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Granite massifs often contain caves, with dimensions ranging from a few meters up to 1,000 m, also referred to as pseudokarst. The speleothems in such caves are mostly composed of either Si-rich (commonly opal-A) or Al-rich authigenic mineraloids. Whereas the formation and geochemical composition of opal-A biospeleothems have been studied and are fairly well understood, knowledge on the Al-rich analogues is scarce. This work reports for the first time a study on the composition, accretion process, age and growth rate of an Al-rich speleothem type flowstone from the A Trapa Cave System (Galicia, NW Spain), developed in a granite cave. To understand the growth process, trickling water was analyzed and the deposition environment inside the cave was characterized. We found that the speleothems are alternating Si- and Al-rich layered deposits formed between 1,635 ± 75 and 1,243 ± 58 cal BP by percolating water that carries underground mineral grains, dissolved ions, and organic matter from soil and the weathered bedrock above the cave.

Granite massifs often contain caves, with dimensions ranging from a few meters up to 1,000 m, also referred to as pseudokarst. The speleothems in such caves are mostly composed of either Si-rich (commonly opal-A) or Al-rich authigenic mineraloids. Whereas the formation and geochemical composition of opal-A biospeleothems have been studied and are fairly well understood, knowledge on the Al-rich analogues is scarce. This work reports for the first time a study on the composition, accretion process, age and growth rate of an Al-rich speleothem type flowstone from the A Trapa Cave System (Galicia, NW Spain), developed in a granite cave. To understand the growth process, trickling water was analyzed and the deposition environment inside the cave was characterized. We found that the speleothems are alternating Si- and Al-rich layered deposits formed between 1,635 ± 75 and 1,243 ± 58 cal BP by percolating water that carries underground mineral grains, dissolved ions, and organic matter from soil and the weathered bedrock above the cave. [ABSTRACT FROM AUTHOR]

A totally new corrosion form has been recently observed inside the Natuturingam cave (better known as Puerto Princesa Underground River) in Palawan (Philippines): the guano holes. They consist of perfectly rounded holes, 4–5 cm wide and up to 10–15 cm deep, developing over a flat limestone surfaces covered by a thin layer of fresh guano

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 mineral has also been discovered, but it has not been possible to carry out detailed mineralogical analyses. These often-rare minerals have formed in this region due to the very extreme hyperarid and salt-rich environment. This research reports the mineralogical results and proposes the genetical mechanisms leading to the formation of antarcticite, powdery anhydrite, and the paragenesis of the halite-darapskite-blödite. This study also shows that Atacama caves may be excellent analogues to study weathering processes and subsurface secondary minerals in hyperarid and hypersaline environments on Mars.

Kahf Kharrat Najem Cave is a small cave in United Arab Emirates (UAE) that hosts a bat colony which is the source of guano deposits and peculiar centimeter-long yellowish stalactites. The mineralogy and geochemistry of these deposits were analyzed using powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopic microanalysis (EDX), scanning electron microscope (SEM), and stable isotope composition (δ13C and δ15N). Urea CO(NH2)2 was found to be the main compound of these stalactites, while allantoin C4H6N4O3 was found to be an accessory urea byproduct. This paper is the first to mention allantoin in a cave environment. We also identified rare sulfate minerals (aphthitalite, alunite) and phosphates that probably correspond to the archerite-biphosphammite series. The occurrence of these rare bat-related minerals is due to the extremely dry conditions in the cave, which accounts for the extraordinary preservation of the guano deposits and allows for the crystallization of these very soluble minerals.

