ELECTRON PARAMAGNETIC RESONANCE (EPR) SPECTROSCOPY AND GEOCHEMISTRY IN TIN EXPLORATION AT RENISON, TASMANIA AUSTRALIA

Abstract

Rock powder of dolomite samples from the Renison mine area of Tasmania, Australia were analyzed by electron paramagnentic resonance spectroscopy (EPR), Atomic Absorption and Mass Spectrometer to identify alteration related to mineralisation. The least-altered dolomite samples, which are not effected by circulation of diagenetic and hydrothermal fluids are characterised by low Mn and Fe and heavier oxygen isotope values. In contrast, the altered samples are characterised by high Fe and Mn and light oxygen isotope values. Significant differences in EPR intensity exist between the unaltered and altered dolomite samples. The highly altered samples close to the nlineralised area are characterised by strong EPR intensities of Mn sextets observed at magnetic flux density sweeps over 326.3 2500 mT and 326.3 1000 mT, which correspond to the higher Mn and Fe and lighter oxygen isotope values. In contrast, in the least-altered dolomites, away from the mineralised area, the EPR intensity and Mn and Fe concentrations are low and oxygen isotope values are more enriched