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At least 289 records · Page 16Linked to original sources
USGS2007

Chemical data for rock, sediment, biological, precipitate, and water samples from abandoned copper mines in Prince William Sound, Alaska

Introduction In the early 20th century, approximately 6 million metric tons of copper ore were mined from numerous deposits located along the shorelines of fjords and islands in Prince William Sound, Alaska. At the Beatson, Ellamar, and Threeman mine sites (fig. 1), rocks containing Fe, Cu, Zn, and Pb sulfide minerals are exposed to chemical weathering in abandoned mine workings and remnant waste piles that extend into the littoral zone. Field investigations in 2003 and 2005 as well as analytical data for rock, sediment, precipitate, water, and biological samples reveal that the oxidation of sulfides at these sites is resulting in the generation of acid mine drainage and the transport of metals into the marine environment (Koski and others, 2008; Stillings and others, 2008). At the Ellamar and Threeman sites, plumes of acidic and metal-enriched water are flowing through beach gravels into the shallow offshore environment. Interstitial water samples collected from beach sediment at Ellamar have low pH levels (to ~3) and high concentrations of metals including iron, copper, zinc, cobalt, lead, and mercury. The abundant precipitation of the iron sulfate mineral jarosite in the Ellamar gravels also signifies a low-pH environment. At the Beatson mine site (the largest copper mine in the region) seeps containing iron-rich microbial precipitates drain into the intertidal zone below mine dumps (Foster and others, 2008). A stream flowing down to the shoreline from underground mine workings at Beatson has near-neutral pH, but elevated levels of zinc, copper, and lead (Stillings and others, 2008). Offshore sediment samples at Beatson are enriched in these metals. Preliminary chemical data for tissue from marine mussels collected near the Ellamar, Threeman, and Beatson sites reveal elevated levels of copper, zinc, and lead compared to tissue in mussels from other locations in Prince William Sound (Koski and others, 2008). Three papers presenting results of this ongoing investigation of sulfide oxidation in Prince William Sound are in press. Koski and others (2008) provide an overview of rock alteration, surface water chemistry, and the distribution of metals at the Ellamar, Threeman, and Beatson mine sites. Based on a 60-day, stream-discharge experiment at Beatson in 2005, Stillings and others (2008) analyze changes in water chemistry during storm events and the flux of metals to the shoreline. Foster and others (2008) investigate the biomass and diversity of microbial communities present in surface waters (streams, seeps, pore waters) using fatty acid methyl ester (FAMES) data and principal component analysis. The publications cited above contain a subset of the total chemical data for rock, sediment, biological, precipitate, and water samples collected from the three mine sites in 2003 and 2005. The purpose of this report is the presentation of complete chemical data sets for all samples collected during the two field periods of fieldwork. Data for a small number of samples collected at two other mines (Schlosser and Fidalgo, fig. 1), visited in 2003, are also included in the tables.

Alaska↗
USGS2007

Chemical data for rock, sediment, biological, precipitate, and water samples from abandoned copper mines in Prince William Sound, Alaska

