Geochemical orientation in drainage in northestern Scheelitiferous province, Brazil

The sampling model adopted in this work consists in a plottage of 150 collection point, where two samples were taken (pan concentrate and stream sediment samples). In the stream sediment sample two granulometries were separated (minor 80 mesh and miro 40 mesh). Some samples were collected in profile begining at the Bodo and Cafuca Mines and some others collected at random in zones not miralized. The samples were analysed for W, Cu, Zn, Mo, As, Sb, F, P, Au, and 30 trace-elements (pattern). In the pan concentrate samples the heavy-mineral fraction were identified too. The main conclusions obtained by this work were: 1) in this area clastic dispersion predominates; 2) the best means to be sampled for detection of mineralized skarn is the pan concentrate; 3) the optimum density for a regional search is 1/30 Km2; 4) the principal pathfinder elements for scheelite are Mo, F, and Cu; 5) the principal geochemical landscape factor in the area is the relief; 6) a regional geochemical survey through stream sediment and pan concentrate sampling is factible to detect scheelite ores and associated mineralizations. It was recommended to a geochemical regional survey, the following criteria: 1) sampling density 1/30 Km2; 2) collection of 1 pan concentrate sample and 1 stream sediment sample both in the same point; 3) to thicken the sampling in areas of uneven refief; 4) in the pan concentrate samples must be analysed W, Au, and 30 trace-elements (pattern) and the stream sediment samples must be analysed for W, F, Cu, Zn and 30 trace-elements (pattern)