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Full-Text Articles in Earth Sciences
Origin Of Secondary Sulfate Minerals On Active Andesitic Stratovolcanoes, D.R. Zimbelman, Robert O. Rye, G.N. Breit
Origin Of Secondary Sulfate Minerals On Active Andesitic Stratovolcanoes, D.R. Zimbelman, Robert O. Rye, G.N. Breit
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Sulfate minerals in altered rocks on the upper flanks and summits of active andesitic stratovolcanoes result from multiple processes. The origin of these sulfates at five active volcanoes, Citlalte´petl (Mexico), and Mount Adams, Hood, Rainier, and Shasta (Cascade Range, USA), was investigated using field observations, petrography, mineralogy, chemical modeling, and stable-isotope data. The four general groups of sulfate minerals identified are: (1) alunite group, (2) jarosite group, (3) readily soluble Fe- and Al-hydroxysulfates, and (4) simple alkaline-earth sulfates such as anhydrite, gypsum, and barite. Generalized assemblages of spatially associated secondary minerals were recognized: (1) alunite+silica±pyrite±kaolinite±gypsum±sulfur, (2) jarosite+alunite+silica; (3) jarosite+smectite+silica±pyrite, (4) …
Characterization Of Gas Chemistry And Noble-Gas Isotope Ratios Of Inclusion Fluids In Magmatic-Hydrothermal And Magmatic-Steam Alunite, Robert O. Rye, G.P. Landis
Characterization Of Gas Chemistry And Noble-Gas Isotope Ratios Of Inclusion Fluids In Magmatic-Hydrothermal And Magmatic-Steam Alunite, Robert O. Rye, G.P. Landis
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Chemical and isotope data were obtained for the active gas and noble gas of inclusion fluids in coarse-grained samples of magmatic-hydrothermal and magmatic-steam alunite from well-studied deposits (Marysvale, Utah; Tambo, Chile; Tapajo´s, Brazil; Cactus, California; Pierina, Peru), most of which are discussed in this Volume. Primary fluid inclusions in the alunite typically are less than 0.2 µm but range up to several micrometers. Analyses of the active-gas composition of these alunitehosted inclusion fluids released in vacuo by both crushing and heating indicate consistent differences in the compositions of magmatic-hydrothermal and magmatic-steam fluids. The compositions of fluids released by crushing were …
Evolution Of The Magmatic-Hydrothermal Acid-Sulfate System At Summitville, Colorado: Integration Of Geological, Stable-Isotope, And Fluid-Inclusion Evidence, Philip M. Bethke, Robert O. Rye, Roger E. Stoffregen, Peter G. Vikre
Evolution Of The Magmatic-Hydrothermal Acid-Sulfate System At Summitville, Colorado: Integration Of Geological, Stable-Isotope, And Fluid-Inclusion Evidence, Philip M. Bethke, Robert O. Rye, Roger E. Stoffregen, Peter G. Vikre
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
The Summitville Au–Ag–Cu deposit is a classic volcanic dome-hosted high-sulfidation deposit. It occurs in the Quartz Latite of South Mountain, a composite volcanic dome that was emplaced along the coincident margins of the Platoro and Summitville calderas at 22.5±0.5 Ma, penecontemporaneous with alteration and mineralization. A penecontemporaneous quartz monzonite porphyry intrusion underlies the district and is cut and overlain by pyrite–quartz stockwork veins with traces of chalcopyrite and molybdenite. Alteration and mineralization proceeded through three hypogene stages and a supergene stage, punctuated by at least three periods of hydrothermal brecciation. Intense acid leaching along fractures in the quartz latite produced …
A Review Of The Stable-Isotope Geochemistry Of Sulfate Minerals In Selected Igneous Environments And Related Hydrothermal Systems, Robert O. Rye
A Review Of The Stable-Isotope Geochemistry Of Sulfate Minerals In Selected Igneous Environments And Related Hydrothermal Systems, Robert O. Rye
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
