Gpr Technique Applied To Mineral Exploration Of Geodes In Basalts: Agate Geode Deposits (Rs, Brazil)

The agate geode deposits occurring in the Salto do<br>Jacuí Mining District (RS, Brazil) are considered to<br>be the world largest ones. They are hosted in<br>tholeiitic basalts of Serra Geral Fm. (Paraná Flood<br>Basalts). The agate geodes occur in highly vesiculated<br>basalts, that are variably weathered. Agate geodes<br>vary in size from 0,10 to 1,0 m, but usually show a<br>mean diameter in the range of 0,25 – 0,40 m. Agate<br>geodes are often completely massive, fulfilled by<br>chalcedony, or by chalcedony and quartz. GPR<br>technique was applied agate geode exploration.<br>Key words: GPR technique, agate geodes, basalts,<br>mineral exploration, geophysic