Heather A Lowers
Heather Lowers is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 31
Microanalysis of samples collected from sandstone-hosted uranium and vanadium deposits in the Colorado Plateau: Utah, New Mexico and Colorado, USA Microanalysis of samples collected from sandstone-hosted uranium and vanadium deposits in the Colorado Plateau: Utah, New Mexico and Colorado, USA
These data are microanalyses of 91 polished thin sections that were examined using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) to identify minerals and observe their relationships at high magnification. Samples are from the Triassic Chinle and Jurassic Morrison Formations and adjacent units, which are the main hosts for sandstone-hosted...
Data release of geochemistry and geochronology for Proterozoic rocks in southwestern Colorado and rocks from drill core from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska Data release of geochemistry and geochronology for Proterozoic rocks in southwestern Colorado and rocks from drill core from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska
This U.S. Geological Survey (USGS) data release provides whole rock major, minor, and trace element geochemical data, mineral chemistry, and monazite and xenotime geochronology for Proterozoic rocks in the Needle Mountains of southwestern Colorado and for Proterozoic rocks sampled from drill cores from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska. Samples from the...
Denali Fault Zone Field, Microvein, and Microbeam Data, Kluane Ranges, Yukon, Canada Denali Fault Zone Field, Microvein, and Microbeam Data, Kluane Ranges, Yukon, Canada
Detailed geologic mapping and sample collection was conducted in rare bedrock exposures of the Denali fault zone during the summer months of 2013, 2014, and 2015 by the U.S. Geological Survey. Data include measurements of structural geologic orientations and documentation of fault zone and host rock characteristics. Representative samples were selected for measurements of fault vein...
Characteristics of Dust Associated with the Development of Rapidly Progressive Pneumoconiosis and Progressive Massive Fibrosis Characteristics of Dust Associated with the Development of Rapidly Progressive Pneumoconiosis and Progressive Massive Fibrosis
Research and surveillance reports have documented a significant increase in coal workers' pneumoconiosis, including the most severe forms of progressive massive fibrosis and rapidly progressive pneumoconiosis in U.S. coal miners, particularly those in Appalachian coalfields. Several possible explanations for these observations include excessive exposures to total respirable dust...
Microanalysis of samples collected from the Sulfur Springs Draw calcrete-type uranium deposit in the Southern High Plains, Texas, USA Microanalysis of samples collected from the Sulfur Springs Draw calcrete-type uranium deposit in the Southern High Plains, Texas, USA
This data release presents the results of microanalysis of 2 samples SSD15_01A (1 thin section and 1 composite chip sample), and SSD15_01B (1 thin section). The samples were collected in 2015 by U.S. Geological Survey geologists Bradley Van Gosen and Susan Hall from surface exposures of uranium mineralization in Sulfur Springs Draw, in Martin County, Texas (Van Gosen and Hall, 2017). The...
Geochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA Geochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA
The Reef Package is a sequence of coarse-grained cumulates that host the J-M Reef Pd-Pt deposit in the Stillwater Complex of Montana. The top of the Reef Package marks the top of economic-grade platinum-group element mineralization and is identified by a distinct change in rock fabric, from the coarse-grained rocks of the Reef Package to finer-grained cumulates in the hanging wall. This...
Geochemical data for the Elk Creek alkaline complex, southeast Nebraska Geochemical data for the Elk Creek alkaline complex, southeast Nebraska
This U.S. Geological Survey (USGS) data release contains analytical data from a suite of rock and mineral samples collected from drill core within the Elk Creek alkaline complex, southeast Nebraska. This complex hosts the Elk Creek carbonatite, a multilithologic carbonatite enriched in niobium, rare earth elements (REEs), scandium, and titanium. Mineralized carbonatites are the world's
Spectroscopy of Expanded Vermiculite Products and Insulation Spectroscopy of Expanded Vermiculite Products and Insulation
This dataset contains descriptions and analytical data (i.e., electron microprobe, X-ray diffraction, spectral reflectance, and scanning electron microprobe analyses) for unexpanded and expanded vermiculite samples. These data are provided for 52 samples of vermiculite attic insulation, horticultural products, aggregate, and packing materials derived from mines near Enoree, South...
Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska
The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral...
Table of Electron Probe Microanalyses of Native Copper and Sulfide Minerals from the White Pine Sediment-hosted Copper Deposit, Michigan Table of Electron Probe Microanalyses of Native Copper and Sulfide Minerals from the White Pine Sediment-hosted Copper Deposit, Michigan
This data release provides electron microprobe geochemical data that was collected as part of a scoping study to evaluate whether unconventional critical element resources may be associated with sediment-hosted copper systems in the Midcontinent Rift. We report abundances of trace elements in native copper and sulfide minerals in 12 thin sections from samples of the Mesoproterozoic lower...
Table of Electron Probe Microanalyses of Cassiterite from the Sullivan Pb-Zn-Ag Deposit, British Columbia Table of Electron Probe Microanalyses of Cassiterite from the Sullivan Pb-Zn-Ag Deposit, British Columbia
This dataset contains results from electron microprobe analyses of cassiterite from the Sullivan Pb-Zn-Ag deposit, British Columbia. These data were collected from two samples and may not reflect the overall variability present at the deposit. An ASCII text file of results is provided in comma-separated by value (csv) format. The file has the name "2019-07-09_Sullivan_Cassiterite".
Mineralogical analyses of drill core samples from the Canyon uranium-copper deposit, a solution-collapse breccia pipe, Grand Canyon area, Coconino County, Arizona, USA Mineralogical analyses of drill core samples from the Canyon uranium-copper deposit, a solution-collapse breccia pipe, Grand Canyon area, Coconino County, Arizona, USA
This data release compiles the X-ray diffraction and electron microscopy analyses of drill core samples collected by the U.S. Geological Survey that were selected to typify the uranium-copper ore bodies of the Canyon deposit. The deposit is hosted by a solution-collapse breccia pipe, in which mineralization exists from about 650 to 2,100 ft (200 to 640 m) below the surface (Mathisen and...
Filter Total Items: 106
Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry
Cultures throughout history have valued jadeite jade (hereinafter jade), a natural material assemblage composed predominately of the NaAl endmember pyroxene, jadeite (NaAlSi2O6) that is prized for its mechanical properties and enticing coloration [1, 2]. The geological setting for the formation of jadeite-rich rocks and associated complex geochemical phenomena is well documented in the...
Authors
Edward P. Vicenzi, Thomas Lameris, Heather A. Lowers, Colin MacRae
Compositional and structural mapping of Northwest Africa 15507 angrite Compositional and structural mapping of Northwest Africa 15507 angrite
Angrite meteorites represent interesting sampling of planetary crustal environments. Quench-textured angrites with strong crystal zoning originated from the shallow surface region, with evidence of reducing conditions during solidification. Plutonic angrites have more coarse-grained igneous and metamorphic textures with comparatively less zoning and are interpreted as having equilibrated...
Authors
Heather A. Lowers, Paul C. Carpenter, Jay Michael Thompson, Anthony Irving
In situ lung dust analysis by automated Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy: A method for assessing inorganic particles in tissue from coal miners In situ lung dust analysis by automated Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy: A method for assessing inorganic particles in tissue from coal miners
Context.— Overexposure to respirable coal mine dust can cause severe lung disease including progressive massive fibrosis (PMF). Field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDS) has been used for in situ lung dust particle analysis for evaluation of disease etiology. Automating such work can reduce time, costs, and user bias.Objective.— To...