Abstract This study investigates the mineral, crystallographic and chemical characteristics of sulfate and phosphate speleothems and the physicochemical conditions that enabled their development in caves in the banded iron formations and lateritic duricrusts of the Carajás region, in eastern Amazonia, Brazil. The X-ray powder diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), electron microprobe (EMPA), thermogravimetry, as well as Raman, infrared, and Mössbauer spectroscopy techniques were used in this investigation. The chemical composition analyses of the guano and cave dripping water were performed by atomic absorption spectroscopy (AAS), spectrophotometry and multi-parameter probe. The results of the analyses revealed aluminite, felsőbányaite, jarosite, spheniscidite, phosphosiderite and amorphous phosphatic material in coralloid type speleothems while spheniscidite, phosphosiderite and strengite were identified in stalactite type speleothems. These minerals are the product of the direct chemical reaction of the bat guano, urine and bones accumulation (with K+, Na+, Ca 2 +, Mg 2 +, NH 4 +) and the iron and aluminum supplied by the lateritic duricrusts from the walls, ceilings and floor of the caves, into a mixture of sulfates and phosphates. Highlights • Were investigated the mineral, crystallographic and chemical characteristics of speleothems. • Aluminite, felsőbányaite, jarosite, phosphosiderite, strengite, and spheniscidite. • The guano and bones supply Na+, K+, Ca2+, Mg2+ and NH 4 + and the lateritic duricrust supply Al and Fe. [ABSTRACT FROM AUTHOR]

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 mineral has also been discovered, but it has not been possible to carry out detailed mineralogical analyses. These often-rare minerals have formed in this region due to the very extreme hyperarid and salt-rich environment. This research reports the mineralogical results and proposes the genetical mechanisms leading to the formation of antarcticite, powdery anhydrite, and the paragenesis of the halite-darapskiteblödite. This study also shows that Atacama caves may be excellent analogues to study weathering processes and subsurface secondary minerals in hyperarid and hypersaline environments on Mars. [ABSTRACT FROM AUTHOR]

Kahf Kharrat Najem Cave is a small cave in United Arab Emirates (UAE) that hosts a bat colony which is the source of guano deposits and peculiar centimeter-long yellowish stalactites. The mineralogy and geochemistry of these deposits were analyzed using powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopic microanalysis (EDX), scanning electron microscope (SEM), and stable isotope composition (δ13C and δ15N). Urea CO(NH2)2 was found to be the main compound of these stalactites, while allantoin C4H6N4O3 was found to be an accessory urea byproduct. This paper is the first to mention allantoin in a cave environment. We also identified rare sulfate minerals (aphthitalite, alunite) and phosphates that probably correspond to the archerite-biphosphammite series. The occurrence of these rare bat-related minerals is due to the extremely dry conditions in the cave, which accounts for the extraordinary preservation of the guano deposits and allows for the crystallization of these very soluble minerals. [ABSTRACT FROM AUTHOR]

Perhaps man’s first motivation to explore caves, beyond using them as shelter, was the search for substances that were not availableelsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interestingfrom the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a singlecompound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although onlya limited number of natural cavities have been investigated in detail, about 350 cave minerals have already been observed, someof which are new to science. The presence of such unexpected richness is a direct consequence of the variety of rocks traversedby water or other fluids before entering a cave and the sediments therein. Different cave environments allow the development ofvarious minerogenetic mechanisms, the most important of which are double exchange reactions, evaporation, oxidation, hydrationdehydration,sublimation, deposition from aerosols and vapors, and segregation. The cave temperature and pH/Eh strictly controlmost of them, although some are driven by microorganisms. The cave environment, due to its long-term stability, can sometimesallow for the development of huge euhedral crystals, such as those found in the Naica caves (Mexico), but the presence of extremelysmall yet complex aggregates of different minerals is far more common. Future development in the field of cave mineralogy will likelybe focused mainly on hydrothermal and sulfuric-acid caves and on the role played by micro-organisms in controlling some of the mostimportant minerogenetic processes in caves.

With the discovery of the József-hegy Cave, a cave of hydrothermal origin with an abundance of minerals unknown so far in Hungarycame to light. Diversity and the frequency of the occurrence of crystals make this cave similar to the Lechuguilla Cave, even ifthe dimensions of the mineral precipitations and the passages do not compare in scale. The variety and mass of carbonates andsulphates are surprising. This paper describes the minerals and speleothems of the József-hegy Cave, their occurrence and genesis,including determined ages. The 41 U/Th measurements suggest that speleothems begun to develop in the upper level of the cavemore than 350 ka ago. Some of these dated old speleothems were developing in dry passages, thus the uppermost passages of theJózsef-hegy Cave have been dry at least for 350 ka. The karst water level was still at the main passage 200 ka ago and dropped to120 m asl by the time of ~100 ka before present.

