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William Ridley

Willian (Ian) Ridley is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.

Professional Experience

  • Previous USGS Assignments
    Staff Scientist, Central Colorado Project Staff Scientist, Integrated Studies of National Parks (Big Bend)
    Section Chief, Branch of Exploration Geochemistry and Branch of Geochemistry

  • Consultant Geochemist, Evergreen, CO

  • Geochemist, Geoexplorers International, Denver, CO

  • Exploration Manager, Beard Oil Company, Evergreen , CO

  • Research Specialist, Exxon Production Research Company, Houston, TX

  • Adjunct Professor, Columbia University, NY, NY

  • Anglo-American Visiting Professor of Geochemistry, University of Witswatersrand, Johanessburg, SA

  • Associate Professor, Columbia University, NY, NY

  • Adjunct Professor, Rutgers University, New Brunswick, NJ

  • Staff Scientist, Lunar and Planetary Institute, Houston, TX

  • National Research Council Associate, NASA-MSC, Houston, TX

  • Research Geologist, British Geological Survey, London, UK

Education and Certifications

  • Ph.D. (Geochemistry, Volcanology), Royal College of Science,Univ. of London  1968

  • Associate (Geochemistry),  Royal School of Mines,  Univ. of London  1968

  • B.Sc. (Geology/Chemistry), Royal College of Science, Univ. of London 1964

Affiliations and Memberships*

  • Adjunct Professor, Colorado School of Mines

Honors and Awards

  • Judd Research Prize, Imperial College, London University

  • NASA Distinguished Service Award

  • USGS Star Award

  • Ten NASA Research Grants

  • Seven NSF Research Grants

  • Four Miscellaneous Awards (EPRI, DOE, ONR)

  • Three USGS Venture Capital Awards

Abstracts and Presentations

  • 141 abstract and extended abstracts

  • 125 peer-reviewed papers

Science and Products

link
periodic table with isotopes

Non-Traditional Stable Isotopes

Understanding the genesis of ore deposits and their behavior in the environment is a subject of great importance to the Nation. A relatively new tool to aid in these efforts to investigate the origin and environmental effects of ore deposits is the use of "heavy" metal stable isotopes. Our research objectives are to utilize various isotopic systems to advance our understanding of ore genesis and...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

Non-Traditional Stable Isotopes

Understanding the genesis of ore deposits and their behavior in the environment is a subject of great importance to the Nation. A relatively new tool to aid in these efforts to investigate the origin and environmental effects of ore deposits is the use of "heavy" metal stable isotopes. Our research objectives are to utilize various isotopic systems to advance our understanding of ore genesis and...
Learn More
link
Bennu mosaic

ASTRA: ASTeroid Resource Assessment

The study was conducted to determine if the USGS process for conducting mineral resource assessments on Earth can be applied to asteroids
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

ASTRA: ASTeroid Resource Assessment

The study was conducted to determine if the USGS process for conducting mineral resource assessments on Earth can be applied to asteroids
Learn More
Filter Total Items: 38

Feasibility study for the quantitative assessment of mineral resources in asteroids

This study was undertaken to determine if the U.S. Geological Survey’s process for conducting mineral resource assessments on Earth can be applied to asteroids. Successful completion of the assessment, using water and iron resources to test the workflow, has resulted in identification of the minimal adjustments required to conduct full resource assessments beyond Earth. We also identify the types
Authors
Laszlo P. Keszthelyi, Justin Hagerty, Amanda Bowers, Karl J. Ellefsen, Ian Ridley, Trude King, David Trilling, Nicholas Moskovitz, Will Grundy
By
Natural Hazards Mission Area, Astrogeology Science Center

Measurement of in situ sulfur isotopes by laser ablation multi-collector ICPMS: opening Pandora’s Box

Laser ablation multi-collector ICPMS is a modern tool for in situ measurement of S isotopes. Advantages of the technique are speed of analysis and relatively minor matrix effects combined with spatial resolution sufficient for many applications. The main disadvantage is a more destructive sampling mechanism relative to the ion microprobe technique. Recent advances in instrumentation allow precise
Authors
William I. Ridley, Michael Pribil, Alan E. Koenig, John F. Slack
By
Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center

