gouffre Mirolda

The cave was discovered in 1971 by Marc Degrinis, a shepherd.{{cite web|language=en|url=http://cds74.free.fr/decouvre/record.html|title=Complément d'information sur le nouveau record du monde de profondeur de spéléologie (january 2003)|access-date=2023-10-20}} In 1972, the AVEN group in Lyon widened the entrance, and explored to a depth of {{convert|-127|m|ft|abbr=on}} to an impenetrable meander. In 1976, an upper entrance, the VF3, at {{convert|2324|m|ft|abbr=on}}, was discovered by the Villefranche Caving Club (EESV) and explored as far as the base of the first {{convert|30|m|ft|abbr=on}} shaft on a narrow slope. The Gouffre Mirolda (CD11) was reinvestigated in 1980 by SC Lyon. With the help of the GS Cavernicole and the SC du Chablais, a depth of {{convert|-850|m|ft|abbr=on}} was reached. In 1981, the river was explored down to {{convert|-1100|m|ft|abbr=on}}. Reinforced by the SS Genève and the Thonon Tauping Club, fossil galleries and upstream tunnels enabled the network to reach a height difference of {{convert|1143|m|ft|abbr=on}} in 1988. The unblocking of the Gouffre VF3 gave access to the system named after Lucien Bouclier, a speleologist who died in 1987 on the massif. The junction was made by the Ursus group between the Gouffre Mirolda and the Réseau Lucien Bouclier in 1992 for a depth of {{convert|-1436|m|ft|abbr=on}}, and also with the Gouffre de la Rondelle Jaune ({{convert|2220|m|ft|abbr=on}}). At the bottom of CD11 the depth was increased in 1993 to {{convert|-1520|m|ft|abbr=on}}, and {{convert|-1610|m|ft|abbr=on}} in 1998.{{Cite magazine |author=Clubs Cavernicoles and Ursus|language=fr|title=-1610 m au gouffre Mirolda|magazine=Spelunca|publisher=Fédération française de spéléologie|number=69|date=April 1998|pages=25–40|issn=0249-0544 |url=https://spelunca.ffspeleo.fr/199804_Spelunca_069.pdf|access-date=2023-10-20}} The Gouffre du Joker ({{convert|2332|m|ft|abbr=on}}) was connected to the network in 1999, increasing its depth to {{convert|-1616|m|ft|abbr=on}}. The terminal sump was dived in 2003, increasing the depth to its current {{convert|-1733|m|ft|abbr=on}}, making it the deepest natural cave in the world from January 2003 until July 2004,{{Cite web|title=Quand Mirolda devint le gouffre le plus profond du monde|url=https://www.ledauphine.com/haute-savoie/2015/07/27/quand-mirolda-devint-le-gouffre-le-plus-profond-du-monde|last=de Sainte Lorette|first=Cedran|date=28 July 2015|website=Le Dauphiné Libéré|language=fr}}{{Cite web|title=Échos des profondeurs|url=http://www.chroniques-souterraines.fr/dossiers/Speleologie/01_Explorations/2006profondeur.pdf|last=Courbon|first=Paul|date=2007|website=chroniques-souterraines.fr|language=fr}} when it was passed by the cave Krubera-Voronja in Georgia.{{Cite journal|first=Paul|last=Courbon|language=fr|title=Le gouffre le plus profond du monde|journal=Spelunca|publisher=Fédération française de spéléologie|volume=155|year=2019|pages=26–31|issn=0249-0544 |url=https://spelunca.ffspeleo.fr/201910_Spelunca_155.pdf|access-date=2023-10-21}} In September 2022 and 2023 the Collectif Mirolda, took over the topography, updated the in-situ equipment and examined the possibilities of further discovery.{{cite web|language=fr|title=Les topographies du système du Criou|url=https://groupe-speleo-vulcain.com/explorations/explorations-a-samoens/les-topographies-du-systeme-du-criou/|access-date=2023-09-14}}{{Cite book|language=fr|first1=Xavier|last1=Robert|first2=Charlotte|last2=Honiat|first3=Prune|last3=Roche|first4=Benoît |last4=Urruty|first5=Johann|last5=Culot|first6=Lionel|last6=Revil|first7=Barnabé|last7=Fourgous|first8=Alexandre|last8= Pont|title=Criou 2023 - Activités spéléologiques 2023 sur le massif du Criou, Samoëns (Haute Savoie)|url=https://groupe-speleo-vulcain.com/wp-content/uploads/2024/03/2023_Rapport_Expe.pdf|date=2024|pages=110}} The cave is the deepest in France. A new survey reduces the depth to -1661 m.{{Cite web|title=Cross section Gouffre Mirolda et réseau Lucien Bouclier|url=https://groupe-speleo-vulcain.com/wp-content/uploads/2024/09/Mirolda-coupe.pdf|date=2024-09-17}} Its name is derived from the forenames of the Rhodanien cavers Michel Schmidt, Roland Chenevier, and Daniel Trouilleux, who were lost in a flood in Gournier Cave in November 1976.{{Cite web|title=Deux spéléologues lyonnais meurent noyés| website=lemonde.fr/archives| date=11 November 1976|language=fr|url=https://www.lemonde.fr/archives/article/1976/11/11/deux-speleologues-lyonnais-meurent-noyes_2947012_1819218.html}}

The highest entrance of the system is at {{convert|2330|m|ft|abbr=on}}. The lowest point of the cave is at {{convert|-1661|m|ft|abbr=on}} at the grand siphon in the gallery.{{Citation|last=Drouin|first=Philippe|title=Gouffres les plus profonds du monde|journal=Spelunca|volume=108|publisher=French Federation of Speleology|page=4|date=September 2007|language=French|url=https://spelunca.ffspeleo.fr/200712_Spelunca_108.pdf}} The bottom of the gallery (after the second siphon) has only been explored once, with potential for further exploration. Behind the second siphon (approximately {{convert|-1620|m|ft|abbr=on}}) the gallery continues for {{convert|22|m|ft|abbr=on}} horizontally and down {{convert|8|m|ft|abbr=on}}, leading to an ancient drainage system. Downstream, the gallery descends over a length of {{convert|251|m|ft|abbr=on}} and a vertical drop of {{convert|110|m|ft|abbr=on}} before coming up against the first siphon at {{convert|-1733|m|ft|abbr=on}}. Past the siphon the gallery divides in two, the left leading up towards the roof and the right leading {{convert|50|m|ft|abbr=on}} to a fossil gallery.{{Citation|last=Colliard|first=Daniel|title=Nouveau record du monde au réseau Mirolda - Lucien Bouclier (Massif du Criou - Samoëns - Haute-Savoie) –1733 m|journal=Spelunca|volume=89|publisher=French Federation of Speleology|pages=5–6|year=2003|language=French|url=http://spelunca.ffspeleo.fr/200303_Spelunca_089.pdf}}

The Gouffre Mirolda is developed in Urgonian Limestone at its contact of the Hauterivian marl following the dip first (E-W), and then (S-W) towards the Giffre valley. The water flows into the alluvial aquifer, and no resurgence is known. As at the Gouffre Jean-Bernard, the upstream section of the Réseau Lucien Bouclier appears to be the oldest part of the system, with the base of the CD 11 developed following the incision of the Giffre valley.{{Cite book|language=fr|author=Comité départemental de spéléologie de Haute-Savoie|title=Grottes et gouffres de Haute-Savoie|year=2022|pages=173–179}}

• Gouffre Jean-Bernard
• List of deepest caves
• List of caves in France
• List of caves

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Category:Landforms of Haute-Savoie

Gouffre Mirolda