In the early 20th century, approximately 6 million metric tons of copper ore were mined from numerous deposits located along the shorelines of fjords and islands in Prince William Sound, Alaska. At the Beatson, Ellamar, and Threeman mine sites (fig. 1), rocks containing Fe, Cu, Zn, and Pb sulfide minerals are exposed to chemical weathering in abandoned mine workings and remnant waste piles that extend into the littoral zone. Field investigations in 2003 and 2005 as well as analytical data for rock, sediment, precipitate, water, and biological samples reveal that the oxidation of sulfides at these sites is resulting in the generation of acid mine drainage and the transport of metals into the marine environment (Koski and others, 2008; Stillings and others, 2008). At the Ellamar and Threeman sites, plumes of acidic and metal-enriched water are flowing through beach gravels into the shallow offshore environment. Interstitial water samples collected from beach sediment at Ellamar have low pH levels (to ~3) and high concentrations of metals including iron, copper, zinc, cobalt, lead, and mercury. The abundant precipitation of the iron sulfate mineral jarosite in the Ellamar gravels also signifies a low-pH environment. At the Beatson mine site (the largest copper mine in the region) seeps containing iron-rich microbial precipitates drain into the intertidal zone below mine dumps (Foster and others, 2008). A stream flowing down to the shoreline from underground mine workings at Beatson has near-neutral pH, but elevated levels of zinc, copper, and lead (Stillings and others, 2008). Offshore sediment samples at Beatson are enriched in these metals. Preliminary chemical data for tissue from marine mussels collected near the Ellamar, Threeman, and Beatson sites reveal elevated levels of copper, zinc, and lead compared to tissue in mussels from other locations in Prince William Sound (Koski and others, 2008). Three papers presenting results of this ongoing investigation of sulfide oxidation in Prince William Sound are in press. Koski and others (2008) provide an overview of rock alteration, surface water chemistry, and the distribution of metals at the Ellamar, Threeman, and Beatson mine sites. Based on a 60-day, stream-discharge experiment at Beatson in 2005, Stillings and others (2008) analyze changes in water chemistry during storm events and the flux of metals to the shoreline. Foster and others (2008) investigate the biomass and diversity of microbial communities present in surface waters (streams, seeps, pore waters) using fatty acid methyl ester (FAMES) data and principal component analysis. The publications cited above contain a subset of the total chemical data for rock, sediment, biological, precipitate, and water samples collected from the three mine sites in 2003 and 2005. The purpose of this report is the presentation of complete chemical data sets for all samples collected during the two field periods of fieldwork. Data for a small number of samples collected at two other mines (Schlosser and Fidalgo, fig. 1), visited in 2003, are also included in the tables.

Alaska↗
USGS2005

"Sour gas" hydrothermal jarosite: Ancient to modern acid-sulfate mineralization in the southern Rio Grande Rift

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 ???10 to 0.4 Ma on the basis of 40Ar/39Ar 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 modern geothermal systems. The duration of hydrothermal jarosite mineralization in one of the deposits was approximately 1.0 my. Most ??18OSO4-OH values indicate that jarosite precipitated between 80 and 240 ??C, which is consistent with the range of filling temperatures of fluid inclusions in late fluorite throughout the rift, and in jarosite (180 ??C) from Pen??a 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 modern 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 ??34S values range from -24??? to 5???, overlapping the values for barite and gypsum at the high end of the range and for sulfides at the low end. Most ??34S values for barite are 10.6??? to 13.1???, and many ??34S values for gypsum range from 13.1??? to 13.9??? indicating that a component of aqueous sulfate was derived from Permian evaporites (??34 S=12??2???). 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 ??34S values for the precursor H2S probably resulted from exchange deeper in the basin with the more abundant Permian SO42- at ???150 to 200 ??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 record of episodic tectonic or hydrologic processes that have operated in the rift over the last 10 my. ?? 2004 Elsevier B.V. All rights reserved.

Chemical Geology↗
USGS2009

Compilation of Mineral Resource Data for Mississippi Valley-Type and Clastic-Dominated Sediment-Hosted Lead-Zinc Deposits

This report contains a global compilation of the mineral resource data for sediment-hosted lead-zinc (SH Pb-Zn) deposits. Sediment-hosted lead-zinc deposits are historically the most significant sources of lead and zinc, and are mined throughout the world. The most important SH Pb-Zn deposits are hosted in clastic-dominated sedimentary rock sequences (CD Pb-Zn) that are traditionally called sedimentary exhalative (SEDEX) deposits, and those in carbonate-dominated sequences that are known as Mississippi Valley-type (MVT) Pb-Zn deposits. In this report, we do not include sandstone-Pb, sandstone-hosted Pb, or Pb-Zn vein districts such as those in Freiberg, Germany, or Coeur d'Alene, Idaho, because these deposits probably represent different deposit types (Leach and others, 2005). We do not include fracture-controlled deposits in which fluorite is dominant and barite typically abundant (for example, Central Kentucky; Hansonburg, N. Mex.) or the stratabound fluorite-rich, but also lead- and zinc-bearing deposits, such as those in southern Illinois, which are considered a genetic variant of carbonate-hosted Pb-Zn deposits (Leach and Sangster, 1993). This report updates the Pb, Zn, copper (Cu), and silver (Ag) grade and tonnage data in Leach and others (2005), which itself was based on efforts in the Canadian Geological Survey World Minerals Geoscience Database Project (contributions of D.F. Sangster to Sinclair and others, 1999). New geological or geochronological data, classifications of the tectonic environment in which the deposits formed, and key references to the geology of the deposits are presented in our report. Data for 121 CD deposits, 113 MVT deposits, and 6 unclassified deposits that were previously classified as either SEDEX or MVT in the Leach and others (2005) compilation, are given in appendix table A1. In some cases, mineral resource data were available only for total district resources, but not for individual mines within the district. For these districts, the resource data are presented in appendix table A2. In addition, numerous figures (appendix figures B1-B9) displaying important grade-tonnage and geologic features are included. These mineral deposit resource data are important for exploration targeting and mineral resource assessments. There is significant variability in the resource data for these deposit types, and ore controls vary from one region to another. Therefore, grade-tonnage estimations are best evaluated as subsets of the data in appendix table A1 where local mineralization styles and ore controls characterize the region being evaluated for grade-tonnage relations. Furthermore, consideration should also be given to the tendency for MVT resources to occur in large mineralized regions.

