Audra P. auteur aut IRD Cazes G. auteur aut IRD Robert Xavier auteur aut IRD Barriquand L. auteur aut IRD Dublyansky Y. auteur aut IRD Koltai G. auteur aut IRD Temovski M. auteur aut IRD Polyak V. auteur aut IRD Carbone C. auteur aut IRD Heresanu V. auteur aut IRD Gruat J.P. auteur aut IRD De Waele J. auteur aut IRD text conferencePaper eng text/pdf reformatted digital access The Gap-Gotan (Cupp-Coutunn) system (Turkmenistan) is known for its mineralogical wealth, thanks to the considerable work carried out by Vladimir Maltsev in the 80s. However, following fieldwork carried out in 2024, Maltsev's speleogenetic hypotheses have been revised, in terms of stages, chronology and processes. Several phases of speleogenesis can be identified. 1) Hydrothermal mineralizing fluids, leading to Pb-Zn deposits in the vicinity, and impregnation of the host rock with sulfides, fluorite, and calcite veins. 2) The formation of large horizontal phreatic conduits at shallow depth, fed by infiltration at high altitude, with dissolution produced by flows reacting with the sulfides in the host rock. This process has been repeated in stages as the base level fell, until the present day. Nowadays similar active phreatic conduits are presumed to exist beneath the gypsum collapses. 3) Once drained, the caves are decorated with gypsum speleothems mainly formed by sulfate-rich seepage from the surface (e.g., chandeliers), and filled with fluvial sediments injected locally from canyon sinkholes. Mapping, isotopic and mineralogical analyses, and U-series and U-Pb dating of the sediments are providing preliminary evidence for this model of speleogenesis in these unique and exceptional caves. specialized TURKMENISTAN 064SEDIM 064GEOREG 064GEOMOR 064PETRO International Congress of Speleology ; Congresso Brasileiro de Espeleologia, 19. ; 38., Belo Horizonte (BRA), 2025/07/20-27 134-139 Calux A. ed. edt IRD Belo Horizonte SBE 2025 https://www.documentation.ird.fr/hor/fdi:010096584 [F B010096584] https://www.documentation.ird.fr/hor/fdi:010096584 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2026-03/010096584.pdf IRD - Base Horizon / Pleins textes 2026-02-11 2026-03-05 fdi:010096584 fre