Jeffrey Phillips (Former Employee)
Science and Products
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.
Crustal Architecture Beneath the Southern Midcontinent (USA) -- Data Grids and 3D Geophysical Models 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...
Filter Total Items: 80
Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York 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...
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
Three-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data 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...
Authors
Anjana K. Shah, Jeffrey Phillips, Kristen A. Lewis, Richard G. Stanley, Peter J. Haeussler, Christopher J. Potter
Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models 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
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017 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
PDEPTH—A computer program for the geophysical interpretation of magnetic and gravity profiles through Fourier filtering, source-depth analysis, and forward modeling 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...
Authors
Jeffrey D. Phillips
Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment 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...
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
Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA 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...
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
Developing integrated methods to address complex resource and environmental issues Developing integrated methods to address complex resource and environmental issues
Introduction This 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...
Sharpening the boundaries - 3D terracing applied to physical property inversions 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
11.12 – Tools and techniques: gravitational method 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...
Authors
Jeffrey Phillips
A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation 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)...
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography 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
Science and Products
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.
Crustal Architecture Beneath the Southern Midcontinent (USA) -- Data Grids and 3D Geophysical Models 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...
Filter Total Items: 80
Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York 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...
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
Three-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data 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...
Authors
Anjana K. Shah, Jeffrey Phillips, Kristen A. Lewis, Richard G. Stanley, Peter J. Haeussler, Christopher J. Potter
Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models 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
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017 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
PDEPTH—A computer program for the geophysical interpretation of magnetic and gravity profiles through Fourier filtering, source-depth analysis, and forward modeling 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...
Authors
Jeffrey D. Phillips
Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment 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...
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
Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA 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...
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
Developing integrated methods to address complex resource and environmental issues Developing integrated methods to address complex resource and environmental issues
Introduction This 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...
Sharpening the boundaries - 3D terracing applied to physical property inversions 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
11.12 – Tools and techniques: gravitational method 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...
Authors
Jeffrey Phillips
A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation 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)...
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography 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
*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