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 and thus general hints for the geographical distribution of ice caves. In the presentation we will also show examples for historical measurements in caves as well as historical descriptions regarding ice cave morphology and dynamics. Beside that the most important facts about the history of theory, regularities and systematic investigations in the past will be illustrated. UNDERGROUND CRYOSPHERE IN THE MONTE CANIN MASSIF, ALPI GIULIE (ITALY) Colucci R.R. 1, 2 , Forte E. 1 & Guglielmin M. 3 1 University of Trieste, Department of Geoscience – via Weiss 2, 34128 Trieste, Italy 2 National Research Council (CNR), ISMAR Trieste – Viale R. Gessi 2, 34123 Trieste, Italy 3 Insubria University, BICOM Varese – via HJ Dunant 3, 21100 Varese, Italy In the Natural Park of the Prealpi Giulie, stands the massif of Monte Canin which represents a particular case study in terms of relationships between climate and environment. The massif is characterized by glacial and periglacial environment with heavy snowfalls (6.80 m at 1800 m ASL, from dec 1st to apr 30th) and cold temperature (MAAT 2000-09 = 3.8 +/- 0.6°C at 1800 m ASL) that allow to find cryospheric conditions normally found in much higher elevations in the Alps. The whole area, for lithological and structural features that characterize it, is affected by a large number of karst caves. Within the area, in a great number of cavities it was reported the presence of snow and ice, and in many of these cases permanent and layered ice was detected. Although the area is affected since several decades of intense research caving, the study of the underground cryosphere started at the end of summer 2010 when a karst cave filled by a permanent ice deposit has been identified to be suitable for a systematic monitoring. The cave entrance, which roughly correspond with the beginning of ice deposits, is located at an elevation of 2285 m a.s.l. representing the most elevated cave filled by ice actually known both in Alpi Carniche and Alpi Giulie (the northeastern most part of Italian Alps). During summer 2011 the cave was instrumented by several temperature probes in rock, air and ice. Actually 14 monitoring sites were overall activated both outside and inside the cave. Two fixed reference marks, in order to detect the spatial and temporal changes of the ice body height, were also installed and are actually measured at every visit. In order to quantify the thickness, the stratigraphy and the internal structure of ice body, the ice mass have been scanned by using Ground Penetrating Radar (GPR) techniques. We acquired 9 profiles using a ZOND instrument equipped with 500 and 800 MHz 17
5 th Int. Workshop on Ice Caves (IWIC – V) Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012 Volume of Abstracts bistatic shielded antennas. Profile spacing was 1m, while trace interval was 0.02cm in order to obtain a very high lateral resolution. GPR sections were combined in order to obtain a volume allowing a pseudo 3D interpretation. We processed the whole dataset adopting a standard processing flow (DC removal, drift correction, background removal, spectral analysis and filtering, amplitude recovery, velocity analysis based on diffraction hyperbolas, time migration and depth conversion), integrated by specific algorithms like adaptive deconvolution to increase vertical resolution and make easier the identification of thin layers and attributes analyses to highlight both vertical and lateral discontinuities. We found a mean EM velocity close to 22cm/ns, which is typical for fresh ice and we imaged several intra ice horizons and the contact between ice and rocks reaching a maximum depth of about 5m below the actual frozen surface. Moreover, the acquired data show an air-filled cave (during the survey reachable also by direct inspection) characterised by the tipical EM phase inversion due to the contact between ice and air. In the central part of the cave, below the ice, a possible debris- filled zone was also tentatively interpreted. EXPLORATION OF ICE CAVES ON MAUNA LOA, HAWAII Pflitsch A. 1 , Schörghofer N. 2 & Smith S. 3 1 Department of Geography, Ruhr-University Bochum, 44801 Bochum, Germany (andreas.pflitsch@rub.de) 2 NASA Astrobiology Institute, University of Hawaii, Honolulu, Hawaii 96822, USA (norbert@hawaii.edu) 3 Cave Conservancy of Hawaii, Hilo, Hawaii, USA (amygdala1881@yahoo.com) The Mauna Loa shield volcano, one of two high summits on the Big Island of Hawaii (20°N), has a high density of lava tubes and mean annual temperatures are well above freezing. We have visited and surveyed two ice caves on the north flank of Mauna Loa. One of the caves is known as “Mauna Loa Ice Cave” since at least 1979. We re-located and visited this cave in November 2011 and found that the ice is still present, but has retreated. Another ice cave has been discovered in 2009 by Stephen Smith, and is named “Arsia Cave”. Two side passages within this lava tube have frozen lakes. One of the ice chambers has a ~2m high ice stalagmite. Water drips from the ceiling and freezes in the ponds, which contain large bubbles. The discrete levels of the bubbles suggest the ice is layered. Although we could not directly measure the depth of the ice lakes, we estimate it to be up to several meters. 18
Page 2 and 3: IWIC - V 5 th INTERNATIONAL WORKSHO
Page 4: President 5 th Int. Workshop on Ice
Page 7 and 8: 5 th Int. Workshop on Ice Caves (IW
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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