Geology and sampling locations of the Prairie Creek Mine area. Red circles represent the study sampling locations; green circles represent previous sampling studies of the MERA program. Quartz-carbonate-sulphide vein showings are represented by purple squares, and MVT showings are represented by light green triangles.
Examples of streams sampled. (a) Rigor Mortis Creek: Quartz-carbonate vein can be seen starting at the top of the hill in the top left of the picture, and continuing down towards the stream. This was not a showing, but was part of the same vein system. The stream can be seen along the bottom of the picture. (b) Funeral Creek, within proximity of the Rico showing (quartz-carbonate-sulphide vein). Quartz-carbonate veins can be traced across the stream.
Variation in alkalinity, conductivity and element concentrations with distance for streams sampled in the Prairie Creek area: (a) Rigor Mortis (b) Funeral (c) Harrison (d) Prairie creeks. Dotted lines represent possible interaction with mineralized showings.
Map of the study area showing the dispersion trends of the elements of interest as a whole. Data represents the sums of the median-normalized concentrations for the elements of interest, each point plotted as a percentile of the entire data range. (a) Filtered waters. (b) Silt sediments digested by aqua regia and analysed by ICP-MS.
Populations of sample sites that show differences in major contributing elements to the summed score value. Group 1 consists of samples along Funeral Creek, and near the Zebra, Road and Samantha showings. Remaining samples are in Group 2.
Tukey box plots for the percent contribution of each trace element to the summed score value, for (a) stream silt sediments and (b) filtered stream water (dissolved cations). Colours correspond to Group 1 (red; symbol on the left) and Group 2 (black; symbol on the right) sample locations, as shown in Figure 6. Whiskers represent extreme values that are not outliers; hollow circles represent outliers (>1.5 × [Q3 − Q1]); triangles represent far outliers (>3 × [Q3 − Q1]). Boxes are constrained at the top and bottom by Q3 (3rd quartile, or 75th percentile) and Q1 (1st quartile, or 25th percentile), respectively. The middle line represents the median; the middle circle represents the mean.
Goethite precipitation identification and textures. (a) SEM, synchrotron microXRF element map and EDS spectra of a grain from sediment sample taken near the Zebra showing. This grain was identified as quartz and dolomite, with a needle-like goethite precipitation around the edges. Red and blue spectra correspond to red and blue stars. (b) SEM, microXRF element map and EDS spectra of another grain from the same sample location. This middle of this grain remains unidentified; however, the botryoidal textured precipitate was identified as goethite. (c) MicroXRD pattern for the botryoidal texture of the grain in (b). Please see online version for colour figure.
SEM images (BSE) and EDS spectra of a smithsonite grain found in a sediment sample near the top of Rigor Mortis Creek, 0.3 km from the first sampling location. The red profile was taken within the grain (white area), and the blue profile was taken from the rim surrounding the grain (light grey area). Dissolution textures are visible, as well as an outer rim, likely composed of clay material. Please see online version for colour figure.
Alteration of a sulphide grain replaced by goethite. (a) SEM photograph from a silt sediment sample taken near the Zebra showing. This grain was identified as goethite, possibly mixed with ferrihydrite. (b) Corresponding synchrotron XRF element map. Concentrations of all three elements mapped (Fe, Pb and S) increase towards the middle as the colouring becomes increasingly white. (c) EDS spectra of points on the grain. Red, blue, and green spectra correspond to red and blue stars on element map. The center of the grain is enriched in Pb and/or S, and is likely galena, while the surrounding iron-rich zones lack Pb and S but contain trace Zn. Please see online version for colour figure.