Open-File Report↗
USGS2025

Geochemistry of quartz and fluid inclusions associated with gold, tungsten, and antimony in the Stibnite-Yellow Pine district, Idaho

Deposits in the historic Stibnite-Yellow Pine district in east-central Idaho were mined for Ag, Au, Hg, Sb, and W. Ore is hosted in breccia and fault zones along NE-striking faults that transect the Atlanta lobe of the Late Cretaceous Idaho batholith and metamorphosed Neoproterozoic to lower Paleozoic rocks. Geochronological studies have delineated five superimposed and zoned hydrothermal events in the mining district which range in age from Late Cretaceous to the Eocene. They formed the following consecutive assemblages: (1) vein and disseminated pre-ore milky quartz (± calcite), muscovite, and brassy pyrite with minor molybdenite and base metal sulfides; (2) vein and disseminated quartz, calcite, sericite, auriferous-pyrite, and arsenopyrite; (3) potassium feldspar, quartz, dolomite, and calcite with vein and disseminated scheelite ± pyrite and arsenopyrite; (4) Au-Ag veins that contain adularia; and (5) breccia, vein, and disseminated quartz, calcite, and stibnite with minor Ag sulfosalts and distal zones of cinnabar and realgar at Fern and Hermes mines. In this study, the pressure, temperature, and composition of ore-forming fluids were measured in Au-, W-, and Sb-bearing samples collected from drill core and surface exposures. Using optical petrography, scanning electron microscopy cathodoluminescence (SEM-CL) and electron microprobe cathodoluminescence (EMPA-CL) imaging, as well as electron microprobe (EMP) and laser ablation-inductively coupled plasma-mass spectrometry trace element analyses, four major overprinting generations of hydrothermal quartz are defined. Fluid inclusion assemblages (FIAs) in each generation of quartz were characterized by microthermometry and laser Raman spectroscopy. Quartz and fluid inclusion paragenesis are as follows: (Qi) altered and overprinted Qi with no coeval FIAs that formed before or during event 1; (Q1) early veins as well as disseminated quartz with dull gray SEM-CL and H 2 O-NaCl-CO 2 FIAs that formed at minimum temperatures and pressures of 281° to 358°C and 1346 to 1789 bar during event 2 (Au); (Q2) vein and disseminated quartz, often euhedral, with H 2 O-NaCl ± CO 2 ± CH 4 FIAs that formed at minimum temperatures and pressures of 183° to 213°C and 72 to 602 bar during event 3 (W); and (Q3) euhedral and disseminated quartz with H 2 O-NaCl FIAs that formed at minimum temperature and pressures of 156° to 161°C and 5 to 6 bar during event 5 (Sb). Stibnite hosts H 2 O-NaCl FIAs trapped at minimum temperatures and pressures of 150° to 189°C and 5 to 12 bar that are similar to those of Q3-hosted FIAs. The quartz paragenetic history in the district follows a progressive temporal path from Tienriched quartz deposited by a relatively deep and higher temperature aqueous-carbonic fluid to a Li, Al, and Sb enriched quartz precipitated from a lower temperature aqueous fluid. Gases in fluid inclusion extracts from ore and gangue minerals were analyzed by mass spectrometry. Noble gas isotope analysis of fluid inclusion extracts revealed three signatures. Pre-ore Qi has R/R A (the isotopic ratio of the sample 3 He/ 4 He to atmospheric 3 He/ 4 He (1.384 × 10 −6 )) values that reflect the composition of the crustal melt-derived Atlanta lobe of the Idaho batholith. Quartz (Q1) and auriferous arsenian pyrite of hydrothermal event 2 have 20 Ne/ 4 He and R/R A values that plot along the air-crust mixing line, and these gases were likely introduced by metamorphic fluids derived from metasedimentary rocks. Stibnite with associated quartz (Q3 ± Q2) have 20 Ne/ 4 He and R/R A values that extend from the air-crust mixing line to the air-mantle mixing line, showing a shift from a crustal signature to an overprinting mantle signature. Late calcite has 20 Ne/ 4 He and R/R A values that extend from air toward the mantle end member, which suggests that magmatic volatiles condensed into meteoric groundwater late in the paragenesis. A mantle volatile source is also supported by high 20 Ne/ 22 Ne ratios. The Stibnite-Yellow Pine district is similar to other Au-W-Sb districts around the world in ore fluid chemistries, with late-stage stibnite being a product of cooling. The fluid pressure-temperature-composition (P-T-X) estimates and the crustal source of He during hydrothermal event 2 gold mineralization are characteristic of orogenic Au deposits, and the observed inclusion reequilibration textures indicate that trapped fluid inclusions were deformed during transitions between the brittle-ductile environment. Scheelite was deposited during event 3 with Q2 quartz and is overgrown by Q3 quartz and stibnite. Our interpretation of the quartz texture, chemistry, and fluid inclusion P-T-X data suggest that Au, W, and Sb mineralization occurred as hydrothermal fluids evolved from H 2 O-NaCl-CO 2 at >300°C and depths of ~4 to 6 km near the ductile to brittle transition to H 2 O-NaCl at ~150°C and epithermal depths as the Idaho batholith was exhumed. Geochronology indicates that from the Late Cretaceous to early Eocene, overprinting hydrothermal events formed deep orogenic Au, intermediate W, and shallow epithermal Au-Ag and Sb. Without comprehensive geochronologic constraints, our fluid inclusion data and textural observations could be interpreted as a single evolving hydrothermal system, as has been done in many other mining districts with similar mineralization.