Authors
Emily A. Sarver, C. Keles, Heather A. Lowers, L. Zell-Baran, Leonard H. T. Go, J. Hua, C. Cool, Cecile Rose, F.H. Green, K. S. Almberg, R. A. Cohen
Trace silicon determination in biological samples by inductively coupled plasma mass spectrometry (ICP-MS): Insight into volatility of silicon species in hydrofluoric acid digests for optimal sample preparation and introduction to ICP-MS Trace silicon determination in biological samples by inductively coupled plasma mass spectrometry (ICP-MS): Insight into volatility of silicon species in hydrofluoric acid digests for optimal sample preparation and introduction to ICP-MS
A method for the determination of trace levels of silicon from biological materials by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. The volatility of water-soluble silicon species, hexafluorosilicic acid (H2SiF6), and sodium metasilicate (Na2SiO3) was investigated by evaporating respective solutions (50 µg/mL silicon) in nitric acid (HNO3), nitric acid +...
Authors
Zikri Arslan, Heather A. Lowers
Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen
The crustal evolution of the southernmost ∼2000–1800 Ma Trans-Hudson orogen (THO) is enigmatic due to burial by Phanerozoic sediments. We provide new insights through petrochronologic analysis of a paragneiss drill core sample. Detrital zircon age peaks at 2625, 2340, and 1880 Ma and Hf isotopes suggest Paleoproterozoic arc development proximal to Archean source(s). Phase equilibria...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Amanda Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
Particle morphology and elemental analysis of lung tissue from post-9/11 military personnel with biopsy-proven lung disease Particle morphology and elemental analysis of lung tissue from post-9/11 military personnel with biopsy-proven lung disease
The relationship between exposure to inhaled inorganic particulate matter and risk for deployment-related lung disease in military personnel is unclear due in part to difficulties characterizing individual exposure to airborne hazards. We evaluated the association between self-reported deployment exposures and particulate matter (PM) contained in lung tissue from previously deployed...
Authors
Heather A. Lowers, Lauren M. Zell-Baran, Zikri Arslan, Camille Moore, Cecile Rose
Hydrothermal monazite and xenotime chemistry as genetic discriminators for intrusion-related and orogenic gold deposits: Implications for an orogenic origin of the Pogo gold deposit, Alaska Hydrothermal monazite and xenotime chemistry as genetic discriminators for intrusion-related and orogenic gold deposits: Implications for an orogenic origin of the Pogo gold deposit, Alaska
Attempts to geochemically distinguish between metamorphic-hydrothermal systems that form orogenic gold deposits and both reduced and oxidized magmatic-hydrothermal systems using isotopes or metal associations have proven ambiguous, particularly for orogenic gold and reduced intrusion-related gold systems. The absence of conclusive geochemical discriminators and the overlap in geologic
Authors
Ryan D. Taylor, Garth E. Graham, Heather A. Lowers
Reconnaissance mineral and cathodoluminescence studies of gold occurrences in the Pogo-Black Mountain area, eastern interior Alaska, USA Reconnaissance mineral and cathodoluminescence studies of gold occurrences in the Pogo-Black Mountain area, eastern interior Alaska, USA
The Pogo Au deposit is the largest of a number of gold occurrences in eastern interior Alaska, that occur along a broad trend from west of Pogo to Black Mountain. Some of these occurrences are hosted in amphibolite facies gneisses and others in mid-Cretaceous igneous rocks that intruded the older metamorphic rocks. All occurrences contain arsenopyrite and pyrite. Whole rock geochemical...
Authors
Garth E. Graham, Erin E. Marsh, Heather A. Lowers, Ryan D. Taylor
The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite
Carbonatite-hosted rare earth element (REE) deposits are the primary source of the world’s light REEs and have the potential to be a source of heavy REEs. The Mount Weld REE deposit in Western Australia is hosted in a lateritic sequence that reflects supergene enrichment of the underlying carbonatite complex. Similar to other carbonatite-related ore deposits, ore from Mount Weld displays...
