Heather A Lowers
Heather Lowers is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 32
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...
Geochemical and mineralogical analyses of uranium ores from the Hack II and Pigeon deposits, solution-collapse breccia pipes, Grand Canyon region, Mohave and Coconino Counties, Arizona, USA Geochemical and mineralogical analyses of uranium ores from the Hack II and Pigeon deposits, solution-collapse breccia pipes, Grand Canyon region, Mohave and Coconino Counties, Arizona, USA
This data release compiles the whole-rock geochemistry, X-ray diffraction, and electron microscopy analyses of samples collected from the uranium ore bodies of two mined-out deposits in the Grand Canyon region of northwestern Arizona - the Hack II and Pigeon deposits. The samples are grab samples of ore collected underground at each mine by the U.S. Geological Survey (USGS) during the...
Tables of electron probe microanalyses from the Copperwood sediment-hosted stratiform copper deposit, Michigan, USA Tables of electron probe microanalyses from the Copperwood sediment-hosted stratiform copper deposit, Michigan, USA
This data release provides electron microprobe analyses of ore minerals from the Copperwood sediment-hosted stratiform copper deposit in the Upper Peninsula of Michigan. The minerals include bornite, chalcocite, native copper, native silver, and pyrite. Minerals were analyzed for Ag, As, Co, Cu, Fe, Hg, Ni, Pb, S, Sb, and Zn. Results with acceptable totals that lie between 98.5 and 101.5...
Data Dictionary for Electron Microprobe Data Collected with Probe for EPMA Software Package Developed by Probe Software Data Dictionary for Electron Microprobe Data Collected with Probe for EPMA Software Package Developed by Probe Software
This data dictionary describes most of the possible output options given in the Probe for EPMA software package developed by Probe Software. Examples of the data output options include sample identification, analytical conditions, elemental weight percents, atomic percents, detection limits, and stage coordinates. Many more options are available and the data that is output will depend...
Lung Bioassay of Ground Dwelling Mammals from the Grand Canyon Uranium Breccia Pipe Region Using Scanning Electron Microscopy Lung Bioassay of Ground Dwelling Mammals from the Grand Canyon Uranium Breccia Pipe Region Using Scanning Electron Microscopy
Small mammal lung tissue sections were examined to help assess the effects of weathering on bioavailability and toxicity from sites in different phases of the mine cycle within the Grand Canyon area. Hematoxylin and eosin slides of lung tissue from brush mouse, deer mice, and pocket gophers were examined by a veterinary pathologist who marked areas of the tissue that showed normal...
In situ geochemical data related to the gold-quartz veins of Grass Valley, California, 2014-2015 In situ geochemical data related to the gold-quartz veins of Grass Valley, California, 2014-2015
In situ geochemical data were obtained for pyrite crystals and native gold from two distinct vein sets in the Grass Valley gold district, California. Samples of the N-S veins were collected underground at the Empire Mine State Historic Park and samples of the E-W veins were collected from drill core provided by the Idaho-Maryland Mining Corporation in 2008. These geochemical data were...
Filter Total Items: 109
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 M. 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
Formation of orogenic gold deposits by progressive movement of a fault-fracture mesh through the upper crustal brittle-ductile transition zone Formation of orogenic gold deposits by progressive movement of a fault-fracture mesh through the upper crustal brittle-ductile transition zone
Orogenic gold deposits are comprised of complex quartz vein arrays that form as a result of fluid flow along transcrustal fault zones in active orogenic belts. Mineral precipitation in these deposits occurs under variable pressure conditions, but a mechanism explaining how the pressure regimes evolve through time has not previously been proposed. Here we show that extensional quartz...
Authors
Miguel Tavares Nassif, Thomas Monecke, T. James Reynolds, Yvette D. Kuiper, Richard J. Goldfarb, Sandra Piazolo, Heather A. Lowers
Quantitative and qualitative correlation of CL and X-ray signals in Cr-bearing jade from Chichén-Itzá Archaeological Zone, Mexico Quantitative and qualitative correlation of CL and X-ray signals in Cr-bearing jade from Chichén-Itzá Archaeological Zone, Mexico
No abstract available.
Authors
E Vicenzi, Thomas Lam, Heather A. Lowers, Paul K. Carpenter, David T. Adams
Cathodoluminescence response of barite at room and liquid nitrogen temperatures Cathodoluminescence response of barite at room and liquid nitrogen temperatures
Rare earth element (REE) enrichment in the Elk Creek carbonatite, Nebraska USA, is comparable to ore grade enrichment in carbonatite-hosted REE deposits[1]. Petrographic examination of textures documents a complex history of crystallization, brecciation, recrystallization, oxidation, and near surface alteration. Barite (BaSO4) is present in most units, including REE-enriched zones, such...
Authors
Heather A. Lowers, Colin MacRae, Nick Wilson, Philip L. Verplanck
Science and Products
Filter Total Items: 32
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...