Idaho↗
USGS1997

Secondary precious metal enrichment by steam-heated fluids in the Crofoot-Lewis hot spring gold-silver deposit and relation to paleoclimate

The Crofoot-Lewis deposit is an adularia-sericite-type (low-sulfidation) epithermal Au-Ag deposit, whose well-preserved paleosurface includes abundant opaline sinters, widespread and intense silicification, bedded hydrothermal eruption breccias, and a large zone of acid sulfate alteration. Radiogenic isotope ages indicate that the system was relatively long-lived, with hydrothermal activity starting around 4 Ma and extending, at least intermittently, for the next 3 m.y.Field evidence indicates that the surficial zone of acid sulfate alteration formed in a steam-heated environment within an active geothermal system. A drop in the water table enabled descending acid sulfate waters to leach Au and Ag from zones of low-grade disseminated mineralization, resulting in the redistribution and concentration of Au and Ag into ore-grade concentrations. These zones of secondary Au-Ag enrichment are associated with opal + alunite + kaolinite + montmorillonite + or - hematite and were deposited in open space fractures at, and within a few tens of meters below, the paleowater table.The stable isotope systematics of alunite and kaolinite in the steam-heated environment are relatively complex, due to variations in the residence time of aqueous SO 4 that formed from the oxidation of H 2 S prior to precipitation of alunite, and the susceptibility of fine-grained kaolinites to hydrogen isotope exchange with later waters. Most of the alunites are enriched in 34 S relative to early sulfide minerals, reflecting partial S isotope exchange between aqueous SO 4 and H 2 S. About half of the alunites give reasonable calculated delta 18 O (sub SO 4 -OH) temperatures for a steam-heated environment indicating O isotope equilibrium between aqueous SO 4 and water. The delta D (sub H 2 O) values of the hydrothermal fluids varied by almost 60 per rail over the life of the meteoric water-dominated system, suggesting significant climate changes.Mineralization is believed to have resulted from large-scale convection of meteoric water controlled largely by basin and range fractures and a high geothermal gradient with H 2 S for Au complexing derived from organic matter in basin sediments. A wet climate resulted in the formation of a large inland lake which provided abundant recharge water for the hydrothermal system. A fluctuating water table controlled by changing climatic conditions enabled steam-heated acid sulfate fluids to overprint lower grade mineralization resulting in ore-grade precious metal enrichment.