Sulfate and sulfide sulfur isotopes (δ34S and δ33S) measured by solution and laser ablation MC-ICP-MS: An enhanced approach using external correction

Isotope ratio measurements using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) commonly use standard-sample bracketing with a single isotope standard for mass bias correction for elements with narrow-range isotope systems measured by MC-ICP-MS, e.g. Cu, Fe, Zn, and Hg. However, sulfur (S) isotopic composition (δ34S) in nature can range from at least − 40 to + 40‰, pote
Authors
Michael Pribil, William I. Ridley, Poul Emsbo
By
Geology, Geophysics, and Geochemistry Science Center

Volcanogenic massive sulfide occurrence model

Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom water
Authors
W.C. Pat Shanks, Randolph A. Koski, Dan L. Mosier, Klaus J. Schulz, Lisa A. Morgan, John F. Slack, W. Ian Ridley, Cynthia Dusel-Bacon, Robert R. Seal, Nadine M. Piatak
By
Energy and Minerals Mission Area, Ecosystems Mission Area, Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Northern Rocky Mountain Science Center

Mineralogy and composition of the oceanic mantle

The mineralogy of the oceanic basalt source region is examined by testing whether a peridotite mineralogy can yield observed whole-rock and olivine compositions from (1) the Hawaiian Islands, our type example of a mantle plume, and (2) the Siqueiros Transform, which provides primitive samples of normal mid-ocean ridge basalt. New olivine compositional data from phase 2 of the Hawaii Scientific Dri
Authors
Keith Putirka, F. J. Ryerson, Michael Perfit, W. Ian Ridley
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology

Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmati
Authors
Axel K. Schmitt, Michael R. Perfit, Kenneth H. Rubin, Daniel F. Stockli, Matthew C. Smith, Laurie A. Cotsonika, Georg F. Zellmer, W. Ian Ridley
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Trace and minor element variations and sulfur isotopes in crystalline and colloform ZnS: Incorporation mechanisms and implications for their genesis

Various models have been proposed to explain the formation mechanism of colloform sphalerite, but the origin is still under debate. In order to decipher influences on trace element incorporation and sulfur isotope composition, crystalline and colloform sphalerite from the carbonate-hosted Mississippi-Valley Type (MVT) deposit near Wiesloch, SW Germany, were investigated and compared to sphalerite
Authors
Katharina Pfaff, Alan Koenig, Thomas Wenzel, Ian Ridley, Ludwig H. Hildebrandt, David L. Leach, Gregor Markl
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Volatile abundances and oxygen isotopes in basaltic to dacitic lavas on mid-ocean ridges: The role of assimilation at spreading centers

Most geochemical variability in MOR basalts is consistent with low- to moderate-pressure fractional crystallization of various mantle-derived parental melts. However, our geochemical data from MOR high-silica glasses, including new volatile and oxygen isotope data, suggest that assimilation of altered crustal material plays a significant role in the petrogenesis of dacites and may be important in
Authors
V.D. Wanless, M.R. Perfit, W.I. Ridley, P.J. Wallace, Craig B. Grimes, E.M. Klein
By
Geosciences and Environmental Change Science Center

Trace elements have limited utility for studying migratory connectivity in shorebirds that winter in Argentina

Trace-element analysis has been suggested as a tool for the study of migratory connectivity because (1) trace-element abundance varies spatially in the environment, (2) trace elements are assimilated into animals' tissues through the diet, and (3) current technology permits the analysis of multiple trace elements in a small tissue sample, allowing the simultaneous exploration of several elements.
Authors
J. Torres-Dowdall, A.H. Farmer, M. Abril, E.H. Bucher, I. Ridley

Dacite petrogenesis on mid-ocean ridges: Evidence for oceanic crustal melting and assimilation

Whereas the majority of eruptions at oceanic spreading centers produce lavas with relatively homogeneous mid-ocean ridge basalt (MORB) compositions, the formation of tholeiitic andesites and dacites at mid-ocean ridges (MORs) is a petrological enigma. Eruptions of MOR high-silica lavas are typically associated with ridge discontinuities and have produced regionally significant volumes of lava. And
Authors
V.D. Wanless, M.R. Perfit, W.I. Ridley, E. Klein

Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition

An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations
Authors
M.J. Pribil, R. B. Wanty, W.I. Ridley, D.M. Borrok

A New Occurrence Model for National Assessment of Undiscovered Volcanogenic Massive Sulfide Deposits

Volcanogenic massive sulfide (VMS) deposits are very significant current and historical resources of Cu-Pb-Zn-Au-Ag, are active exploration targets in several areas of the United States and potentially have significant environmental effects. This new USGS VMS deposit model provides a comprehensive review of deposit occurrence and ore genesis, and fully integrates recent advances in the understandi
Authors
W.C. Pat Shanks, Cynthia Dusel-Bacon, Randolph Koski, Lisa A. Morgan, Dan Mosier, Nadine M. Piatak, Ian Ridley, Robert R. Seal, Klaus J. Schulz, John F. Slack, Roland Thurston
By
Geology, Energy & Minerals Science Center

Science and Products

link
periodic table with isotopes

Non-Traditional Stable Isotopes

Understanding the genesis of ore deposits and their behavior in the environment is a subject of great importance to the Nation. A relatively new tool to aid in these efforts to investigate the origin and environmental effects of ore deposits is the use of "heavy" metal stable isotopes. Our research objectives are to utilize various isotopic systems to advance our understanding of ore genesis and...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

Non-Traditional Stable Isotopes

Understanding the genesis of ore deposits and their behavior in the environment is a subject of great importance to the Nation. A relatively new tool to aid in these efforts to investigate the origin and environmental effects of ore deposits is the use of "heavy" metal stable isotopes. Our research objectives are to utilize various isotopic systems to advance our understanding of ore genesis and...
Learn More
link
Bennu mosaic

ASTRA: ASTeroid Resource Assessment

The study was conducted to determine if the USGS process for conducting mineral resource assessments on Earth can be applied to asteroids
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

ASTRA: ASTeroid Resource Assessment

The study was conducted to determine if the USGS process for conducting mineral resource assessments on Earth can be applied to asteroids
Learn More
Filter Total Items: 38

Feasibility study for the quantitative assessment of mineral resources in asteroids

This study was undertaken to determine if the U.S. Geological Survey’s process for conducting mineral resource assessments on Earth can be applied to asteroids. Successful completion of the assessment, using water and iron resources to test the workflow, has resulted in identification of the minimal adjustments required to conduct full resource assessments beyond Earth. We also identify the types
Authors
Laszlo P. Keszthelyi, Justin Hagerty, Amanda Bowers, Karl J. Ellefsen, Ian Ridley, Trude King, David Trilling, Nicholas Moskovitz, Will Grundy
By
Natural Hazards Mission Area, Astrogeology Science Center

Measurement of in situ sulfur isotopes by laser ablation multi-collector ICPMS: opening Pandora’s Box

Laser ablation multi-collector ICPMS is a modern tool for in situ measurement of S isotopes. Advantages of the technique are speed of analysis and relatively minor matrix effects combined with spatial resolution sufficient for many applications. The main disadvantage is a more destructive sampling mechanism relative to the ion microprobe technique. Recent advances in instrumentation allow precise
Authors
William I. Ridley, Michael Pribil, Alan E. Koenig, John F. Slack
By
Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center

Sulfate and sulfide sulfur isotopes (δ34S and δ33S) measured by solution and laser ablation MC-ICP-MS: An enhanced approach using external correction

Isotope ratio measurements using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) commonly use standard-sample bracketing with a single isotope standard for mass bias correction for elements with narrow-range isotope systems measured by MC-ICP-MS, e.g. Cu, Fe, Zn, and Hg. However, sulfur (S) isotopic composition (δ34S) in nature can range from at least − 40 to + 40‰, pote
Authors
Michael Pribil, William I. Ridley, Poul Emsbo
By
Geology, Geophysics, and Geochemistry Science Center

Volcanogenic massive sulfide occurrence model

Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom water
Authors
W.C. Pat Shanks, Randolph A. Koski, Dan L. Mosier, Klaus J. Schulz, Lisa A. Morgan, John F. Slack, W. Ian Ridley, Cynthia Dusel-Bacon, Robert R. Seal, Nadine M. Piatak
By
Energy and Minerals Mission Area, Ecosystems Mission Area, Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Northern Rocky Mountain Science Center

