Carlos Galán | Universidad del País Vasco UPV/EHU (original) (raw)

Papers by Carlos Galán

Publ.Dpt-Speleol. S.C.Aranzadi, 2023

The cavity under study develops on the edge of a poljé (Liendo valley, Cantabria) very close to t... more The cavity under study develops on the edge of a poljé (Liendo valley, Cantabria) very close to the Cantabrian coast. It presents geomorphological and hydrological features that make the enclave a unique place. The Yesta cave is a springing cavity, crossed by a small underground river that pours its waters into the poljé. The surface drainage of the poljé is concentrated and disappears in a sink (ponor), to cross the limestone outcrop again and emerge in the sea. The cavity presents a curious ecosystem, which includes highly specialized troglobitic species along with troglophilic and trogloxenal forms. Its aquatic fauna stands out in a special way, with populations of leuciscids fish, eels, amphipods, mayfly naiads and aquatic larvae of other insects. The colonization of the cave river by a catadromous fish such as the European eel implies going up the subterranean waters from the sea to the poljé, then the epigeal waters of the same, and again the subterranean cave river. The Yesta cave thus presents a set of unique hydrogeological and ecological features, which are described and discussed in this work.

Publ.Dpt.Speleo. S.C.Aranzadi, 2023

La cavidad objeto de estudio está situada en la primera barra caliza de la extensa unidad hidroge... more La cavidad objeto de estudio está situada en la primera barra caliza de la extensa unidad hidrogeológica Urgoniano Sur, en el monte Sastarri (Aralar guipuzcoano). Es una cueva fósil de 220 m que posee pequeñas filtraciones, gours y lagos subterráneos. Su drenaje deriva al colector del sistema Ormazarreta-Aia iturrieta, el más importante de la sierra, el cual tiene una extensión lateral de 10,8 km y-880 m de desnivel, entre su cabecera en Navarra y la surgencia de Aia en Gipuzkoa. Se presenta una síntesis de datos biológicos y ecológicos obtenidos de prospecciones efectuadas entre 1965 y 2023. Estos datos permaneciían inéditos. La cavidad alberga un ecosistema hipógeo con más de 50 especies cavernícolas. Se describe la cavidad y su fauna.

Publ.Dpt.Speleol. S.C.Aranzadi, 2023

Prospecting carried out in various areas of the southern flank of Mount Gazume (Gipuzkoa, Basque ... more Prospecting carried out in various areas of the southern flank of Mount Gazume (Gipuzkoa, Basque Country) made it possible to find new cavities. These are found in the areas of Ezurtza, Azulegi and Bordatxo. These are old mines that exploited lodes and veins of zinc minerals included in an outcrop of Urgonian reef limestone. Part of the cavities presents natural features and other artificial ones, product of the mining excavation in the contact between the veins of zinc silicates and the enclosing limestone rock. The cavities have some species of troglobite cave fauna (pseudoscorpions, beetles) and an unusual presence of bats. The exploration and topography of three cavities of interest (one of them a chasm) is exposed. Its speleogenesis and the role played by old mines as a refuge for invertebrates and bats are discussed.

Publ.Dpt.Speleo. S.C.Aranzadi, 2023

The hypogeous environment is extensive and little known. Every year new cave networks are discove... more The hypogeous environment is extensive and little known. Every year new cave networks are discovered and explored in different lithologies, in addition to limestone. This medium constitutes a significant proportion of the earth's crust, where the void systems develop three-dimensionally in the volumes of karstificable rocks or those capable of containing caves. The Jaizkibel Formation is a sequence of abyssal turbidites of flysch facies and Eocene age, which alternates thick layers of carbonate sandstone with thin shale interbeds. Karstification processes take place in this sandstone and underground aquifers and numerous cavities (chasms, caves and shelters) have been formed, generally of modest dimensions. Throughout two decades we have discovered and explored more than 400 cavities, including extensive networks of coating caves in the coastal zone, which extend into mesocaverns and smaller voids, constituting a vast ecosystem, which is home to a wide variety of biotopes and a high diversity of cave-dwelling species. The biological surveys carried out have made it possible to gather information on a total of 135 cave-dwelling species. These include marine, littoral, anquihaline, freshwater, and terrestrial forms, with a predominance of trogloxenous and troglophilous species, but also including troglobites species, as well as extraordinarily rare and previously unreported species for the hypogeous environment globally. The paper presents a summary of the data obtained.

