MINERALS AND ROCKS OF THE RUDAWY JANOWICKIE MTS

An old mining region...

Rudawy Janowickie Mts. are one of the mountain ranges in the Sudetes, stretching in the north from the Bóbr river valley and the village

Janowice Wielkie to the Kowarska Pass in the south (ca 18 km). Three main types of rocks make up this range: granitoids forming the western slopes (Karkonosze granite intrusion), metamorphic rocks and sedimentary rocks in contact with metamorphic rocks from the east (see maps and geological schemes attached). Metamorphic rocks include: gneisses, mica schists with inserts of dolomitic marbles, amphibolites, greenstones, chlorite schists, hornfels, keratophyres and rhyolites. There are many abandoned quarries in the granite western part of the range. In the area of metamorphic rocks, there is an inactive amphibolite quarry near the village Wieściszowice and an active quarry on the southern edge of the range near the village Ogorzelec. Southward from the village Wieściszowice, there are excavations after the extraction of pyrite with pyrite-sericite-chlorite-slates. Currently, there are water reservoirs in the excavations with water colored purple, blue and

green from Fe and Cu compounds - this is the ‘Kolorowe Jeziorka’ (Colourful Lakes), currently a nature reserve. In the corridors and caverns of excavations, sulphate secondary minerals crystallise on the walls, e.g. in the excavations 'Purpurowe Jeziorko' (Purple Lake) pseudocopiatite, halotrichite on pyrite-sericite-chlorite-slates, and in the dolomite quarry near Rędziny calcite, dolomite, hematite, serpentine and others. Limestone rocks are still mined in a quarry near Rędziny (dolomitic marbles). In the metamorphic rocks, a polymetallic deposit was discovered

and exploited from the early Middle Ages until the mid-twentieth century. It stretches mainly between two villages, Miedzianka and Ciechanowice. Two groups of minerals occur in the mining area: magnetite-sphalerite-pyrite and vein minerals, including chalcopyrite, bornite, arsenopyrite and cobalt. Apart from the main minerals, gangue minerals such as quartz, chlorites, barite, fluorite and calcite crystallised. In the 'Miedzianka-Ciechanowice' deposit, slight mineralisations of native elements were found: copper, silver, gold and bismuth. The most interesting are secondary minerals, also crystallising currently. Among them, some are presented in the pictures in SP: fluorite, pyrite, chalcopyrite, arsenopyrite, garnets, epidote, quartz, medenbachite, pharmacosiderite, malachite, chrysocolla, hydrozyncite, marcasite, chlorite, chalcocite, black copper oxides, cuprite, psylomelane, tyrolite, agardite, clinoclase, philipsburgite and many others. Some minerals are derivatives of uranium and are radioactive, such as bassetite, cuprosklodowskite, parsonsite, torbernite, trögerite and zeunerite. Many secondary minerals can only be observed under a microscope and can be identified using advanced techniques.