated in period range 10–10 000 s. The indicate a complex 3-D conductivity structure within crust predominantly at contact zone Mountains rift shoulder to northeast. An alternative representation ellipses form bars is introduced. For periods above 100 s, major all strike SSW–NNE invariants φmin φmax exhibit difference least 20°. This conspicuous behaviour small vertical field same can be explained by an anisotropic depth 30–50 km with conductive direction perpendicular Rift axis. anisotropy might originate from orientated Olivine crystals most upper mantle, whereby preferred orientation motion induced due delamination lower beneath Rwenzoris. A high conducting layer found southeast Rwenzoris 15-km matching seismic low-velocity zone. Possibly it indicates partial melt connected volcanic nearby. Generally, increase 45° for longer than 2000 s denoting towards greater depth.