Publ.Dpt.Speleol. S.C.Aranzadi, 2023

The cavity under study is an old mine that exploited veins of zinc silicates and iron oxides incl... more The cavity under study is an old mine that exploited veins of zinc silicates and iron oxides included in a series of Urgonian reef limestone (Aptian-Albian in age, early Cretaceous). In its final part, the mine intercepts an internal chasm in the limestone, with a drop of -80 m, it has small water circulations and various speleothems. Its ecosystem is curious, since it has two differentiated biocenoses. Twelve trogloxenous species inhabit the mine gallery (Eptesicus serotinus bats and two Rhinolophus species, Rana temporaria anurans, three species of Lepidoptera, Limnephilidae caddisfly, tiny scavenger and fungivorous Phoridae diptera, and Dytiscidae aquatic beetles; some of them are reported for the first time for hypogeous habitats), as well as three troglophilous taxa (araneids and chilopods). In the deep zone (a natural chasm of -80 m, without previous communication with the surface and intercepted by the mine) we instead found two troglobites species of ancient origin (Neobisiidae pseudoscorpions and Leptodirinae beetles). The hydrogeological and ecological features of the mine-abyss are presented and discussed in this work.

Publ. Dpt. Speleol. S.C.Aranzadi, 2023

The sandstone of the Jaizkibel Formation forms part of an abyssal turbidite sequence of flysch fa... more The sandstone of the Jaizkibel Formation forms part of an abyssal turbidite sequence of flysch facies and Eocene age, which alternates thick strata of carbonate sandstone with thin shale intercalations. Karstification processes develop in this sandstone and underground aquifers and numerous cavities (chasms, caves and shelters) have been formed.
In the coastal chain of the Jaizkibel, Ulía and Igueldo mountains, we have explored over two decades more than 400 cavities. The largest of them reaches 258 m of gallery development and -70 m of unevenness. Likewise, tunnels of up to 1.6 km of development have been explored that cross the sandstone series and intercept groundwater and minor voids. The data obtained have been the subject of previous publications, but an overall synthesis was lacking, which we present in this paper.

Publ.Dpt.Speleol. S.C. Aranzadi, 2022

Mine galleries often intersect underground voids at different scales and can be reworked by seepa... more Mine galleries often intersect underground voids at different scales and can be reworked by seepage water. Abandoned mines, once their exploitation has ceased, can be colonized by cave organisms, both from the surface and transitional environments, as well as from the deep hypogeal environment, in different lithologies. Recent works in mines in Gipuzkoa in non-karstic Paleozoic terrains have been of great interest, with the discovery of troglobitic species of ancient origin, as well as other troglophiles, rare in caves in classic limestone karst. This has led to expanding biological research in mines, commonly relegated to the background of interest in relation to natural caves. Given the importance of iron mining in Biscay (Basque Country), we decided to prospect a mine with levels rich in iron carbonates (siderite-ankerite) included in early Cretaceous limestone in the area near Bilbao. The work carried out allowed us to find various speleothems and cave organisms, being the discovery in the underground waters of the mine of a large population of troglophilic amphipod crustaceans. The work describes the cavity and its fauna, discussing various aspects of its ecology and hydrogeology.

Publ. Dpt.Speleo. S.C.Aranzadi, 2022

In the Kolosobarne area (upper part of the central syncline of Aralar, Navarra) there is a range ... more In the Kolosobarne area (upper part of the central syncline of Aralar, Navarra) there is a range of potholes and caves. Among them, a cavity (cave-abyss) caught our attention that has an interesting set of speleothems, among which large globular stalactites stand out, made up of a type of moonmilk with a cottony texture and very hydrated. These moonmilk speleothems have been formed by the action of microorganisms. In the vicinity of the speleothems there are extensive mats of bacteria and Amoebozoa protozoa. The cavity also has a hypogeal ecosystem with unique features, with several troglobitic species. The work describes the cavity and its fauna, and discusses the origin of its curious moonmilk speleothems.

Publ.Dpt.Speleol, S.C.Aranzadi, 2022

On the cliff of Elgorri txiki (coast of Mount Ulía, San Sebastián, Basque Country), hanging +4 m ... more On the cliff of Elgorri txiki (coast of Mount Ulía, San Sebastián, Basque Country), hanging +4 m above the sea, there is an upwelling that cascades directly into the sea. The groundwater upwelling comes from an artificial canalization (San Pedro tunnel, 1.5 km long). The tunnel carries a large-diameter pipe, currently inactive, which functions in times of heavy rains as an underwater outfall of rainwater and wastewater from the Pasaia sanitation system. The enclave is hardly visible from the ground and to access the site you have to descend obliquely along the edge of the cliff (45 m drop) and then rope down the front plate a vertical length of -8 m. The front plate of the cliff is formed by a resistant stratum of sandstone from the Jaizkibel Formation (of Eocene age). The current cascading upwelling constitutes a spillway of a small channel existing in the tunnel that crosses the mountain. The biological samplings carried out provided diverse data of interest, hydrogeological and faunal, which we report in a preliminary way.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

The cavity under study develops in dolomite and stratified pink dolomitic limestone of Danian age... more The cavity under study develops in dolomite and stratified pink dolomitic limestone of Danian age (Paleocene, marine Tertiary). Its mouth, 2 m in diameter, is a simple abyss with an absolute vertical drop of -50 m, which gradually widens and at the base of which it forms a room 12 m in diameter, with a clean block floor and numerous parietal stalagmite flowstones. The cavity holds a diverse assemblage of cave taxa, including six troglobitic species. The work discusses the hydrogeology of the sector and describes the cavity and its fauna.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

