Ryan J McAleer, Ph.D.
Ryan J McAleer is a Research Geologist at the Florence Bascom Geoscience Center.
I am a Research Geologist at the Florence Bascom Geoscience Center in Reston, VA. I received a PhD in Geology from Indiana University in 2016. I currently run the 40Ar/39Ar geochronology, electron microprobe, and mineral separation laboratories in Reston, VA. I contribute to National Cooperative Geologic Mapping, Energy, and Mineral program projects as well as collaborative work with universities. I use detailed optical and electron petrography, metamorphic petrology, 40Ar/39Ar and U/Pb geochronology, and a variety of other analytical tools in my research. Some current research projects that I am a part of include work on:
- Determining the age of bedrock beneath the coastal plain of the southeastern U.S.
- Assessing the age and deformation mechanisms along the Blue Ridge Thrust
- The age(s) of the Petersburg Granite
- Causes and uses of photoluminesence in zircon
- Coupled substitution in sphalerite with a focus on germanium
- The age and origin of manganese oxide deposits in Virginia.
Professional Experience
2016-present, Research Geologist, USGS, Reston, VA
2011-2015, Graduate Student, Indiana University, Bloomington, IN
2011-2015, SCEP/Pathways student appointment, USGS, Reston, VA
2007-2010, Geologist, USGS, Reston, VA
Education and Certifications
Ph.D. Metamorphic Petrology, Indiana University, 2016 (Advisor: Bob Wintsch)
M.S. Geology, 2006 (Advisor: Jim Spotila)
B.S. Geology, 2004 (Senior Thesis Advisor: Terry Engelder)
Affiliations and Memberships*
2016-present, Mineralogical Society of America
2011-present, Geological Society of America
2019-present, Microscopy Society of America/Microanalysis Society
Science and Products
Filter Total Items: 27
Coal mine drainage effluents and associated solids major, trace, rare earth element and radium concentrations collected from Pennsylvania, USA
Discharges from abandoned coal mines and associated mine wastes represent historic and persistent sources of pollution in the Appalachian Basin, United States. In this study, we conducted the first-ever survey of radium (Ra) in coal mine drainage (CMD) water and solid samples in the United States. Samples were collected from 4 untreated coal mine discharges and 9 treated coal mine...
Whole rock geochemistry data from the Ordovician Bronson Hill arc and Silurian and Devonian Connecticut Valley - Gaspé trough, Vermont and New Hampshire
This data release includes whole rock (WR) geochemical data for 94 samples. Whole rock geochemistry data were analyzed at Actlabs in Ancaster, Ontario, Canada. Rock samples were collected by Peter Valley, Greg Walsh, Arthur Merschat, and Ryan McAleer. The whole rock geochemistry data characterize the composition of mapped meta-igneous rocks in eastern Vermont and western New Hampshire...
Mofete and San Vito geothermal field ore mineralization data
The Mofete and San Vito geothermal fields, located west of Naples, Italy, are part of the Campi Flegrei volcanic complex. A joint venture in the 1970s between AGIP and ENEL, the Italian National electric and petroleum utilities, respectively, drilled exploratory wells to a depth of ~3000 m in an attempt to locate high-enthalpy fluids for potential power production. Drill core samples...
SEM-CL investigation of sedimentary organic matter samples
High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter (SOM) is widely utilized in the geosciences for evaluation of microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM approaches, the inability...
40Ar/39Ar isotopic data from the Day Nui Con Voi metamorphic massif, Vietnam
This data release includes electron 40Ar/39Ar collected at the U.S. Geological Survey for samples from the Day Nui Con Voi metamorphic massif, Vietnam. Rock samples were collected by Meng-Wan Yeh, Michael J. Kunk and Robert P Wintsch in 2011. Mineral separates were prepared and aliquots of amphibole, muscovite, phlogopite, biotite, and potassium feldspar were analyzed by the 40Ar/39Ar...
