Mineralogy of Iza Cave (Rodnei Mountains, N. Romania)

The secondary minerals from Iza Cave result from the interactions of karst water and/or cave atmosphere with a variety of sedimentaryand metamorphic rocks. The cave passages expose at various extents Eocene limestones and conglomerates, Oligocene blackshales, Upper Precambrian micaschists, marble and dolomitic marble and associated ore deposits. Twelve secondary mineralsidentified in the cave (carbonates, sulfates, phosphates, oxides and hydroxides, and silicates) are presented in this study. Calcite,aragonite, gypsum, brushite and hydroxylapatite are the components of common speleothems in the limestone, dolomite andconglomerate areas of the cave. Ankerite crusts are related to areas with pyrite mineralization within the metamorphic carbonaterocks. Goethite, jarosite, hematite and gypsum form various speleothems in the sectors within micaschists and conglomerates. Largeweathering deposits occurring in passage areas developed within micaschists consist of illite, kaolinite, jarosite, goethite, gypsumand alunite. The extent of the weathering deposits occurring on non-karst rocks in the underground environment makes this cave aparticularly interesting site for studies of water-rock interactions.