Separation of LS-Epithermal Gold Veins Deposit Alterations by Geophysics in Chucotka Region

A number of epithermal gold-silver deposits are located within Okhotsk-Chukotka volcanic belt (Far East of Russia). LS-epithermal veins with the thickness of several meters can contain up to several hundred tons of gold. The search of covered veins is a complicated task for exploration and it is difficult to solve it without geophysics. The example of successful application of audiomagnitotelluric method in Chukotka region was presented by author. As the result of all data analysis the geophysical prospecting criteria were suggested. Unfortunately, not every found vein is commercial. To increase the chance of finding a new deposit the author set the task to define additional prospecting criteria. The induced polarization (IP) method was used to achieve this goal. The main result of the investigation is that the instrument for separation of alterations types was suggested. The chargeability anomalies at 0.31 Hz and 15 mV/V amplitude are connected with illite chlorite alterations of a deposit core. Illite chlorite alteration of the core deposit is also characterized by high resistivity (up to 2000 Ohm-m) and low magnetic susceptibility. The zones of illite and kaolinite alterations surrounding the deposit core are characterized by reduced electrical resistivity (from 50 to 300 Ohm-m).