The stable-isotope geochemistry of sulfate minerals that form principally in I-type igneous rocks and in the various related hydrothermal systems that develop from their magmas and evolved fluids is reviewed with respect to the degree of approach to isotope equilibrium between minerals and their parental aqueous species. Examples illustrate classical stable-isotope systematics and principles of interpretation in terms of fundamental processes that occur in these systems to produce (1) sulfate in igneous apatite, (2) igneous anhydrite, (3) anhydrite in porphyry-type deposits, (4) magmatic-hydrothermal alunite and closely related barites in high-sulfidation mineral deposits, (5) coarse-banded alunite in magmatic-steam systems, (6) …
Sulfur And Oxygen Isotopic Record In Sulfate And Sulfide Minerals Of Early, Deep, Pre-Main Stage Porphyry Cu–Mo And Late Main Stage Base-Metal Mineral Deposits, Butte District, Montana, C.W. Field, L. Zhang, J.H. Dilles, Robert O. Rye, M.H. Reed
Sulfur And Oxygen Isotopic Record In Sulfate And Sulfide Minerals Of Early, Deep, Pre-Main Stage Porphyry Cu–Mo And Late Main Stage Base-Metal Mineral Deposits, Butte District, Montana, C.W. Field, L. Zhang, J.H. Dilles, Robert O. Rye, M.H. Reed
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Typical porphyry-type Cu–Mo mineralization occupies two connected domal centers, the eastern Pittsmont and western Anaconda domes, that predate and largely underlie the well-known, throughgoing, Main Stage polymetallic veins of Butte. Among the sulfur-bearing minerals recovered from deep drill core of this early pre-Main Stage hydrothermal assemblage are anhydrite, chalcopyrite, pyrite, and molybdenite in veinlets bordered by K-silicate alteration, and pyrite from slightly younger quartz–pyrite veinlets with dgray-sericiticT alteration selvages. The ranges of δ34S values for minerals of the K-silicate assemblage are 9.8–18.2%◦ for anhydrite (n=23 samples), 3.0%◦ to 4.7%◦ for molybdenite (n=6), 0.4%◦ to 3.4%◦ for pyrite (n=19), …
Major And Trace Element Composition Of Copiapite-Group Minerals And Coexisting Water From The Richmond Mine, Iron Mountain, California, Heather E. Jamieson, Clare Robinson, Charles N. Alpers, R. Blaine Mccleskey, D. Kirk Nordstrom, Ronald C. Peterson
Major And Trace Element Composition Of Copiapite-Group Minerals And Coexisting Water From The Richmond Mine, Iron Mountain, California, Heather E. Jamieson, Clare Robinson, Charles N. Alpers, R. Blaine Mccleskey, D. Kirk Nordstrom, Ronald C. Peterson
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Copiapite-group minerals of the general formula AR4(SO4)6(OH)2• nH2O, where A is predominantly Mg, Fe2+, or 0.67Al3+, R is predominantly Fe3+, and n is typically 20, are among several secondary hydrous Fe sulfates occurring in the inactive mine workings of the massive sulfide deposit at Iron Mountain, CA, a USEPA Superfund site that produces extremely acidic drainage. Samples of copiapite-group minerals, some with coexisting water, were collected from the Richmond mine. Approximately 200 mL of brownish pore water with a pH of ‒0.9 were …
Secondary Sulfate Minerals Associated With Acid Drainage In The Eastern Us: Recycling Of Metals And Acidity In Surficial Environments, J.M. Hammarstrom, R.R. Seal Ii, A.L. Meier, J.M. Kornfeld
Secondary Sulfate Minerals Associated With Acid Drainage In The Eastern Us: Recycling Of Metals And Acidity In Surficial Environments, J.M. Hammarstrom, R.R. Seal Ii, A.L. Meier, J.M. Kornfeld
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Weathering of metal-sulfide minerals produces suites of variably soluble efflorescent sulfate salts at a number of localities in the eastern United States. The salts, which are present on mine wastes, tailings piles, and outcrops, include minerals that incorporate heavy metals in solid solution, primarily the highly soluble members of the melanterite, rozenite, epsomite, halotrichite, and copiapite groups. The minerals were identified by a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe. Base-metal salts are rare at these localities, and Cu, Zn, and Co are commonly sequestered as solid solutions within Fe- and Fe–Al sulfate minerals. Salt …
Evaluation Of Argon Ages And Integrity Of Fluid-Inclusion Compositions: Stepwise Noble Gas Heating Experiments On 1.87 Ga Alunite From Tapajo´ S Province, Brazil, G.P. Landis, L.W. Snee, C. Juliani
Evaluation Of Argon Ages And Integrity Of Fluid-Inclusion Compositions: Stepwise Noble Gas Heating Experiments On 1.87 Ga Alunite From Tapajo´ S Province, Brazil, G.P. Landis, L.W. Snee, C. Juliani
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Quantitative analyses are reported for active (N2, CH4, CO, CO2, H2, O2, HF, HCl, H2S, SO2) and noble (He, Ar, Ne) gases released by crushing and step heating of magmatic-hydrothermal alunite from the Tapajo´ s gold province in Brazil. This is the oldest known alunite (40Ar/39Ar age of 1.87 Ga), and because it has undergone minimal postdepositional thermal or tectonic strain, it is excellent material to test the retention of gas species in fluid inclusions and within the crystal structure over geological …
Alunite And The Role Of Magmatic Fluids In The Tambo High-Sulfidation Deposit, El Indio–Pascua Belt, Chile, C.L. Deyell, R.O. Rye, G.P. Landis, T. Bissig
Alunite And The Role Of Magmatic Fluids In The Tambo High-Sulfidation Deposit, El Indio–Pascua Belt, Chile, C.L. Deyell, R.O. Rye, G.P. Landis, T. Bissig
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
The Tambo high-sulfidation deposit, located within the El Indio–Pascua belt in Chile, produced almost 25 t (0.8 M oz) of gold from altered Tertiary rhyodacitic volcanic rocks. Episodic magmatic-hydrothermal activity in the district occurred over at least 4 my and is characterized by several stages of acid-sulfate alteration, including magmatic-hydrothermal, magmatic steam, steam-heated, and apparent supergene assemblages. Two stages of Au±Ag mineralization are recognized and are hosted in barite and alunite within hydrothermal breccias and veins. Isotopic compositions of fluid in alunite show a dominant magmatic signature, with only a variable 18O-enriched meteoric water component throughout the entire hydrothermal …
Paleoproterozoic High-Sulfidation Mineralization In The Tapajo´S Gold Province, Amazonian Craton, Brazil: Geology, Mineralogy, Alunite Argon Age, And Stable-Isotope Constraints, Caetano Juliani, Robert O. Rye, Carmen M.D. Nunes, Lawrence W. Snee, Rafael H. Corrêa Silva, Lena V.S. Monteiro, Jorge S. Bettencourt, Rainer Neumann, Arnaldo Alcover Neto
Paleoproterozoic High-Sulfidation Mineralization In The Tapajo´S Gold Province, Amazonian Craton, Brazil: Geology, Mineralogy, Alunite Argon Age, And Stable-Isotope Constraints, Caetano Juliani, Robert O. Rye, Carmen M.D. Nunes, Lawrence W. Snee, Rafael H. Corrêa Silva, Lena V.S. Monteiro, Jorge S. Bettencourt, Rainer Neumann, Arnaldo Alcover Neto
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
The Brazilian Tapajós gold province contains the first evidence of high-sulfidation gold mineralization in the Amazonian Craton. The mineralization appears to be in large nested calderas. The Tapajós–Parima (or Ventuari–Tapajo´ s) geological province consists of a metamorphic, igneous, and sedimentary sequence formed during a 2.10 to 1.87 Ga ocean ̶ continent orogeny. The high-sulfidation mineralization with magmatic-hydrothermal alunite is related to hydrothermal breccias hosted in a rhyolitic volcanic ring complex that contains granitic stocks ranging in age from 1.89 to 1.87 Ga. Cone-shaped hydrothermal breccias, which flare upward, contain vuggy silica and have an overlying brecciated cap of massive silica; …
