A fundamental approach to threshold estimation in exploration geochemistry: probability plots revisited

摘要: Abstract Several threshold estimation (and thus anomaly recognition) procedures are in use of exploration geochemistry. Experiential methods rely on absolute values graphs or tables and highly subjective being dependent the variable experience explorationists. Model-based techniques determination, including mean plus two standard deviations, arbitrary inefficient: thus, they not suitalbe despite widespread have found past. objective include gap statistic probability graph approaches, latter finding much greater acceptance with greatly increased ease a recently available microcomputer software package that can treat many variables easily rapidly. Many critical decisions geochemistry require comprehensive interpretation data, clear insight into recognition anomalous background samples. cannot be made vigorous confident manner unless based fundamental approach to selection. Examples include: (1) element zoning geochemistry: (2) geochemical contrast: (3) isotropic anisotropic nature anomalies: (4) an areal extent anomalies various elements. Methods which incorporate philosophy data each characterized by their own density functions will most successful deriving estimation. In simplest general case, there overlapping populations, character leading naturally extension single concept definition thresholds delimit range overlap. Such concept, conceived applied individual variables, extended n-dimensional case. Univariate approaches continue dominate practical applications foreseeable future except special circumstances.