Authors
Philip Verplanck, Heather A. Lowers, Adam Boehlke, Jay Michael Thompson, Ganesh Bhat, Cameron Mark Mercer
Hyperspectral cathodoluminescence and quantitative EPMA mapping of angrite northwest Africa 15507 Hyperspectral cathodoluminescence and quantitative EPMA mapping of angrite northwest Africa 15507
Angrite meteorites represent alkali depleted planetary crust of basaltic composition, and have both plutonic and volcanic lithologies. NWA 15507 is a microgabbroic specimen (mean grainsize ~1.4 mm) composed predominantly of zoned Al-Ti-augite, Ca-bearing olivine and anorthite together with accessory kirschsteinite, rhönite, hercynite, low-Ni kamacite, merrillite, magnetite and troilite...
Authors
Heather A. Lowers, Jay Michael Thompson, Paul K. Carpenter, Zoe Wilbur, Anthony Irving
Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA
The Proterozoic tectonic evolution of the south-western USA remains incompletely understood due to limited constraints on the timing and conditions of the tectono-metamorphic phases and depositional age of metasedimentary successions. We integrated multi-scale compositional mapping, petrologic modeling, and in situ geochronology to constrain pressure-temperature-time paths from samples...
Authors
Ian William Hillenbrand, Michael L. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda Souders
Characterizing lung particulates using quantitative microscopy in coal miners with severe pneumoconiosis Characterizing lung particulates using quantitative microscopy in coal miners with severe pneumoconiosis
Context.— Current approaches for characterizing retained lung dust using pathologists' qualitative assessment or scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) have limitations. Objective.— To explore polarized light microscopy coupled with image-processing software, termed quantitative microscopy–particulate matter (QM-PM), as a tool to characterize in situ...
Authors
Jeremy T. Hua, Carlyne D. Cool, Heather A. Lowers, Leonard H. T. Go, Lauren M. Zell-Baran, Emily A. Sarver, Kirsten S. Almberg, Kathy D. Pang, Susan M. Majka, Angela D. Franko, Naseema I. Vorajee, Robert A. Cohen, Cecil S. Rose
Science and Products
Filter Total Items: 31
Microanalysis of samples collected from sandstone-hosted uranium and vanadium deposits in the Colorado Plateau: Utah, New Mexico and Colorado, USA Microanalysis of samples collected from sandstone-hosted uranium and vanadium deposits in the Colorado Plateau: Utah, New Mexico and Colorado, USA
These data are microanalyses of 91 polished thin sections that were examined using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) to identify minerals and observe their relationships at high magnification. Samples are from the Triassic Chinle and Jurassic Morrison Formations and adjacent units, which are the main hosts for sandstone-hosted...
Data release of geochemistry and geochronology for Proterozoic rocks in southwestern Colorado and rocks from drill core from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska Data release of geochemistry and geochronology for Proterozoic rocks in southwestern Colorado and rocks from drill core from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska
This U.S. Geological Survey (USGS) data release provides whole rock major, minor, and trace element geochemical data, mineral chemistry, and monazite and xenotime geochronology for Proterozoic rocks in the Needle Mountains of southwestern Colorado and for Proterozoic rocks sampled from drill cores from Colorado, North Dakota, Nevada, Wyoming, Montana, and Nebraska. Samples from the...
Denali Fault Zone Field, Microvein, and Microbeam Data, Kluane Ranges, Yukon, Canada Denali Fault Zone Field, Microvein, and Microbeam Data, Kluane Ranges, Yukon, Canada
Detailed geologic mapping and sample collection was conducted in rare bedrock exposures of the Denali fault zone during the summer months of 2013, 2014, and 2015 by the U.S. Geological Survey. Data include measurements of structural geologic orientations and documentation of fault zone and host rock characteristics. Representative samples were selected for measurements of fault vein...
Characteristics of Dust Associated with the Development of Rapidly Progressive Pneumoconiosis and Progressive Massive Fibrosis Characteristics of Dust Associated with the Development of Rapidly Progressive Pneumoconiosis and Progressive Massive Fibrosis
Research and surveillance reports have documented a significant increase in coal workers' pneumoconiosis, including the most severe forms of progressive massive fibrosis and rapidly progressive pneumoconiosis in U.S. coal miners, particularly those in Appalachian coalfields. Several possible explanations for these observations include excessive exposures to total respirable dust...
