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Jeffrey Phillips

Jeff Phillips is a Scientist Emeritus (Geophysics) in the Geology, Geophysics, and Geochemistry Science Center in Denver, Colorado. He develops and maintains the USGS potential-field geophysical software package for the PC, a public-domain resource for the geophysical community.

Jeff's research focuses on potential-field theory and its application to geologic problems, including water, mineral, and energy resources.

Dr. Phillips has conducted geophysical research for over 40 years in support of USGS programs on Energy and Mineral Resources. He is a specialist in the analysis of potential-field (gravity and magnetic) geophysical data. He has published more than 70 professional reports and presented more than 60 talks at scientific meetings. Dr. Phillips has worked extensively on Energy Resource studies in Alaska and recently participated in Central Asia Mineral Resource Assessments. His recent work for other Federal Agencies includes a dam safety study in California and a geophysical investigation at the former Nevada Test Site.

Professional Experience

  • 2014-Present: Scientist Emeritus

  • 1991-2014: Research Geophysicist

  • 1991-Present: U.S. Geological Survey (Denver, CO)

  • 1980-1986: Branch Representative, Eastern Region, Branch of Geophysics

  • 1975-1991: U.S. Geological Survey (Reston, VA)

  • 1973: U.S. Geological Survey (Menlo Park, CA, and Beaufort Sea, AK)

Education and Certifications

  • Ph.D. (1975), Stanford University (Geophysics)

  • M.S. (1973), Stanford University (Geophysics)

  • A.B. (1970), University of California, Berkeley (Geology)

Affiliations and Memberships*

  • Society of Exploration Geophysicists

  • American Geophysical Union

Abstracts and Presentations

  • McCafferty, A.E., Bedrosian, P.A., and Phillips, J.D., 2019, Critical Mineral Systems Under Cover: Insights from Magnetic, Gravity, and Magnetotelluric 3D Inversion Models, Southern Midcontinent, USA, in Society for Geology Applied to Mineral Deposits (SGA), 2019, Volume 3 - New discoveries – new views - Advances in the Science of Mineral Exploration, p. 1132-1135. 15th SGA Biennial Meeting, Glasg

  • McCafferty, A.E., Phillips, J.D., and Ayuso, R.A., 2017, Crustal architecture beneath the southeast Missouri (USA) Mesoproterozoic Iron-Oxide province from geophysical models: Proceedings of the 14th SGA Biennial Meeting, 20-23 August 2017, Quebec City, Canada: p. 871-874.

  • Phillips, J.D., 2006, The role of negative structural indices in magnetic interpretation - lessons from the Bishop model: Society of Exploration Geophysicists, 2006 Workshop W-5 The Bishop Model: Investigations into the Use and Abuse of Test Models.

  • Phillips, J.D., 2001, Tools and techniques for the application of high-resolution aeromagnetic data to engineering problems: Proceedings, SAGEEP 2001, CD-ROM, 22p.

  • Phillips, J.D., 2001, Designing matched bandpass and azimuthal filters for the separation of potential-field anomalies by source region and source type: Australian Society of Exploration Geophysicists, 15th Geophysical Conference and Exhibition, Expanded Abstracts CD-ROM, 4p.

  • Phillips, J.D., and Grauch, V.J.S., 2001, Some current research on the processing and interpretation of potential-field data at the U.S. Geological Survey: Proceedings of the workshop on future directions in the analysis of potential-field data, August 18, 2001, Perth, Australia. 4p.

