1980 Volume 30 Issue 162 Pages 241-250
In order to accomplish a quick and objective handling of a very large number of data obtained in the exploration work of kuroko deposits in the Hokuroku district, a computer system has been developed and is ready to use routinely. As its first trial the system examines the rock alteration data of the footwall dacite lava of the Ezuri ore deposits.
On the basis of 5 measurable elements (magnetic susceptibility, concentrations of Na, Ca, Kand Mg) which have been measured on some 1, 500 specimens from more than 50 drill holes in an area of 5×6km, 11 variables(magnetic susceptibility, Na, Ca, K, Mg, Alteration Index=K+Mg/Na+K+Mg+Ca, K/Na, Mg/Ca, Na/Na+K+Ca, K/Na+K+Ca, Ca/Na+K+Ca) have been examined. After the calculation of basic statistics, halo maps of these variables are drawn by means of line printer and X-Y plotter. Except for Mg which has no returned a distinct halo, the halo maps obtained are generally quite consistent with the distribution of orebodies. The magnetic susceptibility halo has a bigger extention that embraces nearly all the chemical haloes. Among the chemical haloes those related to"leached elements"(Na, Ca, Alteration Index, Na/Na+K+Ca, K/Na+K+Ca, Ca/Na+K+Ca)show somewhat different patterns from those related to "additional element"(K, K/Na, Mg/Ca).
Usefulness of the alteration halo in the kuroko exploration is quite clear. The filed data processing system saves much of our time and is very useful for future exploration works.
