Trend-surface analysis as an aid in exploration for Mississippi valley-type ore deposits

An examination of the characteristics of Mississippi Valley-type ore deposits shows that these deposits have many similarities which appear to be structurally controlled. To define the relationship between the ore deposits and these structural conditions, trend-surface analysis using the Precambrian surface as the datum plane was performed within the general Missouri area. Examination of the residual maps prepared from this analysis shows that all the ore deposits have the same spatial relationship to areas of strong residual highs. A more detailed study was conducted in the area of the Viburnum Trend using a datum plane just below the ore horizon. The spatial relationship shown on the Precambrian residual map was even better defined in this study. From this study, it appears that the optimum structural conditions necessary for the deposition of Mississippi Valley-type ore deposits exist in regions located next to and slightly downgradient from areas which exceed one positive standard deviation from the trend surface. The methods described in this paper could comprise an extremely useful tool in exploration programs as they can define high probability locations in which to concentrate further exploration efforts.This paper was presented at Symposium 116.3, Quantitative Strategy for Exploration, held as part of the 25th International Geological Congress, Sydney, Australia, August 1976.