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Cavity-Based Secondary Mineralization In Volcanic Tuffs Of Yucca Mountain, Nevada: A New Type Of The Polymineral Vadose Speleothem, Or A Hydrothermal Deposit?, Yuri V. Dublyansky, Sergey Z. Smirnov

International Journal of Speleology

Secondary minerals (calcite, chalcedony, quartz, opal, fl uorite, heulandite, strontianite) residing in open cavities in the Miocene rhyolite tuffs of Yucca Mountain, Nevada have been interpreted by some researchers as "speleothemic" formations, deposited as a result of downward infi ltration of meteoric waters (DOE, 2001, Whelan et al., 2002). The major mineral of the paragenesis, calcite, shows spectacular trend of the textural and crystal morphology change: from anhedral granular occurrences, through (optional) platelet, bladed and scepter varieties, to euhedral blocky morphologies. The trend is consistent with the overall decrease in the supesaturation of the mineral forming solution. Stable isotope properties …