UIS Commission on Karst Hydrogeology and Speleogenesis
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Featured article: conference proceedings
Audra, Philippe
Mádl-Szőnyi, Judit; Erőss, Anita; Mindszenty, Andrea; Tóth, Ádám
Uncommon cave minerals associated to hypogene speleogenesis in southern france
International Symposium on Hierarchical Flow Systems in Karst Regions
Budapest, Hungary
2013
46
46

Five hypogenic-origin caves from Southern France are presented. Investigations using XRD, SEM and Raman spectroscopy, reveal the presence of uncommon cave minerals. Oilloki Cave is a small lead ore mine-cave containing galena, cerussite, and bismuth (present as native element or as sulfide).La Baume Cave is a hydrothermal breccia-pipe, filled with colorful (red, green, white) clays. Some of the clay minerals (clinochlore se-piolite), could originate from hydrothermal weathering of clastic material. The Mala-coste Quarry, harbors a hydrothermal chimney with enlarged vugs lined with calcite spar and filled with iron oxyhydroxides poolfingers (goethite-hematite) and manganese oxides (birnessite, todorokite). Deposition of iron and manganese oxides results of the pH-Eh evolution along the hydrothermal chimney. Pigette Cave is a hydrothermal ver-tical maze with calcite lining and small iron oxyhydroxides and manganese oxides mass-es. The hydrothermal weathering of the walls deposited grains of lithiophorite, barite, and celadonite, which could originate from glauconite. Baume Galinière Cave is a small horizontal maze originating from the oxidation of sulfide masses of pyrite. Beside the common byproducts (gypsum, goethite, sulfur), the six members of the jarosite sub-group are present: jarosite, ammoniojarosite, argentojarosite, hydronium jarosite, natro-jarosite, plumbojarosite, together with fibroferrite. In these caves, three minerals are new cave minerals (bismuth, celadonite, argentojarosite); some others have been men-tioned before only in a few caves worldwide (clinochlore, lithiophorite, ammoniojaro-site, hydronium jarosite, natrojarosite, plumbojarosite, fibroferrite). The mineralogene-sis involves different processes: (i) Deposition in mixing zone from species carried by rising deep flow (barite, galena, bismuth, birnessite, todorokite, lithiophorite); (ii) Hy-drothermal weathering of clay minerals contained in host rock or present as clastic sediments (clinochlore, sepiolite, celadonite); (iii) Oxidation of sulfide masses (goethite, cerussite, jarosite subgroup minerals, fibroferrite).

cave minerals, hypogene speleogenesis, sulfide oxidation, hydrothermal weathering, hydrothermal minerals
978-963-284-369-8