Blue Lake

The Blue Lake is an artificial lake between Hüttenrode and Rübeland in the Harz Mountains, not far from the federal highway 27. The lake was created as part of the mining activities in this region.
In the limestone quarry at Am Garkenholz, which has been operated since 1885, limestone was extracted for the production of quicklime. Remains of a ring oven located close to the lake are witnesses to this limestone extraction. The shaft furnace that was also present here has been completely dismantled. At the quarries at Am Garkenholz, medium to upper Devonian reef limestones were mined on the southern flank of the Braunesumpf volcanic eruption in the transition to the Hüttenröder basin. The reef debris and lagoon limestones, which dip to the east to northeast, are partially mineralized with hematite, for example at the outflow of the lake. In the eastern quarry area, the limestones are tectonically heavily stressed and intensively karstified. In existing cracks, younger pelagic limestones from the upper Devonian to lower Carboniferous have been deposited in the form of Neptunian dikes. At the upper edge of the quarry, karst cavities filled with tertiary clays are exposed. The limestones extracted here are characterized by an average very high calcium carbonate content. Main extraction was stopped after World War II, and the lime ash was filled into the opencast mining pit. In 1955, the extraction was finally discontinued, and the production facilities were gradually dismantled.

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