Mineralogy and composition of the oceanic mantle

The mineralogy of the oceanic basalt source region is examined by testing whether a peridotite mineralogy can yield observed whole-rock and olivine compositions from (1) the Hawaiian Islands, our type example of a mantle plume, and (2) the Siqueiros Transform, which provides primitive samples of normal mid-ocean ridge basalt. New olivine compositional data from phase 2 of the Hawaii Scientific Dri
Authors
Keith Putirka, F. J. Ryerson, Michael Perfit, W. Ian Ridley
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology

Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmati
Authors
Axel K. Schmitt, Michael R. Perfit, Kenneth H. Rubin, Daniel F. Stockli, Matthew C. Smith, Laurie A. Cotsonika, Georg F. Zellmer, W. Ian Ridley
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Trace and minor element variations and sulfur isotopes in crystalline and colloform ZnS: Incorporation mechanisms and implications for their genesis

Various models have been proposed to explain the formation mechanism of colloform sphalerite, but the origin is still under debate. In order to decipher influences on trace element incorporation and sulfur isotope composition, crystalline and colloform sphalerite from the carbonate-hosted Mississippi-Valley Type (MVT) deposit near Wiesloch, SW Germany, were investigated and compared to sphalerite
Authors
Katharina Pfaff, Alan Koenig, Thomas Wenzel, Ian Ridley, Ludwig H. Hildebrandt, David L. Leach, Gregor Markl
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Volatile abundances and oxygen isotopes in basaltic to dacitic lavas on mid-ocean ridges: The role of assimilation at spreading centers

Most geochemical variability in MOR basalts is consistent with low- to moderate-pressure fractional crystallization of various mantle-derived parental melts. However, our geochemical data from MOR high-silica glasses, including new volatile and oxygen isotope data, suggest that assimilation of altered crustal material plays a significant role in the petrogenesis of dacites and may be important in
Authors
V.D. Wanless, M.R. Perfit, W.I. Ridley, P.J. Wallace, Craig B. Grimes, E.M. Klein
By
Geosciences and Environmental Change Science Center

Trace elements have limited utility for studying migratory connectivity in shorebirds that winter in Argentina

Trace-element analysis has been suggested as a tool for the study of migratory connectivity because (1) trace-element abundance varies spatially in the environment, (2) trace elements are assimilated into animals' tissues through the diet, and (3) current technology permits the analysis of multiple trace elements in a small tissue sample, allowing the simultaneous exploration of several elements.
Authors
J. Torres-Dowdall, A.H. Farmer, M. Abril, E.H. Bucher, I. Ridley

Dacite petrogenesis on mid-ocean ridges: Evidence for oceanic crustal melting and assimilation

Whereas the majority of eruptions at oceanic spreading centers produce lavas with relatively homogeneous mid-ocean ridge basalt (MORB) compositions, the formation of tholeiitic andesites and dacites at mid-ocean ridges (MORs) is a petrological enigma. Eruptions of MOR high-silica lavas are typically associated with ridge discontinuities and have produced regionally significant volumes of lava. And
Authors
V.D. Wanless, M.R. Perfit, W.I. Ridley, E. Klein

Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition

An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations
Authors
M.J. Pribil, R. B. Wanty, W.I. Ridley, D.M. Borrok

A New Occurrence Model for National Assessment of Undiscovered Volcanogenic Massive Sulfide Deposits

Volcanogenic massive sulfide (VMS) deposits are very significant current and historical resources of Cu-Pb-Zn-Au-Ag, are active exploration targets in several areas of the United States and potentially have significant environmental effects. This new USGS VMS deposit model provides a comprehensive review of deposit occurrence and ore genesis, and fully integrates recent advances in the understandi
Authors
W.C. Pat Shanks, Cynthia Dusel-Bacon, Randolph Koski, Lisa A. Morgan, Dan Mosier, Nadine M. Piatak, Ian Ridley, Robert R. Seal, Klaus J. Schulz, John F. Slack, Roland Thurston
By
Geology, Energy & Minerals Science Center

*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

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