New insights on the Carburangeli Cave speleogenesis: a flank margin cave in Northern Sicily (Italy)

Flank margin caves form in coastal regions by mixing dissolution. Their development is controlled by the position of the freshsalt water mixing boundary, which in turn, is related to sea-level position. They are characterized by a typical cave pattern and cave-wall morphologies and represent good indicators of past sea levels. This contribution shows the results of recent studies conducted in the Carburangeli Cave, a small sub-horizontal cavity developed in Northern Sicily, close to Palermo. This cave was firstly known for paleontological and archaeological findings and for these reasons, along with its speleological and biological interest, a Nature Reserve has been instituted by the Sicil…

New insights on secondary minerals from Italian sulfuric acid caves

Sulfuric acid minerals are important clues to identify the speleogenetic phases of hypogene caves. Italy hosts ~25% of the known worldwide sulfuric acid speleogenetic (SAS) systems, including the famous well-studied Frasassi, Monte Cucco, and Acquasanta Terme caves. Nevertheless, other underground environments have been analyzed, and interesting mineralogical assemblages were found associated with peculiar geomorphological features such as cupolas, replacement pockets, feeders, sulfuric notches, and sub-horizontal levels. In this paper, we focused on 15 cave systems located along the Apennine Chain, in Apulia, in Sicily, and in Sardinia, where copious SAS minerals were observed. Some of the…

Secondary minerals from salt caves in the Atacama Desert (Chile): a hyperarid and hypersaline environment with potential analogies to the Martian subsurface

Over the past 15 years several expeditions by French, American and especially Italian cavers have unveiled over 50 caves in the Cordillera de la Sal (Atacama Desert, Northern Chile). Many of these caves contain a variety of speleothems and minerals, some of which have rarely been observed within karst systems. Most of the secondary deposits in these caves are composed of halite, but also other halide, carbonate, sulphate, nitrate, phosphate, and silicate minerals have been found. Among the sixteen cave mineral species recognized, atacamite, darapskite, blödite, leonite, anhydrite, and especially antarcticite are worth mentioning. In one of the samples an unknown Ca-Sr-bearing chloride miner…

The influence of light attenuation on the biogeomorphology of a marine karst cave: A case study of Puerto Princesa Underground River, Palawan, the Philippines

Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site.\ud \ud Organic gr…

An Overview of the Hypogene Caves of Sicily

Karst in Sicily develops in both Messinian gypsum and Mesozoic or Tertiary limestone rocks. Caves are also found in the basalts of Mount Etna. Except for some rare cases, until recently most caves developed in limestone were considered to be of epigenetic origin. The discovery of gypsum in some of these caves, and especially detailed morphological studies, have allowed defining a hypogenic origin for a dozen of caves up to now. In some of these, the hypogenic evidences are very clear, while others remain in doubt because of the widespread presence of well-developed condensation-corrosion morphologies not necessarily related to hydrothermal fluids. This paper reports the present knowledge of…

Evaporite karst in Italy: A review

none 16 si Although outcropping rarely in Italy, evaporite (gypsum and anhydrite) karst has been described in detail since the early 20th century. Gypsum caves are now known from almost all Italian regions, but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum mines in Piedmont. During the late 80s and 90s several multidisciplinary studies were carried out in many gypsum areas, resulting in a comprehensive overview, promoting further research in these special karst regions. More recent and detailed studies focused…

The Coastal Sulfuric Acid Cave System of Santa Cesarea Terme (Southern Italy)

Santa Cesarea Terme in Salento is the only area in which hypogenic caves have been recognized in the Apulia region. In this spa area, the rising of sulfidic thermal waters that mix with both recent fresh infiltration waters and coastal salt water has formed four active sulfuric acid speleogenesis (SAS) caves. These caves are characterized by the typical set of sulfuric acid meso- and micromorphologies, and also by the presence of both gypsum and native sulfur. In all caves, biofilms are visible in the sulfidic thermal waters and on the cave walls.

Sulfuric acid speleogenesis (SAS) close to the water table: Examples from southern France, Austria, and Sicily

Caves formed by rising sulfuric waters have been described from all over the world in a wide variety of climate settings, from arid regions to mid-latitude and alpine areas. H2S is generally formed at depth by reduction of sulfates in the presence of hydrocarbons and is transported in solution through the deep aquifers. In tectonically disturbed areas major fractures eventually allow these H2S-bearing fluids to rise to the surface where oxidation processes can become active producing sulfuric acid. This extremely strong acid reacts with the carbonate bedrock creating caves, some of which are among the largest and most spectacular in the world. Production of sulfuric acid mostly occurs at or…

Guano-related phosphate-rich minerals in European caves

International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …

Speleothems in a north Cuban cave register sea-level changes and Pleistocene uplift rates

A review on hypogene caves in Italy

Although hypogene cave systems have been described since the beginning of the 20th century, the importance in speleogenesis of ascending fluids that acquired their aggressiveness from in-depth sources has been fully realized only in the last decades. Aggressiveness of waters can be related to carbonic and sulfuric acids and the related corrosion-dissolution processes give rise to different types of caves and underground morphologies. The abundance of hydrothermal springs and associated travertine deposits, and the widespread interaction between volcanic or sub-volcanic phenomena and karst in many sectors of the Italian peninsula are a strong evidence of hypogene speleogenesis. Furthermore, …

Sulfuric acid caves of Italy: A review

Abstract In Italy, especially along the Apennine Chain, numerous active and inactive sulfuric acid speleogenetic (SAS) caves have been documented in the last two decades. Here we present an overview of these peculiar hypogene systems, illustrating their main geomorphological and mineralogical features, and the microbial signatures observed in the active underground environment. SAS caves are widely distributed in the northern and central Apennines, whereas they are less abundant in the southern Apennines, in the Apulian foreland, in Sicily and in Sardinia. Their location is significantly influenced by lithological and structural rock properties, as they occur in carbonate areas where acidic…