Volume of Abstracts - Università degli Studi di Milano

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5 th Int. Workshop on Ice Caves (IWIC – V) Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012 Volume of Abstracts temperature inversion; later it was explained that cold air is coming from the empty spaces between slope boulders and rubble that cooled down during the winter. Our observations and measurements on several spots showed, that the phenomena is result of the strong “springs” of cold air with stable temperature 2-3º C during summer. The air is coming from holes between rubble on some spots on the slopes of dolina. The same temperature of the air we observe in most of the ice caves during summer. The currents inverse directions during winter, which indicates the existence of a large cave system below the rubble that masks the entrances. The combination of winter cold climate and summer advection of cold air to the dolina created unique type of climate which resulted in formation of permafrost. It exists only in vicinity of this blowholes in altitude 1125 m, the largest areas is about 1 ha large. But permafrost is missing at the bottom of Smrekova draga, indicating, that the lowest temperatures of this dolina are not connected to relief form but to inflow of very cold cave air. Similar observations and measurements were made in some other deep dolines where strong temperature inversions were also observed. They may be all connected with advection of cold air from the cooled caves that are exist parallel or above in the karst massive. MINERAL CRUSTS AT THE SURFACE OF LAKES OF WARM AND COLD ZONES IN THE KUNGUR ICE CAVE Kalinina T. A. 1 , Tchaikovskiy I. I. 1 & Kadebskaya O. I. 1 1 Mining Institute of Ural Branch of Russian Academy of Sciences, Russia (tatyanaak89@mail.ru) Investigation of the mineral pellicles formed at the surface of ponds in the Kungur Ice Cave showed that their structure and the formation mechanism depend on the location in a cold or warm microclimatic zone. Mineral pellicles of a cold zone. Studying of morphology and composition of pellicles from the surface of perennial icings showed that they represent drusy-like aggregates of accomplished gypsum and calcite crystals which grew down from the water-table. On the upper surface there are recognized prints of air bubbles, and also inclusions of allophane spherules and calcite clastic grains. Gypsum is presented by plate crystals (up to 100 microns), combined both with table-cut individuals and those complicated by growth elements: box-shaped and skeletal crystals. Calcite in the form of both separate crystals and split crystal-jams fills openings between gypsum crystal aggregates and also moulds on their surface. Its composition includes isomorphic impurities of magnesium, 33
5 th Int. Workshop on Ice Caves (IWIC – V) Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012 Volume of Abstracts strontium and sodium. Noted was also a singular crystal of gaylussite, the chemical composition of which corresponds to the calculated formula Na1,98Ca1,02 (CO3)2∙5H2O. Mineral pellicles of a warm zone. Studying of mineral pellicles from the lake surface in the Bleznitsy Grotto from a warm part of the cave showed that they are the drusy-like aggregates of sharp calcite rhombohedrons. It is noted that larger crystals compose both separate crystal-jams at the druse surface and marginal parts of mineral crusts. Both small and large individuals are split. Noted were also other minerals (celestine, dolomite, gypsum, halite) which were recognized on the outer side of mineral pellicles in the nests between calcite crystals. Investigation of chemical composition of carbonates and sulfates showed absence of isomorphic impurities. Conclusions. Thus, two various types of mineral pellicles floating on the pond surface are formed in the Kungur Ice Cave. In the cold zone, in the time of water frosting from below there appear essentially gypsum pellicles later covered by calcite. Presence of box-shaped forms on gypsum crystals and various isomorphic impurities in calcite composition (Mg, Sr, Na) reflect the fast disordered crystallization connected with a strong supersaturation caused by water frosting and salts accumulation in a liquid phase. Gaylussite appearance reflects mineralization conditions close to the cryogenic ones. Calcite pellicles crystallize on lakes‟ surface of the warm zone. Their formation is connected with carbon dioxide evaporation and the calcium carbonate supersaturation zone formation in the near-surface water layer. Formation of the dense calcite crust promotes appearance of microreservoirs on its irregular surface where water evaporation and mineral deposition take place just as salt precipitation in the conditions of arid climate. In spite of the identical initial chemical composition of the solutions infiltrated through the carbonate and sulfate massif, different climatic zones are characterized by specific order of mineral crystallization on the water surface. The revealed difference is connected with different climatic conditions and solution supersaturation mechanisms. The described gypsum crusts form in more comfortable conditions on a smooth surface of the reservoirs. Noted were mineral climate indicators, such as thermophile dolomite, gypsum and halite, as well as cryophilic gaylussite. 34
Page 2 and 3: IWIC - V 5 th INTERNATIONAL WORKSHO
Page 4: President 5 th Int. Workshop on Ice
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Page 13 and 14: Dear Participants, we are very plea
Page 46: POSTER PRESENTATIONS
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Volume of Abstracts - Università degli Studi di Milano

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