Whole rock geochemistry and uranium-lead isotopic data from Mesoproterozoic rocks in the Eagle Lake quadrangle, Essex County, New York
This data release includes whole rock (WR) geochemical data, and uranium-lead isotopic data collected using a sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument; the SHRIMP-RG is a type of secondary ion mass spectrometer (SIMS). Whole rock geochemistry data were analyzed at Bureau Veritas Commodities Canada Ltd. Laboratories in Vancouver, British Columbia...
Evidence for strain induced graphitization across a ductile fault zone
A suite of slate samples collected along a 2 km transect crossing the Lishan Fault in central Taiwan were evaluated to assess the role of ductile strain energy in natural graphitization at greenschist facies metamorphic conditions. Scanning electron microscope (SEM) imaging documents phyllosilicate and quartz replacement textures consistent cleavage development via dissolution...
Portable Raman spectroscopic analysis of bulk crushed rock
This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Several sets of rocks comprised of shale and coal samples with various mineralogical composition, thermal maturity, total organic carbon (TOC), and age were used to test...
40Ar/39Ar data from the Gidami gold deposit, Egypt
This data release includes 40Ar/39Ar data from the U.S. Geological Survey for samples from the Gidami gold deposit in the Eastern Desert of Egypt. Rock samples were collected by Basem Zoheir--Benha University/University of Kiel. Potassium-bearing mineral grains were separated from the bulk sample and analyzed by argon geochronology at the U.S. Geological Survey Bascom ARgon Dating (BARD)...
Whole Rock Geochemistry and Uranium Lead Isotopic Data from the Dinwiddie Terrane, Virginia, USA
This data release includes whole rock geochemical data, and uranium-lead isotopic data collected by both Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Sensitive High Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) methods. Whole rock geochemistry was collected by Activation Laboratories in Ancaster, Ontario. LA-ICP-MS data was collected at the PLASMA...
Strain induced molecular heterogeneity in ancient sedimentary organic matter mapped at nanoscales using optical photothermal infrared spectroscopy
Here we report ultra-high resolution infrared mapping of organic matter functional group distribution in Tasmanites (algal microfossils) from the Upper Devonian Ohio Shale using optical photothermal infrared spectroscopy (O-PTIR). O-PTIR is capable of rapidly measuring the vibrational response of samples in situ with ~500-nm spatial resolution, well below the infrared diffraction limit...
Electron microprobe analyses of sphalerite from Central and East Tennessee mining districts, the Red Dog mining district (AK), and the Metaline mining district (WA)
Electron microprobe analyses of sphalerite (ZnS) were collected on samples from current or past mining operations in the USA with a specific focus on germanium (Ge), a byproduct critical mineral recovered from sphalerite. Data and methods reported are part of a research study published in the 'Related External Resources' section below.
Geologic map of the Buckner 7.5-Minute quadrangle, Louisa County, Virginia
The Buckner 7.5-minute quadrangle straddles three terrane boundaries in the Piedmont Physiographic Province in central Virginia: the Chopawamsic terrane, the Elk Hill Complex, and the Goochland terrane. In much of the map area, the Elk Hill Complex separates the Chopawamsic and Goochland terranes. Rocks of the Chopawamsic terrane include Ordovician metavolcanic and metasedimentary rocks...
Bedrock geologic map of the Crown Point quadrangle, Essex County, New York, and Addison County, Vermont
The bedrock geology of the 7.5-minute Crown Point quadrangle consists of deformed and metamorphosed Mesoproterozoic gneisses of the Adirondack Highlands unconformably overlain by weakly deformed lower Paleozoic sedimentary rocks of the Champlain Valley. The Mesoproterozoic rocks occur on the eastern edge of the Adirondack Highlands and represent an extension of the Grenville Province of...
Filter Total Items: 50
Nanometer-scale relationships between sedimentary organic matter molecular composition, fluorescence, cathodoluminescence, and reflectance: The importance of oxygen content at low thermal maturities
Molecular characterization of sedimentary organic matter (SOM), termed macerals, is a common goal when seeking to understand petroleum generation as well as other geologic processes in deep time. However, unambiguous measurement of discrete macerals is challenging due to the small size of organic particles in sedimentary rocks, the proximity of different organic matter types to one...
Authors
Aaron M. Jubb, Paul C. Hackley, Ryan J. McAleer, Jing Qu
Properties of solid bitumen formed during hydrous, anhydrous, and brine pyrolysis of oil shale: Implications for solid bitumen reflectance in source-rock reservoirs
Solid bitumen reflectance (BRo in %) is widely used as a thermal maturity proxy in source-rock reservoirs, yet solid bitumen texture and physical attributes may be affected by varying environmental constraints during its formation, e.g., water saturation, mineral catalysis, or salinity. Herein we investigated the development of solid bitumen properties during artificial maturation using...
Authors
Paul C. Hackley, Justin E. Birdwell, Ryan J. McAleer
Evaluation of solid bitumen created from marine oil shale bituminite under hydrous and anhydrous pyrolysis conditions
To test the influence of environmental conditions on aromaticity of solid bitumen generated during petroleum generation, four organic-rich (26–36 wt% total organic carbon) oil shale samples collected from the Neoproterozoic–Lower Cambrian restricted marine Salt Range Formation in the upper Indus Basin, Pakistan, were pyrolyzed under hydrous and anhydrous conditions. Experiments used...
Authors
Paul C. Hackley, Brett Valentine, Ryan J. McAleer, Javin J. Hatcherian, Jennifer Nedzweckas, Bonnie McDevitt, Imran Khan
Ore mineralization in the Mofete and San Vito geothermal fields, Campi Flegrei volcanic complex, Naples, Italy
The Mofete and San Vito geothermal fields, located west of Naples, Italy, are part of the Campi Flegrei volcanic complex. In the 1970s, exploratory wells were drilled to a depth of ~3000 m in an attempt to locate high-enthalpy fluids for potential power production. Drill core samples from Mofete wells (MF1, MF2, and MF5) and from San Vito wells (SV1 and SV3) contain authigenic ore...
Authors
Harvey E. Belkin, Ryan J. McAleer, Benedetto De Vivo
Evaluation of coal mine drainage and associated precipitates for radium and rare earth element concentrations
Coal mine drainage (CMD) and associated metal-rich precipitates have recently been proposed as unconventional sources of rare earth elements (REEs). However, the potential occurrence of radium (Ra), a known carcinogen, with the REE-bearing phases has not been investigated. We hypothesized that Ra may occur in solids that are precipitated from CMD as a “radiobarite” solid solution ((Ba,Sr...
Authors
Bonnie McDevitt, Charles A. Cravotta, Ryan J. McAleer, John C Jackson, Aaron M. Jubb, Glenn D. Jolly, Benjamin C. Hedin, Nathaniel R. Warner
Ion exchange processes for CO2 mineralization using industrial waste streams: Pilot plant demonstration and life cycle assessment
An attractive technique for removing CO2 from the environment is sequestration within stable carbonate solids (e. g., calcite). However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH>8) from aqueous streams containing dissolved CO2 (pH
Authors
Steven Bustillos, Mario Christofides, Bonnie McDevitt, Madalyn Blondes, Ryan J. McAleer, Aaron M. Jubb, Bu Wang, Gaurav Sant, Dante Simonetti
Mesoproterozoic to Paleozoic tectonics, Pleistocene landforms, and Holocene seismicity in the Blue Ridge: Results from integrated studies of the 9 August 2020, Mw 5.1 earthquake area near Sparta, North Carolina, USA
This field trip examines the results of integrated geologic studies of the 9 August 2020, Mw 5.1 earthquake near Sparta, North Carolina, USA. The earthquake generated ~4 km of coseismic surface rupture of the Little River fault and uplifted a surface area of ~11 km2. The Little River fault is a thrust fault oriented 110–130°/45–70°SW, and mapped fault segments are en echelon with scarp...
Authors
Arthur J. Merschat, Mark W. Carter, Ashley S. Lynn, Kevin G. Stewart, Paula Figueiredo, William Elijah Odom, Ryan J. McAleer, Jorge A. Vazquez, Nicholas E. Powell, Christopher S. Holm-Denoma
Cathodoluminescence differentiates sedimentary organic matter types
High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter is widely utilized in the geosciences for evaluating microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM methods, the inability of SEM to...
Authors
Paul C. Hackley, Ryan J. McAleer, Aaron M. Jubb, Brett Valentine, Justin E. Birdwell
Deformation-induced graphitization and muscovite recrystallization in a ductile fault zone
A suite of slate samples collected along a 2 km transect crossing the Lishan fault in central Taiwan were evaluated to assess the role of ductile deformation in natural graphitization at lower greenschist facies metamorphic conditions. The process of natural aromatization, or graphitization, of an organic precursor is well established as a thermally driven process; however, experimental...
Authors
Martha (Rebecca) Stokes, Aaron M. Jubb, Ryan J. McAleer, David L. Bish, Robert P. Wintsch
Insights into glendonite formation from the upper Oligocene Sagavanirktok Formation, North Slope, Alaska
The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments. The region during the time of Nuwok Member deposition was located at a high latitude...
Authors
John W. Counts, Madeleine Vickers, Martha (Rebecca) Stokes, Whittney Spivey, Kristina Frank Gardner, Jean Self-Trail, Jared T. Gooley, Ryan J. McAleer, Aaron M. Jubb, David W. Houseknecht, Richard O. Lease, Neil Patrick Griffis, Martin S. Vickers, Kasia Śliwińska, Hannah Gail Dooley Tompkins, Adam M. Hudson
Geology of the Mount Rogers area, revisited: Evidence of Neoproterozoic continental rifting, glaciation, and the opening and closing of the Iapetus Ocean, Blue Ridge, VA–NC–TN
Recent field and geochronological studies in eight 7.5-minute quadrangles near Mount Rogers in Virginia, North Carolina and Tennessee recognize (1) important stratigraphic and structural relationships for the Neoproterozoic Mount Rogers and Konnarock Formations, and the northeast end of the Mountain City window; (2) the separation of Mesoproterozoic rocks of the Blue Ridge into three age...
Authors
Arthur J. Merschat, Ryan J. McAleer, Christopher S. Holm-Denoma, C. Scott Southworth
Redefinition of the Petersburg batholith and implications for crustal inheritance in the Dinwiddie terrane, Virginia, USA
Field relations as well as geochemical and petrologic studies of metaigneous rocks assigned to the Pennsylvanian–Permian Petersburg batholith identify at least two distinct rock types: foliated metagranitoid gneiss and massive to porphyritic granite. Foliated metagranitoid gneiss of mostly granodioritic composition is geochemically distinct from associated massive and porphyritic...
Authors
Mark W. Carter, Ryan J. McAleer, Christopher S. Holm-Denoma, Marcie E. Occhi, Brent E. Owens, Jorge A. Vazquez
Non-USGS Publications**
Berger, A.L., Gulick, S.P., Spotila, J.A., Upton, P., Jaeger, J.M., Chapman, J.B., Worthington, L.A., Pavlis, T.L., Ridgway, K.D., Willems, B.A. and McAleer, R.J., 2008. Quaternary tectonic response to intensified glacial erosion in an orogenic wedge. Nature Geoscience, 1(11), p.793.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 27
Coal mine drainage effluents and associated solids major, trace, rare earth element and radium concentrations collected from Pennsylvania, USA
Discharges from abandoned coal mines and associated mine wastes represent historic and persistent sources of pollution in the Appalachian Basin, United States. In this study, we conducted the first-ever survey of radium (Ra) in coal mine drainage (CMD) water and solid samples in the United States. Samples were collected from 4 untreated coal mine discharges and 9 treated coal mine...
Whole rock geochemistry data from the Ordovician Bronson Hill arc and Silurian and Devonian Connecticut Valley - Gaspé trough, Vermont and New Hampshire
This data release includes whole rock (WR) geochemical data for 94 samples. Whole rock geochemistry data were analyzed at Actlabs in Ancaster, Ontario, Canada. Rock samples were collected by Peter Valley, Greg Walsh, Arthur Merschat, and Ryan McAleer. The whole rock geochemistry data characterize the composition of mapped meta-igneous rocks in eastern Vermont and western New Hampshire...