Economic Geology↗
USGS2006

Sediments from bay St. George, Newfoundland

Sediments cored to a depth of about 1 m in Bay St . George , Newfoundland , were examined for grain‐size distribution and minerals. The sediments are light brown silty clays, the principal minerals of which are chlorite and muscovite mica. The scarce sand consists of fresh detrital grains of blue‐green amphibole, biotite, epidote, zoisite, magnetite, garnet, hypersthene, apatite, chlorite, and scarce zircon. Quartz, plagioclase feldspar, and muscovite are abundant. These minerals are all present in the rocks of the adjacent land areas and have been deposited in the sediments with little alteration or change due to weathering. The clay minerals of the sediments are predominantly muscovite and chlorite with a slight admixture of vermiculite and montmorillonite. There is very little mixed‐layering of these minerals. Montmorillonite may be due to diagenetic changes after deposition of these clays in the marine environment of the bay .

Newfoundland↗
USGS1995

Geomagnetism applications

The social uses of geomagnetism include the physics of the space environment, satellite damage, pipeline corrosion, electric power-grid failure, communication interference, global positioning disruption, mineral-resource detection, interpretation of the Earth's formation and structure, navigation, weather, and magnetoreception in organisms. The need for continuing observations of the geomagnetic field, together with careful archiving of these records and mechanisms for dissemination of these data, is emphasized.

Circular↗
USGS1993

Geochemistry of and radioactivity in ground water of the Highland Rim and Central Basin aquifer systems, Hickman and Maury counties, Tennessee

A reconnaissance of the geochemistry of and radioactivity in ground water from the Highland Rim and Central Basin aquifer systems in Hickman and Maury Counties, Tennessee, was conducted in 1989. Water in both aquifer systems typically is of the calcium or calcium magnesium bicarbonate type, but concentrations of calcium, magnesium, sodium, potassium, chloride, and sulfate are greater in water of the Central Basin system; differences in the concentrations are statistically significant. Dissolution of calcite, magnesium-calcite, dolomite, and gypsum are the primary geochemical processes controlling ground-water chemistry in both aquifer systems. Saturation-state calculations using the computer code WATEQF indicated that ground water from the Central Basin system is more saturated with respect to calcite, dolomite, and gypsum than water from the Highland Rim system. Geochemical environments within each aquifer system are somewhat different with respect to dissolution of magnesium-bearing minerals. Water samples from the Highland Rim system had a fairly constant calcium to magnesium molar ratio, implying congruent dissolution of magnesium-bearing minerals, whereas water samples from the Central Basin system had highly variable ratios, implying either incongruent dissolution or heterogeneity in soluble constituents of the aquifer matrix. Concentrations of radionuclides in water were low and not greatly different between aquifer systems. Median gross alpha activities were 0.54 picocuries per liter in water from each system; median gross beta activities were 1.1 and 2.3 picocuries per liter in water from the Highland Rim and Central Basin systems, respectively. Radon-222 concentrations were 559 and 422 picocuries per liter, respectively. Concentrations of gross alpha and radium in all samples were substantially less than Tennessee’s maximum permissible levels for community water-supply systems. The data indicated no relations between concentrations of dissolved radionuclides (uranium, radium-226, radium-228, radon-222, gross alpha, and gross beta) and any key indicators of water chemistry, except in water from the Highland Rim system, in which radon-222 was moderately related to pH and weakly related to dissolved magnesium. The only relation among radiochemical constituents indicated by the data was between radium-226 and gross alpha activity; this relation was indicated for water from both aquifer systems.

Tennessee↗
USGS1973

Problems of underground storage of wastes

Problems of underground storage of waste involve geology in its broadest sense, including hydrology, geochemistry, and geophysics. Wastes may be solid, liquid, or gaseous, and they may be chemically toxic or noxious, esthetically offensive, or radioactive. Some wastes require only temporary containment, whereas others must be isolated for indefinitely long periods. The means and locale for emplacement underground depend upon many governing geological factors, including the physical, chemical, hydrological, and hydraulic properties of the host formation. These must be studied relative to the physical, chemical, and thermal properties of the waste and of potential interactions between the waste and the host formation. Thorough knowledge is essential because lack of it may lead to undesirable or disastrous environmental consequences. Escape of waste may contaminate the surface or near-surface environment; it may destroy the usefulness or accessibility of resources such as ground water, petroleum, and minerals. Effective management of underground waste requires adaptation of current technology and development of new technology.

