Evaluation of the resource potential of economic minerals by fractal modeling and multivariate geostatistical analysis of stream sediment data in the Precambrian Oban, Nigeria, basement terrain and environs
摘要
Exploration for economic minerals using compositional data like stream sediments without centered log ratio transformation of data can lead to spurious data interpretation. Stream sediments were analyzed for major and trace elements using inductively coupled plasma mass spectrophotometry. The data was centered log ratio transformed to open and normalize it for multivariate statistical analysis. Concentration–number fractal model discriminated background, anomalous zones of Ba, Pb, W, and Li. The mean values of barium (Ba), lead (Pb), lithium (Li), and tungsten (W) are 1105 mg kg−1, 35.64 mg kg−1, 36.33 mg kg−1, and 44.5 mg kg−1, respectively. The values are above their respective crustal average abundances of 425 mg kg-1, 12.5 mg kg-1, 20 mg kg-1, and 1.5 mg kg−1. Metal ratios of Ba (2.60), Pb (2.85), Li (1.82), and W (29.63) exceeded 1, showing their higher enrichment in sediments than other elements. Multivariate statistical analysis established a strong correlation among these elements. Principal component analysis (PCA) exhibited four factors with a total variance of 84.50%. Significant loadings of principal components are traceable to geochemical processes related to surficial weathering, mineralization, and igneous and volcanic weathering. Anomalous concentrations of Ba, Pb, W, and Li suggest possible mineralization of barite, galena, wolframite, and lepidolite/spodumene, respectively, in the area. Centered log normalized data and fractal models obtained more credible data interpretation compared to non-normalized data. Combining mineralogical analysis of rocks with sediment analysis will improve future studies. A detailed geophysical exploration of areas with identified anomalous concentrations of these economic ores is required.