that time the cave was 6.4 km long including some extensive pools. From 2002 members of Grup Espeleo Llubí and Secció d'Espeleologia de l'ANEM faced the challenge of investigating a slight draught of air at one remote chamber. In 2004 Grup Espeleo Llubí achieved a major breakthrough when a draughting slot was discovered, leading the explorers into the biggest known chamber in the cave so far. The discovery fueled the fires and the cavers begun the exploration of a maze of passageways and chambers. Along the way, cavers from Secció d'espeleologia de Voltors and Grup Espeleològic EST joined the team that is still exploring, surveying and studying this impressive and complex cave; important underwater extensions are currently being explored and surveyed by cave divers from Grup Nord de Mallorca and lately also Grup Espeleo Llubí. The cave is located in the Llucmajor municipality in southern Mallorca, being developed in the natural area of Migjorn (coordinates UTM/WGS84, 489120; 4.357.510). A great deal of galleries and chambers lies beneath the Vallgornera housing estate (east of Cala The Cova des Pas de Vallgornera lies in the Llucmajor municipality, in southern Mallorca, and is the longest cave in the Balearic Islands. Currently its surveyed length is over 74,000 m, including more than 17,000 m of underwater extensions. The cave was discovered accidentally in 1968, but it was in 2004 when a major breakthrough shed light on its real extension and importance. The cave roughly shows two tiers of passages, apart from the underwater extensions, the first one is between 7 and 11 m above the mean sea level, the second one is about at the water table level. The importance of the cave is not only related to its extension, but also to the presence of a wide variety of speleothems and outstanding solutional morphologies that evidence a complex evolution. The cave is under the protection of Conselleria de Medi Ambient, Govern de les Illes Balears (the Regional Environmental Authority) and was declared Site of Community Importance, within the Natura 2000 Network.

Cova des Pas de Vallgornera is a unique karst cave located at the Llucmajor coastal platform that stands out not only because of its length, more than 78 km, but also for its particular morphological suite, richness and variety of speleothems and mineral infillings. Although the mineralogy of speleothems and minerals related to hypogene morphologies has been studied and described, the existence of minerals derived from guano deposits was still poorly investigated. The cave hosted bat colonies until the collapse of its natural entrances, circa 2.4 My ago, since then until its discovery in 1968, the cave remained sealed. These particular environmental conditions, kept along millennia, helped the interaction of guano-related leachates with the bedrock and clay deposits provoking dissolution and mineral precipitation. Moreover, thanks to the discovery of guano-associated cave minerals, it has also been possible to determine the presence of morphologies related to ancient guano deposits. In this paper, we report on features caused by bat's biomechanical erosion, bat claws and bat thumb marks and the influence of geobiological modifications caused by guano deposits on stalagmites and fallen boulders, haystack-shaped stalagmites, stalagmites covered in niches and crypto-corrosion features on fallen boulders. In addition, an array of guanorelated minerals is reported, being phosphates the most abundant mineral group identified, underlining the broad presence of fluorapatite from all the studied sites. Among the oxides and hydroxides, nordstrandite, gibbsite and todorokite are especially common. Finally, connections between microclimatic conditions in the cave and the location of bat roosting and breeding sites are discussed. littoral karstic cave,

Cova de sa Guitarreta is located in the southern part of Mallorca Island (western Mediterranean). It was formed presumably by hypogenic processes in Upper Miocene reefal calcarenites. The cave hosts an important breeding colony of bats during the end of spring and early summer. Its microclimate is influenced by the presence of a thermal phreatic water table (27.7ºC) as well as by bat populations remaining in the cave along the reproductive season. The morphological bat-related features include bat claws and thumb marks scratches, together with several morphologies linked to bat excreta and aggressive leachates from guano. From the mineralogical point of view, this cave outstands regarding the presence of cave minerals linked to guano: nine phosphates have been identified, comprising three of them that are reported for the first time in Mallorcan caves (newberyite, struvite and whitlockite). Particularly interesting is the dichotomy between struvite and newberyite: the first one occurs when the cave is occupied by bat colonies (spring-summer), whereas in the colder seasons would occur the transformation of metastable struvite into a more stable newberyite. Caves with seasonal cyclical occupation of bat colonies could provide a new arena for the study of the guano-related mineral assemblages.