Search results for "Speleogenesis"
showing 10 items of 15 documents
An Overview of the Hypogene Caves of Sicily
2017
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…
L'impact méconnu des chauves-souris et du guano dans l'évolution morphologique tardive des cavernes
2016
The little known impact of bats and bat guano in the late stages of cave morphogenesis. Bats are considered as symbolic caves inhabitants. The colonies, sometimes huge, may occupy caves through long periods. Large guano deposits were accumulated. Some have been mined for phosphates, either by hand or at the industrial scale. Bats impact is triple: breathing releases CO2, urine is corrosive, and guano mineralization releases acids (carbonic, nitric, sulfuric, and phosphoric). Such aggressive compounds have an effect on carbonate rock and flowstones, either by direct ground corrosion at the contact of the guano, or by condensation-corrosion on walls and ceilings. The speleogenetic impact of t…
New knowledge on the Monte Conca gypsum karst system (Central-western Sicily, Italy)
2011
The Monte Conca karst system is located in Central-Western Sicily, where Messinian evaporites are widespread. Here, the evaporites lie on lower Messinian-middle Serravallian clayey-marly-sandy deposits and are overlain locally by Pliocene marly limestones. These successions are affected by E-W, and to a lesser degree N-S and NW-SE, high-angle faults that have also produced lateral contacts between the gypsum units and the clayey-marly deposits. The cave passages reachaltogether about 2.4 km in lengthand 130 m in depth, and the system consists of a sink cave, a resurgence and a relict resurgence. At large scale it is characterized by superimposed levels of sub-horizontal galleries connected …
Acqua Fitusa cave: An example of inactive water-table sulphuric acid cave in Central Sicily
2012
Description of the sulphuric acid cave in Sicily (see pdf attached)
Upper pleistocene interstratal piping-cave speleogenesis: The seso cave system (central pyrenees, northern spain)
2015
The Seso Cave System (SCS, South Central Pyrenees, Northeastern Spain) develops in poorly soluble marly interstratum between limestone beds of Eocene age. We propose an innovative and singular pseudokarstic speleogenetic model under vadose conditions based on cave morphological evidence, physicochemical and mineralogical characteristics of the Eocene marly host rock, U-Th dating of cave deposits, and local geological and geomorphological information. Eocene marls are shown to be sensitive to dispersion processes supported by their high clay content and the high concentration of sodium and low electrical conductivity in the seepage water. Runoff inside the cave results from water that infilt…
Speleogenesis of the Hermannshöhle cave system (Austria): Constraints from 230Th/U-dating and palaeomagnetic analysis
2015
Hermannshöhle is a show cave located near Kirchberg/Wechsel in Lower Austria. Together with three nearby and genetically connected caves, it forms the Hermannshöhlen cave system (HHS). With a length of 5 km, the HHS is the longest cave in the Lower Austroalpine unit. It is arranged as an extreme three-dimensional maze on a ground area of 200 x 200 x 82 m. Speleothems are abundant in this cave and represent the focus of this study. Low carbon isotope values indicate the presence of a soil-covered catchment above the HHS during times of speleothem deposition. 28 samples were dated by the 230Th/U-method and, in combination with palaeomagnetic data from a 5 m-high sediment profile, indicate mul…
Flank Margin Caves In Telogenetic Limestones In Italy
2017
Almost 20% of Italy is characterized by the outcropping of carbonate massifs ranging in age from Cambrian to Quaternary. Coastal karst is present in many Italian regions: from North-East to South and West: the Gulf of Trieste, the Conero (South of Ancona, Marche), the Adriatic coast of Apulia including Gargano, Murge and Salento, Maratea in Basilicata, Cilento in Campania, Circeo and Gaeta in Latium, Argentario and Giannutri Island in Tuscany, the southernmost part of the Ligurian Alps, Palermo Mts., San Vito Lo Capo, Syracuse coast and Marettimo Island in Sicily, and, especially, in Sardinia, which has carbonate rocks touching the sea along the coast of Balai near Porto Torres, Capo Caccia…
Hypogenic caves of Sicily (Southern Italy)
2013
First results of a study on hypogenic caves in Sicily are presented. Inactive water-table sulphuric acid caves and 3D maze caves linked to rising of thermal waters rich in H2S were recognized. Cave patterns are guided by structural planes, medium and small scale morphological features are due mainly to condensation-corrosion processes. Calcite and gypsum represent the most common cave minerals. Different types of phosphates linked to the presence of large bat guano deposits were analyzed.
Sulfuric acid speleogenesis (SAS) close to the water table: Examples from southern France, Austria, and Sicily
2016
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…
Sulfuric acid caves of Italy: A review
2019
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…