Sails: a new gypsum speleothem from Naica, Chihuahua, Mexico

Abstract

The caves of Naica (Chihuahua, Mexico) are perhaps the most famous mine caves of the world due to the presence of giganticgypsum crystals. Nevertheless, very little research has been carried out on this karst area until now. A multidisciplinary investigationstarted in 2006 with the aim not only to define the genesis and the age of the Naica gypsum crystals, but also on other scientificaspects of these caves.This paper describes a completely new type of gypsum speleothem: the “sails”, observed only inside the Cueva de las Velas, one ofthe caves of the Naica system. This speleothem consists of extremely thin, elongated skeleton crystals that have grown epitaxiallyonly on the tips of the gypsum crystals pointing upward. The genesis of sails is strictly related to the environmental conditions setup inside the cave just after the artificial lowering of the groundwater by mine dewatering (less than 20 yr ago). In a few years sail speleothems will disappear entirely and therefore this study is fundamental to preserve at least the memory of them.

Keywords

• gypsum speleothems
• speleogenesis
• mine caves
• Naica
• Mexico