On the coast of Mount Ulía (San Sebastián, Basque Country), near the Faro de la Plata, there is a... more On the coast of Mount Ulía (San Sebastián, Basque Country), near the Faro de la Plata, there is a small valley that ends abruptly in a cliff that falls directly into the sea. At its base there is a coastal strip, with large collapsed blocks, and at its ends subvertical plates with interstratum cavities. The rocks in which the cavities develop constitute a sequence of abyssal turbidites, with flysch facies, in which thick strata of carbonate sandstone alternate with thin intercalations of mudstone and marl (Jaizkibel Formation, Eocene age). Among the thick sandstone strata and under collapsing blocks, caves have been formed with various features of interest. They are home to a cave fauna that includes coastal and marine species that frequent cavities, cracks and anquihaline pools in the tidal flat. The work describes the cavities found and their hypogeal fauna, illustrating their most relevant features through digital photography.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

The coastline of Mount Ulía (San Sebastián, Basque Country) has numerous steep cliffs. At their b... more The coastline of Mount Ulía (San Sebastián, Basque Country) has numerous steep cliffs. At their base, the development of cavities in sandstone is frequent. A rope descent with a drop of -107 m allows access to the enclave of Usotaita 2, with several rock points and collapsed blocks. At the base of the overhanging walls, formed by thick strata of sandstone from the Jaizkibel Formation (abyssal turbidites of Eocene age), and between the blocks attached to the tips, cavities and geoforms develop, with various features of interest. The fauna found includes coastal and marine species that frequent caves, cracks and anquihaline pools in the tidal flat. Their adaptations for life in the hypogeal environment are variable. The work describes the cavities found and their hypogeal fauna, illustrating their most relevant features through digital photography.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

A rope descent from a cliff with a drop of -105 m allows access to the Usotaita enclave, located ... more A rope descent from a cliff with a drop of -105 m allows access to the Usotaita enclave, located on the coast of Mount Ulía (San Sebastián, Basque Country). The enclave has several rock points, formed by thick strata of sandstone from the Jaizkibel Formation (abyssal turbidites of Eocene age), with overhanging walls on its west side, and a small coastal strip with large collapsed blocks. At the base of the overhanging walls and between the blocks attached to the points, a set of cavities develops, with various features of interest. The caves have a fauna made up of coastal and marine species that frequent cracks, spaces under blocks, underwater caves and anquihaline pools in the tidal flat. Their adaptations for life in the subterranean environment are variable. Crustaceans (24 species), polychaetes (5 species) y molluscs (5 species) predominate, for a total of 54 taxa, 27 of them troglophiles. The work describes the cavities found and their hypogeal fauna.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

The cavity under study develops in Urgonian reef limestones (Aptian-Albian in age, early Cretaceo... more The cavity under study develops in Urgonian reef limestones (Aptian-Albian in age, early Cretaceous). It consists of a wide descending gallery, which in its final part has two internal chasms, -20 m and -12 m, and a small lower gallery. The cavity totals -44 m of unevenness and 205 m of development. It is located on the northern flank of Mount Gazume, on the bottom of the Alzolaras valley. It has numerous speleothems and various types of gours, as well as a diverse set of cave taxa, including eight troglobitic species. The work discusses the hydrogeology of the sector and describes the cavity and its fauna.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

In the NE part of Mount Gazume (Gipuzkoa, Basque Country) there is an outcrop of black dolomitic ... more In the NE part of Mount Gazume (Gipuzkoa, Basque Country) there is an outcrop of black dolomitic limestone with carniolas streaks of Jurassic age (Lías), where a group of five mines was exploited at the beginning of the 20th century, for the extraction of iron ores, which were transported by wagon and an 11.4 km aerial cable to a loading point on the coast of Zarauz. The mines caught our attention for presenting flooded areas inhabited by newts, salamanders and anurans, as well as for serving as a refuge for bats and cave-dwelling invertebrates. The largest of the mines intersects a natural limestone cavity in the subsoil, without prior communication with the surface, which totals 487 m of development of galleries and -27 m of unevenness. The cavity, crossed by a small underground river, has various speleothems and a set of cave species, including eight troglobitic species. The work describes the cavity and its fauna.troglobias. El trabajo describe la cavidad y su fauna.

