The structural geology of the Ruth-Hope and Silversmith mines

The Ruth-Hope and Silversmith areas are mainly underlain by structurally-competent quartzites, sandy limestones, and thick argillites. Bedding attitudes are steep; several major and minor recumbent folds occur within the local section of bedding structures. The strong northeasterly-trending Standard-Silversmith lode system is represented locally by the Hope, New Ruth, and Silversmith lodes. The Old Ruth-Stewart section lies about one-half mile north, and in the footwall of the main belt. Lodes strike easterly to northeasterly across the trend of bedding structures; they dip to the southeast at moderate to high angles. The most important ore minerals are argentiferous galena, sphalerite, and grey copper. The major bedding structure of the Old Ruth-Stewart section is a recumbent anticline which is convex to the southwest. Bedding within the New Ruth-West Silversmith section dips moderately to steeply southwest. The pattern of lode and cross-fault displacements is reasonably consistent within the mines area. From evidence provided by minor structures, the relative displacements were such that lode hanging walls moved downward to the east and southeast; normal displacements occurred on all cross-faults. Within the productive part of the Old Ruth Mine, mineralization apparently followed a late normal displacement within a major strand of the lode. Lode movements, at least later ones, were, to some extent, transmitted by cross-faults which join the offset segments of the lodes. Also, to a minor extent, the cross-faults contain ore minerals which probably entered by way of fault-lode linking fractures. Apparently porphyry, alteration, and ore were emplaced consecutively, but concurrently with displacements on the lodes and cross-faults. The stronger mineralization of the northeasterly-trending fractures was probably due to a close timing of ore deposition with more intense late movements on this set of fractures. In addition, deeper "ore channels" could be expected within fractures which cross-cut, rather than parallel the bedding. That the West Silversmith porphyry "plug" was emplaced as a separate body, and is not a faulted block from the main Silversmith Stock was proved by the study of flow structures within the "plug".Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat