Mineralogy and Speleogenesis of the Ice-Cave from Poiana Vârtop (Bihor Mountains, Romania)

The cave of Poiana Vârtop in the NW Bihor Mountains hosts the fourth largest underground perennial glacier in Romania with a volume estimated to 12,000 m 3 . The ice accumulated within the cave as a result of trapping of subzero winter air through its single entrance near the top of the cave. The speleothem mineralogy is dominated by calcite, with minor amounts of included aragonite. Crusts of carbonate-hydroxylapatite (associated with bat guano) and goethite (associated with pyrite in the host limestone) are found at a few locations. Based on structural observations, dye traces, and cave galleries orientations, it is inferred that the cave is part of a much larger hydrologic karst system that also includes the nearby Humpleu-Poienita cave network