Publ.Dpt.Speleol. S.C. Aranzadi , 2022

In the semi-desert region of the Bardenas (Navarra), numerous cavities are formed by piping proce... more In the semi-desert region of the Bardenas (Navarra), numerous cavities are formed by piping processes in the clay of the Tudela Formation, of Miocene age. This contributes to the modeling of the region, since the caves and sinkholes evolve by successive collapse to form gorges and gullies, which extend the dendritic network of ravines that dissect the plains and slopes of the plateaus. In the area of Caldero Sur, to the W of the Piskerra plateau, there is an area of wide ravines limited by low walls, whose morphology is scalloped by inlets and outlets, corresponding to the progressive retreat of their walls. In one of them, with a flat bottom, perforations and sinkholes have been formed that cross the walls, constituting caves and sinkholes with temporary water circulations. The piping process is very active and in a short period of time it excavates new galleries, which evolve through erosion and removal of sediments until the ground is cut. In this way piping caves are formed and destroyed, widening the ravines. The studied cave, of 54 m development and -12 m uneven, exemplifies these processes, and contains features of the different phases of speleogenesis and gallery destruction. The cavity has acicular gypsum speleothems and various geoforms. The work describes the cavity and discusses its genesis and morphological evolution.

Publ. Dpt. Espeleol. S.C. Aranzadi, 2022

In the upper central part of Mount Ulía there are several small valleys with rocks in which Eocen... more In the upper central part of Mount Ulía there are several small valleys with rocks in which Eocene carbonate sandstone strata outcrop. These sandstones are part of a flysch facies abyssal turbidite sequence that alternates thick sandstone strata with thin mudstone intercalations, called Jaizkibel Formation. In these rocks there are shelters, small cavities and numerous mesocaverns, including the cave under study. The caves have been formed by intergranular dissolution, with some cavities containing water springs and underground water circulation. Similarly, many of them have sandy detrital fillings, clastic blocks and various types of speleothems and geoforms. The cavity studied presents a set of cave species, organized in an ecosystem comparable to that found in limestone caves, with the presence of gastropod molluscs, araneids, harvestmen, isopods, diplopods, chilopods, springtails, lepidoptera, diptera, coleoptera and chiroptera. The work describes the cavity and its fauna, and discusses various aspects of its ecology and hydrogeology.

Publ. Dpt. Speleol. S.C. Aranzadi, 2022

The coastal front of Mount Ulía has steep flanks and is cut out by vertical cliffs, with numerous... more The coastal front of Mount Ulía has steep flanks and is cut out by vertical cliffs, with numerous inlets and outlets, product of the advance of normal and marine erosion. The sandstone strata (of the flysch series, of Eocene age) have a subvertical disposition and have better resisted erosion, forming prominent rock points and cliffs with a drop of more than 100 m. At its base, the detached rock blocks and plates form a thin coastal strip, battered by the waves, in the intertidal zone. In these places of difficult access there are inter-strata and coating caves, under large blocks of sandstone. The intergranular dissolution of the sandstone has fundamentally intervened in its formation, with cavities containing freshwater springs and others that invade the sea during high tides. Biological surveys carried out in the largest cavities, allowed finding various species of cave fauna, including Mystacocarida, Copepoda and Amphipoda crustaceans, which inhabit anquihaline biotopes. The caves have curious examples of speleothems and geoforms. The karstic features of these sandstone caves and the fauna that inhabits their subterranean environment are described.

Munibe (Ciencias Naturales), nº 51., 2001

We present a preliminary research on geomorphology and fauna for the study of the SUC (Superficia... more We present a preliminary research on geomorphology and fauna for the study of the SUC (Superficial Underground Compartment) in Gipuzkoa (Basque Country). The survey has taken place in coluvial deposits and hillside sediments, in two transitional biotopes, from different lithologies, dating from the Paleozoic to the Eocene Age. We offer the first data about the biocoenosis of the SUC in this area. Among the hypogeous fauna we have found out Entomobryidae springtails, Bathysciinae (Cholevidae: Leptodirinae) beetles, Rhagidiidae mites, Gnatobdellida leeches and several representatives of the edaphic environment.

Munibe (Ciencias Naturales), nº 47 , 1995

The meaning of Spreading concept is pointed. This concept indicates who very big is a cavity hori... more The meaning of Spreading concept is pointed. This concept indicates who very big is a cavity horizontaly. Spread and Deep are similar
concepts. They define the maximun length between the extrem points of a maze of galleries, in horizontal and vertical sense, respectively. The meaning of cuantitative expressions used in Speleology is commented.

Publ.Dpt-Speleol. S.C.Aranzadi, 2023

The cavity under study develops on the edge of a poljé (Liendo valley, Cantabria) very close to t... more The cavity under study develops on the edge of a poljé (Liendo valley, Cantabria) very close to the Cantabrian coast. It presents geomorphological and hydrological features that make the enclave a unique place. The Yesta cave is a springing cavity, crossed by a small underground river that pours its waters into the poljé. The surface drainage of the poljé is concentrated and disappears in a sink (ponor), to cross the limestone outcrop again and emerge in the sea. The cavity presents a curious ecosystem, which includes highly specialized troglobitic species along with troglophilic and trogloxenal forms. Its aquatic fauna stands out in a special way, with populations of leuciscids fish, eels, amphipods, mayfly naiads and aquatic larvae of other insects. The colonization of the cave river by a catadromous fish such as the European eel implies going up the subterranean waters from the sea to the poljé, then the epigeal waters of the same, and again the subterranean cave river. The Yesta cave thus presents a set of unique hydrogeological and ecological features, which are described and discussed in this work.

