The naturally occurring background radiation which is always present on earth, identifies underground variations by the level and type of radiation being emitted. This so-called background radiation underlies local variations and is influenced by many factors. In particular , the radioactive content of different kinds of rocks varies, E.g.
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granite, which contains quartz, shows a little more radioactivity than basalt
- sulphites and oxides on the other hand reduce the average radiation.
Other changes occur when the background radiation is viewed through kimberlite pipes, the bluish source rock of diamonds. In addition the background radiation shows other changes when it passes through water and oil.
Many ores have by-products, uranium or thorium as well as impurities, which create unstable isotopes, E.g;
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titanium is often found together with thorium
- unstable gold isotope stimulated by impurities and cosmic radiation.
All of the differences can be registered by our scintillation counters (isotope sensors).
