Geological and morphological observations in the eastern part of the Gran Caverna de Santo Tomás, Cuba (results of the "Santo Tomás 2003" speleological expedition)

This paper deals with activities of the "Santo Tomás 2003" expedition, carried out in December 2003 by Italian and Cuban cavers at Gran Caverna de Santo Tomás. The Gran Caverna de Santo Tomás is the most famous karst cave on the island of Cuba and it is now more than 46km long. It lies in the Pinar del Rio Province (western Cuba), and comprises seven different levels of caves, the lowest of which is active and occupied by the Arroyo de Santo Tomás. Its location is part of the Sierra de los Organos mountain ridge, a classical example of cone karst, which is characterized by the presence of a number of mogotes, typically isolated carbonate hills with vertical walls and rounded tops. The Gran Caverna de Santo Tomás is developed within the Sierra de Quemado, and has been explored since 1954 by Antonio Núñez Jiménez, the well-known Cuban explorer and caver. Activity during the 2003 expedition included topographical survey, and geological and morphological observations in the Sector of Gran Caverna de Santo Tomás closer to the Valle de Santo Tomás. Most of the work was devoted to the Salón del Caos, one of the largest caverns in the karst system, which enlarged due to a great number of huge rockfalls from the roof and walls of the original chamber. © British Cave Research Association, 2005.