Publ.Dpt.Speleo. S.C.Aranzadi, 2023

La cavidad objeto de estudio está situada en la primera barra caliza de la extensa unidad hidroge... more La cavidad objeto de estudio está situada en la primera barra caliza de la extensa unidad hidrogeológica Urgoniano Sur, en el monte Sastarri (Aralar guipuzcoano). Es una cueva fósil de 220 m que posee pequeñas filtraciones, gours y lagos subterráneos. Su drenaje deriva al colector del sistema Ormazarreta-Aia iturrieta, el más importante de la sierra, el cual tiene una extensión lateral de 10,8 km y-880 m de desnivel, entre su cabecera en Navarra y la surgencia de Aia en Gipuzkoa. Se presenta una síntesis de datos biológicos y ecológicos obtenidos de prospecciones efectuadas entre 1965 y 2023. Estos datos permaneciían inéditos. La cavidad alberga un ecosistema hipógeo con más de 50 especies cavernícolas. Se describe la cavidad y su fauna.

Publ.Dpt.Speleol. S.C.Aranzadi, 2023

Prospecting carried out in various areas of the southern flank of Mount Gazume (Gipuzkoa, Basque ... more Prospecting carried out in various areas of the southern flank of Mount Gazume (Gipuzkoa, Basque Country) made it possible to find new cavities. These are found in the areas of Ezurtza, Azulegi and Bordatxo. These are old mines that exploited lodes and veins of zinc minerals included in an outcrop of Urgonian reef limestone. Part of the cavities presents natural features and other artificial ones, product of the mining excavation in the contact between the veins of zinc silicates and the enclosing limestone rock. The cavities have some species of troglobite cave fauna (pseudoscorpions, beetles) and an unusual presence of bats. The exploration and topography of three cavities of interest (one of them a chasm) is exposed. Its speleogenesis and the role played by old mines as a refuge for invertebrates and bats are discussed.

Publ.Dpt.Speleo. S.C.Aranzadi, 2023

The hypogeous environment is extensive and little known. Every year new cave networks are discove... more The hypogeous environment is extensive and little known. Every year new cave networks are discovered and explored in different lithologies, in addition to limestone. This medium constitutes a significant proportion of the earth's crust, where the void systems develop three-dimensionally in the volumes of karstificable rocks or those capable of containing caves. The Jaizkibel Formation is a sequence of abyssal turbidites of flysch facies and Eocene age, which alternates thick layers of carbonate sandstone with thin shale interbeds. Karstification processes take place in this sandstone and underground aquifers and numerous cavities (chasms, caves and shelters) have been formed, generally of modest dimensions. Throughout two decades we have discovered and explored more than 400 cavities, including extensive networks of coating caves in the coastal zone, which extend into mesocaverns and smaller voids, constituting a vast ecosystem, which is home to a wide variety of biotopes and a high diversity of cave-dwelling species. The biological surveys carried out have made it possible to gather information on a total of 135 cave-dwelling species. These include marine, littoral, anquihaline, freshwater, and terrestrial forms, with a predominance of trogloxenous and troglophilous species, but also including troglobites species, as well as extraordinarily rare and previously unreported species for the hypogeous environment globally. The paper presents a summary of the data obtained.

Publ.Dpt.Speleol. S.C.Aranzadi, 2023

The cavity under study is an old mine that exploited veins of zinc silicates and iron oxides incl... more The cavity under study is an old mine that exploited veins of zinc silicates and iron oxides included in a series of Urgonian reef limestone (Aptian-Albian in age, early Cretaceous). In its final part, the mine intercepts an internal chasm in the limestone, with a drop of -80 m, it has small water circulations and various speleothems. Its ecosystem is curious, since it has two differentiated biocenoses. Twelve trogloxenous species inhabit the mine gallery (Eptesicus serotinus bats and two Rhinolophus species, Rana temporaria anurans, three species of Lepidoptera, Limnephilidae caddisfly, tiny scavenger and fungivorous Phoridae diptera, and Dytiscidae aquatic beetles; some of them are reported for the first time for hypogeous habitats), as well as three troglophilous taxa (araneids and chilopods). In the deep zone (a natural chasm of -80 m, without previous communication with the surface and intercepted by the mine) we instead found two troglobites species of ancient origin (Neobisiidae pseudoscorpions and Leptodirinae beetles). The hydrogeological and ecological features of the mine-abyss are presented and discussed in this work.