The secondary minerals from Iza Cave result from the interactions of karst water and/or cave atmosphere with a variety of sedimentaryand metamorphic rocks. The cave passages expose at various extents Eocene limestones and conglomerates, Oligocene blackshales, Upper Precambrian micaschists, marble and dolomitic marble and associated ore deposits. Twelve secondary mineralsidentified in the cave (carbonates, sulfates, phosphates, oxides and hydroxides, and silicates) are presented in this study. Calcite,aragonite, gypsum, brushite and hydroxylapatite are the components of common speleothems in the limestone, dolomite andconglomerate areas of the cave. Ankerite crusts are related to areas with pyrite mineralization within the metamorphic carbonaterocks. Goethite, jarosite, hematite and gypsum form various speleothems in the sectors within micaschists and conglomerates. Largeweathering deposits occurring in passage areas developed within micaschists consist of illite, kaolinite, jarosite, goethite, gypsumand alunite. The extent of the weathering deposits occurring on non-karst rocks in the underground environment makes this cave aparticularly interesting site for studies of water-rock interactions.

Cioclovina Cave in Romania’s Southern Carpathians is a world-renowned cave site for its paleontological, anthropological, andmineralogical (type locality of ardealite) finds. To date, over 25 mineral species have been documented, some unusual for a caveenvironment. This paper presents details on the occurrence of collinsite [Ca2(Mg,Fe2+)(PO4)2·2H2O], atacamite [Cu22+Cl(OH)3], andkröhnkite [Na2Cu2+(SO4)2·2H2O] based on single-crystal X-ray diffraction, electron microprobe, stable isotope analyses, and scanningelectron microscope imaging. This is the first reported occurrence of kröhnkite in a cave environment. Atacamite representsthe weathering product (in the presence of Lower-Cretaceous limestone-derived chlorine) of copper minerals washed into the cavefrom nearby ore bodies. Atacamite and kröhnkite have similar sources for copper and chlorine, whereas sodium probably originatesfrom weathered Precambrian and Permian detrital rocks. Collinsite is believed to have precipitated from bat guano in a damp, nearneutralpH environment. The results show the following sequence of precipitation: ardealite-brushite-(gypsum)-atacamite-kröhnkite.This suggests that the observed mineral paragenesis is controlled by the neutralization potential of the host-rock mineralogy and theconcentrations of Ca, Cl, Cu, and Na.

By means of diphractometric X-rays analyses on powders, we emphasize an association of minerals in the Limanu Cave from South Dobrogea, made up of hydroxylapatite, brushite, calcite, gypsum and dolomite as the main minerals and quartz and illite as secondary minerals

After diffractometric X-ray analyses through the powder method, made on sampling tests from two caves in the Perşani Mountains karst, mineral associations made up of calcite, magnesium calcite, aragonite, dolomite, brushite, hydroxylapatite, carbonate-hydroxylapatite, gypsum and α-quartz were emphasized. Tables are presented with the resulting data from the diffractometric analyses, including the computed parameters of the elementary cells of each mineral species

By means of RX and IR analyses we emphasize an associations of minerals in Peştera Liliecilor (Liliecilor Cave) from the Olteţului Gorges made up by hydroxylapatite, carbonate-hydroxylapatite, ardealite, brushite and gypsum as the main minerals and quartz and illite as secondary minerals. In the final part of the paper, the authors present some opinions about the possible genesis of the mineral species

This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Muscă Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al10.91Fe3+0.06Na0.1Ca0.02Mg0.08)Σ=11.17[(PO4)8.78(SiO4)0.056]Σ=8.83(OH)6.17·43.79H2O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) Å, b = 15.00(4) Å, c = 22.661(1) Å, and V = 3660.62 Å3 (Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40° and 200°C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.

The usual tools are X-ray powder diffraction, the optical microscope, and the scanning electron microscope. X-ray diffraction gives a definitive fingerprint by which the mineral can be identified by comparison with a catalog of reference patterns. However, samples must be ground to powder and unstable hydrated minerals may decompose before analysis is complete. Raman spectroscopy also provides a fingerprint useful for mineral identification but with the additional advantage that some a-priori interpretation of the spectra is possible (distinguishing carbonates from sulfates, for example). Because excitation of the spectra is by means of a laser beam, it is possible to measure the spectra of samples in sealed glass containers, thus preserving unstable samples. Because laser beams can be focused, spectra can be obtained from individual grains. New technology has reduced the size of the instrument and also the sensitivity of the optical system to vibration and transport so that a portable instrument has become possible. The sampling probe is linked to the spectrometer by optical fibers so that large specimens can be examined without damage. Comparative spectra of common cave minerals demonstrate the value of Raman spectra as an identification technique.

