Accession Number : AD0428062

Title :   DIRECTIONAL MAGNETOTELLURIC SPECTRA AT GARCHY, NIVRE,

Corporate Author : CALIFORNIA UNIV BERKELEY SPACE SCIENCES LAB

Personal Author(s) : Fournier, H. ; Ward, S. H. ; Fournier, H.

Report Date : 19 NOV 1963

Pagination or Media Count : 26

Abstract : Performance of magnetotelluric soundings in surroundings of the geophysical center of Garchy has given, starting from the surface of the ground, the following results: (l) in a '3 sheets complex,' the existence of sedimentary layers, subhorizontals of a total thickness of about 1200 m. (2) A perturbed layer, for which magnetotelluric results, expressed in ohm-meters, are very dependent of the direction of the soundings. This, with a maximum of resistivity for, approximately, the azimuth 10 grade W, which corresponds to a direction quite parallel to the Loire valley and a minimum in an azimuth normal to the preceding one. (3) A layer in the Upper Mantle, of about 700 km of thickness and an apparent resistivity around 650 ohm-meters. (4) A layer of rather high conductivity may start around 750 km below the surface. (Author)

Descriptors :   (*GEOMAGNETISM, GEOPHYSICS), (*GEOPHYSICS, GEOMAGNETISM), SEDIMENTARY ROCK, GEOPHYSICAL PROSPECTING, ELECTRIC FIELDS, MAGNETIC FIELDS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE