Palaeoenvironment of lateritic bauxites with vertical and lateral differentiation, 1983, Valeton Ida,

Formation of lateritic bauxites of the type described in this paper occurs world-wide in Cretaceous and Tertiary coastal plains. The bauxites form elongate belts, sometimes hundreds of kilometres long, parallel to Lower Tertiary shorelines in India and South America and their distribution is not related to a particular mineralogical composition of the parent rock. The lateral movement of the major elements Al, Si, Fe, Ti is dependent on a high level and flow of groundwater. Varying efficiency of subsurface drainage produces lateral facies variations. Interfingering of marine and continental facies indicate a sea-land transition zone where the type of sediments also varies with minor tectonic movements or sea-level changes. A typical sediment association is found in India, Africa, South and North America. It consists of (i) red beds rich in detrital and dissolved material of reworked laterites, (ii) lacustrine sediments and hypersaline precipitates, (iii) lignites intercalated with marine clays, layers of siderite, pyrite, marcasite and jarosite, and (iv) marine chemical sediments rich in oolitic iron ores or glauconite. A model is developed to account for element distributions in lateritic bauxites in terms of groundwater levels and flow. Finally it is shown that many high-level bauxites are formed in coastal plains and that they are subsequently uplifted to their present altitude

Hydrobasaluminite and Aluminite in Caves of the Guadalupe Mountains, New Mexico, 1998, Polyak, V. J. , Provencio, P.

Hydrobasaluminite, like alunite and natroalunite, has formed as a by-product of the H2S-H2SO4 speleogenesis of Cottonwood Cave located in the Guadalupe Mountains of New Mexico. This mineral is found as the major component of white pockets in the dolostone bedrock where clay-rich seams containing kaolinite, dickite, and illite have altered during speleogenesis to hydrobasaluminite, amorphous silica, alunite, and hydrated halloysite (endellite). Gibbsite and amorphous silica are associated with the hydrobasaluminite in a small room of Cottonwood Cave. Opalline sediment on the floor of this room accumulated as the cave passage evolved. Jarosite, in trace amounts, occurs in association with the opalline sediment and most likely has the same origin as hydrobasaluminite and alunite. The hydrobasaluminite was found to be unstable at 25ºC and 50% RH, converting to basaluminite in a few hours. Basaluminite was not detected in the cave samples. Aluminite has precipitated as a secondary mineral in the same small room where hydrobasaluminite occurs. It comprises a white to bluish-white, pasty to powdery moonmilk coating on the cave walls. The bedrock pockets containing hydrobasaluminite provide the ingredients from which aluminite moonmilk has formed. It appears that recent cave waters have removed alumina and sulfate from the bedrock pocket minerals and have deposited aluminite and gypsum along the cave wall. Gypsum, amorphous silica and sulfate-containing alumina gels are associated with the aluminite moonmilk.

LOW-TEMPERATURE ACID WEATHERING IN NEWHAVEN, SUSSEX, UNITED KINGDOM, AND ITS APPLICATION TO THEORETICAL MODELING IN RADIOACTIVE WASTE-DISPOSAL SITES, 2000, De Putter T, Bernard A, Perruchot A, Nicaise D, Dupuis C,

Tertiary weathered sediments located immediately to the west of the harbor at Newhaven, Sussex, UK, were investigated by examination of major and trace elements by scanning electron microscope (SEM), microprobe, and inductively coupled plasma mass spectrometer (ICP-MS), and the mineralogy was studied by optical petrography, X-ray diffraction (XRD), transmission electron microscope (TEM), selective leaching, and thermodynamic modeling. Studied outcrops experienced acid leaching by sulfuric acid percolating downward through Tertiary sediments overlying Cretaceous chalk. The progressive neutralization of the percolating acid fluids resulted in 'sequentially' layered neoformation of minerals: jarosite, iron oxides, aluminous minerals (sulfates, oxyhydroxides), gypsum, and Fe-Mn oxides. Substantial agreement was found between field observations and mineral assemblages obtained by modeling with the program CHILLER. These results suggest that the initial assumptions on the weathering process and mechanisms are correct. The relevance and implications of this study in the modeling of future denudation and weathering processes of radioactive waste-disposal sites (both deeply buried sites for high-level waste and surface sites for low-level waste) are discussed. Neoformed phases, such as jarosite, aluminous minerals, and silico-aluminous gels may play a significant role in the efficient trapping of mobilized pollutant radionuclides

'Sour gas' hydrothermal jarosite: ancient to modem acid-sulfate mineralization in the southern Rio Grande Rift, 2005, Lueth V. W. , Rye R. O. , Peters L. ,

As many as 29 mining districts along the Rio Grande Rift in southern New Mexico contain Rio Grande Rift-type (RGR) deposits consisting of fluorite-barite sulfide-jarosite, and additional RGR deposits occur to the south in the Basin and Range province near Chihuahua, Mexico. Jarosite occurs in many of these deposits as a late-stage hydrothermal mineral coprecipitated with fluorite, or in veinlets that crosscut barite. In these deposits, many of which are limestone-hosted, jarosite is followed by natrojarosite and is nested within silicified or argillized wallrock and a sequence of fluorite-barite sulfide and late hematite-gypsum. These deposits range in age from similar to 10 to 0.4 Ma on the basis of Ar-40/Ar-39 dating of jarosite. There is a crude north-south distribution of ages, with older deposits concentrated toward the south. Recent deposits also occur in the south, but are confined to the central axis of the rift and are associated with modem geothermal systems. The duration of hydrothermal jarosite mineralization in one of the deposits was approximately 1.0 my. Most Delta(18)O(SO4)-OH values indicate that jarosite precipitated between 80 and 240 degrees C, which is consistent with the range of filling temperatures of fluid inclusions in late fluorite throughout the rift, and in jarosite (180 degrees C) from Pena Blanca, Chihuahua, Mexico. These temperatures, along with mineral occurrence, require that the jarosite have had a hydrothermal origin in a shallow steam-heated environment wherein the low pH necessary for the precipitation of jarosite was achieved by the oxidation of H2S derived from deeper hydrothermal fluids. The jarosite also has high trace-element contents (notably As and F), and the jarosite parental fluids have calculated isotopic signatures similar to those of modem geothermal waters along the southern rift; isotopic values range from those typical of meteoric water to those of deep brine that has been shown to form from the dissolution of Permian evaporite by deeply circulating meteoric water. Jarosite delta(34)S values range from -24 parts per thousand to 5 parts per thousand, overlapping the values for barite and gypsum at the high end of the range and for sulfides at the low end. Most delta(34)S values for barite are 10.6 parts per thousand to 13.1 parts per thousand and many delta(34)S values for gypsum range from 13.1 parts per thousand to 13.9 parts per thousand indicating that a component of aqueous sulfate was derived from Permian evaporites (delta(34)S = 12 2 parts per thousand). The requisite H2SO4 for jarosite formation was derived from oxidation of H2S which was likely largely sour gas derived from the thermochemical reduction of Permian sulfate. The low delta(34)S values for the precursor H2S probably resulted from exchange deeper in the basin with the more abundant Permian SO42-- at similar to 150 to 200 degrees C. Jarosite formed at shallow levels after the PH buffering capacity of the host rock (typically limestone) was neutralized by precipitation of earlier minerals. Some limestone-hosted deposits contain caves that may have been caused by the low pH of the deep basin fluids due to the addition of deep-seated HF and other magmatic gases during periods of renewed rifting. Caves in other deposits may be due to sulfuric acid speleogenesis as a result of H2S incursion into oxygenated groundwaters. The isotopic data in these 'sour gas' jarosite occurrences encode a recod of episodic tectonic or hydrologic processes that have operated in the rift over the last 10 my. (c) 2004 Elsevier B.V. All rights reserved

Mineralogy of Iza Cave (Rodnei Mountains, N. Romania), 2011, Tă, Maş, Tudor, Kristály Ferenc, Barbutudoran Lucian

The secondary minerals from Iza Cave result from the interactions of karst water and/or cave atmosphere over a variety of sedimentary and metamorphic rocks. The cave passages expose at various extents Eocene limestones and conglomerates, Oligocene black shales, Upper Precambrian micaschists, marble and dolomitic marble and associated ore deposits.
Twelve secondary minerals identified 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 and conglomerate areas of the cave. Ankerite crusts are related to areas with pyrite mineralization within the metamorphic carbonate rocks. Goethite, jarosite, hematite and gypsum form various speleothems in the sectors within micaschists and conglomerates. Large weathering deposits occurring in passage areas developed within micaschists consist of illite, kaolinite, jarosite, goethite, gypsum and alunite. The extent of the weathering deposits occurring on non-karst rocks in the underground environment makes this cave a particularly interesting site for studies of water-rock interactions.

Hypogenic origin of Provalata Cave, Republic of Macedonia: a distinct case of successive thermal carbonic and sulfuric acid speleogenesis, 2013, Temovski Marjan, Audra Philippe, Mihevc Andrej, Spangenberg Jorge E. , Polyak Victor, Mcintosh William, Bigot Jeanyves.

Provalata Cave (Republic of Macedonia) is a small but remarkable hypogenic cave, developed in Cambrian marbles by successive thermal carbonic and sulfuric acid speleogenesis. The cave has a thick partly corroded calcite crust, abundant gypsum deposits, with cupolas, ceiling and wall channels, feeders and replacement pockets as some of the most characteristic morphological features. Distribution of morphology and deposits suggest a hypogenic origin in two distinct speleogenetic phases: the first by thermal CO2 rich waters, the second by sulfuric acid dissolution, which were separated by complete infilling of cave passages with pyroclastic-derived clays. In the first phase of speleogenesis, cave passages were formed by dissolution along fractures due to cooling of rising carbonated thermal waters. These phreatic morphologies were later covered with a thick calcite crust deposited in a shallow phreatic environment. In Early Pleistocene the cave was completely filled with clays due to deposition of pyroclastic rocks in a lacustrine environment in the nearby Mariovo Basin. Mariovo Lake sediments were later incised by the Buturica River, which cut down into Cambrian marbles, creating its superimposed valley. Incision lowered the water table and allowed removal of the clay deposits in Provalata Cave. The second phase of speleogenesis started after introduction of H2S associated with rising thermal waters. Oxidation produced sulfuric acid, which rapidly dissolved first calcite crust, then marble host rock. Condensation-corrosion by sulfuric vapors replaced carbonate rock with gypsum producing replacement pockets as well as second generation of pockets and cupolas. The contact of sulfuric acid with the clay deposits formed alunite, jarosite, and natroalunite. 40Ar/39Ar dating gave maximum ages of 1.6 Ma (alunite) and 1.46 Ma (jarosite) for this last stage of speleogenesis, thus making it the second 40Ar/39Ar dating of a sulfuric cave in Europe (after Kraushöhle in Austria), and the first dated cave in the Republic of Macedonia.

Uncommon cave minerals associated to hypogene speleogenesis in Southern France, 2013, Audra, Philippe

Five hypogenic-origin caves from Southern France are presented. Investigations using XRD, SEM and Raman spectroscopy, reveal the presence of uncommon cave minerals. Oilloki Cave is a small lead ore mine-cave containing galena, cerussite, and bismuth (present as native element or as sulfide).La Baume Cave is a hydrothermal breccia-pipe, filled with colorful (red, green, white) clays. Some of the clay minerals (clinochlore se-piolite), could originate from hydrothermal weathering of clastic material. The Mala-coste Quarry, harbors a hydrothermal chimney with enlarged vugs lined with calcite spar and filled with iron oxyhydroxides poolfingers (goethite-hematite) and manganese oxides (birnessite, todorokite). Deposition of iron and manganese oxides results of the pH-Eh evolution along the hydrothermal chimney. Pigette Cave is a hydrothermal ver-tical maze with calcite lining and small iron oxyhydroxides and manganese oxides mass-es. The hydrothermal weathering of the walls deposited grains of lithiophorite, barite, and celadonite, which could originate from glauconite. Baume Galinière Cave is a small horizontal maze originating from the oxidation of sulfide masses of pyrite. Beside the common byproducts (gypsum, goethite, sulfur), the six members of the jarosite sub-group are present: jarosite, ammoniojarosite, argentojarosite, hydronium jarosite, natro-jarosite, plumbojarosite, together with fibroferrite. In these caves, three minerals are new cave minerals (bismuth, celadonite, argentojarosite); some others have been men-tioned before only in a few caves worldwide (clinochlore, lithiophorite, ammoniojaro-site, hydronium jarosite, natrojarosite, plumbojarosite, fibroferrite). The mineralogene-sis involves different processes: (i) Deposition in mixing zone from species carried by rising deep flow (barite, galena, bismuth, birnessite, todorokite, lithiophorite); (ii) Hy-drothermal weathering of clay minerals contained in host rock or present as clastic sediments (clinochlore, sepiolite, celadonite); (iii) Oxidation of sulfide masses (goethite, cerussite, jarosite subgroup minerals, fibroferrite).

HYPOGENE SULFURIC ACID SPELEOGENESIS AND RARE SULFATE MINERALS (FIBROFERRITE, JAROSITE SUBGROUP) BAUME GALINIERE CAVE (ALPES-DE-HAUTE-PROVENCE, FRANCE), 2013, Audra P. Gá, Zquez F. Rull F. Bigot J. Y. Camus H.

 

The oxidation of sulfide sources (H2S gas, pyrite, hydrocarbons) produces sulfuric acid that strongly reacts with bedrock, causing limestone dissolution and complex interactions with other minerals. This type of cave development, known as sulfuric acid speleogenesis, is a subcategory of hypogenic speleogenesis, where aggressive water rises from depth. It also produces uncommon minerals, mainly sulfates. Baume Galinière is located in Southern France, in the Vaucluse spring watershed. This small maze cave displays characteristic features such as corrosion notches, calcite dikes and iron crusts, and sulfate minerals. Thirteen minerals were identified, including elemental sulfur, calcite, quartz, pyrite, goethite, gypsum, 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. Together with other hypogenic caves in the Vaucluse watershed, Baume Galinière Cave owes its origin in buried conditions to deep water rising along major faults, mixing with meteoric water at the contact of the karst aquifer and overlying impervious cover, and causing pyrite deposition. Sulfuric acid speleogenesis occurred later after base level drop, when the cave arrived in shallow phreatic then in vadose zone, with oxidation of pyrites involving sulfidic gases. Attenuated oxidation is still occurring through condensation of incoming air from outside. Baume Galinière Cave records the position of the paleo-cover and documents its retreat in relationship to valley incision caused by uplift and tilting of the Vaucluse block during Neogene.

Hypogene Sulfuric Acid Speleogenesis and rare sulfate minerals in Baume Galini`ere Cave (Alpes-de-Haute-Provence, France). Record of uplift, correlative cover retreat and valley dissection, 2015, Audra Philippe, GÒ‘azquez Fernando, Rull Fernando, Bigot Jeanyves, Camus Hubert

The oxidation of hydrocarbons and sulfide sources (H2S, 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, 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.

Hypogene Sulfuric Acid Speleogenesis and rare sulfate minerals in Baume Galinière Cave (Alpes-de-Haute-Provence, France). Record .., 2015, Audra P. , Gázquez F. , Rull F. , Bigot J. Y. , Camus H.

The oxidation of hydrocarbons and sulfide sources (H2S, 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.