Mofete and San Vito geothermal field ore mineralization data
The Mofete and San Vito geothermal fields, located west of Naples, Italy, are part of the Campi Flegrei volcanic complex. A joint venture in the 1970s between AGIP and ENEL, the Italian National electric and petroleum utilities, respectively, drilled exploratory wells to a depth of ~3000 m in an attempt to locate high-enthalpy fluids for potential power production. Drill core samples...
SEM-CL investigation of sedimentary organic matter samples
High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter (SOM) is widely utilized in the geosciences for evaluation of microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM approaches, the inability...
40Ar/39Ar isotopic data from the Day Nui Con Voi metamorphic massif, Vietnam
This data release includes electron 40Ar/39Ar collected at the U.S. Geological Survey for samples from the Day Nui Con Voi metamorphic massif, Vietnam. Rock samples were collected by Meng-Wan Yeh, Michael J. Kunk and Robert P Wintsch in 2011. Mineral separates were prepared and aliquots of amphibole, muscovite, phlogopite, biotite, and potassium feldspar were analyzed by the 40Ar/39Ar...
Whole rock geochemistry and uranium-lead isotopic data from Mesoproterozoic rocks in the Eagle Lake quadrangle, Essex County, New York
This data release includes whole rock (WR) geochemical data, and uranium-lead isotopic data collected using a sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument; the SHRIMP-RG is a type of secondary ion mass spectrometer (SIMS). Whole rock geochemistry data were analyzed at Bureau Veritas Commodities Canada Ltd. Laboratories in Vancouver, British Columbia...
Evidence for strain induced graphitization across a ductile fault zone
A suite of slate samples collected along a 2 km transect crossing the Lishan Fault in central Taiwan were evaluated to assess the role of ductile strain energy in natural graphitization at greenschist facies metamorphic conditions. Scanning electron microscope (SEM) imaging documents phyllosilicate and quartz replacement textures consistent cleavage development via dissolution...
Portable Raman spectroscopic analysis of bulk crushed rock
This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Several sets of rocks comprised of shale and coal samples with various mineralogical composition, thermal maturity, total organic carbon (TOC), and age were used to test...
40Ar/39Ar data from the Gidami gold deposit, Egypt
This data release includes 40Ar/39Ar data from the U.S. Geological Survey for samples from the Gidami gold deposit in the Eastern Desert of Egypt. Rock samples were collected by Basem Zoheir--Benha University/University of Kiel. Potassium-bearing mineral grains were separated from the bulk sample and analyzed by argon geochronology at the U.S. Geological Survey Bascom ARgon Dating (BARD)...
Whole Rock Geochemistry and Uranium Lead Isotopic Data from the Dinwiddie Terrane, Virginia, USA
This data release includes whole rock geochemical data, and uranium-lead isotopic data collected by both Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Sensitive High Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) methods. Whole rock geochemistry was collected by Activation Laboratories in Ancaster, Ontario. LA-ICP-MS data was collected at the PLASMA...
Strain induced molecular heterogeneity in ancient sedimentary organic matter mapped at nanoscales using optical photothermal infrared spectroscopy
Here we report ultra-high resolution infrared mapping of organic matter functional group distribution in Tasmanites (algal microfossils) from the Upper Devonian Ohio Shale using optical photothermal infrared spectroscopy (O-PTIR). O-PTIR is capable of rapidly measuring the vibrational response of samples in situ with ~500-nm spatial resolution, well below the infrared diffraction limit...
Electron microprobe analyses of sphalerite from Central and East Tennessee mining districts, the Red Dog mining district (AK), and the Metaline mining district (WA)
Electron microprobe analyses of sphalerite (ZnS) were collected on samples from current or past mining operations in the USA with a specific focus on germanium (Ge), a byproduct critical mineral recovered from sphalerite. Data and methods reported are part of a research study published in the 'Related External Resources' section below.
Geologic map of the Buckner 7.5-Minute quadrangle, Louisa County, Virginia
The Buckner 7.5-minute quadrangle straddles three terrane boundaries in the Piedmont Physiographic Province in central Virginia: the Chopawamsic terrane, the Elk Hill Complex, and the Goochland terrane. In much of the map area, the Elk Hill Complex separates the Chopawamsic and Goochland terranes. Rocks of the Chopawamsic terrane include Ordovician metavolcanic and metasedimentary rocks...