Geochemical and mineralogical analyses of uranium ores from the Hack II and Pigeon deposits, solution-collapse breccia pipes, Grand Canyon region, Mohave and Coconino Counties, Arizona, USA Geochemical and mineralogical analyses of uranium ores from the Hack II and Pigeon deposits, solution-collapse breccia pipes, Grand Canyon region, Mohave and Coconino Counties, Arizona, USA
This data release compiles the whole-rock geochemistry, X-ray diffraction, and electron microscopy analyses of samples collected from the uranium ore bodies of two mined-out deposits in the Grand Canyon region of northwestern Arizona - the Hack II and Pigeon deposits. The samples are grab samples of ore collected underground at each mine by the U.S. Geological Survey (USGS) during the...
Tables of electron probe microanalyses from the Copperwood sediment-hosted stratiform copper deposit, Michigan, USA Tables of electron probe microanalyses from the Copperwood sediment-hosted stratiform copper deposit, Michigan, USA
This data release provides electron microprobe analyses of ore minerals from the Copperwood sediment-hosted stratiform copper deposit in the Upper Peninsula of Michigan. The minerals include bornite, chalcocite, native copper, native silver, and pyrite. Minerals were analyzed for Ag, As, Co, Cu, Fe, Hg, Ni, Pb, S, Sb, and Zn. Results with acceptable totals that lie between 98.5 and 101.5...
Data Dictionary for Electron Microprobe Data Collected with Probe for EPMA Software Package Developed by Probe Software Data Dictionary for Electron Microprobe Data Collected with Probe for EPMA Software Package Developed by Probe Software
This data dictionary describes most of the possible output options given in the Probe for EPMA software package developed by Probe Software. Examples of the data output options include sample identification, analytical conditions, elemental weight percents, atomic percents, detection limits, and stage coordinates. Many more options are available and the data that is output will depend...
Lung Bioassay of Ground Dwelling Mammals from the Grand Canyon Uranium Breccia Pipe Region Using Scanning Electron Microscopy Lung Bioassay of Ground Dwelling Mammals from the Grand Canyon Uranium Breccia Pipe Region Using Scanning Electron Microscopy
Small mammal lung tissue sections were examined to help assess the effects of weathering on bioavailability and toxicity from sites in different phases of the mine cycle within the Grand Canyon area. Hematoxylin and eosin slides of lung tissue from brush mouse, deer mice, and pocket gophers were examined by a veterinary pathologist who marked areas of the tissue that showed normal...
In situ geochemical data related to the gold-quartz veins of Grass Valley, California, 2014-2015 In situ geochemical data related to the gold-quartz veins of Grass Valley, California, 2014-2015
In situ geochemical data were obtained for pyrite crystals and native gold from two distinct vein sets in the Grass Valley gold district, California. Samples of the N-S veins were collected underground at the Empire Mine State Historic Park and samples of the E-W veins were collected from drill core provided by the Idaho-Maryland Mining Corporation in 2008. These geochemical data were...
Filter Total Items: 109
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 M. 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
Formation of orogenic gold deposits by progressive movement of a fault-fracture mesh through the upper crustal brittle-ductile transition zone Formation of orogenic gold deposits by progressive movement of a fault-fracture mesh through the upper crustal brittle-ductile transition zone
Orogenic gold deposits are comprised of complex quartz vein arrays that form as a result of fluid flow along transcrustal fault zones in active orogenic belts. Mineral precipitation in these deposits occurs under variable pressure conditions, but a mechanism explaining how the pressure regimes evolve through time has not previously been proposed. Here we show that extensional quartz...
Authors
Miguel Tavares Nassif, Thomas Monecke, T. James Reynolds, Yvette D. Kuiper, Richard J. Goldfarb, Sandra Piazolo, Heather A. Lowers
Quantitative and qualitative correlation of CL and X-ray signals in Cr-bearing jade from Chichén-Itzá Archaeological Zone, Mexico Quantitative and qualitative correlation of CL and X-ray signals in Cr-bearing jade from Chichén-Itzá Archaeological Zone, Mexico
No abstract available.
Authors
E Vicenzi, Thomas Lam, Heather A. Lowers, Paul K. Carpenter, David T. Adams
Cathodoluminescence response of barite at room and liquid nitrogen temperatures Cathodoluminescence response of barite at room and liquid nitrogen temperatures
Rare earth element (REE) enrichment in the Elk Creek carbonatite, Nebraska USA, is comparable to ore grade enrichment in carbonatite-hosted REE deposits[1]. Petrographic examination of textures documents a complex history of crystallization, brecciation, recrystallization, oxidation, and near surface alteration. Barite (BaSO4) is present in most units, including REE-enriched zones, such...
Authors
Heather A. Lowers, Colin MacRae, Nick Wilson, Philip L. Verplanck