Home – Home – Jornals – Russian Geology and Geophysics 2002 number 1

An effective and precise technique for vector magnetic survey has been developed for searching and prospecting for iron-ore deposits, using equipment including a fluxgate theodolite to measure declination and inclination and a proton (or quantum) magnetometer to measure the modulus of geomagnetic field vector. A high efficiency of survey, comparable with the performance of M-27 magnetometer component surveys, is reached by optimization of declination and inclination measurement with a fluxgate theodolite and by minimization of the number of astronomical measurements of the geographical azimuth of mira (profile). The accuracy of angular measurements corresponds to the requirements of quality of measured diurnal variations in the geomagnetic field. The actual accuracy of all components of magnetic induction vectors under the conditions of strongly differentiated magnetic field of iron-ore deposits depends significantly on the accuracy of tying the measurement points in plan and on the precision of coincidence of the fluxgate magnetometer with the sensor of the module magnetometer. Analysis of accuracy of vector measurements will be the subject of a special paper. Here, only tentative data are given.
Our technique is tested on the small Samson magnetic deposit in the Khakass Autonomous Region. It appeared to be reliable in estimation of orebody parameters from results of interpretation of vector magnetic anomalies by selection of 2D models for types of beds varying in magnetization, size, position in plan, and depth. The reliability of the estimates of parameters of anomalous objects is illustrated by variants of selection based on various elements of anomalous field. A way is directed to construct an algorithm for solving inverse problems of vector magnetometry for complicated 3D bodies, taking into account mutual magnetization of their parts by own fields of the deposit, which is the subject of a special study.