Microanalysis of samples collected from the Sulfur Springs Draw calcrete-type uranium deposit in the Southern High Plains, Texas, USA Microanalysis of samples collected from the Sulfur Springs Draw calcrete-type uranium deposit in the Southern High Plains, Texas, USA
This data release presents the results of microanalysis of 2 samples SSD15_01A (1 thin section and 1 composite chip sample), and SSD15_01B (1 thin section). The samples were collected in 2015 by U.S. Geological Survey geologists Bradley Van Gosen and Susan Hall from surface exposures of uranium mineralization in Sulfur Springs Draw, in Martin County, Texas (Van Gosen and Hall, 2017). The...
Geochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA Geochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA
The Reef Package is a sequence of coarse-grained cumulates that host the J-M Reef Pd-Pt deposit in the Stillwater Complex of Montana. The top of the Reef Package marks the top of economic-grade platinum-group element mineralization and is identified by a distinct change in rock fabric, from the coarse-grained rocks of the Reef Package to finer-grained cumulates in the hanging wall. This...
Geochemical data for the Elk Creek alkaline complex, southeast Nebraska Geochemical data for the Elk Creek alkaline complex, southeast Nebraska
This U.S. Geological Survey (USGS) data release contains analytical data from a suite of rock and mineral samples collected from drill core within the Elk Creek alkaline complex, southeast Nebraska. This complex hosts the Elk Creek carbonatite, a multilithologic carbonatite enriched in niobium, rare earth elements (REEs), scandium, and titanium. Mineralized carbonatites are the world's
Spectroscopy of Expanded Vermiculite Products and Insulation Spectroscopy of Expanded Vermiculite Products and Insulation
This dataset contains descriptions and analytical data (i.e., electron microprobe, X-ray diffraction, spectral reflectance, and scanning electron microprobe analyses) for unexpanded and expanded vermiculite samples. These data are provided for 52 samples of vermiculite attic insulation, horticultural products, aggregate, and packing materials derived from mines near Enoree, South...
Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska
The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral...
Table of Electron Probe Microanalyses of Native Copper and Sulfide Minerals from the White Pine Sediment-hosted Copper Deposit, Michigan Table of Electron Probe Microanalyses of Native Copper and Sulfide Minerals from the White Pine Sediment-hosted Copper Deposit, Michigan
This data release provides electron microprobe geochemical data that was collected as part of a scoping study to evaluate whether unconventional critical element resources may be associated with sediment-hosted copper systems in the Midcontinent Rift. We report abundances of trace elements in native copper and sulfide minerals in 12 thin sections from samples of the Mesoproterozoic lower...
Table of Electron Probe Microanalyses of Cassiterite from the Sullivan Pb-Zn-Ag Deposit, British Columbia Table of Electron Probe Microanalyses of Cassiterite from the Sullivan Pb-Zn-Ag Deposit, British Columbia
This dataset contains results from electron microprobe analyses of cassiterite from the Sullivan Pb-Zn-Ag deposit, British Columbia. These data were collected from two samples and may not reflect the overall variability present at the deposit. An ASCII text file of results is provided in comma-separated by value (csv) format. The file has the name "2019-07-09_Sullivan_Cassiterite".
Mineralogical analyses of drill core samples from the Canyon uranium-copper deposit, a solution-collapse breccia pipe, Grand Canyon area, Coconino County, Arizona, USA Mineralogical analyses of drill core samples from the Canyon uranium-copper deposit, a solution-collapse breccia pipe, Grand Canyon area, Coconino County, Arizona, USA
This data release compiles the X-ray diffraction and electron microscopy analyses of drill core samples collected by the U.S. Geological Survey that were selected to typify the uranium-copper ore bodies of the Canyon deposit. The deposit is hosted by a solution-collapse breccia pipe, in which mineralization exists from about 650 to 2,100 ft (200 to 640 m) below the surface (Mathisen and...