Publ. Dpt. Speleol. S.C.Aranzadi, 2023

The sandstone of the Jaizkibel Formation forms part of an abyssal turbidite sequence of flysch fa... more The sandstone of the Jaizkibel Formation forms part of an abyssal turbidite sequence of flysch facies and Eocene age, which alternates thick strata of carbonate sandstone with thin shale intercalations. Karstification processes develop in this sandstone and underground aquifers and numerous cavities (chasms, caves and shelters) have been formed.
In the coastal chain of the Jaizkibel, Ulía and Igueldo mountains, we have explored over two decades more than 400 cavities. The largest of them reaches 258 m of gallery development and -70 m of unevenness. Likewise, tunnels of up to 1.6 km of development have been explored that cross the sandstone series and intercept groundwater and minor voids. The data obtained have been the subject of previous publications, but an overall synthesis was lacking, which we present in this paper.

Publ.Dpt.Speleol. S.C. Aranzadi, 2022

Mine galleries often intersect underground voids at different scales and can be reworked by seepa... more Mine galleries often intersect underground voids at different scales and can be reworked by seepage water. Abandoned mines, once their exploitation has ceased, can be colonized by cave organisms, both from the surface and transitional environments, as well as from the deep hypogeal environment, in different lithologies. Recent works in mines in Gipuzkoa in non-karstic Paleozoic terrains have been of great interest, with the discovery of troglobitic species of ancient origin, as well as other troglophiles, rare in caves in classic limestone karst. This has led to expanding biological research in mines, commonly relegated to the background of interest in relation to natural caves. Given the importance of iron mining in Biscay (Basque Country), we decided to prospect a mine with levels rich in iron carbonates (siderite-ankerite) included in early Cretaceous limestone in the area near Bilbao. The work carried out allowed us to find various speleothems and cave organisms, being the discovery in the underground waters of the mine of a large population of troglophilic amphipod crustaceans. The work describes the cavity and its fauna, discussing various aspects of its ecology and hydrogeology.

Publ. Dpt.Speleo. S.C.Aranzadi, 2022

In the Kolosobarne area (upper part of the central syncline of Aralar, Navarra) there is a range ... more In the Kolosobarne area (upper part of the central syncline of Aralar, Navarra) there is a range of potholes and caves. Among them, a cavity (cave-abyss) caught our attention that has an interesting set of speleothems, among which large globular stalactites stand out, made up of a type of moonmilk with a cottony texture and very hydrated. These moonmilk speleothems have been formed by the action of microorganisms. In the vicinity of the speleothems there are extensive mats of bacteria and Amoebozoa protozoa. The cavity also has a hypogeal ecosystem with unique features, with several troglobitic species. The work describes the cavity and its fauna, and discusses the origin of its curious moonmilk speleothems.

Publ.Dpt.Speleol, S.C.Aranzadi, 2022

On the cliff of Elgorri txiki (coast of Mount Ulía, San Sebastián, Basque Country), hanging +4 m ... more On the cliff of Elgorri txiki (coast of Mount Ulía, San Sebastián, Basque Country), hanging +4 m above the sea, there is an upwelling that cascades directly into the sea. The groundwater upwelling comes from an artificial canalization (San Pedro tunnel, 1.5 km long). The tunnel carries a large-diameter pipe, currently inactive, which functions in times of heavy rains as an underwater outfall of rainwater and wastewater from the Pasaia sanitation system. The enclave is hardly visible from the ground and to access the site you have to descend obliquely along the edge of the cliff (45 m drop) and then rope down the front plate a vertical length of -8 m. The front plate of the cliff is formed by a resistant stratum of sandstone from the Jaizkibel Formation (of Eocene age). The current cascading upwelling constitutes a spillway of a small channel existing in the tunnel that crosses the mountain. The biological samplings carried out provided diverse data of interest, hydrogeological and faunal, which we report in a preliminary way.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

The cavity under study develops in dolomite and stratified pink dolomitic limestone of Danian age... more The cavity under study develops in dolomite and stratified pink dolomitic limestone of Danian age (Paleocene, marine Tertiary). Its mouth, 2 m in diameter, is a simple abyss with an absolute vertical drop of -50 m, which gradually widens and at the base of which it forms a room 12 m in diameter, with a clean block floor and numerous parietal stalagmite flowstones. The cavity holds a diverse assemblage of cave taxa, including six troglobitic species. The work discusses the hydrogeology of the sector and describes the cavity and its fauna.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

On the coast of Mount Ulía (San Sebastián, Basque Country), near the Faro de la Plata, there is a... more On the coast of Mount Ulía (San Sebastián, Basque Country), near the Faro de la Plata, there is a small valley that ends abruptly in a cliff that falls directly into the sea. At its base there is a coastal strip, with large collapsed blocks, and at its ends subvertical plates with interstratum cavities. The rocks in which the cavities develop constitute a sequence of abyssal turbidites, with flysch facies, in which thick strata of carbonate sandstone alternate with thin intercalations of mudstone and marl (Jaizkibel Formation, Eocene age). Among the thick sandstone strata and under collapsing blocks, caves have been formed with various features of interest. They are home to a cave fauna that includes coastal and marine species that frequent cavities, cracks and anquihaline pools in the tidal flat. The work describes the cavities found and their hypogeal fauna, illustrating their most relevant features through digital photography.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

