Gregory P. Meeker

The Composition and Morphology of Amphiboles from the Rainy Creek Complex, Near Libby, Montana

Abstract Thirty samples of amphibole-rich rock from the largest mined vermiculite deposit in the world in the Rainy Creek alkaline-ultramafic complex near Libby, Montana, were collected and analyzed. The amphibole-rich rock is the suspected cause of an abnormally high number of asbestos-related diseases reported in the residents of Libby, and in former mine and mill workers. The amphibole-rich samples were analyzed to determine composition and morphology of both fibrous and non-fibrous amphiboles. Sampling was carried out across the accessible portions of the deposit to obtain as complete a representation of the distribution of amphibole types as possible. The range of amphibole compositions, determined from electron probe microanalysis and X-ray diffraction analysis, indicates the presence of winchite, richterite, tremolite, and magnesioriebeckite. The amphiboles from Vermiculite Mountain show nearly complete solid solution between these end-member compositions. Magnesio-arfvedsonite and edenite may also be present in low abundance. An evaluation of the textural characteristics of the amphiboles shows the material to include a complete range of morphologies from prismatic crystals to asbestiform fibers. The morphology of the majority of the material is intermediate between these two varieties. All of the amphiboles, with the possible exception of magnesioriebeckite, can occur in fibrous or asbestiform habit. The Vermiculite Mountain amphiboles, even when originally present as massive material, can produce abundant, extremely fine fibers by gentle abrasion or crushing.

Linking geological and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria.

Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.

Geologic occurrences of erionite in the United States: an emerging national public health concern for respiratory disease

Erionite, a mineral series within the zeolite group, is classified as a Group 1 known respiratory carcinogen. This designation resulted from extremely high incidences of mesothelioma discovered in three small villages from the Cappadocia region of Turkey, where the disease was linked to environmental exposures to fibrous forms of erionite. Natural deposits of erionite, including fibrous forms, have been identified in the past in the western United States. Until recently, these occurrences have generally been overlooked as a potential hazard. In the last several years, concerns have emerged regarding the potential for environmental and occupational exposures to erionite in the United States, such as erionite-bearing gravels in western North Dakota mined and used to surface unpaved roads. As a result, there has been much interest in identifying locations and geologic environments across the United States where erionite occurs naturally. A 1996 U.S. Geological Survey report describing erionite occurrences in the United States has been widely cited as a compilation of all US erionite deposits; however, this compilation only focused on one of several geologic environments in which erionite can form. Also, new occurrences of erionite have been identified in recent years. Using a detailed literature survey, this paper updates and expands the erionite occurrences database, provided in a supplemental file (US_erionite.xls). Epidemiology, public health, and natural hazard studies can incorporate this information on known erionite occurrences and their characteristics. By recognizing that only specific geologic settings and formations are hosts to erionite, this knowledge can be used in developing management plans designed to protect the public.

Characterization and modeling of illite crystal particles and growth mechanisms in a zoned hydrothermal deposit, Lake City, Colorado

Abstract Mean thickness measurements and crystal-thickness distributions (CTDs) of illite particles vary systematically with changes in hydrothermal alteration type, fracture density, and attendant mineralization in a large acid-sulfate/Mo-porphyry hydrothermal system at Red Mountain, near Lake City, Colorado. The hydrothermal illites characterize an extensive zone of quartz-sericite-pyrite alteration beneath two deeply rooted bodies of magmatic-related, quartz-alunite altered rock. Nineteen illites from a 3000 ft vertical drill hole were analyzed by XRD using the PVP-10 intercalation method and the computer program MudMaster (Bertaut-Warren-Averbach technique). Mean crystallite thicknesses, as determined from 001 reflections, range from 5-7 nanometers (nm) at depths from 0-1700 ft, then sharply increase to 10-16 nm at depths between 1800-2100 ft, and decrease again to 4-5 nm below this level. The interval of largest particle thickness correlates strongly with the zone of most intense quartz-sericite-pyrite alteration (QSP) and attendant high-density stockwork fracturing, and with the highest concentrations of Mo within the drill core. CTD shapes for the illite particles fall into two main categories: asymptotic and lognormal. The shapes of the CTDs are dependent on conditions of illite formation. The asymptotic CTDs correspond to a nucleation and growth mechanism, whereas surface-controlled growth was the dominant mechanism for the lognormal CTDs. Lognormal CTDs coincide with major through-going fractures or stockwork zones, whereas asymptotic CTDs are present in wallrock distal to these intense fracture zones. The increase in illite particle size and the associated zone of intense QSP alteration and stockwork veining was related by proximity to the dacitic magma(s), which supplied both reactants and heat to the hydrothermal system. However, no changes in illite polytype, which in other studies reflect temperature transitions, were observed within this interval.

