Geoenvironmental application of statistical techniques used in marine mineral exploration: Fid-Bau Portal

Geoenvironmental application of statistical techniques used in marine mineral exploration

Owen, Robert M. / Paulsen, Sean C. / Noakes, John E.

Recent research efforts have involved the development of computer programs and quantitative techniques designed specifically to facilitate the reduction and interpretation of large geochemical data sets acquired during marine mineral exploration surveys. The purpose of this study is to examine the applicability of these same techniques in developing meaningful interpretations of geoenvironmental data.

A suite of sediment samples from the Mobile‐Tombigbee River system in southern Alabama were subjected to bulk geochemical and mineralogical analyses. A Q‐mode factor analysis of the geochemical data suggests reveals that > 98% of the total variance in data is explained by two factors: (1) a relatively labile component of predominantly detrital aluminosilicates and iron and manganese oxyhydroxides, and (2) a mixture of quartz, feldspar, and ilmentite. The geochemical associations in both of these factors primarily reflect differences in sediment grain size. A linear modeling procedure was used to determine specific associations between certain trace metals and different mineralogical host phases, including composite clay (illite and illite‐smectite), quartz + albite, kaolinite, goethite, and ilmenite. This information facilitates an understanding of the distribution of trace metals in the sediment, thereby giving insight to the potential bioavailability and environmental threat of various trace metal contaminants. Elements (or that portion of elements) associated with the more labile sedimentary components, such as oxyhydroxide and organic carbon phases, represent the greatest environmental hazard, due to their potential release during change of sedimentary conditions.