The coastline of Mount Ulía (San Sebastián, Basque Country) has numerous steep cliffs. At their b... more The coastline of Mount Ulía (San Sebastián, Basque Country) has numerous steep cliffs. At their base, the development of cavities in sandstone is frequent. A rope descent with a drop of -107 m allows access to the enclave of Usotaita 2, with several rock points and collapsed blocks. At the base of the overhanging walls, formed by thick strata of sandstone from the Jaizkibel Formation (abyssal turbidites of Eocene age), and between the blocks attached to the tips, cavities and geoforms develop, with various features of interest. The fauna found includes coastal and marine species that frequent caves, cracks and anquihaline pools in the tidal flat. Their adaptations for life in the hypogeal environment are variable. The work describes the cavities found and their hypogeal fauna, illustrating their most relevant features through digital photography.

Publ.Dpt.Speleol. S.C.Aranzadi, 2022

A rope descent from a cliff with a drop of -105 m allows access to the Usotaita enclave, located ... more A rope descent from a cliff with a drop of -105 m allows access to the Usotaita enclave, located on the coast of Mount Ulía (San Sebastián, Basque Country). The enclave has several rock points, formed by thick strata of sandstone from the Jaizkibel Formation (abyssal turbidites of Eocene age), with overhanging walls on its west side, and a small coastal strip with large collapsed blocks. At the base of the overhanging walls and between the blocks attached to the points, a set of cavities develops, with various features of interest. The caves have a fauna made up of coastal and marine species that frequent cracks, spaces under blocks, underwater caves and anquihaline pools in the tidal flat. Their adaptations for life in the subterranean environment are variable. Crustaceans (24 species), polychaetes (5 species) y molluscs (5 species) predominate, for a total of 54 taxa, 27 of them troglophiles. The work describes the cavities found and their hypogeal fauna.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

The cavity under study develops in Urgonian reef limestones (Aptian-Albian in age, early Cretaceo... more The cavity under study develops in Urgonian reef limestones (Aptian-Albian in age, early Cretaceous). It consists of a wide descending gallery, which in its final part has two internal chasms, -20 m and -12 m, and a small lower gallery. The cavity totals -44 m of unevenness and 205 m of development. It is located on the northern flank of Mount Gazume, on the bottom of the Alzolaras valley. It has numerous speleothems and various types of gours, as well as a diverse set of cave taxa, including eight troglobitic species. The work discusses the hydrogeology of the sector and describes the cavity and its fauna.

Publ.Dpt.Speleo. S.C.Aranzadi, 2022

In the NE part of Mount Gazume (Gipuzkoa, Basque Country) there is an outcrop of black dolomitic ... more In the NE part of Mount Gazume (Gipuzkoa, Basque Country) there is an outcrop of black dolomitic limestone with carniolas streaks of Jurassic age (Lías), where a group of five mines was exploited at the beginning of the 20th century, for the extraction of iron ores, which were transported by wagon and an 11.4 km aerial cable to a loading point on the coast of Zarauz. The mines caught our attention for presenting flooded areas inhabited by newts, salamanders and anurans, as well as for serving as a refuge for bats and cave-dwelling invertebrates. The largest of the mines intersects a natural limestone cavity in the subsoil, without prior communication with the surface, which totals 487 m of development of galleries and -27 m of unevenness. The cavity, crossed by a small underground river, has various speleothems and a set of cave species, including eight troglobitic species. The work describes the cavity and its fauna.troglobias. El trabajo describe la cavidad y su fauna.

Publ.Dpt.Speleol. S.C. Aranzadi , 2022

In the semi-desert region of the Bardenas (Navarra), numerous cavities are formed by piping proce... more In the semi-desert region of the Bardenas (Navarra), numerous cavities are formed by piping processes in the clay of the Tudela Formation, of Miocene age. This contributes to the modeling of the region, since the caves and sinkholes evolve by successive collapse to form gorges and gullies, which extend the dendritic network of ravines that dissect the plains and slopes of the plateaus. In the area of Caldero Sur, to the W of the Piskerra plateau, there is an area of wide ravines limited by low walls, whose morphology is scalloped by inlets and outlets, corresponding to the progressive retreat of their walls. In one of them, with a flat bottom, perforations and sinkholes have been formed that cross the walls, constituting caves and sinkholes with temporary water circulations. The piping process is very active and in a short period of time it excavates new galleries, which evolve through erosion and removal of sediments until the ground is cut. In this way piping caves are formed and destroyed, widening the ravines. The studied cave, of 54 m development and -12 m uneven, exemplifies these processes, and contains features of the different phases of speleogenesis and gallery destruction. The cavity has acicular gypsum speleothems and various geoforms. The work describes the cavity and discusses its genesis and morphological evolution.

