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
Whole rock geochemistry data from the Ordovician Bronson Hill arc and Silurian and Devonian Connecticut Valley - Gaspé trough, Vermont and New Hampshire
Mofete and San Vito geothermal field ore mineralization data
SEM-CL investigation of sedimentary organic matter samples
40Ar/39Ar isotopic data from the Day Nui Con Voi metamorphic massif, Vietnam
Whole rock geochemistry and uranium-lead isotopic data from Mesoproterozoic rocks in the Eagle Lake quadrangle, Essex County, New York
Evidence for strain induced graphitization across a ductile fault zone
Portable Raman spectroscopic analysis of bulk crushed rock
40Ar/39Ar data from the Gidami gold deposit, Egypt
Whole Rock Geochemistry and Uranium Lead Isotopic Data from the Dinwiddie Terrane, Virginia, USA
Strain induced molecular heterogeneity in ancient sedimentary organic matter mapped at nanoscales using optical photothermal infrared spectroscopy
Electron microprobe analyses of sphalerite from Central and East Tennessee mining districts, the Red Dog mining district (AK), and the Metaline mining district (WA)
Trace element composition and molecular-scale speciation characterization of sphalerite from Central and East Tennessee mining districts, Red Dog mining district (AK), and Metaline mining district (WA)
Bedrock geologic map of the Crown Point quadrangle, Essex County, New York, and Addison County, Vermont
Cathodoluminescence differentiates sedimentary organic matter types
Deformation-induced graphitization and muscovite recrystallization in a ductile fault zone
Insights into glendonite formation from the upper Oligocene Sagavanirktok Formation, North Slope, Alaska
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
Redefinition of the Petersburg batholith and implications for crustal inheritance in the Dinwiddie terrane, Virginia, USA
Mapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy
A novel non-destructive workflow for examining germanium and co-substituents in ZnS
The Sukari gold deposit, Egypt: Geochemical and geochronological constraints on the ore genesis and implications for regional exploration
Vein-type gold formation during late extensional collapse of the Eastern Desert, Egypt: the Gidami deposit
Germanium redistribution during weathering of Zn mine wastes: Implications for environmental mobility and recovery of a critical mineral
U-Pb and fission-track data from zircon and apatite resolve latest- and post-Alleghanian thermal histories along the Fall Line of the Atlantic margin of the southeastern United States
Evaluating aromatization of solid bitumen generated in the presence and absence of water: Implications for solid bitumen reflectance as a thermal proxy
Non-USGS Publications**
**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
- Data
Filter Total Items: 26
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, USA. The daMofete 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 from Mofete wSEM-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 of SEM to d40Ar/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 method at thWhole 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, Canada. SHREvidence 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-precipitation procesPortable 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 the metho40Ar/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) LaboratorWhole 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 at the USGStrain 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. Our resultElectron 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.Trace element composition and molecular-scale speciation characterization of sphalerite from Central and East Tennessee mining districts, Red Dog mining district (AK), and Metaline mining district (WA)
Germanium (Ge) is an element deemed critical globally, and used in electronics, communication, and defense applications. The supply of Ge is limited and as demand for it increases, its criticality increases. Germanium is exclusively recovered as a byproduct of either coal mining or zinc (Zn) mining, and the main mineral hosting Ge in Zn deposits is sphalerite (ZnS). However, the mechanisms of Ge e - Maps
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 Laurentia. - Multimedia
- Publications
Filter Total Items: 43
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 differentiateAuthorsPaul C. Hackley, Ryan J. McAleer, Aaron M. Jubb, Brett J. Valentine, Justin E. BirdwellDeformation-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 studies haAuthorsMartha (Rebecca) Stokes, Aaron M. Jubb, Ryan J. McAleer, David Bish, Robert WintschInsights 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, similar toAuthorsJohn 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. HudsonGeology 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 groups; aAuthorsArthur J. Merschat, Ryan J. McAleer, Christopher Holm-Denoma, C. Scott SouthworthRedefinition 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 granitic rocks. TAuthorsMark W. Carter, Ryan J. McAleer, Christopher Holm-Denoma, Marcie E. Occhi, Brent E. Owens, Jorge A. VazquezMapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy
Elucidating the molecular structure of sedimentary organic matter (SOM) is key to understanding petroleum generation processes, as well as ancient sedimentary environments. SOM structure is primarily controlled by biogenic source material (e.g., marine vs. terrigenous), depositional conditions, and subsurface thermal history. Additional factors, e.g., strain, may also impact the molecular structurAuthorsAaron M. Jubb, Martha (Rebecca) Stokes, Ryan J. McAleer, Paul C. Hackley, Eoghan Dillion, Jing QuA novel non-destructive workflow for examining germanium and co-substituents in ZnS
A suite of complementary techniques was used to examine germanium (Ge), a byproduct critical element, and co-substituent trace elements in ZnS and mine wastes from four mineral districts where germanium is, or has been, produced within the United States. This contribution establishes a comprehensive workflow for characterizing Ge and other trace elements, which captures the full heterogeneity of sAuthorsSarah M. Hayes, Ryan J. McAleer, Nadine M. Piatak, Sarah Jane White, Robert R. SealThe Sukari gold deposit, Egypt: Geochemical and geochronological constraints on the ore genesis and implications for regional exploration
The Sukari gold deposit (>15 Moz Au) in the Eastern Desert of Egypt is hosted by a deformed granitoid stock (Sukari tonalite-trondhjemite intrusion) and mainly occurs as a network of crosscutting sulfide-bearing quartz (± carbonate) veins and intensely sulfidized-silicified-sericitized wall rock. Emplacement of the Sukari intrusion into a tectonized Neoproterozoic accretionary complex was controllAuthorsBasem Zoheir, Astrid Holzheid, Armin Zeh, Ryan J. McAleer, Mohamed El-Behairy, Ulrich Schwarz-Schampera, Torsten Graupner, David Lentz, Fahui XiongVein-type gold formation during late extensional collapse of the Eastern Desert, Egypt: the Gidami deposit
Orogenic gold deposits, though construed to focused fluid flow during orogenesis, commonly post-date the main accretionary events. Several lines of evidence indicate that orogenic gold formation in the Arabian–Nubian Shield continued through the orogen collapse stage and associated rapid exhumation and thermal re-equilibration. The Gidami gold deposit in the Eastern Desert of Egypt is associated wAuthorsBasem Zoheir, Ryan J. McAleer, Matthew Steele-MacInnis, Armin Zeh, Wyatt M. Bain, Spencer PouletteGermanium redistribution during weathering of Zn mine wastes: Implications for environmental mobility and recovery of a critical mineral
Germanium (Ge) is a metal used in emerging energy technologies, communications, and defense, and has been deemed critical by the United States due to its essential applications and scarce supply. Germanium is recovered as a byproduct of zinc (Zn) sulfides, and mining and processing of these materials lead to waste that could act both as a source of extractable Ge and a source for exposure to humanAuthorsSarah Jane White, Nadine M. Piatak, Ryan J. McAleer, Sarah M. Hayes, Robert R. Seal, Laurel A. Schaider, James P. ShineU-Pb and fission-track data from zircon and apatite resolve latest- and post-Alleghanian thermal histories along the Fall Line of the Atlantic margin of the southeastern United States
Although the Atlantic continental margin of the eastern United States is an archetypal passive margin, episodes of rejuvenation following continental breakup are increasingly well documented. To better constrain this history of rejuvenation along the southern portion of this continental margin, we present zircon U-Pb (ZUPb) age, zircon fission-track (ZFT) age, apatite U-Pb (AUPb) age, and apatiteAuthorsWilliam H. Craddock, Paul O'Sullivan, Ryan J. McAleerEvaluating aromatization of solid bitumen generated in the presence and absence of water: Implications for solid bitumen reflectance as a thermal proxy
Geological models for petroleum generation suggest thermal conversion of oil-prone sedimentary organic matter in the presence of water promotes increased liquid saturate yield, whereas absence of water causes formation of an aromatic, cross-linked solid bitumen residue. To test the influence of hydrogen from water, organic-rich (22 wt% total organic carbon, TOC) mudrock samples from the Eocene lacAuthorsPaul C. Hackley, Aaron M. Jubb, Patrick L. Smith, Ryan J. McAleer, Brett J. Valentine, Javin J. Hatcherian, Palma J. Botterell, Justin E. BirdwellNon-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