Filter Total Items: 106
Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry
Cultures throughout history have valued jadeite jade (hereinafter jade), a natural material assemblage composed predominately of the NaAl endmember pyroxene, jadeite (NaAlSi2O6) that is prized for its mechanical properties and enticing coloration [1, 2]. The geological setting for the formation of jadeite-rich rocks and associated complex geochemical phenomena is well documented in the...
Authors
Edward P. Vicenzi, Thomas Lameris, Heather A. Lowers, Colin MacRae
Compositional and structural mapping of Northwest Africa 15507 angrite Compositional and structural mapping of Northwest Africa 15507 angrite
Angrite meteorites represent interesting sampling of planetary crustal environments. Quench-textured angrites with strong crystal zoning originated from the shallow surface region, with evidence of reducing conditions during solidification. Plutonic angrites have more coarse-grained igneous and metamorphic textures with comparatively less zoning and are interpreted as having equilibrated...
Authors
Heather A. Lowers, Paul C. Carpenter, Jay Michael Thompson, Anthony Irving
In situ lung dust analysis by automated Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy: A method for assessing inorganic particles in tissue from coal miners In situ lung dust analysis by automated Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy: A method for assessing inorganic particles in tissue from coal miners
Context.— Overexposure to respirable coal mine dust can cause severe lung disease including progressive massive fibrosis (PMF). Field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDS) has been used for in situ lung dust particle analysis for evaluation of disease etiology. Automating such work can reduce time, costs, and user bias.Objective.— To...
Authors
Emily A. Sarver, C. Keles, Heather A. Lowers, L. Zell-Baran, Leonard H. T. Go, J. Hua, C. Cool, Cecile Rose, F.H. Green, K. S. Almberg, R. A. Cohen
Trace silicon determination in biological samples by inductively coupled plasma mass spectrometry (ICP-MS): Insight into volatility of silicon species in hydrofluoric acid digests for optimal sample preparation and introduction to ICP-MS Trace silicon determination in biological samples by inductively coupled plasma mass spectrometry (ICP-MS): Insight into volatility of silicon species in hydrofluoric acid digests for optimal sample preparation and introduction to ICP-MS
A method for the determination of trace levels of silicon from biological materials by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. The volatility of water-soluble silicon species, hexafluorosilicic acid (H2SiF6), and sodium metasilicate (Na2SiO3) was investigated by evaporating respective solutions (50 µg/mL silicon) in nitric acid (HNO3), nitric acid +...
Authors
Zikri Arslan, Heather A. Lowers
Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen
The crustal evolution of the southernmost ∼2000–1800 Ma Trans-Hudson orogen (THO) is enigmatic due to burial by Phanerozoic sediments. We provide new insights through petrochronologic analysis of a paragneiss drill core sample. Detrital zircon age peaks at 2625, 2340, and 1880 Ma and Hf isotopes suggest Paleoproterozoic arc development proximal to Archean source(s). Phase equilibria...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Amanda Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
Particle morphology and elemental analysis of lung tissue from post-9/11 military personnel with biopsy-proven lung disease Particle morphology and elemental analysis of lung tissue from post-9/11 military personnel with biopsy-proven lung disease
The relationship between exposure to inhaled inorganic particulate matter and risk for deployment-related lung disease in military personnel is unclear due in part to difficulties characterizing individual exposure to airborne hazards. We evaluated the association between self-reported deployment exposures and particulate matter (PM) contained in lung tissue from previously deployed...