Kenya is one of the few countries in which karst cavities are scarce with respect to volcanic ones, which are widespread throughout the whole country. The great variability in lava composition allowed the evolution of very different cavities, some of which are amongst the largest lava tubes of the world. As normal for such a kind of cave, the hosted speleothems and cave minerals are scarce but important from the minerogenetic point of view. Anyway up to present no specific mineralogical research have been carried out therein. During the 8th International Symposium on Volcanospeleology, held in Nairobi in February 1998, some of the most important volcanic caves of Kenya have been visited and their speleothems and/or chemical deposits sampled: most of them were related to thick guano deposits once present inside these cavities. Speleothems mainly consisted of opal or gypsum, while the deposits related to guano often resulted in a mixture of sulphates and phosphates. The analyses confirmed the great variability in the minerogenetic mechanisms active inside the volcanic caves, which consequently allow the evolution of several different minerals even if the total amount of chemical deposit is scarce. Among the observed minerals kogarkoite, phillipsite and hydroxyapophyllite, must be cited because they are new cave minerals not only for the lava tubes of Kenya, but also for the world cave environment. The achieved results are compared with the available random data from previous literature in order to allow an updated overview on the secondary cave minerals of Kenya.

The oxidation of hydrocarbons and sulfide sources (H 2 S, pyrite) produces sulfuric acid that strongly reacts with bedrock, causing limestone dissolution and complex interactions with other minerals from the bedrock or from cave fillings, mainly clays. This type of cave development, known as Sulfuric Acid Speleogenesis (SAS), is a subcategory of hypogene speleogenesis, where aggressive water rises from depth. It also produces uncommon minerals, mainly sulfates, the typical byproducts of SAS. Baume Galinière is located in Southern France, in the Vaucluse spring watershed. This small maze cave displays characteristic SAS features such as corrosion notches, calcite geodes, iron crusts, and various sulfate minerals. Sulfur isotopes of SAS byproducts (jarosite and gypsum) clearly show they derive from pyrite oxidation. Using XRD and micro-Raman spectroscopy, thirteen minerals were identified, including elemental sulfur, calcite, quartz, pyrite, goethite, gypsum, and fibroferrite, plus all of the six members of the jarosite subgroup (jarosite, argentojarosite, ammoniojarosite, hydroniumjarosite, natrojarosite, plumbojarosite). The Baume Galinière deposits are the first documented cave occurrence of argentojarosite and the second known occurrence of plumbojarosite, hydronium jarosite, ammoniojarosite, and fibroferrite. In the Vaucluse watershed, there were numerous upwellings of deep water along major faults, located at the contact of the karstic aquifer and the overlying impervious covers. The mixing of deep and meteoric waters at shallow depths caused pyrite depositions in numerous caves, including Baume Galinière. Sulfuric Acid Speleogenesis occurred later after base-level drop, when the cave was under shallow phreatic conditions then in the vadose zone, with oxidation of pyrites generating sulfuric acid. Attenuated oxidation is still occurring through condensation of moisture from incoming air. Baume Galinière Cave records the position of the semi-impervious paleo-cover and documents its retreat in relationship to valley incision caused by uplift and tilting of the Vaucluse block during the Neogene. [ABSTRACT FROM AUTHOR]

During the last Conference of the FEALC (Speleological Federation of Latin America and Caribbean Islands) which was held in the town of Malargue, Mendoza, in February 1997, two volcanic caves not far from that town were visited and sampled for cave mineral studies. The first cave (Cueva del Tigre) opens close to the Llancanelo lake, some 40 kms far from Malargue and it is a classical lava tube. Part of the walls and of the fallen lava blocks are covered by white translucent fibres and grains. The second visited cave is a small tectonic cavity opened on a lava bed some 100 km southward of Malargue. The cave “El Abrigo de el Manzano” is long no more than 10-12 meters with an average width of 3 meters and it hosts several bird nests, the larger of which is characterized by the presence of a relatively thick pale yellow, pale pink flowstone. Small broken or fallen samples of the secondary chemical deposits of both these caves have been collected in order to detect their mineralogical composition. In the present paper the results of the detailed mineralogical analyses carried out on the sampled material are shortly reported. In the Cueva del Tigre lava tube the main detected minerals are Sylvite, Thenardite, Bloedite and Kieserite, all related to the peculiar dry climate of that area. The flowstone of “El Abrigo de el Manzano” consists of a rather complex admixture of several minerals, the large majority of which are phosphates but also sulfates and silicates, not all yet identified. The origin of all these minerals is related to the interaction between bird guano and volcanic rock.

