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La Verna is a show cave in the commune of Sainte-Engrâce in the department of Pyrénées-Atlantiques in France. of mined tunnel leads into the Salle de la Verna, the largest chamber in a show cave in the world.〔(【引用サイトリンク】title=Valorisation touristique de la salle souterraine La Verna Pierre Saint-Martin - Ministère du Développement durable )〕 It has a diameter of , a height of , a surface area of and a volume of .〔http://www.atm3d.com/v5/pdf/verna.pdf〕 A river cascades into the chamber from half way up the east wall, and sinks into boulders near the base of the chamber. La Verna chamber is part of the Gouffre de la Pierre-Saint-Martin and the Gouffre des Partages cave systems.〔Bientôt un siècle d’explorations à la Pierre Saint Martin »〕 The development of these cavities, directly connected to La Verna, is . Explorations still continue in the extensive Pierre-Saint-Martin karst. So far, 13 big underground rivers and a total of of passages, chambers and pits have been mapped. 〔ARSIP INFO Edition Spéciale "Les Traversées de La Pierre-Saint-Martin" p.15 - 2014〕〔http://s391384129.onlinehome.fr/arsip/images/Synthese/Synthese%20PSM%2015_01%20Vue%20generale〕 The chamber was named after the Lyon scouts, La Verna Troop, who helped in the attempted rescue of Marcel Loubens who died following a fall during the 1952 explorations. In 2003 a standard 4 person hot-air balloon was flown in Salle de la Verna.〔(【引用サイトリンク】title=On a volé sous la terre )〕 ==Geology== Most of the Gouffre de la Pierre-Saint-Martin is formed by dissolution in Cretaceous limestones, and the main river reaches a base level where it flows over insoluble schists of the Paleozoic basement rocks. The Salle de la Verna has formed where the river flows off the schist onto Devonian limestone. Over time, the river found a route through the soluble limestones, leaving the original downstream river passage (the Gallerie Aranzadi) high and dry. The chamber was formed by a process of solution and collapse, beginning about 200,000 years ago. The unconformity between the Paleozoic and Mesozoic rocks is clearly exposed in the walls of the chamber. The water finds its way from the infiltration zones on the high limestone plateaus, at an altitude of , to the springs further down, in the valley of Saint-Engrâce.〔Jean François PERNETTE – « Rivières sous le Pierre » - F. Nathan – 1983〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「La Verna cave」の詳細全文を読む スポンサード リンク
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