Page 210 - Introduction to Mineral Exploration

9: MINERAL EXPLORATION DATA 193

Au Felsite Au Felsite

Au OR Felsite Felsite XOR Au

FIG. 9.11 Boolean algebra. The Au Felsite Au Felsite
circles are diagrammatic
representations of two sets, felsite
and Au. The possible combinations
are shown. XOR is for felsite or Au
but not where they overlap. Felsite NOT Au Au AND Felsite

55,000

50,000

45,000

250,000 255,000 260,000 265,000 270,000 275,000 280,000

Legend
10
km
Prospect N
Lithological
outline Felsite Intersection
felsite and
Sample Au >1000 ppb
catchment Au >1000 ppb
FIG. 9.12 Simple Boolean search in south Devon data for the presence of acid volcanics (felsite) and gold in
catchment >1000 ppb, based on the maps of Figs. 9.3 and 9.8. The selected lithological units and catchments
are shown by outlining and the very small area which meets both these criteria is in black and arrowed.