Cova des Pas de Vallgornera (CPV) is the premier cave of the Balearic Archipelago. Over 74 km of passages develop within two carbonate lithofacies (reef front and back reef), which ultimately control the patterns of the cave and to some degree its mineral infilling. The diversity of speleothem-forming minerals is four times greater around or within hypogenerelated features (vents, rims, cupolas), compared to any other vadose passages in the cave. The mineralogy of speleothems (crusts, nodules, crystals, earthy masses) associated with hypogene features in the seaward upper maze of Sector F is characterized by the presence of aragonite, ankerite, huntite, clay minerals, and quartz. In the Tragus and Nord sectors, however, the dominant mineral is dolomite, along with aragonite, celestine, huntite, clay minerals, and quartz. Calcite is by far the most ubiquitous mineral throughout the cave. Detailed macroscopic and scanning electron microanalysis and imaging have permitted the investigation of textural relationships between the minerals associated with vents, rims, and vent's roof and walls. These studies along with morphological and stable isotope analyses confirm that not all minerals are connected with a hypogene stage in the cave evolution, and furthermore, none of them appears to be sulfuric acid by-products. Instead, the mineral assemblages documented in speleothems from CPV clearly support at least three speleogenetic pathways, namely seacoast mixing, ascending of warm groundwaters, and meteoric recharge (vadose). Thus, cave minerals in Cova des Pas de Vallgornera hold the keys to reconstruction and understanding of processes and conditions under which they precipitated, allowing to establish their relationship with various speleogenetic pathways. [ABSTRACT FROM AUTHOR]

The “espada” speleothems of Cueva de las Espadas (Naica Mine, Chihuahua, Mexico) comprise a high-purity selenite core overlain by successive deposits of calcite, gypsum and aragonite. Gypsum precipitated under water from a hydrothermal solution (~58°C) when the water table was above the cave level ca. 57ka, during the last glaciation, and some intervals during deglaciation and the Holocene. Aragonite was deposited at lower temperatures (~26°C) in a perched lake occupying the cave bottom, when the water table dropped below the cave level during brief dry intervals during deglaciation and the early Holocene. The isotopic composition of gypsum water of crystallization shows that the deglaciation–Holocene aquifer water was enriched in deuterium by 12.8–8.7‰ relative to water from the last glaciation. This is attributed to an increased relative moisture contribution from the Gulf of Mexico during deglaciation and the Holocene compared to the last glaciation. This indicates that drier conditions occurred in the Naica area during the Holocene than around 57ka. Furthermore, trace element analyses of gypsum served to deduce the circulation regime of the Naica aquifer during the past 60,000yr, and also suggest that higher aquifer recharge occurred during the last glaciation. [ABSTRACT FROM AUTHOR]

Abstract: Whereas most karstic caves worldwide are formed by carbonic acid, a small but significant number of sub-surface cavities are the product of sulfuric acid speleogenesis (SAS). In the Eastern Alps, no cave has so far been attributed to this type. In this multidisciplinary study we demonstrate that Kraushöhle in northern Styria was indeed formed by SAS. The cave pattern shows individual chambers, 3D-mazes and blind galleries, as well as typical SAS morphologies such as cupolas, gypsum replacement pockets, corrosion notches and convection niches. “Ceiling pendant drip holes” are described here for the first time and these corrosion features are fully consistent with the SAS model. Other features of Kraushöhle include thick gypsum deposits with strongly depleted δ34S values and other minerals – mostly sulfates – indicating highly acidic conditions. We also studied acid–rock interaction processes giving rise to widespread corrosion and concomitant replacement by gypsum. Petrographic and geochemical analyses reveal the presence of a distinctive alteration layer of highly increased porosity at the interface between the host limestone and the secondary gypsum. Dissolution and replacement of the limestone was fast enough to prevent the development of C and O isotopic alteration halos but resulted in selective leaching of elements. This stable isotope signal is thus different from the pronounced isotope gradient commonly observed in CO2-dominated hypogenic caves. Petrographic observations reveal that the limestone–gypsum replacement was a nearly constant volume process. [Copyright &y& Elsevier]

