In the present work we present a case history where the Controlled Source Audiomagnetotelluric - CSAMT method have been applied to unveil the geological structure of Regis, a kimberlite pipe in Minas Gerais state, Brazil. The kimberlite outcrops were discovered in the late 1970's by surface geological mapping. Three CSAMT profiles, two striking north-south and the third striking east-west were acquired crossing the kimberlite crater. The Stratagem CSAMT sounding stations, with electrodes and coils laid in the classical cross configuration. Typical site spacing spanned from 50 to 100 m along each profile. The frequency range spanned from 10 Hz to 100 kHz, adequate for shallow investigations (depths less than 500 m). Shallow conductive anomalies were identified and associated to the main kimberlitic body. The present work subsidized the location of two successful drill holes within the studied pipe and allowed a proposition of a new geological model for the pipe.
kimberlites; CSAMT; 2-D inversion
