Multiparameter geophysical logging at the Yava lead deposit: a statistical approach
Anne Cinq-Mars, C. J. Mwenifumbo, P. G. Killeen and M. Chouteau
Journal name: Geophysical Prospecting
Issue: Vol 40, No 8, November 1992 pp. 829 - 848
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The present study describes multiparameter geophysical logging carried out at the Yava sandstone lead deposit, Nova Scotia, Canada. Statistical analysis of the multiparameter data set shows that the spectral gamma-gamma ratio log (SGG ratio) is the most useful technique for characterizing the disseminated sulphide mineralization.
Principal component analysis (PCA) indicates that the apparent chargeability (IP parameter) responds to the presence of clay minerals in the sandstone in addition to disseminated sulphides, so that the induced polarization method (IP) does not accurately delineate the disseminated galena content as was originally assumed in the preliminary log interpretation. PCA has also confirmed that the SGG ratio and density are related to lead content and that lithological variations can be delineated with natural radioactivity and resistivity.
The zinc content of the deposit was poorly characterized by geophysical logs. Sphalerite occurrences seem to be localized as narrow bands (< 1 cm) which were not geophysically detectable.