Heather A Lowers
Heather Lowers is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
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Organic petrology and micro-spectroscopy of Tasmanites microfossils: Applications to kerogen transformations in the early oil window
USGS Spectral Library Version 7
Mineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA
The distribution and composition of REE-bearing minerals in placers of the Atlantic and Gulf coastal plains, USA
Rare earth element (REE) resources are currently of great interest because of their importance as raw materials for high-technology manufacturing. The REE-phosphates monazite (light REE enriched) and xenotime (heavy REE enriched) resist weathering and can accumulate in placer deposits as part of the heavy mineral assemblage. The Atlantic and Gulf coastal plains of the southeastern United States ar
Ore mineralogy and textural zonation in the world-class epithermal Waihi Vein System, Hauraki Goldfield
Petrology and diagenetic history of the upper shale member of the Late Devonian-Early Mississippian Bakken Formation, Williston Basin, North Dakota
Lithostratigraphic, borehole-geophysical, hydrogeologic, and hydrochemical data from the East Bay Plain, Alameda County, California
Sedimentology of SPICE (Steptoean positive carbon isotope excursion): A high-resolution trace fossil and microfabric analysis of the middle to late Cambrian Alum Shale Formation, southern Sweden
Characterisation of a natural quartz crystal as a reference material for microanalytical determination of Ti, Al, Li, Fe, Mn, Ga and Ge
Evaluation of selected static methods used to estimate element mobility, acid-generating and acid-neutralizing potentials associated with geologically diverse mining wastes
The Lepanto Cu–Au deposit, Philippines: A fossil hyperacidic volcanic lake complex
Assessment of the geoavailability of trace elements from selected zinc minerals
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Organic petrology and micro-spectroscopy of Tasmanites microfossils: Applications to kerogen transformations in the early oil window
The transformation of kerogen to hydrocarbons in the early stages of oil generation is critical for understanding the resource potential of liquid-rich shale plays. Organic petrology commonly is used for visual evaluation of type, quality, and thermal maturity of organic matter, but the relationship of visual petrographic changes to chemical transformations is not well characterized. To improve unAuthorsPaul C. Hackley, Clifford C. Walters, S.R. Kelemen, Maria Mastalerz, Heather A. LowersUSGS Spectral Library Version 7
We have assembled a library of spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns [μm]). Laboratory samples of specific minerals, plants, chemical compounds, and manmade materials were measured. In many cases, samples were purified, so that unique spectral features of a material caAuthorsRaymond F. Kokaly, Roger N. Clark, Gregg A. Swayze, K. Eric Livo, Todd M. Hoefen, Neil C. Pearson, Richard A. Wise, William Benzel, Heather A. Lowers, Rhonda L. Driscoll, Anna J. KleinMineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA
Mineral thermometry and fluid inclusion studies were conducted on variably altered and mineralized samples from the Mesoproterozoic Pea Ridge iron oxide-apatite (IOA)-rare earth element (REE) deposit in order to constrain P-T conditions, fluid chemistry, and the source of salt and volatiles during early magnetite and later REE mineralization.Scanning electron microscopy (SEM)-cathodoluminescence aAuthorsAlbert H. Hofstra, Corey J. Meighan, Xinyu Song, Iain Samson, Erin E. Marsh, Heather A. Lowers, Poul Emsbo, Andrew G. HuntThe distribution and composition of REE-bearing minerals in placers of the Atlantic and Gulf coastal plains, USA
Rare earth element (REE) resources are currently of great interest because of their importance as raw materials for high-technology manufacturing. The REE-phosphates monazite (light REE enriched) and xenotime (heavy REE enriched) resist weathering and can accumulate in placer deposits as part of the heavy mineral assemblage. The Atlantic and Gulf coastal plains of the southeastern United States ar
AuthorsCarleton R. Bern, Anjana K. Shah, William Benzel, Heather A. LowersOre mineralogy and textural zonation in the world-class epithermal Waihi Vein System, Hauraki Goldfield