Science and Products

link
geophysical map of Mount Rainier

Geophysical Research and Development

The Geophysical Research and Development Project supported the development of new and existing geophysical techniques for addressing critical geological problems. Research conducted under this project included development of needed geophysical methods and software, development of new geophysical instrumentation, and applications of geophysical techniques to frontier areas of geology.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

Geophysical Research and Development

The Geophysical Research and Development Project supported the development of new and existing geophysical techniques for addressing critical geological problems. Research conducted under this project included development of needed geophysical methods and software, development of new geophysical instrumentation, and applications of geophysical techniques to frontier areas of geology.
Learn More

Crustal Architecture Beneath the Southern Midcontinent (USA) -- Data Grids and 3D Geophysical Models

Regional grid files and 3D voxel models were used to study crustal architecture beneath the Southern Midcontinent (USA) by McCafferty and others (2019). The study covered a rectangular, multi-state area of 924 by 924 kilometers centered on Missouri, and a corresponding volume extending from the topographic surface to a depth of 50 kilometers below sea level. The grid files consist of surface grids
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Global geoscience transect 8: Quebec-Maine-Gulf of Maine transect, southeastern Canada, northeastern United States of America

No abstract available.

Geophysical studies of the Charleston, South Carolina, area; onshore aeromagnetic map

No abstract available.
Filter Total Items: 77

Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York

The eastern Adirondack Highlands of northern New York host dozens of iron oxide-apatite (IOA) deposits containing magnetite and rare earth element (REE)-bearing apatite. We use new aeromagnetic, aeroradiometric, ground gravity, and sample petrophysical and geochemical data to image and understand these deposits and their geologic framework. Aeromagnetic total field data reflect highly magnetic leu
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
By
Geology, Geophysics, and Geochemistry Science Center

Three-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data

We use gravity, magnetic, seismic reflection, well, and outcrop data to determine the three-dimensional shape and structural features of south-central Alaska’s Susitna basin. This basin is located within the Aleutian-Alaskan convergent margin region and is expected to show effects of regional subduction zone processes. Aeromagnetic data, when filtered to highlight anomalies associated with sources
Authors
Anjana K. Shah, Jeffrey Phillips, Kristen A. Lewis, Richard G. Stanley, Peter J. Haeussler, Christopher J. Potter
By
Geology, Geophysics, and Geochemistry Science Center

Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models

Several types of critical mineral-bearing ore deposits in the southern Midcontinent region of the U.S. are hosted in Mesoproterozoic igneous rocks largely concealed beneath Paleozoic cover. Discerning the architecture of igneous intrusions and volcanic centers in the crust is fundamental to understanding the geologic evolution of this vast region and its mineral resources. To advance the understan
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017

The U.S. Geological Survey (USGS) recently completed an assessment of undiscovered, technically recoverable oil and gas resources in the Susitna Basin of southern Alaska. Using a geology-based methodology, the USGS estimates that mean undiscovered volumes of about 2 million barrels of oil and nearly 1.7 trillion cubic feet of gas may be found in this area.
Authors
Richard G. Stanley, Christopher J. Potter, Kristen A. Lewis, Paul G. Lillis, Anjana K. Shah, Peter J. Haeussler, Jeffrey D. Phillips, Zenon C. Valin, Christopher J. Schenk, Timothy R. Klett, Michael E. Brownfield, Ronald M. Drake, Thomas M. Finn, Seth S. Haines, Debra K. Higley, David W. Houseknecht, Phuong A. Le, Kristen R. Marra, Tracey J. Mercier, Heidi M. Leathers-Miller, Stanley T. Paxton, Ofori N. Pearson, Marilyn E. Tennyson, Cheryl A. Woodall, Margarita V. Zyrianova
By
Energy and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Minerals, Energy, and Geophysics Science Center

PDEPTH—A computer program for the geophysical interpretation of magnetic and gravity profiles through Fourier filtering, source-depth analysis, and forward modeling

PDEPTH is an interactive, graphical computer program used to construct interpreted geological source models for observed potential-field geophysical profile data. The current version of PDEPTH has been adapted to the Windows platform from an earlier DOS-based version. The input total-field magnetic anomaly and vertical gravity anomaly profiles can be filtered to produce derivative products such as
Authors
Jeffrey D. Phillips
By
Water Resources Mission Area, Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment

A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to tectonic zones that include magmatic arcs where the occurr
Authors
Jane M. Hammarstrom, Mark J. Mihalasky, Stephen Ludington, Jeffrey Phillips, Byron R. Berger, Paul Denning, Connie Dicken, John C. Mars, Michael L. Zientek, Richard J. Herrington, Reimar Seltmann
By
Mineral Resources Program, Geology, Energy & Minerals Science Center

Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA

High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-copper-gold (IOCG) deposits. Results delineate the
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
By
Mineral Resources Program, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Developing integrated methods to address complex resource and environmental issues

IntroductionThis circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the USGS Mineral R
By
Mineral Resources Program, Alaska Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Sharpening the boundaries - 3D terracing applied to physical property inversions

Physical property inversions typically result in smooth property distributions, without the sharp boundaries expected of true geologic sources. Here we explore the use of 3D terracing as a way to force the inverted physical properties to have sharp boundaries. Terracing during inversion is preferable to post-inversion terracing because it results in a better fit to the observed data.
Authors
Jeffrey Phillips, Robert W. Simpson
By
Geology, Geophysics, and Geochemistry Science Center

11.12 – Tools and techniques: gravitational method

The gravitational method is used to investigate density variations within the subsurface at depths of several meters to tens of meters, as in depth-to-bedrock investigations, or at depths of several kilometers, as in sedimentary basin thickness investigations. This chapter covers fundamental relations, densities of Earth materials, instruments, field procedures, data reduction, filtering, forward
Authors
Jeffrey Phillips
By
Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation

The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR).   In late September 2010, the U.S. Geological Survey (USGS) conducted a gro
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
By
Geology, Geophysics, and Geochemistry Science Center

Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography

A physical property inversion approach based on the use of 3D (or 2D) Fourier transforms to calculate the potential-field within a 3D (or 2D) volume from a known physical property distribution within the volume is described. Topographic surfaces and observations at arbitrary locations are easily accommodated. The limitations of the approach and applications to real data are considered.
Authors
Jeffrey Phillips
By
Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Science and Products

link
geophysical map of Mount Rainier

Geophysical Research and Development

The Geophysical Research and Development Project supported the development of new and existing geophysical techniques for addressing critical geological problems. Research conducted under this project included development of needed geophysical methods and software, development of new geophysical instrumentation, and applications of geophysical techniques to frontier areas of geology.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

Geophysical Research and Development

The Geophysical Research and Development Project supported the development of new and existing geophysical techniques for addressing critical geological problems. Research conducted under this project included development of needed geophysical methods and software, development of new geophysical instrumentation, and applications of geophysical techniques to frontier areas of geology.
Learn More

Crustal Architecture Beneath the Southern Midcontinent (USA) -- Data Grids and 3D Geophysical Models

Regional grid files and 3D voxel models were used to study crustal architecture beneath the Southern Midcontinent (USA) by McCafferty and others (2019). The study covered a rectangular, multi-state area of 924 by 924 kilometers centered on Missouri, and a corresponding volume extending from the topographic surface to a depth of 50 kilometers below sea level. The grid files consist of surface grids
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Global geoscience transect 8: Quebec-Maine-Gulf of Maine transect, southeastern Canada, northeastern United States of America

No abstract available.

Geophysical studies of the Charleston, South Carolina, area; onshore aeromagnetic map

No abstract available.
Filter Total Items: 77

Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York

The eastern Adirondack Highlands of northern New York host dozens of iron oxide-apatite (IOA) deposits containing magnetite and rare earth element (REE)-bearing apatite. We use new aeromagnetic, aeroradiometric, ground gravity, and sample petrophysical and geochemical data to image and understand these deposits and their geologic framework. Aeromagnetic total field data reflect highly magnetic leu
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
By
Geology, Geophysics, and Geochemistry Science Center

Three-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data

We use gravity, magnetic, seismic reflection, well, and outcrop data to determine the three-dimensional shape and structural features of south-central Alaska’s Susitna basin. This basin is located within the Aleutian-Alaskan convergent margin region and is expected to show effects of regional subduction zone processes. Aeromagnetic data, when filtered to highlight anomalies associated with sources
Authors
Anjana K. Shah, Jeffrey Phillips, Kristen A. Lewis, Richard G. Stanley, Peter J. Haeussler, Christopher J. Potter
By
Geology, Geophysics, and Geochemistry Science Center

Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models

Several types of critical mineral-bearing ore deposits in the southern Midcontinent region of the U.S. are hosted in Mesoproterozoic igneous rocks largely concealed beneath Paleozoic cover. Discerning the architecture of igneous intrusions and volcanic centers in the crust is fundamental to understanding the geologic evolution of this vast region and its mineral resources. To advance the understan
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017

The U.S. Geological Survey (USGS) recently completed an assessment of undiscovered, technically recoverable oil and gas resources in the Susitna Basin of southern Alaska. Using a geology-based methodology, the USGS estimates that mean undiscovered volumes of about 2 million barrels of oil and nearly 1.7 trillion cubic feet of gas may be found in this area.
Authors
Richard G. Stanley, Christopher J. Potter, Kristen A. Lewis, Paul G. Lillis, Anjana K. Shah, Peter J. Haeussler, Jeffrey D. Phillips, Zenon C. Valin, Christopher J. Schenk, Timothy R. Klett, Michael E. Brownfield, Ronald M. Drake, Thomas M. Finn, Seth S. Haines, Debra K. Higley, David W. Houseknecht, Phuong A. Le, Kristen R. Marra, Tracey J. Mercier, Heidi M. Leathers-Miller, Stanley T. Paxton, Ofori N. Pearson, Marilyn E. Tennyson, Cheryl A. Woodall, Margarita V. Zyrianova
By
Energy and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Minerals, Energy, and Geophysics Science Center

PDEPTH—A computer program for the geophysical interpretation of magnetic and gravity profiles through Fourier filtering, source-depth analysis, and forward modeling

PDEPTH is an interactive, graphical computer program used to construct interpreted geological source models for observed potential-field geophysical profile data. The current version of PDEPTH has been adapted to the Windows platform from an earlier DOS-based version. The input total-field magnetic anomaly and vertical gravity anomaly profiles can be filtered to produce derivative products such as
Authors
Jeffrey D. Phillips
By
Water Resources Mission Area, Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment

A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to tectonic zones that include magmatic arcs where the occurr
Authors
Jane M. Hammarstrom, Mark J. Mihalasky, Stephen Ludington, Jeffrey Phillips, Byron R. Berger, Paul Denning, Connie Dicken, John C. Mars, Michael L. Zientek, Richard J. Herrington, Reimar Seltmann
By
Mineral Resources Program, Geology, Energy & Minerals Science Center

Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA

High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-copper-gold (IOCG) deposits. Results delineate the
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
By
Mineral Resources Program, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Developing integrated methods to address complex resource and environmental issues

IntroductionThis circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the USGS Mineral R
By
Mineral Resources Program, Alaska Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Sharpening the boundaries - 3D terracing applied to physical property inversions

Physical property inversions typically result in smooth property distributions, without the sharp boundaries expected of true geologic sources. Here we explore the use of 3D terracing as a way to force the inverted physical properties to have sharp boundaries. Terracing during inversion is preferable to post-inversion terracing because it results in a better fit to the observed data.
Authors
Jeffrey Phillips, Robert W. Simpson
By
Geology, Geophysics, and Geochemistry Science Center

11.12 – Tools and techniques: gravitational method

The gravitational method is used to investigate density variations within the subsurface at depths of several meters to tens of meters, as in depth-to-bedrock investigations, or at depths of several kilometers, as in sedimentary basin thickness investigations. This chapter covers fundamental relations, densities of Earth materials, instruments, field procedures, data reduction, filtering, forward
Authors
Jeffrey Phillips
By
Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation

The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR).   In late September 2010, the U.S. Geological Survey (USGS) conducted a gro
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
By
Geology, Geophysics, and Geochemistry Science Center

Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography

A physical property inversion approach based on the use of 3D (or 2D) Fourier transforms to calculate the potential-field within a 3D (or 2D) volume from a known physical property distribution within the volume is described. Topographic surfaces and observations at arbitrary locations are easily accommodated. The limitations of the approach and applications to real data are considered.
Authors
Jeffrey Phillips
By
Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry 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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