Overview and recommendations for medical screening and diagnostic evaluation for postdeployment lung disease in returning US warfighters.

Objective: To review inhalational exposures and respiratory disease risks in US military personnel deployed to Iraq and Afghanistan and to develop consensus recommendations for medical screening and diagnostic referral. Methods: A Working Group of physicians and exposure scientists from academia and from the Departments of Defense and Veterans Affairs was convened in February 2010. Results: Despite uncertainty about the number of people affected and risk factors for adverse pulmonary outcomes in this occupational setting, the Working Group recommended: (1) standardized approaches to pre- and postdeployment medical surveillance; (2) criteria for medical referral and diagnosis; and (3) case definitions for major deployment-related lung diseases. Conclusions: There is a need for targeted, practical medical surveillance for lung diseases and for a standardized diagnostic approach for all symptomatic deployed personnel.

The 4.56 Ga UPb age of the MET 780058 ureilite

The UThPb and SmNd isotopic systematics of mineral separates from the Ca-rich ureilite MET 78008 are reported. Extensive acid leaching procedures were used to eliminate terrestrial contamination because the amounts of U, Th, Pb, Sm, and Nd are extremely low in the meteorite. The three residues without terrestrial Pb contamination yield a PbPb age of 4.563 ± 0.021 Ga. On a UPb concordia diagram, the residue data corrected for an initial lead isotopic composition calculated with μ = 11.7 for 3 Ma from starting Canon Diablo troilite Pb in indicate a 2O7Pb∗/206Pb∗ model age of 4.563 Ga. The SmNd isotopic data are scattered around the 4.56-Ga chondritic isochron. However, the SmNd model age for handpicked augite is 4.573 ± 0.029 Ga, assuming an initial CHUR composition. Two separates show a positive 142Nd anomaly similar to those found in other meteorites of the same age (4.5–4.6 Ga). These SmNd isotopic results support the PbPb and UPb ages of this meteorite. Therefore, it is very likely that the formation age of ureilites is consistent with the so-called “4.56-Ga canonical age of meteorites.” It is also possible that extensive igneous processes for generating the ultramatic mineralogy of ureilites took place in the parent body within a few million years after formation of the solar nebula.

Differentiation of commercial vermiculite based on statistical analysis of bulk chemical data: Fingerprinting vermiculite from Libby, Montana U.S.A.

Abstract Major-, minor-, and trace-element compositions, as determined by X-ray fluorescence (XRF) analysis, were obtained on 34 samples of vermiculite to ascertain whether chemical differences exist to the extent of determining the source of commercial products. The sample set included ores from four deposits, seven commercially available garden products, and insulation from four attics. The trace-element distributions of Ba, Cr, and V can be used to distinguish the Libby vermiculite samples from the garden products. In general, the overall composition of the Libby and South Carolina deposits appeared similar, but differed from the South Africa and China deposits based on simple statistical methods. Cluster analysis provided a good distinction of the four ore types, grouped the four attic samples with the Libby ore, and, with less certainty, grouped the garden samples with the South Africa ore.

Summary of the development of a signature for detection of residual dust from collapse of the World Trade Center buildings.

The collapse of the World Trade Center (WTC) towers on September 11, 2001, caused lower Manhattan and adjacent areas to be covered in millimeters to centimeters of dust. WTC dust penetrated into indoor spaces, and public health concerns remain regarding exposure to possible residual dust in the affected areas. The goal of the studies outlined in this review was to determine which, if any, components of the bulk WTC dust are sufficiently above typical background dust levels in New York City to develop an analytical method to screen for the component(s). Components of the <150-μm-size fraction of the dust are gypsum, phases compatible with crushed concrete, man-made vitreous fibers (MMVFs), silica, lead, chrysotile asbestos, and other materials. Slag wool was the most common WTC MMVF, whereas soda-lime glass and rock wool were minor to trace constituents. Most background samples also contained gypsum, phases compatible with concrete, and MMVF. However, the proportions of the various MMVF in background samples are typically unlike those characteristic of bulk WTC dust. Results indicate that slag wool can be used as a signature marker to identify areas that contain potential residual WTC dust contamination at concentrations that are less than average background levels for the material.