Abstract: In this paper, we report on many phosphate containing natural minerals found in the Jenolan Caves – Australia. Such minerals are formed by the reaction of bat guano and clays from the caves. Among these cave minerals is the montgomeryite mineral [Ca4MgAl4(PO4)6·(OH)4·12H2O]. The presence of montgomeryite in deposits of the Jenolan Caves – Australia has been identified by X-ray diffraction (XRD). Raman spectroscopy complimented with infrared spectroscopy has been used to characterise the crystal structure of montgomeryite. The Raman spectrum of a standard montgomeryite mineral is identical to that of the Jenolan Caves sample. Bands are assigned to H2PO4 −, OH and NH stretching vibrations. By using a combination of XRD and Raman spectroscopy, the existence of montgomeryite in the Jenolan Caves – Australia has been proven. A mechanism for the formation of montgomeryite is proposed. [Copyright &y& Elsevier]

Abstract: Many phosphate containing minerals are found in the Jenolan Caves. Such minerals are formed by the reaction of bat guano and clays from the caves. Among these cave minerals is the mineral taranakite (K,NH4)Al3(PO4)3(OH)·9(H2O) which has been identified by X-ray diffraction. Jenolan Caves taranakite has been characterised by Raman spectroscopy. Raman and infrared bands are assigned to H2PO4, OH and NH stretching vibrations. By using a combination of XRD and Raman spectroscopy, the existence of taranakite in the caves has been proven. [Copyright &y& Elsevier]

The present note is an updated inventory of all known cave minerals as March 2011. After including the new minerals described since the last edition of the Cave Minerals of the World book (1997) and made the necessary corrections to incorporate all discreditations, redefinitions, or revalidation proposed by the Commission on New Minerals, Nomenclatures and Classification (CNMNC) of the International Mineralogical Association (IMA), we summed up 319 cave minerals, many of these only known from caves. Some of the minerals building up speleothems are powerful tracers of changes in Quaternary climate, other minerals are useful for reconstructing landscape evolution, or allow discriminating between various speleogenetic pathways. Thus, it is expected that the search for new cave minerals will continue and even more attention will be given to those species that carries information that allow for addressing different problems in various earth sciences fields. In view of the exponential increase of cave minerals over the past 50 years, cave mineralogy conceivably has the potential to grow in the future, especially considering the new advances in analytical facilities. [ABSTRACT FROM AUTHOR]

Perhaps man's first motivation to explore caves, beyond using them as shelter, was the search for substances that were not available elsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interesting from the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a single compound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although only a limited number of natural cavities have been investigated in detail, about 350 cave minerals have already been observed, some of which are new to science. The presence of such unexpected richness is a direct consequence of the variety of rocks traversed by water or other fluids before entering a cave and the sediments therein. Different cave environments allow the development of various minerogenetic mechanisms, the most important of which are double exchange reactions, evaporation, oxidation, hydration-dehydration, sublimation, deposition from aerosols and vapors, and segregation. The cave temperature and pH/Eh strictly control most of them, although some are driven by microorganisms. The cave environment, due to its long-term stability, can sometimes allow for the development of huge euhedral crystals, such as those found in the Naica caves (Mexico), but the presence of extremely small yet complex aggregates of different minerals is far more common. Future development in the field of cave mineralogy will likely be focused mainly on hydrothermal and sulfuric-acid caves and on the role played by micro-organisms in controlling some of the most important minerogenetic processes in caves. [ABSTRACT FROM AUTHOR]