Bedrock geologic map of the Crown Point quadrangle, Essex County, New York, and Addison County, Vermont
The bedrock geology of the 7.5-minute Crown Point quadrangle consists of deformed and metamorphosed Mesoproterozoic gneisses of the Adirondack Highlands unconformably overlain by weakly deformed lower Paleozoic sedimentary rocks of the Champlain Valley. The Mesoproterozoic rocks occur on the eastern edge of the Adirondack Highlands and represent an extension of the Grenville Province of...
Filter Total Items: 50
Nanometer-scale relationships between sedimentary organic matter molecular composition, fluorescence, cathodoluminescence, and reflectance: The importance of oxygen content at low thermal maturities
Molecular characterization of sedimentary organic matter (SOM), termed macerals, is a common goal when seeking to understand petroleum generation as well as other geologic processes in deep time. However, unambiguous measurement of discrete macerals is challenging due to the small size of organic particles in sedimentary rocks, the proximity of different organic matter types to one...
Authors
Aaron M. Jubb, Paul C. Hackley, Ryan J. McAleer, Jing Qu
Properties of solid bitumen formed during hydrous, anhydrous, and brine pyrolysis of oil shale: Implications for solid bitumen reflectance in source-rock reservoirs
Solid bitumen reflectance (BRo in %) is widely used as a thermal maturity proxy in source-rock reservoirs, yet solid bitumen texture and physical attributes may be affected by varying environmental constraints during its formation, e.g., water saturation, mineral catalysis, or salinity. Herein we investigated the development of solid bitumen properties during artificial maturation using...
Authors
Paul C. Hackley, Justin E. Birdwell, Ryan J. McAleer
Evaluation of solid bitumen created from marine oil shale bituminite under hydrous and anhydrous pyrolysis conditions
To test the influence of environmental conditions on aromaticity of solid bitumen generated during petroleum generation, four organic-rich (26–36 wt% total organic carbon) oil shale samples collected from the Neoproterozoic–Lower Cambrian restricted marine Salt Range Formation in the upper Indus Basin, Pakistan, were pyrolyzed under hydrous and anhydrous conditions. Experiments used...
Authors
Paul C. Hackley, Brett Valentine, Ryan J. McAleer, Javin J. Hatcherian, Jennifer Nedzweckas, Bonnie McDevitt, Imran Khan
Ore mineralization in the Mofete and San Vito geothermal fields, Campi Flegrei volcanic complex, Naples, Italy
The Mofete and San Vito geothermal fields, located west of Naples, Italy, are part of the Campi Flegrei volcanic complex. In the 1970s, exploratory wells were drilled to a depth of ~3000 m in an attempt to locate high-enthalpy fluids for potential power production. Drill core samples from Mofete wells (MF1, MF2, and MF5) and from San Vito wells (SV1 and SV3) contain authigenic ore...
Authors
Harvey E. Belkin, Ryan J. McAleer, Benedetto De Vivo
Evaluation of coal mine drainage and associated precipitates for radium and rare earth element concentrations
Coal mine drainage (CMD) and associated metal-rich precipitates have recently been proposed as unconventional sources of rare earth elements (REEs). However, the potential occurrence of radium (Ra), a known carcinogen, with the REE-bearing phases has not been investigated. We hypothesized that Ra may occur in solids that are precipitated from CMD as a “radiobarite” solid solution ((Ba,Sr...
Authors
Bonnie McDevitt, Charles A. Cravotta, Ryan J. McAleer, John C Jackson, Aaron M. Jubb, Glenn D. Jolly, Benjamin C. Hedin, Nathaniel R. Warner
Ion exchange processes for CO2 mineralization using industrial waste streams: Pilot plant demonstration and life cycle assessment
An attractive technique for removing CO2 from the environment is sequestration within stable carbonate solids (e. g., calcite). However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH>8) from aqueous streams containing dissolved CO2 (pH
Authors
Steven Bustillos, Mario Christofides, Bonnie McDevitt, Madalyn Blondes, Ryan J. McAleer, Aaron M. Jubb, Bu Wang, Gaurav Sant, Dante Simonetti
Mesoproterozoic to Paleozoic tectonics, Pleistocene landforms, and Holocene seismicity in the Blue Ridge: Results from integrated studies of the 9 August 2020, Mw 5.1 earthquake area near Sparta, North Carolina, USA
This field trip examines the results of integrated geologic studies of the 9 August 2020, Mw 5.1 earthquake near Sparta, North Carolina, USA. The earthquake generated ~4 km of coseismic surface rupture of the Little River fault and uplifted a surface area of ~11 km2. The Little River fault is a thrust fault oriented 110–130°/45–70°SW, and mapped fault segments are en echelon with scarp...
