During the period 2010-2012 OJSC “SiGMA” has performed a complex of geophysical works in the Ozernovskoye ore field.The works included electrical exploration by the induced polarization method in IP – MG modification (Induced Polarization – Mean Gradient).The maintask of the exploration was to select and localize anomalous zones, clarify their spatial attitude and delineate potential ore bodies; clarify the boundaries ofhydrothermally altered rocks, and to plot the dykes and dislocations with a break of continuity
Multidimensional statistical analysis was performed by use of “Structural analysis” software package.The results of statistical processing are presented in the Supplement 1.
On the results, we would like to note that the array of all digital data is divided into five classes. Samples of first and second class (colors grey and green) have afairly large amount of digital data and reflect general characteristics of the area host rocks,and differing only slightly on their apparent resistivity mean values (about 250-300 Ohm*m) they differ to a considerable extent on the values of their differential polarizability (2.7% – for first and1.14% – for second class).The objects of the first class are mostly locatedin the south-western part of the surveying plane-table, in the “BAM” area; the objects of the second class occupy the main part of the surveying plane-table.
Tothird and forth classes (pale yellow and darkyellow) thoseobjects are classified which have increased mean values of apparent resistivity (400-450 Ohm*m), but differ on their differential polarizability mean values (≈1% for third and≈2%for forth class).The objects of these classes can characterize zoneswith lowconductivity with a different degree of electronic conductorsavailability.The replacement zones with different degree of mineralization (sulphidization) may be classified to the objects of 3-d and 4-th classes.
Objects with high mean values of apparent resistivity(≈ 900 Ohm*m) and lowmean values of differential polarizability (≈1%) got in 5-th classification group (red color). Having analyzed geophysical and geological data, we would assume that silification zones witha low sulphide mineralizationassociated withthe metasomatic processes in the host rocks correspond to 5-th class objects.In view of prospecting, these objects may be of specialinterest asquartzite bodies inside themetasomatically altered field.
Thus, the performed statistical analysisof geophysical parameters distribution over the areamade it possible to find the main, 5th class of objects whichare of interest for prospecting and characterized with high mean values of apparent resistivity and low differential polarizability,whatis most likely connected with a highsilificationdegree ofthis type rocks.The objects of 3-d and 4-th classesmay be of interestforprospectingfor gold-sulphide typeas the metasomatically altered zones.
During a final stage of geophisical data processing, the boundaries of bodies with increased resistanceand tectonic zones within the area were delineated taking into account the statistical analysis results. The results of statistical processing are presented in graphical application 2.
As one may see on the presented map, all the bodies have sub-latitudinal strike and aredivided by tectonicfaults with a little shiftto north-south.Tectonicfaults in the resistance fieldsare quite clearly highlited as the zones of increased conductivity. And at the same time, some tectonic faults are distinquished by increased values of differential polarizability and because of that they may be charactized as the zones of increased sulphidization and watering.