The Purcăreţ - Boiu Mare Plateau and the southern edge of the Baia Mare Depression, in Salaj and Maramures Counties, NW Romania, host over 200 caves located in limestones ranging in age from Upper Eocene to Badenian. The carbonate rocks are interposed with non-karst rocks consisting of shales, sandstones and marls. Four caves hosted by limestones of different lithologies have been investigated for secondary minerals in the composition of their speleothems. Calcite, gypsum, goethite, jarosite, brushite, hydroxylapatite and taranakite were found in the composition of crusts, crystals, aggregates and earthy masses. The mineral association was characterized by means of X-ray diffraction and scanning electron microscopy. Gypsum, goethite and jarosite resulted from sulfide oxidation, whereas the phosphate associations formed through the interaction of phosphoric acid from bat guano with the limestones and detrital sediments. In Lii Cave, hydroxylapatite was also identified in black crusts deposited on fossil rib fragments within the limestones. [ABSTRACT FROM AUTHOR]

Eighteen minerals belonging to eight chemical groups were identified from three caves within Şălitrari Mountain, in the upper Cerna River basin (Romania) by means of scanning electron microscopy, electron microprobe analysis, and X-ray powder diffraction. One passage in the Great Cave from Şălitrari Mountain, the largest cave investigated, exhibits abnormal relative humidity and temperature ranges, allowing for a particular depositional environment. The cave floor is covered by alluvial sediments (ranging from cobble, sand, and clay to silt-sized material), bear bones, bat guano, and rubble. These materials reacted with percolating meteoric water and hydrogen sulfide-rich hypogene hot solutions, precipitating a variety of secondary minerals. Most of these minerals are common in caves (e.g. calcite, gypsum, brushite), however, some of them (alunite, aluminite, and darapskite) require very particular environments in order to form and persist. Cave passage morphologies suggest a complex speleogenetic history that includes changes from phreatic to vadose conditions. The latter was punctuated by a sulfuric acid dissolution/precipitation phase, partly overprinted by present-day vadose processes. The cave morphology and the secondary minerals associated with the alluvial sediments in these caves are used to unravel the region’s speleogenetic history. [ABSTRACT FROM AUTHOR]

This paper reports on the identification of four rare minerals in the phosphate deposit in Cioclovina Cave, Romania. Berlinite, AlPO4 and hydroxylellestadite, Ca5[(Si,P,S)O4]3(OH,F,Cl) are minerals that can form only at high temperatures, and would not be expected in a sedimentary environment. In this study we review the characteristics of berlinite and hydroxylellestadite from a heated sedimentary sequence in Cioclovina Cave (Romania) and refine their structure from single-crystal X-ray data. Two other minerals, churchite-(Y), YPO4·2H2O and foggite, CaAl(PO4)(OH)2·H2O are, for the first time, described from a cave environment. The minerals were documented by means of single-crystal X-ray investigations, X-ray powder diffraction, and electron-microprobe (EMPA) analyses. In addition, laboratory synthesis of berlinite was conducted and vibrational spectroscopy data were collected for hydroxylellestadite and churchite-(Y). Based on these investigations, we suggest that locally the heavily compacted phosphate-bearing clay sediments underwent a natural heating process. It is likely that in-situ bat guano combustion is responsible for generating the high-temperature environment needed for the genesis of berlinite and hydroxylellestadite. The occurrence of churchite-(Y) and foggite is related to guano-leaches that reacted with subjacent limestone and different allogenic cave sediments. [ABSTRACT FROM AUTHOR]

Berlinite is a mineral indicative of high-temperature formation and, therefore, it would not be expected to be present in a sedimentary environment. In this study, we review the characteristics of a berlinite-bearing deposit and present a single-crystal structure investigation based on X-ray data: the refinement converged at R1(F) = 0.0276, wR2(F²) = 0.0657 for 677 reflections (2θMoKα ≤ 70°) and 31 variables in space-group P3121 [a = 4.9458(10), c = 10.9526(20) Å, V = 232.0 ų, Z = 3{AlPO4}]. The average bond distances within the two crystallographically unique TO4 tetrahedra are 1.734 and 1.526 Å, respectively. From the scattering power at these T sites and the stereochemistry, the presence of an AlO4 tetrahedron linked to a PO4 tetrahedron is established. Consequently, the sample from Cioclovina Cave is verified as AlPO4 (modification berlinite), reconfirming the first description of this mineral from a sedimentary occurrence, which underwent an obvious natural heating process. [ABSTRACT FROM AUTHOR]