Chapter 8 Petrogenesis and mineralogic residence of selected elements in the meade peak phosphatic shale member of the permian phosphoria formation, Southeast Idaho

Abstract The Meade Peak Phosphatic Shale Member of the Permian Phosphoria Formation hosts the ore mined by the phosphate industry of southeast Idaho. It also hosts environmentally sensitive elements (ESE) such as Se, As, Hg, Ni, Cd, Zn, and Cr. Primary chemistry, elemental distribution patterns, and mineralogy within the Meade Peak were modified by element migration and possibly the introduction of elements. Fluids moved within the Meade Peak throughout its history, although the passage of fluids was highly variable in space and time, resulting in small domains of different rock chemistry and different mineralogy. Timing of major events affecting the Meade Peak and mineral habit are used to differentiate among detrital, diagenetic, epigenetic, and supergene mineral assemblages. Cross-cutting relationships among minerals are too rare to provide much paragenetic infor- mation. Carbonate fluorapatite (CFA) occurs in several forms, but dominantly as pelloids, some of which may have formed in situ during diagenesis. The other volumetrically signifi- cant form of CFA is interstitial cement that formed during diagenesis. Beginning during diagenesis and continuing intermittently, multiple generations of carbonate (dolomite and calcite) formed overgrowths and texturally complex carbonate cements. Movement and precipitation of silica followed a similar pattern. The ammonium feldspar buddingtonite, which generally rims orthoclase, also formed during diagenesis. Bacteria apparently played a significant role during diagenesis as well as during supergene processes, resulting in extreme fractionation of S isotopes and the possible bacterially mediated formation of minerals such as glauconite and sphalerite. Catagenesis, apparently culminating in oil generation, was the last significant diagenetic change. Thrusting accompanied by fluid (oil and brine) migration began during catagenesis in the Late Jurassic or Cretaceous and continued into the early Eocene. Fluorite ± carbonate ± barite± bitumen veins formed as a result of brittle deformation and accompanying fluid movement. This fracturing event may have been associated with a period of extension and normal faulting (Neogene to Holocene). Passage of the Yellowstone hot spot to the north of the area during the Neogene is marked by silicic domes and basaltic flows. The enrichment of Hg in fracture coatings might be the result of deposition from warm fluids associated with the emplacement of the silicic domes or a generally elevated, regional thermal gradient associated with the volcanism. Many of the fracture systems are still open and continue to provide fluid pathways that are the primary depositional sites for a wide variety of supergene minerals (such as Se, efflorescent salts) and element associations (such as Hg, Cd-S, Fe-Cr-O) in which many of the ESE are concentrated. Native Se is the most commonly identified host of Se in the studied samples. The largest concentration of Se occurs in open-fracture systems that cross-cut waste rock and ore units. The age(s) of native Se formation is not known; how- ever, the latest period of Se mobility is the present. Direct measurement of efflorescent “salts” forming on new mine faces indicate that several ESE, including both Se and Zn, are concentrated on the faces soon after they are exposed. Zinc is present as hydrous sulfates, but the residence of Se in these “salts” is unknown.

Development of Standardized Lunar Regolith Simulant Materials

Lunar exploration requires scientific and engineering studies using standardized testing procedures that ultimately support flight certification of technologies and hardware. It is necessary to anticipate the range of source materials and environmental constraints that are expected on the Moon and Mars, and to evaluate in-situ resource utilization (ISRU) coupled with testing and development. We describe here the development of standardized lunar regolith simulant (SLRS) materials that are traceable inter-laboratory standards for testing and technology development. These SLRS materials must simulate the lunar regolith in terms of physical, chemical, and mineralogical properties. A summary of these issues is contained in the 2005 Workshop on Lunar Regolith Simulant Materials [l]. Lunar mare basalt simulants MLS-1 and JSC-1 were developed in the late 1980s. MLS-1 approximates an Apollo 11 high-Ti basalt, and was produced by milling of a holocrystalline, coarse-grained intrusive gabbro (Fig. 1). JSC-1 approximates an Apollo 14 basalt with a relatively low-Ti content, and was obtained from a glassy volcanic ash (Fig. 2). Supplies of MLS-1 and JSC-1 have been exhausted and these materials are no longer available. No highland anorthosite simulant was previously developed. Upcoming lunar polar missions thus require the identification, assessment, and development of both mare and highland simulants. A lunar regolith simulant is manufactured from terrestrial components for the purpose of simulating the physical and chemical properties of the lunar regolith. Significant challenges exist in the identification of appropriate terrestrial source materials. Lunar materials formed under comparatively reducing conditions in the absence of water, and were modified by meteorite impact events. Terrestrial materials formed under more oxidizing conditions with significantly greater access to water, and were modified by a wide range of weathering processes. The composition space of lunar materials can be modeled by mixing programs utilizing a low-Ti basalt, ilmenite, KREEP component, high-Ca anorthosite, and meteoritic components. This approach has been used for genetic studies of lunar samples via chemical and modal analysis. A reduced composition space may be appropriate for simulant development, but it is necessary to determine the controlling properties that affect the physical, chemical and mineralogical components of the simulant.