The Waihi district in the Hauraki Goldfield of New Zealand contains adularia-sericite epithermal gold-silver veins that have produced more than 7.7 Moz gold. The outermost veins of the district (Martha, Favona, Moonlight, and Cowshed) contain abundant colloform, cherty, and black quartz fill textures, with minor crustiform and massive quartz. The central veins (Amaranth, Trio, and Union) contain pAuthorsJeffrey L. Mauk, Erin G Skinner, Sarah J Fyfe, Andrew H Menzies, Heather A. Lowers, Alan E. KoenigPetrology and diagenetic history of the upper shale member of the Late Devonian-Early Mississippian Bakken Formation, Williston Basin, North Dakota
The organic-rich upper shale member of the upper Devonian–lower Mississippian Bakken Formation (Williston Basin, North Dakota, USA) has undergone significant diagenetic alteration, irrespective of catagenesis related to hydrocarbon generation. Alteration includes precipitation of numerous cements, replacement of both detrital and authigenic minerals, multiple episodes of fracturing, and compactionAuthorsNeil S. Fishman, Sven O. Egenhoff, Adam Boehlke, Heather A. LowersLithostratigraphic, borehole-geophysical, hydrogeologic, and hydrochemical data from the East Bay Plain, Alameda County, California
The U.S. Geological Survey, in cooperation with the East Bay Municipal Utility District, carried out an investigation of aquifer-system deformation associated with groundwater-level changes at the Bayside Groundwater Project near the modern San Francisco Bay shore in San Lorenzo, California. As a part of the Bayside Groundwater Project, East Bay Municipal Utility District proposed an aquifer storaAuthorsMichelle Sneed, Patricia v.P. Orlando, James W. Borchers, Rhett R. Everett, Michael Solt, Mary McGann, Heather Lowers, Shannon MahanSedimentology of SPICE (Steptoean positive carbon isotope excursion): A high-resolution trace fossil and microfabric analysis of the middle to late Cambrian Alum Shale Formation, southern Sweden
The Cambrian Alum Shale Formation in the Andrarum-3 core from Scania, southern Sweden, consists of black siliciclastic mudstone with minor carbonate intercalations. Four facies comprise three siliciclastic mudstones and one fine-grained carbonate. The facies reflect deposition along a transect from deep ramp to basin on a Cambrian shelf. The three mudstone facies contain abundant clay clasts and lAuthorsSven Egenhoff, Neil Fishman, Per Ahlberg, Jorg Maletz, Allison Jackson, Ketki Kolte, Heather A. Lowers, James Mackie, Warren Newby, Matthew PetrowskyCharacterisation of a natural quartz crystal as a reference material for microanalytical determination of Ti, Al, Li, Fe, Mn, Ga and Ge
A natural smoky quartz crystal from Shandong province, China, was characterised by laser ablation ICP-MS, electron probe microanalysis (EPMA) and solution ICP-MS to determine the concentration of twenty-four trace and ultra trace elements. Our main focus was on Ti quantification because of the increased use of this element for titanium-in-quartz (TitaniQ) thermobarometry. Pieces of a uniform growtAuthorsAndreas Audetat, Dieter Garbe-Schonberg, Andreas Kronz, Thomas Pettke, Brian G. Rusk, John J. Donovan, Heather LowersEvaluation of selected static methods used to estimate element mobility, acid-generating and acid-neutralizing potentials associated with geologically diverse mining wastes
A comparison study of selected static leaching and acid–base accounting (ABA) methods using a mineralogically diverse set of 12 modern-style, metal mine waste samples was undertaken to understand the relative performance of the various tests. To complement this study, in-depth mineralogical studies were conducted in order to elucidate the relationships between sample mineralogy, weathering featureAuthorsPhilip L. Hageman, Robert R. Seal, Sharon F. Diehl, Nadine M. Piatak, Heather LowersThe Lepanto Cu–Au deposit, Philippines: A fossil hyperacidic volcanic lake complex
Hyperacidic lakes and associated solfatara in active volcanoes are the expression of magmatic gas expansion from source to surface. Here we show for the first time, that the vein system that comprises the ~ 2 Ma high-sulfidation, Lepanto copper–gold deposit in the Mankayan district (Philippines) was associated with a contemporary hyperacidic volcanic lake complex—possibly the first such lake recogAuthorsByron R. Berger, Richard W. Henley, Heather A. Lowers, Michael PribilAssessment of the geoavailability of trace elements from selected zinc minerals
This assessment focused on five zinc-bearing minerals. The minerals were subjected to a number of analyses including quantitative X-ray diffraction, optical microscopy, leaching tests, and bioaccessibility and toxicity studies. Like a previous comprehensive assessment of five copper-bearing minerals, the purpose of this assessment was to obtain structural and chemical information and to characteriAuthorsRhonda L. Driscoll, Phillip L. Hageman, William Benzel, Sharon F. Diehl, Suzette Morman, LaDonna M. Choate, Heather Lowers - News