Journal of Research of the U.S. Geological Survey↗
USGS2020

Antimony mobility during the early stages of stibnite weathering in tailings at the Beaver Brook Sb deposit, Newfoundland

The aqueous speciation and mineralogy of antimony (Sb) in waters and tailings at Beaver Brook antimony deposit have been analyzed to understand Sb mobility during the initial stages of stibnite (Sb2S3) weathering in a near-surface environment. Dissolution of stibnite in oxidizing conditions releases Sb in drainage water and Sb is incorporated into the mineral structures of several secondary minerals. The most abundant Sb host in Beaver Brook tailings is primary stibnite, which dissolves, releasing Sb(III) to the pore water which rapidly oxidizes to Sb¬(V). The maximum concentration of Sb in tailings pore water is 26.4 mg/L and only 0.9% is in form of Sb(III). In all surface water, Sb concentration ranges from 0.01 to 26.1 mg/L (average 9.4 mg/L) and is mostly present in its Sb(V) (98.9 to 99.2 % of total Sb). The secondary minerals containing Sb formed in tailings impoundment, include tripuhyite-like Sb-Fe oxides (FeSbO4) where Sb is an important part of their structure with variable Fe/Sb ratios and Sb concentrations of up to 37.8% by weight (average of 21.7%). These are important Sb host phases in the top 30 cm of tailings. Iron oxides enriched in Sb, such as goethite (FeOOH), where Sb (average of 3.9% by weight) is adsorbed or incorporated in the structure are common but represent less than 1.3 % of the total mass of Sb. The elevated Mg concentrations in tailing ponds and pore water promote the precipitation of brandholzite (Mg[Sb(OH)6]2·6H2O) (in association with gypsum) during dry periods, which is easily dissolved during rainy periods. Brandholzite dissolution may significantly contribute to the concentration of dissolved Sb, together with stibnite dissolution, whereas Sb-Fe oxides are stable in the neutral pH, oxidized surface environment. Arsenic (As) accompanies Sb in all media but its behaviour differs from that of Sb. The source of As is arsenopyrite, which decomposes more slowly than stibnite. This may be due to the formation of oxidation rims on arsenopyrite grains composed of Fe, As, S, Sb and Ca which slow the dissolution, whereas no rims are seen on stibnite. Also, despite similar As and Sb concentration in bulk tailings, the concentration of Sb in drainage water is higher than that of As. In pore water, As(III) is the dominant oxidation state of As suggesting that the oxidation of dissolved As is slower than that of Sb.

Newfoundland↗
USGS2001

Remnant colloform pyrite at the haile gold deposit, South Carolina: A textural key to genesis

Auriferous iron sulfide-bearing deposits of the Carolina slate belt have distinctive mineralogical and textural features-traits that provide a basis to construct models of ore deposition. Our identification of paragenetically early types of pyrite, especially remnant colloform, crustiform, and layered growth textures of pyrite containing electrum and pyrrhotite, establishes unequivocally that gold mineralization was coeval with deposition of host rocks and not solely related to Paleozoic tectonic events. Ore horizons at the Haile deposit, South Carolina, contain many remnants of early pyrite: (1) fine-grained cubic pyrite disseminated along bedding; (2) fine- grained spongy, rounded masses of pyrite that may envelop or drape over pyrite cubes; (3) fragments of botryoidally and crustiform layered pyrite, and (4) pyritic infilling of vesicles and pumice. Detailed mineral chemistry by petrography, microprobe, SEM, and EDS analysis of replaced pumice and colloform structures containing both arsenic compositional banding and electrum points to coeval deposition of gold and the volcanic host rocks and, thus, confirms a syngenetic origin for the gold deposits. Early pyrite textures are present in other major deposits of the Carolina slate belt, such as Ridgeway and Barite Hill, and these provide strong evidence for models whereby the sulfide ores formed prior to tectonism. The role of Paleozoic metamorphism was to remobilize and concentrate gold and other minerals in structurally prepared sites. Recognizing the significance of paragenetically early pyrite and gold textures can play an important role in distinguishing sulfide ores that form in volcanic and sedimentary environments from those formed solely by metamorphic processes. Exploration strategies applied to the Carolina slate belt and correlative rocks in the eastern United States in the Avalonian basement will benefit from using syngenetic models for gold mineralization.