Authors
Arthur J. Merschat, Mark W. Carter, Ashley S. Lynn, Kevin G. Stewart, Paula Figueiredo, William Elijah Odom, Ryan J. McAleer, Jorge A. Vazquez, Nicholas E. Powell, Christopher S. Holm-Denoma
Cathodoluminescence differentiates sedimentary organic matter types
High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter is widely utilized in the geosciences for evaluating microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM methods, the inability of SEM to...
Authors
Paul C. Hackley, Ryan J. McAleer, Aaron M. Jubb, Brett Valentine, Justin E. Birdwell
Deformation-induced graphitization and muscovite recrystallization in a ductile fault zone
A suite of slate samples collected along a 2 km transect crossing the Lishan fault in central Taiwan were evaluated to assess the role of ductile deformation in natural graphitization at lower greenschist facies metamorphic conditions. The process of natural aromatization, or graphitization, of an organic precursor is well established as a thermally driven process; however, experimental...
Authors
Martha (Rebecca) Stokes, Aaron M. Jubb, Ryan J. McAleer, David L. Bish, Robert P. Wintsch
Insights into glendonite formation from the upper Oligocene Sagavanirktok Formation, North Slope, Alaska
The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments. The region during the time of Nuwok Member deposition was located at a high latitude...
Authors
John W. Counts, Madeleine Vickers, Martha (Rebecca) Stokes, Whittney Spivey, Kristina Frank Gardner, Jean Self-Trail, Jared T. Gooley, Ryan J. McAleer, Aaron M. Jubb, David W. Houseknecht, Richard O. Lease, Neil Patrick Griffis, Martin S. Vickers, Kasia Śliwińska, Hannah Gail Dooley Tompkins, Adam M. Hudson
Geology of the Mount Rogers area, revisited: Evidence of Neoproterozoic continental rifting, glaciation, and the opening and closing of the Iapetus Ocean, Blue Ridge, VA–NC–TN
Recent field and geochronological studies in eight 7.5-minute quadrangles near Mount Rogers in Virginia, North Carolina and Tennessee recognize (1) important stratigraphic and structural relationships for the Neoproterozoic Mount Rogers and Konnarock Formations, and the northeast end of the Mountain City window; (2) the separation of Mesoproterozoic rocks of the Blue Ridge into three age...
Authors
Arthur J. Merschat, Ryan J. McAleer, Christopher S. Holm-Denoma, C. Scott Southworth
Redefinition of the Petersburg batholith and implications for crustal inheritance in the Dinwiddie terrane, Virginia, USA
Field relations as well as geochemical and petrologic studies of metaigneous rocks assigned to the Pennsylvanian–Permian Petersburg batholith identify at least two distinct rock types: foliated metagranitoid gneiss and massive to porphyritic granite. Foliated metagranitoid gneiss of mostly granodioritic composition is geochemically distinct from associated massive and porphyritic...
Authors
Mark W. Carter, Ryan J. McAleer, Christopher S. Holm-Denoma, Marcie E. Occhi, Brent E. Owens, Jorge A. Vazquez
Non-USGS Publications**
Berger, A.L., Gulick, S.P., Spotila, J.A., Upton, P., Jaeger, J.M., Chapman, J.B., Worthington, L.A., Pavlis, T.L., Ridgway, K.D., Willems, B.A. and McAleer, R.J., 2008. Quaternary tectonic response to intensified glacial erosion in an orogenic wedge. Nature Geoscience, 1(11), p.793.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government