1.3 MB - Instituto de Ciencias de la Tierra Jaume Almera

30 Carbonates Evaporites (2011) 26:29–40
The present study documents a methodological
approach useful for the geological and geomorphological
characterization of these special environments and discusses
the conditioning of karst development.
Setting
Torca Teyera is a large shaft, 738 m deep, located on
the northern part of the Picos de Europa (Fig. 1), a
mountain massif located in the Cantabrian Mountains of
northern Spain. From the structural standpoint, Picos de
Europa belongs to the Cantabrian Zone of the Variscides
domain (Lotze 1945; Julivert et al. 1972; Alonso et al.
2009). The bedrock consists mainly of 1,200 m of carboniferous
limestone affected by E–W to NW–SE and
south-directed imbricate variscan system thrust (Fig. 2).
The décollement level of the structures is above siliciclastic
rocks from the Pisuerga-Carrión province (Pérez-
Estaún et al. 1988; Marquínez 1989; Farias and Heredia
1994; Bahamonde et al. 2007; Merino-Tomé et al. 2009).
During the Alpine orogeny, some of these thrusts were
reactivated, causing the rotation of some thrust sheets
Fig. 1 Situation map of the
Picos de Europa massif. The
locations of the cave of study
(Torca Teyera, Fig. 5) are also
shown
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and leading to the formation of the main relief
(Alonso et al. 1996; Pulgar et al. 1999; Gallastegui
Suárez 2000).
Picos de Europa is characterized by a rough and calcareous
relief with peaks exceeding 2,500 m above sea
level (asl) and by the presence of narrow canyons, such as
the Cares Gorge. Canyons up to 2,000-m deep evidence the
important fluvial incision derived from uplifting. The karst
forms dominate the landscape (Hoyos Gómez 1979; Smart
1984, 1986; Hoyos Gómez and Herrero 1989; Santos
Alonso and Marquínez García, 2005), although glacial and
periglacial features are preserved (Alonso 1991; González
Suárez and Alonso 1994; Gale and Hoare 1997; Alonso
1998; Jiménez-Sánchez and Farias Arquer 2002; González
Trueba 2006, 2007; Moreno et al. 2009; Serrano Cañadas
and González Trueba 2004). Moreover, nival, gravity and
fluviotorrential processes also control the geomorphological
evolution of the landscape.
Torca Teyera shaft was discovered, explored and surveyed
by the Groupe Spéléo du Doubs, the Société Suisse
de Spéléo-Section de Genève, the Société des Amateurs des
Caverns and the Spéléo Club of Nyon between 1979
and 1982 (Borreguero 1986). During these explorations,