Economic Geology↗
USGS2015

Geochemistry and occurrence of selenium: An overview

Selenium (Se) is both beneficial and toxic to animals, plants, and humans. Consequently, it is imperative to know its concentration in the environment and to understand the processes controlling its distribution. Determinations of Se concentrations in a variety of materials indicate that Se is widely distributed throughout the environment. The processes responsible for its distribution include volcanic activity, the burning of fossil fuels, the weathering of rocks and soils, groundwater transport, precipitation of minerals, adsorption, chemical or bacterial reduction and oxidation, and metabolic uptake and release by plants and animals. The importance of a particular process in controlling the distribution of Se is intimately linked to the speciation of Se, which is controlled by the pH and redox conditions of the environment. Selenium can exist as selenide (Se 2− ), elemental Se (Se 0 ), selenite (SeO 2− 3 ), and selenate (SeO 2− 4 ). Each oxidation state exhibits different chemical behavior. Selenide and elemental Se occur in acidic, reducing, and organic-rich environments. Metal selenides, Se-sulfides, and elemental Se are insoluble, and therefore biologically unavailable. For the pH and redox conditions of most soil and aquatic environments, SeO 2− 3 and SeO 2− 4 ; should be the dominant forms of Se. Selenite is immobilized by adsorption onto particles, particularly Fe oxyhydroxides. Selenate is highly mobile and biologically available because of the solubility of its salts and its weak adsorption by particles. Microbial action can change the speciation of Se through oxidation or reduction, or through the formation of organic Se compounds.

Book chapter↗
USGS2017

The precipitation of indium at elevated pH in a stream influenced by acid mine drainage

Indium is an increasingly important metal in semiconductors and electronics and has uses in important energy technologies such as photovoltaic cells and light-emitting diodes (LEDs). One significant flux of indium to the environment is from lead, zinc, copper, and tin mining and smelting, but little is known about its aqueous behavior after it is mobilized. In this study, we use Mineral Creek, a headwater stream in southwestern Colorado severely affected by heavy metal contamination as a result of acid mine drainage, as a natural laboratory to study the aqueous behavior of indium. At the existing pH of ~ 3, indium concentrations are 6–29 μg/L (10,000 × those found in natural rivers), and are completely filterable through a 0.45 μm filter. During a pH modification experiment, the pH of the system was raised to > 8, and > 99% of the indium became associated with the suspended solid phase (i.e. does not pass through a 0.45 μm filter). To determine the mechanism of removal of indium from the filterable and likely primarily dissolved phase, we conducted laboratory experiments to determine an upper bound for a sorption constant to iron oxides, and used this, along with other published thermodynamic constants, to model the partitioning of indium in Mineral Creek. Modeling results suggest that the removal of indium from the filterable phase is consistent with precipitation of indium hydroxide from a dissolved phase. This work demonstrates that nonferrous mining processes can be a significant source of indium to the environment, and provides critical information about the aqueous behavior of indium.

Colorado↗
USGS2017

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris, and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Picea and Artemisia, but the low percentages of many other types of longdistance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils (Arenaria rubella, Cerastium alpinum type, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosum var. alpinum, Armeria maritima, etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand. ?? 1998 University of Washington.

Quaternary Research↗
USGS2012

Chemistry of rock-forming minerals of the Cretaceous-Paleocene batholith in southwestern Japan and implications for magma genesis