Authors
Heather A. Lowers, Lauren M. Zell-Baran, Zikri Arslan, Camille Moore, Cecile Rose
Hydrothermal monazite and xenotime chemistry as genetic discriminators for intrusion-related and orogenic gold deposits: Implications for an orogenic origin of the Pogo gold deposit, Alaska Hydrothermal monazite and xenotime chemistry as genetic discriminators for intrusion-related and orogenic gold deposits: Implications for an orogenic origin of the Pogo gold deposit, Alaska
Attempts to geochemically distinguish between metamorphic-hydrothermal systems that form orogenic gold deposits and both reduced and oxidized magmatic-hydrothermal systems using isotopes or metal associations have proven ambiguous, particularly for orogenic gold and reduced intrusion-related gold systems. The absence of conclusive geochemical discriminators and the overlap in geologic
Authors
Ryan D. Taylor, Garth E. Graham, Heather A. Lowers
Reconnaissance mineral and cathodoluminescence studies of gold occurrences in the Pogo-Black Mountain area, eastern interior Alaska, USA Reconnaissance mineral and cathodoluminescence studies of gold occurrences in the Pogo-Black Mountain area, eastern interior Alaska, USA
The Pogo Au deposit is the largest of a number of gold occurrences in eastern interior Alaska, that occur along a broad trend from west of Pogo to Black Mountain. Some of these occurrences are hosted in amphibolite facies gneisses and others in mid-Cretaceous igneous rocks that intruded the older metamorphic rocks. All occurrences contain arsenopyrite and pyrite. Whole rock geochemical...
Authors
Garth E. Graham, Erin E. Marsh, Heather A. Lowers, Ryan D. Taylor
The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite
Carbonatite-hosted rare earth element (REE) deposits are the primary source of the world’s light REEs and have the potential to be a source of heavy REEs. The Mount Weld REE deposit in Western Australia is hosted in a lateritic sequence that reflects supergene enrichment of the underlying carbonatite complex. Similar to other carbonatite-related ore deposits, ore from Mount Weld displays...
Authors
Philip Verplanck, Heather A. Lowers, Adam Boehlke, Jay Michael Thompson, Ganesh Bhat, Cameron Mark Mercer
Hyperspectral cathodoluminescence and quantitative EPMA mapping of angrite northwest Africa 15507 Hyperspectral cathodoluminescence and quantitative EPMA mapping of angrite northwest Africa 15507
Angrite meteorites represent alkali depleted planetary crust of basaltic composition, and have both plutonic and volcanic lithologies. NWA 15507 is a microgabbroic specimen (mean grainsize ~1.4 mm) composed predominantly of zoned Al-Ti-augite, Ca-bearing olivine and anorthite together with accessory kirschsteinite, rhönite, hercynite, low-Ni kamacite, merrillite, magnetite and troilite...
Authors
Heather A. Lowers, Jay Michael Thompson, Paul K. Carpenter, Zoe Wilbur, Anthony Irving
Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA
The Proterozoic tectonic evolution of the south-western USA remains incompletely understood due to limited constraints on the timing and conditions of the tectono-metamorphic phases and depositional age of metasedimentary successions. We integrated multi-scale compositional mapping, petrologic modeling, and in situ geochronology to constrain pressure-temperature-time paths from samples...
Authors
Ian William Hillenbrand, Michael L. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda Souders
Characterizing lung particulates using quantitative microscopy in coal miners with severe pneumoconiosis Characterizing lung particulates using quantitative microscopy in coal miners with severe pneumoconiosis
Context.— Current approaches for characterizing retained lung dust using pathologists' qualitative assessment or scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) have limitations. Objective.— To explore polarized light microscopy coupled with image-processing software, termed quantitative microscopy–particulate matter (QM-PM), as a tool to characterize in situ...
Authors
Jeremy T. Hua, Carlyne D. Cool, Heather A. Lowers, Leonard H. T. Go, Lauren M. Zell-Baran, Emily A. Sarver, Kirsten S. Almberg, Kathy D. Pang, Susan M. Majka, Angela D. Franko, Naseema I. Vorajee, Robert A. Cohen, Cecil S. Rose