Page 67 - Geochemical Remote Sensing of The Sub-Surface

44 O.F. Putikov and B. Wen

PI: cI-nM, gg
25
Pbtotai, 10 -3 %

/ ~ ~ Pbto~.
" " "\'" 0

I I I I I

ll l II I
,lltl I I I

I I 0pm,
I

Fig. 2-22 Results obtained by the CHIM method over polymetallic mineralisation in Rudny Altay,
Russia: Pbcl~lM- concentration of mobile forms of lead (CHIM); Pbtotal- total concentration of lead
(lithogeochemistry); 1- unconsolidated sandy-clay overburden; 2- volcaniclastic strata; 3- poly-
metallic ore; 4- low-grade disseminated ore (reproduced with permission from Ryss, 1983).

The first publication on CHIM (Ryss and Goldberg, 1973) contains some examples
of the successful applications of the method. For ground mode CHIM these include
investigations of known polymetallic ore bodies at Altay and the copper-nickel
composition at depths of 10-100 m of ore bodies in the Kola peninsula. The detection of
copper-nickel ores in boreholes by logging mode CHIM is demonstrated.
The polymetallic sulphide deposit at Rudny Altay comprises a number of nearly
vertical ore bodies at depths of 450-500 m in a tuff-slate formation. The tuff-slate is
covered by dense Mesozoic-Cenozoic clays 40-50 m thick. The lithogeochemical survey
does not yield clear anomalies. But the CHIM results for lead delineate satisfactorily the
position of the ore bodies and their approximate projection to the surface (Fig. 2-22).
In the far east of Russia a cassiterite stockwork at a depth of 700 m lies between
sandstone and aleurolite (Fig. 2-23). The results of the conventional geochemical survey
and rock samples from trenches fail to reveal the position of the ore body (Fig. 2-23,
curves A, B). The CHIM survey, however, gives a good expression with up to 16 lag Sn
compared with a background of 0.5-1 lag (Fig. 2-23, curve C). This anomaly has a width
of 250 m and practically coincides with the projection of the ore body to the surface.