Petrographic descriptions and electron microprobe analyses of minerals are presented for 35 specimens from seven suites chosen to examine the transition from magnetite series to ilmenite series granitoids along two transects across the Cretaceous-Paleocene Inner Zone batholith of southwestern Japan. Regularities in chemical compositions of amphiboles, biotites, and feldspars suggest that fundamentally similar processes produced the magmas that formed the two series. Constant or decreasing Fe/(Fe+Mg) for biotites and amphiboles with increasing host rock silica content, coupled with the absence of early formed magnetite and sphene, suggest that magnetite series rocks may have become oxidized during crystallization near the level of intrusion, through the processes of second boiling and differential loss of hydrogen. For the Daito-Yokota, magnetite series suite, Fe/(Fe+Mg) for biotites decreased from 0.48 to 0.37 as SiO 2 content of the host rock increased from 55.3 to 75.5 wt %; for an ilmenite series suite from the Takanawa Peninsula, Fe/(Fe+Mg) for biotites increased from 0.51 to 0.77 with an increase in host rock SiO 2 from 53.4 to 75.5. Detailed consideration of amphibole chemistry shows predominance of edenitic and tschermakitic substitution schemes as well as coupling between substitutions of Ti in octahedral sites and Al IV . Interrelations between amphibole and biotite chemistry show that Fe/(Fe+Mg) and Mn contents can be interpreted in terms of equilibration, whereas Ti content cannot. The chemistry of chlorites correlates well with that of biotites; primary and secondary muscovites are distinct in composition. Plagioclase in all studied suites shows igneous zoning appropriate to host rock composition; perthitic alkali feldspars in all samples have lost albite component, and temperatures based on the two-feldspar geothermometer are low. The biotite-apatite geothermometer is also inoperative for this group of samples because fully fluorinated apatites typically occur in biotites of modest F content. Whereas magnetites have reequilibrated, analyses of ilmenites for the representative Daito-Yokota and Takanawa suites corroborate biotite compositional data and suggest that f O2 probably differed by 2 to 3 orders of magnitude during crystallization of silica-rich magnetite and ilmenite series granites. Whole-rock chemistry supports mineral chemistry in suggesting that the studied granitoids have crystallized from magmas generated in a lower crustal environment in which mantle-derived magmas partially melted source materials with igneous characteristics.

Journal of Geophysical Research Solid Earth↗
USGS2010

Advances in the hydrogeochemistry and microbiology of acid mine waters

The last decade has witnessed a plethora of research related to the hydrogeochemistry and microbiology of acid mine waters and associated tailings and waste-rock waters. Numerous books, reviews, technical papers, and proceedings have been published that examine the complex bio-geochemical process of sulfide mineral oxidation, develop and apply geochemical models to site characterization, and characterize the microbial ecology of these environments. This review summarizes many of these recent works, and provides references for those investigating this field. Comparisons of measured versus calculated Eh and measured versus calculated pH for water samples from several field sites demonstrate the reliability of some current geochemical models for aqueous speciation and mass balances. Geochemical models are not, however, used to predict accurately time-dependent processes but to improve our understanding of these systems and to constrain possible processes that contribute to actual or potential water quality issues. Microbiological studies are demonstrating that there is much we have yet to learn about the types of different microorganisms and their function and ecology in mine-waste environments. A broad diversity of green algae, bacteria, archaea, yeasts, and fungi are encountered in acid mine waters, and a better understanding of their ecology and function may potentially enhance remediation possibilities as well as our understanding of the evolution of life.

International Geology Review↗
USGS2015

The quality of our Nation's waters: Water quality in the Northern Atlantic Coastal Plain surficial aquifer system, Delaware, Maryland, New Jersey, New York, North Carolina, and Virginia, 1988-2009

The surficial aquifer system of the Northern Atlantic Coastal Plain is made up of unconfined aquifers that underlie most of the area. This aquifer system is a critical renewable source of drinking water and is the source of most flow to streams and of recharge to underlying confined aquifers. Millions of people rely on the surficial aquifer system for public and domestic water supply, in particular in the densely populated areas of Long Island, New York, and in southern New Jersey, but also in more rural areas. Because the aquifer sediments are permeable and the water table is shallow, the surficial aquifer system is vulnerable to contamination from chemicals that are applied to the land surface and carried into groundwater with infiltrating rainfall and snowfall. Major Findings The quality of most groundwater produced for public and domestic water supply is suitable for drinking, although contaminants at concentrations greater than human-health benchmarks have been detected in some places Nitrate is one of the most widespread contaminants in groundwater Radium occurs commonly in groundwater as a result of the degradation of uranium and thorium minerals naturally present in aquifer sediments Chemicals in groundwater move slowly and can be detected in the environment for several decades after they enter the surficial aquifer system

Delaware, Maryland, New Jersey, New York, North Ca↗