![]() Heyday of Gold Prospecting in Alder Gulch This was supplemented in 1867 by the introduction of hydraulic mining, and in 1898 with the introduction of floating bucket dredges. Initially, the deposits were mined by hand, using sluice boxes. One of these streams, Alder Creek, was found to contain gold in 1863. By the mid-1800s, explorers and prospectors who had made their way into the Montana Territory would discover the wealth of gold the streams in this area contained, and a stampede of humanity would descend on the pristine valleys in pursuit of their fortunes. Uplift and subsequent erosion would exposed these rocks, and the gold and garnets they contained would start to concentrate in the streams that drained the area. Pay dirt containing garnets was stockpiled and later used to fill buckets that were sold at the Red Rock Mine. Eventually, these tectonic forces would push these metamorphic layers, called “basement rocks”, toward the surface, and they would shed their mantle of younger rocks and sediment that had buried them so deeply. Still later tectonic forces bent and folded these metamorphic rocks like so much warm taffy, and faulting allowed the injection of hydrothermal solutions carrying silica, gold, and traces of copper and other minerals. Limestone would be changed to marble and soapstone. Minerals in the shale differentiated into mica, hornblende, and garnets. The sandstone layers were compressed and welded into quartzite and the shale deposits became slate, and then gneiss and schist. As time passed, these deposits would be deeply buried and subjected to the metamorphic processes of high temperatures and crushing pressure. Silt and sand would have been finding their way into the primordial oceans, and in turn these sediments would go on to be compressed into shale and sandstone. The atmosphere of our planet at that time would have been toxic, with little, if any, oxygen present, yet the geologic forces of mountain building and erosion would have been going gangbusters. If any life forms existed, they would have been microscopic. Imagine the earth 2.75 billion years ago in southwest Montana. This is what a typical screen of garnet-bearing pay dirt looked like once the garnets had been concentrated. ![]()
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