"Sour Gas" Hydrothermal Jarosite: Ancient To Modern Acid-Sulfate Mineralization In The Southern Rio Grande Rift, Virgil W. Lueth, Robert O. Rye, Lisa Peters
"Sour Gas" Hydrothermal Jarosite: Ancient To Modern Acid-Sulfate Mineralization In The Southern Rio Grande Rift, Virgil W. Lueth, Robert O. Rye, Lisa Peters
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
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–bariteFsulfide and late hematite– gypsum. These deposits range in age from ~10 to …
Stable-Isotope Geochemistry Of The Pierina High-Sulfidation Au–Ag Deposit, Peru: Influence Of Hydrodynamics On So42-–H2S Sulfur Isotopic Exchange In Magmatic-Steam And Steam-Heated Environments, Richard H. Fifarek, Robert O. Rye
Stable-Isotope Geochemistry Of The Pierina High-Sulfidation Au–Ag Deposit, Peru: Influence Of Hydrodynamics On So42-–H2S Sulfur Isotopic Exchange In Magmatic-Steam And Steam-Heated Environments, Richard H. Fifarek, Robert O. Rye
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
The Pierina high-sulfidation Au–Ag deposit formed 14.5 my ago in rhyolite ash flow tuffs that overlie porphyritic andesite and dacite lavas and are adjacent to a crosscutting and interfingering dacite flow dome complex. The distribution of alteration zones indicates that fluid flow in the lavas was largely confined to structures but was dispersed laterally in the tuffs because of a high primary and alteration-induced permeability. The lithologically controlled hydrodynamics created unusual fluid, temperature, and pH conditions that led to complete SO4 2‒–H2S isotopic equilibration during the formation of some magmatic-steam and steam-heated alunite, a phenomenon not …
Supergene Destruction Of A Hydrothermal Replacement Alunite Deposit At Big Rock Candy Mountain, Utah: Mineralogy, Spectroscopic Remote Sensing, Stable-Isotope, And Argon-Age Evidences, Charles G. Cunningham, Robert O. Rye, Barnaby W. Rockwell, Michael J. Kunk, Terry B. Councell
Supergene Destruction Of A Hydrothermal Replacement Alunite Deposit At Big Rock Candy Mountain, Utah: Mineralogy, Spectroscopic Remote Sensing, Stable-Isotope, And Argon-Age Evidences, Charles G. Cunningham, Robert O. Rye, Barnaby W. Rockwell, Michael J. Kunk, Terry B. Councell
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Big Rock Candy Mountain is a prominent center of variegated altered volcanic rocks in west-central Utah. It consists of the eroded remnants of a hypogene alunite deposit that, at ~21 Ma, replaced intermediate-composition lava flows. The alunite formed in steam-heated conditions above the upwelling limb of a convection cell that was one of at least six spaced at 3- to 4- km intervals around the margin of a monzonite stock. Big Rock Candy Mountain is horizontally zoned outward from an alunite core to respective kaolinite, dickite, and propylite envelopes. The altered rocks are also vertically zoned from a lower pyrite– …
Chemical Openness And Potential For Misinterpretation Of The Solute Environment Of Coastal Sabkhat, Warren W. Wood, Ward E. Sanford, Shaun K. Frape
Chemical Openness And Potential For Misinterpretation Of The Solute Environment Of Coastal Sabkhat, Warren W. Wood, Ward E. Sanford, Shaun K. Frape
Geochemistry of Sulfate Minerals: A Tribute to Robert O. Rye
Sabkha deposits in the geologic record are commonly used to interpret the environmental conditions of deposition. Implicit in this use is the assumption that the solute system is chemically closed, that is, the authigenic minerals represent the composition of the fluids in their environment of origin. Thermodynamic and mass-balance calculations based on measurements of water and solute flux of contemporary Abu Dhabi coastal sabkha system, however, demonstrate that the system is open for sodium and chloride, where nearly half of the input is lost, but closed for sulfur, where nearly 100% is retained. Sulfur and chloride isotopes were consistent with …