Publ. Dpt. Espeleol. S.C. Aranzadi, 2022

In the upper central part of Mount Ulía there are several small valleys with rocks in which Eocen... more In the upper central part of Mount Ulía there are several small valleys with rocks in which Eocene carbonate sandstone strata outcrop. These sandstones are part of a flysch facies abyssal turbidite sequence that alternates thick sandstone strata with thin mudstone intercalations, called Jaizkibel Formation. In these rocks there are shelters, small cavities and numerous mesocaverns, including the cave under study. The caves have been formed by intergranular dissolution, with some cavities containing water springs and underground water circulation. Similarly, many of them have sandy detrital fillings, clastic blocks and various types of speleothems and geoforms. The cavity studied presents a set of cave species, organized in an ecosystem comparable to that found in limestone caves, with the presence of gastropod molluscs, araneids, harvestmen, isopods, diplopods, chilopods, springtails, lepidoptera, diptera, coleoptera and chiroptera. The work describes the cavity and its fauna, and discusses various aspects of its ecology and hydrogeology.

Publ. Dpt. Speleol. S.C. Aranzadi, 2022

The coastal front of Mount Ulía has steep flanks and is cut out by vertical cliffs, with numerous... more The coastal front of Mount Ulía has steep flanks and is cut out by vertical cliffs, with numerous inlets and outlets, product of the advance of normal and marine erosion. The sandstone strata (of the flysch series, of Eocene age) have a subvertical disposition and have better resisted erosion, forming prominent rock points and cliffs with a drop of more than 100 m. At its base, the detached rock blocks and plates form a thin coastal strip, battered by the waves, in the intertidal zone. In these places of difficult access there are inter-strata and coating caves, under large blocks of sandstone. The intergranular dissolution of the sandstone has fundamentally intervened in its formation, with cavities containing freshwater springs and others that invade the sea during high tides. Biological surveys carried out in the largest cavities, allowed finding various species of cave fauna, including Mystacocarida, Copepoda and Amphipoda crustaceans, which inhabit anquihaline biotopes. The caves have curious examples of speleothems and geoforms. The karstic features of these sandstone caves and the fauna that inhabits their subterranean environment are described.

Munibe (Ciencias Naturales), nº 51., 2001

We present a preliminary research on geomorphology and fauna for the study of the SUC (Superficia... more We present a preliminary research on geomorphology and fauna for the study of the SUC (Superficial Underground Compartment) in Gipuzkoa (Basque Country). The survey has taken place in coluvial deposits and hillside sediments, in two transitional biotopes, from different lithologies, dating from the Paleozoic to the Eocene Age. We offer the first data about the biocoenosis of the SUC in this area. Among the hypogeous fauna we have found out Entomobryidae springtails, Bathysciinae (Cholevidae: Leptodirinae) beetles, Rhagidiidae mites, Gnatobdellida leeches and several representatives of the edaphic environment.

Munibe (Ciencias Naturales), nº 47 , 1995

The meaning of Spreading concept is pointed. This concept indicates who very big is a cavity hori... more The meaning of Spreading concept is pointed. This concept indicates who very big is a cavity horizontaly. Spread and Deep are similar
concepts. They define the maximun length between the extrem points of a maze of galleries, in horizontal and vertical sense, respectively. The meaning of cuantitative expressions used in Speleology is commented.

Se presenta una visión actualizada de las aguas subterráneas contenidas en acuíferos (formaciones... more Se presenta una visión actualizada de las aguas subterráneas contenidas en acuíferos (formaciones geológicas permeables) en zonas kársticas de Venezuela. Muchas de ellas ocupan posiciones de cabecera de cuenca y son altamente vulnerables a la contaminación. Poseen ecosistemas con especies cavernícolas singulares y únicas en el mundo, incluyendo formas troglobias pertenecientes a linajes de antiguo origen, de gran interés zoológico, paleogeográfico y evolutivo. La salud de estos acuíferos es a su vez importante por su creciente aporte al suministro de agua para el agro y las poblaciones de su entorno. Se describen de manera sistemática los distintos tipos de karst y su distribución en el territorio, señalando los sistemas de cavernas que albergan los ríos subterráneos y acuíferos kársticos más caudalosos. A su vez se presenta una breve sinopsis de ecología subterránea, incluyendo datos y referencias sobre las especies cavernícolas más relevantes. El medio físico posee también rasgos geológicos e hidrológicos sobresalientes porque se desarrolla sobre extensos volúmenes de roca en el subsuelo. En estos sistemas se forman galerías y vacíos por disolución, pero también se deposita una gran diversidad de minerales secundarios en forma de espeleotemas, de vistosos diseños y variadas composiciones mineralógicas, algunos de los cuales resultaron al momento de su descripción ser desconocidos en otra región del planeta. Las aguas subterráneas constituyen, además, recursos hídricos de gran importancia para el agro, la industria y el consumo humano, particularmente en zonas áridas, de marcada estacionalidad o donde los ríos de superficie están contaminados. Por ello trataremos aspectos relacionados con el estado actual, la calidad de las aguas y la conservación de los recursos hídricos subterráneos.